77 results on '"Duffield, T. F."'
Search Results
2. Comparative efficacy of blanket versus selective dry-cow therapy: a systematic review and pairwise meta-analysis.
- Author
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Winder, C. B., Sargeant, J. M., Kelton, D. F., Leblanc, S. J., Duffield, T. F., Glanville, J., Wood, H., Churchill, K. J., Dunn, J., Bergevin, M. d., Dawkins, K., Meadows, S., and O'Connor, A. M.
- Subjects
META-analysis ,BLANKETS ,SEALING compounds ,MASTITIS ,COWS ,DAIRY cattle - Abstract
A systematic review and meta-analysis were conducted to determine the efficacy of selective dry-cow antimicrobial therapy compared to blanket therapy (all quarters/all cows). Controlled trials were eligible if any of the following were assessed: incidence of clinical mastitis during the first 30 DIM, frequency of intramammary infection (IMI) at calving, or frequency of IMI during the first 30 DIM. From 3480 identified records, nine trials were data extracted for IMI at calving. There was an insufficient number of trials to conduct meta-analysis for the other outcomes. Risk of IMI at calving in selectively treated cows was higher than blanket therapy (RR = 1.34, 95% CI = 1.13, 1.16), but substantial heterogeneity was present (I
2 = 58%). Subgroup analysis showed that, for trials using internal teat sealants, there was no difference in IMI risk at calving between groups, and no heterogeneity was present. For trials not using internal teat sealants, there was an increased risk in cows assigned to a selective dry-cow therapy protocol, compared to blanket treatment, with substantial heterogeneity in this subgroup. However, the small number of trials and heterogeneity in the subgroup without internal teat sealants suggests that the relative risk between treatments may differ from the determined point estimates based on other unmeasured factors. [ABSTRACT FROM AUTHOR]- Published
- 2019
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- View/download PDF
3. Comparative efficacy of teat sealants given prepartum for prevention of intramammary infections and clinical mastitis: a systematic review and network meta-analysis.
- Author
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Winder, C. B., Sargeant, J. M., Hu, D., Wang, C., Kelton, D. F., Leblanc, S. J., Duffield, T. F., Glanville, J., Wood, H., Churchill, K. J., Dunn, J., Bergevin, M. D., Dawkins, K., Meadows, S., Deb, B., Reist, M., Moody, C., and O'Connor, A. M.
- Subjects
SEALING compounds ,INFECTION prevention ,META-analysis ,MASTITIS ,BOVINE mastitis ,INTRA-abdominal infections ,DAIRY cattle - Abstract
A systematic review and network meta-analysis were conducted to assess the relative efficacy of internal or external teat sealants given at dry-off in dairy cattle. Controlled trials were eligible if they assessed the use of internal or external teat sealants, with or without concurrent antimicrobial therapy, compared to no treatment or an alternative treatment, and measured one or more of the following outcomes: incidence of intramammary infection (IMI) at calving, IMI during the first 30 days in milk (DIM), or clinical mastitis during the first 30 DIM. Risk of bias was based on the Cochrane Risk of Bias 2.0 tool with modified signaling questions. From 2280 initially identified records, 32 trials had data extracted for one or more outcomes. Network meta-analysis was conducted for IMI at calving. Use of an internal teat sealant (bismuth subnitrate) significantly reduced the risk of new IMI at calving compared to non-treated controls (RR = 0.36, 95% CI 0.25–0.72). For comparisons between antimicrobial and teat sealant groups, concerns regarding precision were seen. Synthesis of the primary research identified important challenges related to the comparability of outcomes, replication and connection of interventions, and quality of reporting of study conduct. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
4. Comparative efficacy of antimicrobial treatments in dairy cows at dry-off to prevent new intramammary infections during the dry period or clinical mastitis during early lactation: a systematic review and network meta-analysis.
- Author
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Winder, C. B., Sargeant, J. M., Hu, D., Wang, C., Kelton, D. F., Leblanc, S. J., Duffield, T. F., Glanville, J., Wood, H., Churchill, K. J., Dunn, J., Bergevin, M. D., Dawkins, K., Meadows, S., Deb, B., Reist, M., Moody, C., and O'Connor, A. M.
- Subjects
MASTITIS ,META-analysis ,INTRA-abdominal infections ,BOVINE mastitis ,COWS ,LACTATION ,DEFINITIONS ,DAIRY farms - Abstract
A systematic review and network meta-analysis were conducted to assess the relative efficacy of antimicrobial therapy given to dairy cows at dry-off. Eligible studies were controlled trials assessing the use of antimicrobials compared to no treatment or an alternative treatment, and assessed one or more of the following outcomes: incidence of intramammary infection (IMI) at calving, incidence of IMI during the first 30 days in milk (DIM), or incidence of clinical mastitis during the first 30 DIM. Databases and conference proceedings were searched for relevant articles. The potential for bias was assessed using the Cochrane Risk of Bias 2.0 algorithm. From 3480 initially identified records, 45 trials had data extracted for one or more outcomes. Network meta-analysis was conducted for IMI at calving. The use of cephalosporins, cloxacillin, or penicillin with aminoglycoside significantly reduced the risk of new IMI at calving compared to non-treated controls (cephalosporins, RR = 0.37, 95% CI 0.23–0.65; cloxacillin, RR = 0.55, 95% CI 0.38–0.79; penicillin with aminoglycoside, RR = 0.42, 95% CI 0.26–0.72). Synthesis revealed challenges with a comparability of outcomes, replication of interventions, definitions of outcomes, and quality of reporting. The use of reporting guidelines, replication among interventions, and standardization of outcome definitions would increase the utility of primary research in this area. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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5. Management practices for male calves on Canadian dairy farms.
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Renaud, D. L., Duffield, T. F., LeBlanc, S. J., Haley, D. B., and Kelton, D. F.
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CALF physiology , *CALVES , *CATTLE nutrition , *PRECONDITIONING of calves , *ANIMAL behavior , *ANIMAL health - Abstract
Morbidity, mortality, and antimicrobial use and resistance are major concerns in the rearing of male dairy calves, so information to support disease prevention is important. The objective of this cross-sectional study was to describe management practices associated with the care of male calves during their first days of life on Canadian dairy farms. A survey was completed by dairy producers across Canada between March 1 and April 30, 2015. The survey included 192 questions covering producer background, farm characteristics, biosecurity practices, disease prevalence, calf health, animal welfare, lameness, milking hygiene, reproduction, and Internet and social media use. A total of 1,025 surveys were completed online, by telephone, or by mail, representing 9% of all dairy farms in Canada. Five percent of respondents (n = 49) answered that they had euthanized at least 1 male calf at birth in the previous year, and blunt force trauma was commonly used in these cases. The majority of respondents always fed colostrum to male calves; however, 9% (n = 80) did not always feed colostrum. Almost 40% (n = 418) of respondents reported always dipping the navels of male calves, 12% (n = 123) vaccinated male calves, and 17% (n = 180) did not provide the same quantity of feed to male calves as heifer calves. The care of male calves differed greatly depending on the geographical region of the respondents. However, some regional effects may be confounded by economic conditions and the logistics of marketing male dairy calves in different parts of the country. Herd size was another important variable in many aspects of the management of male calves on dairy farms. Larger herd sizes were more likely to use an appropriate method of euthanasia at birth but were less likely to always feed colostrum to their male calves or feed them the same as female calves. Familiarity with the Code of Practice for the Care and Handling of Dairy Cattle (National Farm Animal Care Council) by respondents was associated with better care of male calves on dairy farms. The results of this survey suggest that the treatment of male dairy calves on Canadian dairy farms varies and that there are opportunities to improve the health management of male calves on the farms of origin. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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6. Effects of a combination butaphosphan and cyanocobalamin product and insulin on ketosis resolution and milk production.
- Author
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Gordon, J. L., Duffield, T. F., Herdt, T. H., Kelton, D. F., Neuder, L., and LeBlanc, S. J.
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VITAMIN B12 , *PROINSULIN , *PANCREATIC secretions , *MILK contamination , *MILK yield - Abstract
The objective of this study was to determine the effects of butaphosphan-cyanocobalamin (B+C), glargine insulin, and propylene glycol on resolution of ketosis and average daily milk yield after treatment. Cows from 16 herds in Ontario, Canada, and 1 herd in Michigan were tested at weekly intervals between 3 and 16 DIM. Ketosis was defined as blood β-hydroxybutyrate (BHB) ≥1.2 mmol/L. All ketotic cows were given a baseline treatment of 3 d of 300 g of propylene glycol orally. Animals were then randomly assigned to treatment with 3 doses of either 25 mL of B+C or 25 mL of saline placebo and 1 dose of either 2 mL (200 IU) of glargine insulin or 2 mL of saline placebo in a 2 × 2 factorial arrangement. Outcomes of interest on all farms were ketosis cure (blood BHB <1.2 mmol/L 1 wk postenrollment), maintenance of ketosis cure (blood BHB <1.2 mmol/L 1 and 2 wk postenrollment), and blood BHB concentrations at 1 and 2 wk postenrollment. Milk weights were collected daily in 1 large freestall herd. Repeated measures ANOVA was used to evaluate blood BHB concentrations 2 wk after treatment and milk production for 30 d after treatment. Poisson regression was used to examine the effect of treatment on cure and maintenance of cure. Due to a regulatory delay causing temporary unavailability of B+C in Canada, data were analyzed in 2 sets of models: one for insulin and the corresponding placebo (n = 620) and one for the full trial (n = 380). Animals with blood glucose concentrations ≤2.2 mmol/L at the time of ketosis diagnosis were 2.1 times more likely (95% CI = 1.2 to 3.7) to be cured if treated with B+C. Animals in lactation 3 or higher that had blood glucose concentrations <2.2 mmol/L at enrollment produced 4.2 kg/d (95% CI = 1.4 to 7.1) more milk if treated with insulin versus placebo and 2.8 kg/d (95% CI = 0.9 to 4.7) more milk if treated with B+C versus placebo. Animals in lactation 3 or higher with blood glucose ≥2.2 mmol/L that were treated with insulin produced 2.3 kg/d (95% CI = 0.3 to 4.4) less milk than untreated controls. No interaction was observed between treatments. This evidence suggests that B+C and insulin may be beneficial for ketosis treatment in animals with blood glucose <2.2 mmol/L at ketosis diagnosis. It also suggests that blood glucose concentration may be an important predictor of success of ketosis treatment. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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7. Short communication: Validation of a point-of-care glucometer for use in dairy cows.
- Author
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Wittrock, J. A. M., Duffield, T. F., and Leblanc, S. J.
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BLOOD sugar measurement , *DAIRY cattle , *3-Hydroxybutyric acid , *MEASURING instruments , *VETERINARY clinical pathology , *SODIUM fluoride - Abstract
The purpose of this study was to evaluate the diagnostic performance of a hand-held electronic glucometer (Precision Xtra; Abbott Diabetes Care Inc., Mississauga, ON, Canada) for cow-side use in dairy cattle. This device has been validated for measuring blood concentrations of β-hydroxybutyrate in dairy cows. This study was designed to assess the accuracy of whole-blood glucose measurements from the glucose meter relative to a reference chemical analyzer in a diagnostic laboratory. Duplicate samples were taken from the same cows at the same time, into blood tubes with either the glycolysis-inhibiting preservative sodium fluoride (NaF) or without preservative. Glucometer readings were taken on whole blood with no preservative, and laboratory measurements were conducted on serum preserved with NaF. Blood samples were collected from cows between 3 wk before and 5 wk after calving, including during a glucose tolerance test conducted 1 wk before expected calving. Passing-Bablok and Bland-Altman data analyses were used to evaluate the performance of the glucometer relative to the laboratory results. A strong correlation was observed in 709 samples from 81 cows between the hand-held meter and serum from samples preserved with NaF (R² = 0.95). Overall, 96% of measurements with the glucometer fell within the 95% confidence limits of analysis in the laboratory, although at higher-than-physiologic glucose concentrations (>5.2 mmol/L) the glucometer tended to overestimate. The hand-held glucometer appears suitable for rapid measurement of glucose under field conditions in dairy cattle. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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8. Meta-analysis of the effects of monensin in beef cattle on feed efficiency, body weight gain, and dry matter intake.
- Author
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Duffield, T. F., Merrill, J. K., and Bagg, R. N.
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BEEF cattle feeding & feeds , *META-analysis , *MONENSIN , *BODY weight , *WEIGHT gain , *DRY matter in animal nutrition - Abstract
A meta-analysis of the impact of monensin on growing and finishing beef cattle was conducted after a search of the literature. A total of 40 peer-reviewed articles and 24 additional trial reports with monensin feeding in beef cattle were selected, after meeting apriori quality criteria. Data for each trial were extracted and analyzed using meta-analysis software in STATA. Estimated effect size of monensin was calculated for feed efficiency (FE), ADG, and DMI. Monensin use in growing and finishing beef cattle reduced DMI (P < 0.001) and improved both ADG (P < 0.001) and FE (P < 0.001). The average concentration of monensin in feed across studies was 28.1 mg/ kg feed ( 100% DM) and this resulted in approximately a 6.4% (but only 2.5 to 3.5% in the last 2 decades) increase in FE, 3% decrease in DMI, and 2.5% increase in ADG. All 3 outcomes displayed moderate and significant heterogeneity of monensin response (I2, which is a measure of variation beyond chance, = 29% for FE, 42% for DMI, and 23% for ADG); therefore, random effects models were used for those outcomes. There were no single influential studies that overweighted the findings for any outcome. Meta-regression analysis of the effect sizes obtained from these data showed that dietary factors, dose, and study design were influential in modifying effect size of monensin treatment. Use of corn silage in the diet influenced the effect size of monensin for DMI and FE, with diets containing corn silage resulting in a greater improvement in FE and a larger effect on reducing DMI. Studies conducted to assess multiple doses of monensin showed similar effects to the use of corn silage in the diet. Studies conducted in the United States or with higher ADG in control animals (>1.17 kg/d) showed less effect of monensin on ADG. Pen-level studies showed a greater monensin increase on ADG than did those conducted on individual animals. Linear effect of monensin dose was observed for FE, DMI, and ADG outcomes, with greater effects on improving FE and reducing DMI with larger doses of monensin but lesser improvement in ADG with increasing dose. These findings confirm that monensin improves FE in growing and finishing beef cattle, and that this effect is linear with dose. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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9. Risk factors and effects of postpartum anovulation in dairy cows.
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Dubuc, J., Duffield, T. F., Leslie, K. E., Walton, J. S., and Leblanc, S. J.
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ANOVULATION , *DAIRY cattle , *FATTY acids , *CARRIER proteins , *DAIRY farming , *CLINICAL trials , *CATTLE parturition - Abstract
The objectives were to identify risk factors for and to quantify the effect of postpartum anovulation on reproductive performance in dairy cows. Data from 2,178 Holstein cows in 6 commercial herds enrolled in a randomized clinical trial were used. Data on periparturient disease incidence, calving history, and body condition score were collected. Cows were examined at wk 5 postpartum for reproductive tract disease; cytological endometritis was defined as ≥6% polymorphonuclear cells in endometrial cytology, and purulent vaginal discharge was defined as the presence of mucopurulent or purulent vaginal discharge. Cows were followed until 300 d in milk (DIM) for reproductive performance. Serum nonesterified fatty acids (NEFA) concentration was measured once during the week before expected calving. Serum β-hydroxybutyrate, NEFA, and haptoglobin were measured at wk 1, 2, and 3 postpartum. Serum progesterone (P4) was measured at wk 3, 5, 7, and 9 postpartum. The end of the postpartum anovulation period was defined as the first sampling time at which P4 was >1 ng/mL. Statistical analyses were performed using logistic regression models and Cox proportional hazard models. The prevalence of anovulation was 72, 44, 26, and 17% at wk 3, 5, 7, and 9, respectively. Cows were classified according to their ovulatory status as having luteal function at 21 DIM (Cyc21), as having low P4 at 21 DIM but having luteal function at least once at 35 or 49 or 63 DIM (Cyc63), or being anovulatory at 63 DIM (Anov63; no samples with P4 >1 ng/ mL). Factors associated with early ovulation (Cyc21) included season, parity, decreased haptoglobinemia, and decreased serum NEFA concentration before and after parturition. Risk factors for prolonged anovulation (Anov63) included cytological endometritis, increased haptoglobinemia, and greater serum NEFA concentrations before and after parturition. Cows classified as Anov63 had an increased median time to first breeding compared with Cyc63 (74.1 vs. 73.2 d). The effect of prolonged postpartum anovulation on median time to pregnancy was conditional on parity group; a detrimental effect was present in cows of parity ≥3 (129 d for Cyc21, 151 d for Cyc63, and 180 d for Anov63), but no effect was observed in cows of parity ≥2. Overall, these findings suggest that postpartum anovulation was associated with indicators of energy balance and uterine inflammation, and with detrimental effects on reproductive performance. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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10. The effect of meloxicam on behavior and pain sensitivity of dairy calves following cautery dehorning with a local anesthetic.
- Author
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Heinrich, A., Duffield, T. F., Lissemore, K. D., and Millman, S. T.
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DEHORNING , *CALVES , *LIDOCAINE , *VACCINATION , *SURGERY , *PHYSIOLOGY , *ANIMAL behavior - Abstract
Effects of a single injection of meloxicam on calf behavior, pain sensitivity, and feed and water intakes were examined following dehorning. Sixty Holstein heifer calves were blocked by age and randomly assigned to receive an i.m. injection of meloxicam (0.5 mg/kg) or a placebo. All calves were given a lidocaine cornual nerve block (5 mL per horn). Treatments and nerve blocks were administered 10 min before cautery dehorning. Continuous sampling of behavior was performed during five 1-h intervals using video recordings, and total daily activity was monitored using an accelerometer. A pain sensitivity test was administered with a pressure algometer, and feed and water intakes were recorded daily. Calves were sham-dehorned 24 h before actual dehorning to establish baseline values, and all variables were assessed at the same times following dehorning and sham dehorning for up to 48 h post-dehorning. Meloxicam-treated calves displayed less ear flicking during the 44 h following dehorning (increases of 4.29 ± 1.10 and 1.31 ± 0.66 ear flicks/h in the first 24 h, and increases of 3.27 ± 0.89 and 0.55 ± 0.50 ear flicks/h during the second 24 h, for control and meloxicam calves, respectively) and less head shaking during the first 9 h following dehorning (increase of 2.53 ± 0.54 and 0.85 ± 0.46 headshakes/h over baseline for control and meloxicam, respectively). Meloxicamtreated calves were less active than controls during the first 5 h following dehorning (activity 34.1 ± 3.2 and 30.6 ± 2.6 for control and meloxicam, respectively) and displayed less sensitivity to pressure algometry 4 h after dehorning (pressure tolerance of 1.62 ± 0.13 kg of force and 2.13 ± 0.15 kg of force for control and meloxicam calves, respectively). Changes in behavior suggest that meloxicam was effective for reducing post-surgical pain and distress associated with calf dehorning. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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11. Short communication: Haptoglobin as an early indicator of metritis.
- Author
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Huzzey, J. M., Duffield, T. F., LeBlanc, S. J., Veira, D. M., Weary, D. M., and von Keyserlingk, M. A. G.
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HAPTOGLOBINS , *BIOMARKERS , *UTERINE diseases , *CATTLE diseases , *CATTLE parturition - Abstract
The purpose of this study was to determine whether haptoglobin (Hp) could be used as a predictive measure for metritis. Cattle were grouped into 3 health categories based on the condition of vaginal discharge and body temperature after calving: severe metritis (n = 12), mild metritis (n = 32), and healthy (n = 23). Blood was collected and analyzed for Hp concentration on d -20 ± 5, -6 ± 2, -2 ± 1, and d 0 relative to calving, and then every 3 d after calving until d +21. Cows with mild and severe metritis had greater Hp concentrations than healthy cows between d 0 and d +12. Mean (+SE) Hp concentrations peaked on d +3 in the cows with mild metritis (1.06 ± 0.15 g/L) and on d +6 in cows with severe metritis (1.62 ± 0.47 g/L). Mean concentrations for the healthy group were 0.58 ± 0.12 g/L and 0.31 ± 0.08 g/L on d +3 and d +6, respectively. Clinical signs of pathological discharge for the mildly and severely metritic cows did not occur until, on average, 8.6 ± 3.9 d and 5.3 ± 1.9 d after calving, respectively. Cows with Hp concentrations ≥1 g/L on d +3 were 6.7 times more likely to develop severe or mild metritis; this predictive threshold has a sensitivity of 50% and specificity of 87%. These results indicate that an acute phase inflammatory response precedes clinical metritis and that Hp screening may assist in the early detection of metritis, providing increased opportunities for early treatment and prevention. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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12. The impact of meloxicam on postsurgical stress associated with cautery dehorning.
- Author
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Heinrich, A., Duffield, T. F., Lissemore, K. D., Squires, E. J., and Millman, S. T.
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ANTI-inflammatory agents , *PHARMACODYNAMICS , *DRUG efficacy , *PHYSIOLOGICAL stress , *DEHORNING - Abstract
The objectives were to determine the duration of the stress response associated with cautery dehorning and to assess the effectiveness of the nonsteroidal anti-inflammatory drug meloxicam (Metacam, 20 mg/mL solution for injection) for reducing that response. Sixty Holstein heifer calves were blocked by age and randomly assigned to receive an i.m. injection of meloxicam or a placebo (0.5 mg/kg). All calves were given a lidocaine cornual nerve block delivered 5 mL per side 10 rain before dehorning. To establish baseline values, calves were sham dehorned 24 h before actual dehorning. Blood samples were taken via indwelling jugular catheters at 0, 0.5, 1, 1.5, 2, 4, 6, and 24 h after the procedure. Heart and respiratory rates were also taken at these times. Data were analyzed using PROC MIXED in SAS. Analysis of covariance was employed to assess the difference between sham and dehorning at each time period. Dehorning was associated with elevated serum cortisol (d - 1: 33.9 ± 1.26; d 0: 46.2 ± 2.33 nmol/L) and heart rate (d -1: 108 ± 1.8; d 0: 109.4 ± 2.4 beats per minute) in both groups for 24 h, and elevated respiratory rate (sham: 42.2 ± 1.95 vs. dehorning: 45.1 ± 2.19 respirations per minute) in both groups for 6 h. A treatment x time interaction was found for cortisol, with meloxicam calves having lower serum cortisol than controls until 6 h after dehorning (meloxicam: 49.7 ± 4.37 vs. control: 63.0 ± 6.94 nmol/L). There was no difference between the treatment groups at 24 h (meloxicam: 35.2 ± 2.74 and control: 34.8 ± 3.64 nmol/L of cortisol). Overall, the changes in heart rates (increase meloxicam: 3.74 ± 0.96 vs. control: 4.70 ± 1.87) and respiratory rates (increase meloxicam: 2 ± 0.1 vs. control: 4 ± 0.2) were greater in the control group compared with the meloxicam group. These results indicate that meloxicam reduced the physiological stress response to dehorning. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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- View/download PDF
13. Impact of hyperketonemia in early lactation dairy cows on health and production.
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Duffield, T. F., Lissemore, K. D., McBride, B. W., and Leslie, K. E.
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ACETONEMIA , *DAIRY cattle , *LIVESTOCK diseases , *HEALTH of cattle , *MILK yield , *HOLSTEIN-Friesian cattle - Abstract
Data from 1,010 lactating lactating, predominately component-fed Holstein cattle from 25 predominately tie-stall dairy farms in southwest Ontario were used to identify objective thresholds for defining hyperketonemia in lactating dairy cattle based on negative impacts on cow health, milk production, or both. Serum samples obtained during wk 1 and 2 postpartum and analyzed for β-hydroxybutyrate (BHBA) concentrations that were used in analysis. Data were time-ordered so that the serum samples were obtained at least 1 d before the disease or milk recording events. Serum BHBA cutpoints were constructed at 200 µmol/L intervals between 600 and 2,000 l, mol/L. Critical cutpoints for the health analysis were determined based on the threshold having the greatest sum of sensitivity and specificity for predicting the disease occurrence. For the production outcomes, models for first test day milk yield, milk fat, and milk protein percentage were constructed including covariates of parity, precalving body condition score, season of calving, test day linear score, and the random effect of herd. Each cutpoint was tested in these models to determine the threshold with the greatest impact and least risk of a type 1 error. Serum BHBA concentrations at or above 1,200 µmol/L in the first week following calving were associated with increased risks of subsequent displaced abomasum [odds ratio (OR) = 2.60] and metritis (OR = 3.35), whereas the critical threshold of BHBA in wk 2 postpartum on the risk of abomasal displacement was ≥1,800 µmol/L (OR = 6.22). The best threshold for predicting subsequent risk of clinical ketosis from serum obtained during wk 1 and wk 2 postpartum was 1,400 µmol/L of BHBA (OR = 4.25 and 5.98, respectively). There was no association between clinical mastitis and elevated serum BHBA in wk 1 or 2 postpartum, and there was no association between wk 2 BHBA and risk of metritis. Greater serum BHBA measured during the first and second week postcalving were associated with less milk yield, greater milk fat percentage, and less milk protein percentage on the first Dairy Herd Improvement test day of lactation. Impacts on first Dairy Herd Improvement test milk yield began at BHBA ≥1,200 µmol/L for wk 1 samples and ≥1,400 µmol/L for wk 2 samples. The greatest impact on yield occurred at 1,400 µmol/L (-1.88 kg/d) and 2,000 µmol/L (-3.3 kg/d) for sera from the first and second week postcalving, respectively. Hyperketonemia can be defined at 1,400 µmol/L of BHBA and in the first 2 wk postpartum increases disease risk and results in substantial loss of milk yield in early lactation. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
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14. A Meta-Analysis of the Impact of Monensin in Lactating Dairy Cattle. Part 3. Health and Reproduction.
- Author
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Duffield, T. F., Rabiee, A. R., and Lean, I. J.
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META-analysis , *LACTATION , *DAIRY cattle , *HEALTH , *REPRODUCTION - Abstract
A meta-analysis of the impact of monensin on health and reproductive outcomes in dairy cattle was conducted. A total of 16 papers were identified with sufficient data and quality to evaluate health and reproductive outcomes for monensin. The available trials provided approximately 9,500 cows with sufficient data for analysis. This provided good statistical power to examine the effects of monensin on health and reproduction. Over all the trials analyzed, monensin decreased the risk of ketosis [relative risk (RR) = 0.75], displaced abomasums (RR = 0.75), and mastitis (RR = 0.91). No significant effects of monensin were found for milk fever, lameness, dystocia, retained placenta, or metritis. Monensin had no effect on first-service conception risk (RR = 0.97) or days to pregnancy (hazard ratio = 0.93). However, the impact of monensin on dystocia, retained placenta, and metritis was heterogeneous for all 3 outcome measures and random effect models were utilized. Causes of the heterogeneity were explored with meta-regression. Days of treatment with monensin before calving increased the risk of dystocia. Delivery method of monensin influenced the incidence of retained placenta and metritis, with risk being lower with controlled release capsule treatment compared with delivery in either topdress or in a total mixed ration. Days of treatment before calving also influenced retained placenta with an increase in risk with more days treated before calving. Improvements in ketosis, displaced abomasums, and mastitis with monensin were achieved. Exposure to prolonged treatment in the dry period with monensin may increase the risk of dystocia and retained placenta. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
15. A Meta-Analysis of the Impact of Monensin in Lactating Dairy Cattle. Part 2. Production Effects.
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Duffield, T. F., Rabiee, A. R., and Lean, I. J.
- Subjects
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VETERINARY drugs , *MILK yield , *DAIRY cattle , *COMPOSITION of milk , *MILKFAT , *MILK proteins - Abstract
A meta-analysis of the impact of monensin on production outcomes in dairy cattle was conducted using the 36 papers and 77 trials that contained eligible data. Statistical analyses were conducted in STATA and included a consideration of fixed or random effects models, assessment of publication bias, and impact of influential studies. Meta-regression was used to investigate sources of heterogeneity of response. There were 71 trials containing data from 255 trial sites and 9,677 cows examining milk production and composition. Monensin use in lactating dairy cattle significantly decreased dry matter intake by 0.3 kg, but increased milk yield by 0.7 kg and improved milk production efficiency by 2.5%. Monensin decreased milk fat percentage 0.13%, but had no effect on milk fat yield; however, there was significant heterogeneity between studies for both of these responses. Milk protein percentage was decreased 0.03%, but protein yield was increased 0.016 kg/d with treatment. Monensin had no effect on milk lactose percentage. Monensin increased body condition score by 0.03 and similarly improved body weight change (0.06 kg/d). Analysis of milk fatty acid profile data indicated that monensin was associated with a reduction of short-chain fatty acids (from 1 to 12% reduction) and stearic acid (-7.8%). The impact of monensin on linoleic and linolenic acids was variable, but monensin significantly increased conjugated linoleic acid (22%). Meta-regression of the effect of monensin on milk component percentages and yields indicated an influence of delivery method, stage of lactation, dose, and diet. Increasing concentrations of C18:1 in the diet enhanced the effect of monensin on decreasing milk fat yield, whereas increasing the rumen peptide balance increased the effect of monensin on milk protein yield. These findings indicate a benefit of monensin for improving milk production efficiency while maintaining body condition. The effect of monensin on milk fat percentage and yield was influenced by diet. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
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16. A Meta-Analysis of the Impact of Monensin in Lactating Dairy Cattle, Part 1. Metabolic Effects.
- Author
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Duffield, T. F., Rabiee, A. R., and Lean, I. J.
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VETERINARY drugs , *DAIRY cattle , *LACTATION , *METABOLISM , *KETONES - Abstract
A meta-analysis of the impact of monensin on metabolism of dairy cattle was conducted following a search of the literature. A total of 59 studies with monensin feeding in dairy cattle were identified in which 30 papers and 45 trials contained metabolic data. The phydroxybutyrate (BHBA) data were obtained from over 4,000 cows and 115 trial sites. Data for each trial were extracted and analyzed using meta-analysis software in Stata. Estimated effect sizes of monensin were calculated on blood concentrations of BHBA, acetoacetate, nonesterified fatty acids (NEFA), glucose, cholesterol, urea, calcium, insulin, and milk urea. Monensin use in lactating dairy cattle significantly reduced blood concentrations of BHBA 13%, acetoacetate 14%, and NEFA 7%. Monensin increased glucose 3% and urea 6%. Monensin had no significant effect on cholesterol, calcium, milk urea, or insulin. Heterogeneity was significant for BHBA and cholesterol [I2 (measure of variation beyond chance) = 37 and 54%, respectively]; therefore, random effects models were used for those analytes. Publication bias existed with the monensin effect on BHBA, with a tendency for studies to be published if there was a significant reduction in this ketone. Meta-regression analysis of the effect sizes obtained from the metabolic data showed that method of delivery, timing of administration, stage of lactation, and diet were influential in modifying effect size of monensin treatment. Use of top dress or delivery via a controlled release capsule reduced the magnitude of effect on BHBA (coefficient +0.353); however, top dress use compared with controlled release capsule or total mixed ration enhanced the monensin effect on glucose (coefficient +0.296). There was a greater impact with monensin on reducing BHBA in early lactation (coefficient -0.151) and in pasture-based trials (coefficient -0.194). Use of monensin in both the pre- and postcalving periods was associated with an enhanced impact on NEFA (coefficient -0.254). Monensin had less impact on serum glucose in the precalving time period (coefficient -0.237). These findings demonstrate an improvement in the energy metabolism of dairy cows supplemented with monensin. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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17. Technical note: A system for continuous recording of ruminal pH in cattle.
- Author
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AlZahal, O., Rustomo, B., Odongo, N. E., Duffield, T. F., and McBride, B. W.
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CATTLE inspection ,HYDROGEN-ion concentration ,RUMEN microbiology ,BODY composition of cattle ,HEALTH of cattle ,CATTLE physiology ,CATTLE handling ,FORAGE plants ,BIOCHEMISTRY - Abstract
Continuous recording of ruminal pH in cannulated cattle has been practiced to study rumen metabolism. However, most systems reported did not permit animal mobility during pH recording. Therefore, the objective of this study was to develop a continuous rumen pH data acquisition system that permitted animal mobility during data acquisition. A further objective was to compare the pH readings obtained using the continuous recording system to readings obtained at the same time using spot sampling. The continuous recording system was composed of a heavy-duty electrode and a data logger. The electrode was attached to a 0.5-kg weight to help maintain the electrode in the ventral sac of the rumen. The electrode was connected via a 0.5-m cable to a lightweight data logger that was mounted on the animal's back using a belt wrapped around the girth. The data logger was battery powered and could hold over 13,000 pH data values. A personal digital assistant was used to configure and download data from the data logger during the experiment. Ruminal pH was continuously recorded (every 10 s) using a dry Holstein cow fed alfalfa hay ad libitum in a 3-d experiment to compare the performance of the continuous system to spot samples taken from the ventral sac of the rumen, the same location as the continuous electrode. The spot samples were collected 3 times per d for 3 d. At every sampling time, 3 replicate samples were collected, pH was determined immediately using a handheld pH meter, and readings were averaged (n = 3) and compared with the average of the 3 pH readings recorded using the continuous system at the same time. The pH recorded by spot sampling (6.63 ± 0.04) was greater (P = 0.009) than that of the continuous system (6.56 ± 0.03), with a correlation of r = 0.88 (P = 0.002). The continuous recording system has the potential to facilitate measurement of ruminal pH in free-roaming cattle. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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18. Effects of Rumen-Protected Choline and Monensin on Milk Production and Metabolism of Periparturient Dairy Cows.
- Author
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Zahra, L. C., Duffield, T. F., Leslie, K. E., Overton, T. R., Putnam, D., and LeBlanc, S. J.
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- *
CHOLINE , *MILK yield , *METABOLISM , *DAIRY cattle , *CATTLE parturition - Abstract
Choline and monensin may be supplemented during the transition period with the objectives of aiding in fat metabolism and improving energy balance, respectively. The objectives of this study were to determine the effects of supplementing rumen-protected choline (RPC) and monensin in a controlled-release capsule (CRC) on metabolism, dry matter intake, milk production, and liver function in transition dairy cattle. Three weeks before expected calving, 182 Holsteins were randomly assigned to receive one of the following: a monensin CRC, 56 g/d of RPC until 28 d in milk, CRC + RPC, or neither supplement (control). Blood samples were collected at enrollment, 1 wk before calving, and in the first and second weeks after calving. Liver biopsies were obtained from multiparous cows randomly selected from each treatment group within 24 h and again 3 wk postpartum. Daily milk production was recorded through 60 d in milk. There were no interactions of the effects of RPC and CRC on any of the outcomes measured. Overall, cows that received RPC produced 1.2 kg/d more milk in the first 60 d of lactation, but this effect was attributable to an increase in milk production of 4.4 kg/d among cows with a body condition score ≥4 at 3 wk before calving; fat cows that received RPC ate 1.1 kg of DM/d more from wk 3 before calving through wk 4 after calving. Monensin supplementation significantly increased serum concentrations of glucose and urea, lowered concentrations of β-hydroxybutyric acid and aspartate aminotransferase in the peripartum period, and increased liver glycogen content at 3 wk into lactation. The metabolic effects of CRC are consistent with previous studies, and the effects on liver are novel. The mechanism by which RPC increased milk production was not revealed in this study and merits further research. [ABSTRACT FROM AUTHOR]
- Published
- 2006
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19. Effects of mild heat stress and grain challenge on acid-base balance and rumen tissue histology in lambs.
- Author
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Odongo, N. E., AlZahal, O., Lindinger, M. I., Duffield, T. F., Valdes, E. V., Terrell, S. P., and McBride, B. W.
- Subjects
LAMBS ,PHYSIOLOGICAL effects of heat ,RUMEN (Ruminants) ,HISTOLOGY ,BLOOD plasma ,HUMIDITY ,BLOOD testing ,ERYTHROCYTES ,BLOOD proteins - Abstract
The effect of heat stress (HS) and grain challenge (GC) on acid-base balance and rumen tissue histology in lambs was investigated using 24 yearling weather lambs (58 ± 4.5 kg of BW) in a 2 × 2 factorial experiment with repeated measures for day (10, 14, and 17) of sampling. The factors were temperature [thermoneutral zone (TN) vs. HS] and diet (control vs. GC). Lambs were blocked by BW and assigned to 1 of 4 treatments in temperature-controlled rooms: 1) TN (temperature = 18 to 20°C; relative humidity = 30%; 2) TN + GC; 3) HS (temperature = 35°C for 9 h/d, 20°C for 15 h/d; relative humidity = 40%); and 4) HS + GC. Venous blood samples were collected at 1800 on the first day of GC (d 10), in the middle of GC (d 14), and at the end of the trial (d 17) by jugular venipuncture and analyzed for pH, gases, hematocrit, plasma ions, and total protein. After all measurements in live animals were taken on d 17, lambs were slaughtered, and tissue samples were obtained from the ventral sac of the rumen for histological assessment. Except for the concentration of plasma glucose (P = 0.04) and total protein (P < 0.01), there were no (P > 0.05) diet × temperature interactions. With HS, the concentration of Na
+ and Cl- in the control group decreased at d 14 and then increased by d 17, and respiration rates in the control group decreased linearly (P < 0.05). Compared with the control group, respiration rates and the concentration of Cl- in the GC lambs increased linearly over time, whereas the concentration of Na+ decreased linearly (P < 0.05) across time. Under HS, the partial pressure of carbon dioxide, total carbon dioxide, the partial pressure of oxygen and oxygen saturation, and the concentration of Mg2+ , glucose, and HCO3 - showed quadratic (P < 0.05) responses with time. In both treatments, DMI, base excess of extracellular fluid, base excess of blood, and standard bicarbonate increased linearly (P < 0.05), and hematocrit, plasma protein, Ca2+ , anion gap, and plasma strong ion difference decreased linearly (P < 0.05) across day. Compared with the control group, the GC group had decreased papillae count in the ruminal ventral sac (1.3 vs. 1.5; P < 0.05). These results suggest that under RS the acidifying effects of GC on acid-base balance in lambs were counteracted in the short-term through respiratory adaptation. [ABSTRACT FROM AUTHOR]- Published
- 2006
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20. Ovarian Follicular Activity in Lactating Holstein Cows Supplemented with Monensin.
- Author
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Tallam, S. K., Duffield, T. F., Leslie, K. E., Bagg, R., Dick, P., Vessie, G., and Walton, J. S.
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- *
CATTLE reproduction , *COWS , *DAIRY processing , *DAIRY industry , *PROSTAGLANDINS , *CATTLE breeding , *REPRODUCTIVE technology - Abstract
The objective of this study was to determine effects of monensin on ovarian follicular development and reproductive performance in postpartum dairy cows. Forty-eight multiparous Holstein cows were randomly assigned to receive either a control total mixed ration (n = 24) or the same diet plus 22 mg of monensin/kg (n = 24) from 21 d before anticipated calving until cows were either confirmed pregnant or were >180 d postpartum. Monensin had no effect on development of the first dominant follicle postpartum or the numbers of class 1 (3 to 5 mm), 2 (6 to 9 mm), or 3 (10 to 15 mm) follicles. Control cows had more class 4 (>15 mm) follicles at 10 to 13 d postpartum than cows in the monensin group. The first dominant follicle postpartum ovulated, regressed, or became cystic unrelated to differences between diets. However, the first ovulation postpartum occurred earlier in monensin-fed cows than in the control group (27.2 ± 2.1 d vs. 32.4 ± 1.5 d), with no dietary effects on the diameter of the ovulating follicle. Similarly, treatments did not differ in the proportion of cows with 2 or 3 waves of ovarian follicular development per cycle, nor in the number of follicles of all classes during the breeding period. Times of ovulation following treatment with prostaglandin F[sub2α] were not different between dietary groups. Pregnancy rates after timed artificial insemination were similar between diets. Supplementation with monensin resulted in a shorter postpartum interval to first ovulation but did not affect other reproductive measures in healthy, lactating dairy cows. [ABSTRACT FROM AUTHOR]
- Published
- 2003
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21. The relationship between feed acidogenic value and in vitro ruminal pH changes.
- Author
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Rustomo, B., Cant, J. P., Fan, M. P., Duffield, T. F., Odongo, N. E., and McBride, B. W.
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IN vitro studies ,COMPOSITION of feeds ,REGRESSION analysis ,STARCH ,CARBOHYDRATES ,ANIMAL feeds - Abstract
The increasing use of ruminally fermentable carbohydrate in diets is considered the critical link between nutrition and sub-acute ruminal acidosis in dairy cows. However, starch or non fibre carbohydrate (NFC) content of the diet is not a satisfactory predictor of rumen pH changes due to the high variation in the rate and extent of starch or NFC fermentation in the rumen. A simple in vitro technique was used to assess acidogenic value (AV) of feedstuffs. This technique is based on the dissolution of Ca from CaCO
3 after 24 and 48 h incubation of feedstuffs in rumen liquor. A series of feeds, ranging from energy, fiber and protein sources were evaluated. Ruminal fluid pH changes in the incubation medium were also measured at the end of 24 and 48 h incubation. The relationship between AV and rumen fluid pH and AV and feed chemical composition was determined using regression analysis. Comparison between 24 and 48 h incubations were conducted using paired t-test. Non fiber carbohydrate-rich feedstuffs had the highest AV; forage sources had intermediate AV and high-protein feedstuffs had the lowest AV. There were no differences in apparent AV and rumen fluid pH changes between 24 and 48 h incubation, suggesting a rapid initial fermentation rate and little or no further fermentation after 24 h. Thus, the 24 h AV measurements might be acceptable to qualitatively rank feedstuffs based on the estimated accumulated acid-load during fermentation. The rate of rumen fluid pH changes showed similar patterns to AV in ranking feedstuffs. Energy sources showed the highest rumen fluid pH decrease; fiber sources were intermediate and protein sources were lowest in rumen fluid pH change after 24 h of incubation suggesting that NFC-rich feedstuffs had the lowest rumen buffering capacity compared to fiber and protein rich feedstuffs. Rumen fluid pH changes after 24 h of incubation had a stronger relationships with AV for all feedstuffs (R2 = 0.74) compared to starch (R2 = 0.35) and NFC (R2 = 0.56). The best predictors of feed AV were NFC and ADF (R2 = 0.81). However, further studies are needed to examine the effect of feed AV on in vivo ruminal pH changes in dairy cows. [ABSTRACT FROM AUTHOR]- Published
- 2006
22. Effect of frequency of feed delivery on the feeding behaviour, growth, and rumen temperature of limit-fed dairy heifers
- Author
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Greter, A. M., AlZahal, O., Duffield, T. F., McBride, B. W., Widowski, T. M., and DeVries, T. J.
- Published
- 2014
- Full Text
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23. Effects of monensin and dietary soybean oil on milk fatty acid proflle in lactating cows.
- Author
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AlZahal, O., Odongo, N. E., Or-Rashid, M., Mutsvangwa, T., Duffield, T. F., Bagg, R., Dick, P., Vessie, G., and McBride, B. W.
- Subjects
SOY oil ,SOYMILK ,FATTY acids ,MONENSIN ,COWS ,SILAGE ,MILK ,MILKFAT - Abstract
Seventy-two lactating Holstein dairy cows (100-150 DIM) were used in a 2 x 3 factorial experiment to investigate the effects of monensin (MN; 0 and 22 ppm Rumensin Premix®, DM basis) and dietary soybean oil inclusion (SBO; 0, 1.7, and 3.5%, DM basis) on milk fatty acid (FA) proflle. A TMR (% DM; corn silage, 34; haylage, 22.7; hay, 4.5; high moisture corn, 20; and protein supplement, 18.8 %) was offered ad libitum. The trial consisted of a 2-wk baseline period, a 3-wk adaptation period, a 2-wk treatment period, and a 4-wk wash-out period. Feed and milk samples were collected three times per wk and composited over each experimental period. Soybean oil linearly reduced total shortand medium-chain (≤ C
14 ) and saturated FA concentrations. Soybean oil linearly increased total mono- and polyunsaturated, t11-C18:1 , and total CLA. M0nensin had no effect on concentrations of total shortand medium-chain (≤ C14 ), saturated, mono- and polyunsaturated FA. Monensin, SBO, and their interaction increased total transand t10-C18:1 FA. This translated into a signiflcant drop of 11 and 23% in fat percentage when MN was used with 1.7 and 3.5% SBO, respectively. These results show that MN lowers milk fat percentage and the magnitude of this response is dependent upon the level of dietary SBO inclusion. [ABSTRACT FROM AUTHOR]- Published
- 2006
24. Effects of rumen acid-load from feed and forage particle size on ruminal pH, feed intake and milk production and composition.
- Author
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Rustomo, B., AlZahal, O., Odongo, N. E., Duffield, T. F., and McBride, B. W.
- Subjects
COMPOSITION of milk ,MILK yield ,FORAGE ,PARTICLES ,FAT content of milk ,ALFALFA ,ANIMAL feeds - Abstract
This study evaluated the effects of concentrate acidogenic value (AV) and forage particle size (FPS) on ruminal pH, feed intake and milk production and composition in lactating dairy cows. Four rumenfistulated dairy cows (114 ± 14 DIM) were randomly assigned to one of four treatments in a 4 x 4 Latin square with a 2 x 2 factorial treatment arrangement. Four isoenergetic (NEl = 1.5 Mcal/kg) and isonitrogenous (CP = 17.4 % DM) concentrate diets with either a low (LAV) or high AV (HAV) were fed in either a coarse (CS) or finely chopped (FS) corn silage/alfalfa haylage based TMR. Production data were analyzed using PROC GLM of SAS using the model: Yijkl = μ + αi + βj + γk + δl + (γ x δ)kl + εijkl; where Yijkl = dependent variable, μ = overall mean, αi = effect of cow (i = 1, 2, 3, 4), βj = effect of period (j = 1, 2, 3, 4), γk = effect of AV (k = 1, 2), δl = effect of FPS(l = 1, 2), (γ x δ)kl = effect of γk x δl interaction, and εijkl = random residual error. Repeated measurements of ruminal pH data were analyzed using PROC MIXED. Increasing dietary AV increased rumen acid-load (decreased mean, minimum and maximum ruminal pH), time below rumen pH 5.6 to 6.0 and area below rumen pH 5.6 and 6.0. Increasing FPS increased maximum ruminal pH and reduced time below pH 6.4 to 6.8 for HAV diets whereas increased FPS increased time below pH 6.4 to 6.8 for LAV diets. Time distribution for HAV diets was shifted downward to a lower pH range compared to the LAV diets. Increasing dietary AV had no effect on DMI but reduced OM and NDF intake. There was a correlation (r = -0.54, P = 0.03) between milk fat content and time below pH 5.6. The correlation between time below pH 5.6 and rumen acid-load was stronger (r = 0.58, P = 0.02) than that between time below 5.6 and the intake of starch, r = 0.40; NFC, r = 0.20; FPS, r = 0.005 and peNDF, r = 0.26; P > 0.05). These results suggest that coarse FPS can attenuate ruminal pH drops. However, the ameliorating effects of FPS on ruminal pH are more apparent in HAV diets than in LAV diets. [ABSTRACT FROM AUTHOR]
- Published
- 2006
25. Effects of rumen acid-load from feeds on ruminal pH, dry matter intake, fiber degradability and milk production in the lactating dairy cow.
- Author
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Rustomo, B., AlZahal, O., Cant, J. P., Fan, M. P., Duffield, T. F., Odongo, N. E., and McBride, B. W.
- Subjects
ALFALFA ,MILK yield ,MILK ,FEED corn silage ,LACTOSE ,COWS ,MILK proteins ,ANIMAL feeds - Abstract
The objective of this study was to evaluate the effects of rumen acidload from feeds on ruminal pH, dry matter intake, fiber degradability and milk production in lactating dairy cows. Two isoenergetic (NEl =1.73 Mcal/kg DM) and isonitrogenous (CP = 22.1% DM) concentrate diets with either a low (LAV) or high acidogenic value (HAV) were fed in a corn silage/alfalfa haylage based TMR. The diets, fed for ad libitum intake, were offered twice daily at 0700 and 1300 and DM intake recorded daily. Four rumen-fistulated dairy cows (230 ± 30 DIM) were randomly assigned to one of the two treatments in a crossover design with two periods of 3 wk (14 d adaptation, 7 d data collection) each. The cows were milked twice daily at 0500 and 1500, and milk samples pooled twice weekly for compositional analysis. Ruminal pH was measured continuously for 3 d using an indwelling pH electrode. Forage degradability was determined using the in situ technique. Data were analyzed using PROC GLM of SAS using the model: Yijk = μ + α
i + βj + τk + εijk, where Yijk = dependent variable, μ = overall mean, αi = effect of cow (i = 1, 2, 3, 4) βj = effect of period (j = 1, 2) τk = effect of treatment (k = 1, 2), and εijk = random residual error. The repeated measurements of ruminal pH were analyzed using PROC MIXED of SAS. Increasing dietary AV decreased maximum ruminal pH, but had no effect on minimum and mean daily ruminal pH. High AV cows had longer time spent below ruminal pH 5.6 and greater area below ruminal pH 5.6 to 6.0 than the LAV cows. The time distribution curve of HAV cows was shifted to a lower pH range and tended to have longer time spent at ruminal pH 5.0 to 5.6 and shorter time spent at ruminal pH 6.2 to 6.8 than LAV cows. Increasing dietary AV reduced the 72 h in situ NDF degradability of alfalfa/grass hay, increased milk yield, lactose %, lactose yield and milk protein yield. These results emphasize the significance of ruminal pH alterations when evaluating the effect of feed AV on ruminal pH and suggest that feed AV could be used to predict ruminal pH changes in vivo. [ABSTRACT FROM AUTHOR]- Published
- 2006
26. Associations of serum haptoglobin in newborn dairy calves with health, growth, and mortality up to 4 months of age.
- Author
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Murray, C. F., Windeyer, M. C., Duffield, T. F., Haley, D. B., Pearl, D. L., Waalderbos, K. M., and Leslie, K. E.
- Subjects
- *
HAPTOGLOBINS , *BOVINE respiratory syncytial virus diseases , *VIRUS diseases in cattle , *SERUM , *CATTLE parturition - Abstract
The objective of this research was to investigate factors associated with serum haptoglobin (Hp) levels in newborn calves. In addition, the associations between serum Hp levels in newborn calves with growth, morbidity, and mortality in calves <4 mo of age were investigated. A total of 1,365 Holstein heifer calves from 15 dairy farms were enrolled in this study from January to December, 2008. Following calving, a birth record was completed, including information on the calving event, colostrum administration, and other details. During weekly farm visits, each calf was assessed at 1 to 8 d, 5 to 21 d, 36 to 42 d, and 90 to 120 d of age. At these sampling times, each calf was assessed using a standardized clinical score for general health, and height and weight were measured. At 1 to 8 d of age, a blood sample was collected to measure serum total protein and Hp concentrations. Treatment events and death loss were recorded throughout the study by the farm staff. Serum Hp concentration in the first week of life was not significantly associated with the degree of calving difficulty. However, serum Hp was higher in calves with a higher rectal temperature and depressed attitude at the first sampling time. Furthermore, the association between serum Hp and the severity of nasal discharge varied by age at first sampling time. Calves with higher Hp in their first week of life had significantly higher total health scores throughout the entire sampling period. Haptoglobin was not significantly associated with average daily gain or treatment for bovine respiratory disease. Yet, for every 1 g/L increase in serum Hp in the first week of life, the odds of being treated for any ther disease during the study period increased by 7.6 times. Treatment for bovine respiratory disease, diarrhea, or any other disease resulted in increased odds of calf mortality. In addition, Hp concentration in the first week of life was associated with mortality in calves <4 mo of age. The optimal cut point for Hp was determined to be 0.13 g/L for the prediction of disease and death, although the sensitivity of Hp concentration alone as a diagnostic test for individual calves was low. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
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27. Effect of frequency of feed delivery on the behavior and productivity of lactating dairy cows.
- Author
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Hart, K. D., McBride, B. W., Duffield, T. F., and Devries, T. J.
- Subjects
- *
LACTATION in cattle , *HOLSTEIN-Friesian cattle , *DAIRY cattle feeding & feeds , *DRY matter in animal nutrition , *MILK yield , *MILKING - Abstract
The objective of this study was to determine the effect of feed delivery frequency on the behavioral patterns and productivity of lactating dairy cows. Twelve freestall-housed, lactating Holstein dairy cows, including 6 primiparous (PP) and 6 multiparous (MP), milked 3x/d (at 1400, 2200, and 0600h), were exposed to each of 3 treatments (over 21-d periods) in a replicated Latin square design. Treatments included feed delivery frequency of (1) 1x/d (at 1400 h), (2) 2x/d (at 1400 and 2200 h), and (3) 3x/d (at 1400, 2200, and 0600 h). Milk production as well as feeding, lying, and rumination behaviors were electronically monitored for each animal for the last 7 d of each treatment period. Milk samples were collected for the last 3 d of each period for milk component analysis. Dry matter intake (DMI) varied with feed delivery frequency, with greatest DMI observed in cows fed 3x/d (27.8 kg/d) compared with those fed 2x/d (27.0 kg/d) or 1x/d (27.4 kg/d). Treatment had no effect on milk yield (41.3 kg/d) or efficiency of production (1.54 kg of milk/kg of DMI). Cows that did not receive delivery of feed following the 2200 h milking (treatment 1) and 0600 h milking (treatments 1 and 2) had lower DMI during the first hour after milking than those that received feed at all milkings (treatment 3). Total feeding time and meal frequency, size, and duration did not vary by treatment, but PP cows consumed smaller meals at a slower rate, resulting in lower DMI compared with MP cows. Primiparous cows consumed 50.1% and 26.1% less dry matter than MP cows during the first meal following the first and second milkings, respectively. Lying time did not vary by treatment, but PP cows spent more time lying (10.3 vs. 8.3 h/d) than MP cows. Under 3x/d milking schedules, greater feed delivery frequency resulted in greater DMI as a function of increased DMI following the return from milking and the delivery of feed. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
28. Effect of milking frequency on the behavior and productivity of lactating dairy cows.
- Author
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Hart, K. D., McBride, B. W., Duffield, T. F., and DeVries, T. J.
- Subjects
- *
MILKING , *DAIRY cattle , *HOLSTEIN-Friesian cattle , *CATTLE reproduction , *COMPOSITION of milk - Abstract
The objective of this study was to determine the effect of milking frequency on the behavioral patterns and productivity of lactating dairy cows. Twelve freestall-housed, lactating Holstein dairy cows (7 primiparous and 5 multiparous) were exposed to each of 2 treatments (over 21-d periods) in a replicated crossover design. Treatments were milking frequency of 2x/d (at 0600 and 1800 h) or 3x/d (at 0600, 1400, and 2200 h). Milk production, feeding, lying, and rumination behavior were monitored for each animal for the last 7 d of each treatment period. Milk samples were collected for the last 3 d of each period for milk component analysis. The results indicated that cows milked 3x/d produced 2.9 kg/d more milk than those milked 2x/d. Primiparous cows consumed 3.9 kg/d less dry matter (DM) than did multiparous cows. The extra time (14.6 min/d) required for milking 3x/d altered the distribution of cow behavioral activity throughout the day. Although this did not affect total daily lying or rumination time, we observed a tendency for cows milked 2x/d to spend less time (224.6 vs. 237.5 min/d) feeding and, thus, those cows tended to consume their feed at a faster rate (0.13 vs. 0.12 kg of DM/min) than cows milked 3x/d. For multiparous cows, the increase in feeding activity was facilitated through having longer (40.1 vs. 36.8 min/meal) and numerically larger meals (4.8 vs. 4.6 kg of DM/meal) when milked 3x/d. Alternatively, primiparous cows consumed smaller (2.9 vs. 3.2 kg of DM/meal) and more frequent meals (9.1 vs. 7.7 meals/d) throughout the day when milked 3x/d, resulting in a tendency for greater DM intake (24.7 vs. 23.6 kg/d) compared with primiparous cows milked 2x/d. These results indicate that under 3x/d milking schedules, primiparous cows will positively adjust their feeding behavior to achieve similar production increases as multiparous cows. In summary, milking 3x/d can be used to improve production; however, greater milking frequency elicits varying effects on the behavior of primiparous and multiparous cows, suggesting that grouping and management of cows based on parity may be beneficial. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
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29. Growing dairy heifers prefer supplementary long straw when fed a nutrient-dense ration in a limited amount.
- Author
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Greter, A. M., Prinsen, M., Duffield, T. F., Mcbride, B. W., Widowski, T. M., and Devries, T. J.
- Subjects
- *
DAIRY cattle feeding & feeds , *RUMEN (Ruminants) , *RUMINATION (Digestion) , *ANIMAL feeding behavior , *ANIMAL nutrition - Abstract
The objective of this study was to determine whether limit-fed heifers will choose to consume long particles, rather than short, of a low-nutritive feedstuff to ameliorate rumen function and meet foraging needs. Ten Holstein heifers 261.6 ± 39.2 (mean ± SD) d of age were exposed to each of 2 dietary treatments, in a random order, over 2 successive 7-d treatment periods (4-d adaptation period and a 3-d data collection period) using a crossover design. The treatments were (1) a provision of long particle oat straw (85% of particles > 8 mm; LS) and (2) provision of short particle oat straw (45% of particles >8 mm; SS). Both treatments were offered following consumption of a limit-fed, nutrient-dense total mixed ration fed at 2.05% of body weight. Following each 7-d period, heifers were given access to both types of straw during an additional 2-d preference period; individual intakes were recorded daily. Feeding and lying behavior were recorded during the last 3 d of each treatment period. Ruminal temperature was recorded during the last 3 d of each treatment period using a telemetric acquisition system and rumen boluses. Dry matter intake of both the total mixed ration (6.3 kg/d) and straw (0.36 kg/d) was similar between treatments. Heifers fed LS spent more time feeding (197.7 vs. 175.2 min/d) throughout the day than heifers fed SS due to the increase in time required to consume long particles in the LS (59.8 vs. 34.2 min/d). Daily lying time (974.7 min/d) and time spent standing without eating (278.9 min/d) was similar between treatments. The preference period showed a strong preference ratio for LS rather than SS (preference ratio = 0.83), with heifers consuming 0.43 ± 0.2 kg/d of LS and 0.07 ± 0.1 kg/d of SS (mean ± SD). Heifers maintained similar mean (38.3°C), minimum (35.1°C), and maximum (38.9°C) rumen temperature across treatments. The amount of time that rumen temperature was elevated over 38.6°C, 39.0°C, and 39.4°C was similar between treatments. In conclusion, heifers will consume similar amounts of supplementary long or short straw if provided to them alongside of a limit-fed TMR. Limit-fed heifers do, however, show a clear preference for LS when offered the choice, suggesting that they find LS to be more satisfactory for achieving rumen fill or meeting their behavioral foraging needs. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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30. Short communication: Effects of frequency of feed delivery and bunk space on the feeding behavior of limit-fed dairy heifers.
- Author
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Greter, A. M., Westerveld, R. S., Duffield, T. F., McBride, B. W., Widowski, T. M., and Devries, T. J.
- Subjects
- *
HEIFERS , *CATTLE behavior , *CATTLE feeding & feeds , *DAIRY farms , *COMPETITION (Biology) - Abstract
The objective of this experiment was to determine the interaction between feed bunk space and frequency of feed provision on the feeding behavior patterns and growth of growing dairy heifers fed a limited amount. Sixteen Holstein dairy heifers (183.4 ± 9.1 d of age, mean ± standard deviation) were divided into 4 groups of 4. The groups were exposed to each of 4 treatments, using a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments, over 21-d periods (14-d adaptation period, 7-d data collection periods). The treatments were arranged in 2 feed delivery frequencies (once per day at 1200 h: lx/d, and twice per day at 1200 and 1400 h: 2x/d) and 2 levels of feed bunk space (adequate feed bunk space: 0.40 m/heifer, and reduced feed bunk space: 0.29 m/heifer). Pen dry matter intake (DMI) was recorded daily, average daily gain (ADG) was recorded weekly, and variability in ADG was calculated from the standard deviation of ADG. Feeding, unrewarded behavior (time at feed bunk without feed present), and competitive behavior were recorded using time-lapse video. Feeding and unrewarded behavior were measured for the last 7 d of each period, whereas competitive behavior was recorded on d 16, 18, and 20 of each period. Lying time was recorded for the last 7 d of each period. A tendency for interaction between feed bunk space and frequency of feed delivery on the feed efficiency of limit-fed dairy heifers was noted. Heifers provided restricted bunk space were reported as being less efficient when fed 2x/d; however, no other interactions were found. Although DMI and variability in ADG were similar between treatments, ADG was higher (1.0 vs. 0.9 kg/d) when heifers were provided with 0.40 m of feed bunk space and tended to be higher when fed lx/d compared with that of heifers given restricted bunk space or fed 2x/d. Heifers fed lx/d spent more time feeding throughout the day (70.5 vs. 58.9 min/d) than heifers fed 2x/d. Heifers fed at a restricted bunk space or fed lx/d were approximately 25% more variable in feeding time than heifers fed 2x/d or with adequate bunk space. Heifers spent a similar amount of time in unrewarded visits to the feed bunk (28.9 min/d). Although feed bunk space did not affect competition (3.6 displacements/d), heifers fed 1x/d were displaced twice as frequently than heifers fed 2x/d. Regardless of treatment, heifers spent a similar amount of time lying down and standing without eating. Overall, providing sufficient feed bunk space to allow all limit-fed heifers to feed simultaneously improves feed efficiency and ADG and reduces variability in feeding time. Additionally, although delivering feed 1x/d resulted in increased competition, it also enabled heifers to gain adequate weight and spend more time feeding each day. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
31. The association of serum metabolites with clinical disease during the transition period.
- Author
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Chapinal, N., Carson, M., Duffield, T. F., Capel, M., Godden, S., Overton, M., Santos, J. E. P., and LeBlanc, S. J.
- Abstract
The objective of this observational field study was to validate the relationship of serum concentrations of nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), and calcium with disease in early lactation across different management systems. Fifty-five Holstein freestall dairy herds located across the United States and Canada were selected and visited weekly for blood sample collection from 2,365 cows. Only diseases that were consistently recorded across herds and blood samples collected before the disease occurred were considered. Metabolite concentrations in serum in wk-1 relative to calving were considered as predictors of retained placenta (RP) and metritis, and metabolite concentrations in serum in wk-1 and wk+1 relative to calving were considered as predictors of displaced abomasum (DA). For each disease, each metabolite, and week of sampling in the case of DA, a critical threshold was calculated based on the highest combined sensitivity and specificity and used to categorize the serum concentrations into high and low risk categories. Multivariable logistic regression models were built for each disease of interest and week of sampling, considering cow as the experimental unit and herd as a random effect. Cows with precalving serum NEFA concentrations =0.3 mEq/L were more likely to develop RP [odds ratio (OR) = 1.8; 95% confidence interval (CI) = 1.3 to 2.6] and metritis (OR = 1.8; 95% CI = 1.5 to 2.9) after calving than cows with lower NEFA concentrations. Precalving NEFA =0.5 mEq/L (OR = 2.4; 95% CI = 1.5 to 3.7), postcalving NEFA =1.0 mEq/L (OR = 2.7; 95% CI = 1.7 to 4.4), and postcalving calcium =2.2 mmol/L (OR = 3.1; 95% CI = 1.9 to 5.0) were associated with subsequent risk of DA. In conclusion, elevated serum NEFA concentrations within 1 wk before calving were associated with increased risk of RP, metritis, and DA after calving. Serum NEFA and calcium concentrations in the 2 wk around calving in combination were associated with the risk of DA. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
32. Short communication: effect of sampling time relative to the first daily feeding on interpretation of serum fatty acid and β-hydroxybutyrate concentrations in dairy cattle.
- Author
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Quiroz-Rocha, G. F., LeBlanc, S. J., Duffield, T. F., Jefferson, B., Wood, D., Leslie, K. E., and Jacobs, R. M.
- Subjects
- *
FATTY acids , *3-Hydroxybutyric acid , *DAIRY cattle feeding & feeds , *CATTLE parturition , *ENERGY metabolism , *STATISTICAL sampling - Abstract
Serum nonesterified fatty acid (NEFA) and β-hydroxybutyrate (BHBA) concentrations are used to evaluate energy status in peripartum dairy cows. Blood samples from 37 cows in the week before parturition and 47 cows in the first week after parturition from 3 dairy herds were taken 1 h before the first feeding (-1 h) as well as 4 and 10 h after the first feeding. Nonesterified fatty acid concentrations were measured in samples from cows before calving and BHBA was measured in samples from lactating cows. Mean NEFA concentrations in the prepartum cows were significantly higher at -1 h (0.20 mmol/L) than at 4 h (0.14 mmol/L), but were not different between 4 and 10 h (0.17 mmol/L). Using a cutpoint of NEFA ⩾0.4 mmol/L, 32% of cows had high concentrations at -1 h compared with 16% of the same cows at 4 and 10 h. There were no differences in mean BHBA between -1 h (646 μmol/L) and 4 h (596 μmol/L), but mean BHBA was higher at 10 h (711 μmol/L) than at -1 h. Using a cutpoint of BHBA ⩾1,400 μmol/L, there were no differences in the proportions of high BHBA, which were 9, 11, and 13% of cows at -1, 4, and 10 h, respectively. Prandial effects on serum NEFA may affect interpretation of this analyte. In order not to misclassify cows when assessing energy status, samples for NEFA must at least be taken at a consistent time relative to feeding within a given herd. When sampling cows to monitor elements of energy metabolism in the prepartum period, there was twice the probability of detecting animals with NEFA values ⩾0.4 mmol/L if they were sampled 1 h before the first feed delivery compared with sampling the same cows 4 or 10 h after feeding. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
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33. Invited review: use of meta-analysis in animal health and reproduction: methods and applications.
- Author
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Lean, I. J., Rabiee, A. R., Duffield, T. F., and Dohoo, I. R.
- Subjects
- *
META-analysis , *ANIMAL health , *ANIMAL sexual behavior , *BAYESIAN analysis , *ZOOLOGY - Abstract
The objectives of this paper are to provide an introduction to meta-analysis and systematic review and to discuss the rationale for this type of research and other general considerations. We highlight methods used to produce a rigorous meta-analysis and discuss some aspects of interpretation of meta-analysis drawing on examples from the animal and veterinary science literature. Meta-analysis is a rapidly expanding area of research that has been relatively underutilized in animal and veterinary science. It is a quantitative, formal, epidemiological study design used to systematically assess previous research studies to derive conclusions about that body of research. Outcomes from a meta-analysis may include a more precise estimate of the effect of treatment or risk factor for disease, or other outcomes, than any individual study contributing to the pooled analysis. The examination of variability or heterogeneity in study results is also a critical outcome. The benefits of meta-analysis include a consolidated and quantitative review of a large, and often complex, sometimes apparently conflicting, body of literature. Meta-analytic methods place less emphasis on dichotomous outcomes from null hypothesis significance testing and greater emphasis on determining the magnitude and the precision of an effect of interest. A substantial benefit of meta-analysis is the potential to investigate new hypotheses using existing data, both through the development of a priori hypotheses and by examination of the heterogeneity in study responses. The specification of the outcome and hypotheses that are tested is critical to the conduct of meta-analyses, as is a sensitive literature search. A failure to identify the majority of existing studies can lead to erroneous conclusions; however, there are methods of examining data to identify the potential for studies to be missing; for example, by the use of funnel plots. Many of the statistical methods to conduct meta-analysis are widely used. Bayesian methods are well suited to meta-analysis. The post-hoc methods used to evaluate heterogeneity and publication bias, which include the I2 statistic, L'Abbé plots, Galbraith plots, Rosenthal's N, and influential study analysis are exclusively used in meta-analysis. Examples where meta-analyses have been repeated in animal science or veterinary medicine show good consistency in estimates of effect. Findings of studies to date have provided new understandings of rumen modifiers, milk fever, parasite control, mastitis, somatotropin, and reproductive manipulations. Rigorously conducted meta-analyses are useful tools to improve animal well-being and productivity. The need to integrate findings from many studies ensures that meta-analytic research is desirable and the large body of research now generated makes the conduct of this research feasible. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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34. Effects of Prepartum Administration of a Monensin Controlled Release Capsule on Rumen pH, Feed Intake, and Milk Production of Transition Dairy Cows.
- Author
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Fairfield, A. M., Plaizier, J. C., Duffield, T. F., Lindinger, M. I., Bagg, R., Dick, P., and McBride, B. W.
- Subjects
- *
DAIRY cattle feeding & feeds , *ANTIBIOTICS , *RUMEN (Ruminants) , *MILK yield , *LACTATION , *HOLSTEIN-Friesian cattle , *CATTLE parturition , *COMPOSITION of milk - Abstract
Effects of prepartum administration of a monensin controlled release capsule (CRC) on rumen pH, dry matter intake, and milk production during the transition period and early lactation were determined in 16 multiparous Holstein cows. Cows were divided into blocks of 2 depending on calving date. Cows were fed either a close-up dry cow or a lactating cow total mixed ration ad libitum. Rumen pH was monitored continuously using indwelling probes. Monensin did not affect average daily rumen pH, time below pH 6, time below pH 5.6, area below pH 6, and area below pH 5.6 throughout the experiment. Average daily pH, time below pH 6, and time below pH 5.6 before calving were 6.62, 65.6 min/d, and 17.6 min/d, respectively, and did not differ among the weeks before calving. Average daily pH, time below pH 6, and time below pH 5.6 were 6.19, 443.3 min/d, and 115.5 min/d, respectively, during the first week after calving, and were 6.36, 204.3 min/d, and 52.4 min/d, respectively, during the sixth week after calving. In the weeks after calving, average daily pH showed a quadratic increase, time below pH 6 showed a quadratic decrease, and time below pH 5.6 showed a linear decrease. Monensin did not affect dry matter intake and daily yields of milk, milk fat, and milk protein. Results suggest that prepartum administration of a monensin CRC did not increase rumen pH in multiparous cows fed the experimental diets during the transition period and early lactation. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
35. Prevalence and Risk Factors for Postpartum Anovulatory Condition in Dairy Cows.
- Author
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Walsh, R. B., Kelton, D. F., Duffield, T. F., Leslie, K. E., Walton, J. S., and LeBlanc, S. J.
- Subjects
- *
CATTLE parturition , *ANOVULATION , *GENETIC research , *COWS , *PREGNANCY in animals , *SKIM milk - Abstract
The objectives of this research were to determine the prevalence of the anovulatory condition within a temperate region of North America and identify cow-level and herd-level risk factors for this condition. A total of 1,341 cows from 18 herds were classified as cycling or anovular based on skim milk progesterone concentration determined at 46 and 60 ± 7 d in milk. Calving history, periparturient disease incidence, body condition score, milk ketone concentration in the first 2 wk of lactation, and first 305-d mature-equivalent milk projections were recorded. Reproductive and culling information was retrieved monthly from the Dairy Herd Improvement Association. The cow-level prevalence of anovulation was 19.5%, with a herd-specific range from 5 to 45%. Accounting for the effect of clustering at the herd level, cows experiencing a difficult calving, cows with twin calvings, displaced abomasum, and cows with subclinical ketosis in the first week after calving were at greater risk for diagnosis of anovulation. Anovular cows within herds using ovulation synchronization programs were inseminated at the same time postpartum with a 6-percentage point reduction in the probability of pregnancy relative to cycling herdmates (29.7 vs. 35.9%, respectively), whereas anovular cows in herds breeding based on observed estrus were inseminated 8 d later and suffered a 10-percentage point reduction in the probability of pregnancy at first insemination (20.3 vs. 30.5). Time to pregnancy was delayed in anovular cows by 30 d (156 vs. 126 d). Using survival analysis, the impact of anovulation decreased with time. The daily probability of pregnancy (hazard ratio) was similar to cycling cows by 165 d in milk. The results underline the important associations of peripartum health with reproductive function and performance. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
36. The Association of Herd Milk Production and Management with a Return-Over-Feed Index in Ontario Dairy Herds.
- Author
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McLaren, C. J., Lissemore, K. D., Duffield, T. F., Leslie, K. E., Kelton, D. F., and Grexton, B.
- Subjects
- *
DAIRY farms , *MILK yield , *DAIRY industry , *COWS , *LACTATION - Abstract
Associations of herd milk production and management variables to a return-over-feed (ROF) herd profit index were examined among 95 dairy farms. The ROF index is derived from 2 important determinants of profit on dairy farms: milk income and feed cost. All producers were participants in the Dairy Herd Improvement (DHI) ROF program in Ontario, Canada during 2002. Nutrition, housing, health, and other management data were collected through a phone survey of herd managers. Herd milk production, milk component percentages, and somatic cell count data were obtained from the Ontario DHI database. The linear regression model accounting for significant variation in ROF with highest R² (0.66) included standardized milk production, milk protein percentage, milk fat percentage, and use of monensin in lactating cow rations. A 1-kg increase in standardized milk production (kg/d per cow) or a 0.1 percentage unit increase in milk protein was associated with $0.35/d per cow or $0.26/d per cow increase, respectively, in the ROF of the dairy herd. However, a 0.1 percentage unit increase in milk fat was associated with a $0.10/d per cow decrease in ROF, probably because of a negative association of milk fat with milk yield. Use of monensin in lactating cow rations was associated with a $0.39/d per cow increase in ROF. In a separate model (R² = 0.27) that examined management factors independent of production variables, herds using 3 times daily milking had a $1.25/d per cow higher ROF vs. herds using twice daily, whereas use of an Escherichia coli mastitis vaccine was associated with $0.59/ d per cow higher ROF. Production-related variables accounted for more variation in the ROF index than management variables, and the latter, e.g., use of monensin, only marginally increased R2 of production-based regression models. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
37. Metabolic Predictors of Displaced Abomasum in Dairy Cattle.
- Author
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LeBlanc, S. J., Leslie, K. E., and Duffield, T. F.
- Subjects
- *
CATTLE , *DAIRY farms , *FATTY acids , *COWS , *FEMALE livestock - Abstract
The objective of this field study was to identify metabolic tests available in clinical practice that identified cows at increased risk of left displaced abomasum (LDA). A technician visited 1044 cows in 20 herds weekly from 1 wk before expected calving until 1 wk postpartum. Cows were assigned a body condition score and samples were collected at each visit for measurement of serum nonesterified fatty acids (NEFA), cholesterol, β-hydroxybutyrate (BHBA), glucose, urea, calcium, and phosphorus, and a milk sample was collected postpartum for measurement of BHBA. The probability of LDA was modeled with multivariable logistic regression accounting for clustering. There were 53 cases of LDA (incidence risk = 5.1%) and the median time of diagnosis was 11 d in milk. In cows with LDA, mean NEFA concentrations began to diverge from the mean in cows without LDA 14 d before calving, whereas mean serum BHBA concentrations did not diverge until the day of calving. Prepartum, only NEFA concentration was associated with risk of subsequent LDA. Between 0 and 6 d before calving, cows with NEFA concentration ≥0.5 mEq/L were 3.6 times more likely to develop LDA after calving. For prospective application, among samples taken 4 to 10 d before expected calving, the optimum NEFA cut-point remained 0.5 mEq/L. The sensitivity, specificity, and likelihood ratio (LR) were 46%, 82%, and 2.6, respectively. Between 1 and 7 d postpartum, retained placenta, metritis, and increasing serum concentrations of BHBA and NEFA were associated with increased risk of subsequent LDA. However, considered separately, postpartum serum BHBA was a more sensitive and specific test than NEFA concentration. The odds of LDA were 8 times greater in cows with serum BHBA ≥1200 µmol/L (LR = 3.5). Cows with milk BHBA concentration ≥200 µmol/L were 3.4 times more likely to develop LDA. Serum calcium concentration was not associated with LDA. Strategic use of metabolic tests to monitor ... [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
38. Genetic Susceptibility to Neospora caninum Infection in Holstein Cattle in Ontario.
- Author
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Pan, Y., Jansen, G. B., Duffield, T. F., Hietala, S., Kelton, D., Lin, C. Y., and Peregrine, A. S.
- Subjects
- *
CATTLE , *ABORTION in animals , *HOLSTEIN-Friesian cattle , *ENZYME-linked immunosorbent assay , *FEMALE livestock - Abstract
Neospora caninum has been reported to be an important cause of endemic fetal loss and occasional abortion epidemics in cattle around the world. This study examined 12,016 sera collected from 9723 Holstein cows on 125 herds across Ontario in 1998, 1999, and 2000. An enzyme-linked immunosorbent assay was used to examine the sera for antibodies to N. caninum. The overall prevalence of N. caninum antibodies in the cattle was 11.2% and the prevalence in individual herds varied from 0 to 70.4%. Among 3109 daughter-dam pairs, 619 positive dams had 252 positive daughters, giving a detected vertical transmission rate of 40.7%. In contrast, there were only 6.7% positive daughters from negative dams (167 of 2490). Pedigree edits left 8031 cows with 1463 sires for estimation of heritability. Five genetic models (sire model, animal model, siredam model, a sire-maternal grandsire model, and a maternal effects model) with fixed effects of bleeding year-month, age of the animals, and herd were fitted to the data. The estimated heritability of susceptibility to N. caninum ranged between 0.084 and 0.124. The sire-maternal grandsire model and the maternal effects model provided better fit than the other models because the maternal genetic variance was much greater than the direct genetic variance. To reduce the incidence of N. caninum infection, more emphasis should be placed on management practices than on genetic selection. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
39. Validation of commercial luminometry swabs for total bacteria and coliform counts in colostrum-feeding equipment.
- Author
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Renaud, D. L., Kelton, D. F., Leblanc, S. J., Haley, D. B., Jalbert, A. B., and Duffield, T. F.
- Subjects
- *
CATTLE , *COLOSTRUM , *CALF physiology , *BACTERIAL contamination , *BIOLUMINESCENCE , *ADENOSINE triphosphate - Abstract
A sufficient quantity and quality of colostrum must be fed quickly to the newborn calf while minimizing bacterial contamination. Adenosine triphosphate bioluminescence swabs offer a potential rapid on-farm alternative to assess bacterial contamination of colostrum. The objective of this study was to validate the Hygiena (Camarillo, CA) AquaSnap Total (AS), SuperSnap (SS), PRO-Clean (PC), and MicroSnap Coliform (MS) swabs as well as visual hygiene assessment for detection of elevated bacterial counts in or on colostrum-feeding equipment. From April to October 2016, 18 esophageal tube feeders, 49 nipple bottles, and 6 pails from 52 dairy farms in Ontario were evaluated for cleanliness. Following visual hygiene assessment, sterile physiological saline (15 mL) was poured into each piece of equipment, mixed for 2 min to ensure total surface coverage, and poured into a sterile collection container through the feeding end. The fluid was split into equal aliquots, with one being evaluated by conventional culture and the other evaluated using the luminometry swabs. Nonparametric receiver operator curves were used to compare the test performance of the luminescence reading (relative light units; RLU) from each type of swab to conventional bacterial culture. The area under the curve comparing the AS swab to total bacterial count (cut point >100,000 cfu/mL) was 0.89, and using a cut point of 631 RLU correctly classified 84% of samples with a sensitivity of 88% and a specificity of 77%. The area under the curve comparing the MS swab to total coliform count (cut point >10,000 cfu/mL) was 0.85, and using a cut point of 44 RLU correctly classified 89% of samples with a sensitivity of 83% and a specificity of 90%. Visual hygiene assessment, PC and SS swabs were not reliable indicators for feeding equipment cleanliness. The results suggest that the AS and MS swabs can be used as an alternative to traditional laboratory bacterial counts to evaluate cleanliness of colostrum-feeding equipment. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
40. Randomized clinical field trial on the effects of butaphosphancyanocobalamin and propylene glycol on ketosis resolution and milk production.
- Author
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Gordon, J. L., LeBlanc, S. J., Kelton, D. F., Herdt, T. H., Neuder, L., and Duffield, T. F.
- Subjects
- *
MILK yield , *VITAMIN B12 , *ACETONEMIA , *PROPYLENE glycols , *LACTATION in cattle , *THERAPEUTICS , *CATTLE - Abstract
The purpose of this study was to determine the effects of a butaphosphan-cyanocobalamin combination product (B+C) and 2 durations of propylene glycol treatment (PG; 3 versus 5 d) on ketosis resolution and early lactation milk yield. Cows from 9 freestall herds (8 in Ontario and 1 in Michigan) were tested at weekly intervals between 3 and 16 d in milk. Ketosis was defined as blood β-hydroxybutyrate (BHB) ≥1.2 mmol/L. Ketotic cows were randomly assigned to treatment with 25 mL of B+C or 25 mL of saline placebo for 3 d and 3 or 5 d of 300 g of PG orally in a 2 × 2 factorial arrangement. Outcomes evaluated for all farms included ketosis cure (blood BHB <1.2 mmol/L at 1 wk after enrollment), maintenance of ketosis cure (blood BHB <1.2 mmol/L 1 and 2 wk after enrollment), and blood BHB concentrations at 1 and 2 wk after enrollment. Daily milk weights were collected in 3 herds. Poisson regression was used to evaluate cure and maintenance of cure, whereas repeated-measures ANOVA was used to evaluate blood BHB concentrations in the 2 wk after enrollment and average daily milk production in the 30 d after treatment. A total of 594 animals were enrolled in the study with 124 treated with B+C and 5 d of PG, 176 treated with B+C and 3 d of PG, 128 treated with saline and 5 d of PG, and 166 treated with saline and 3 d of PG. Animals with blood BHB >2.4 mmol/L at the time of enrollment were 1.7 times more likely [95% confidence interval (CI): 1.4 to 2.2] to cure and had a decrease of 0.25 ± 0.11 mmol/L blood BHB at 1 wk after enrollment if treated with 5 d of PG compared with 3 d, though this response was not seen in animals with BHB of 1.2 to 2.4 mmol/L at enrollment. Cows with blood glucose concentrations <2.2 mmol/L at enrollment produced 3.1 kg/d (95% CI: 1.3 to 5.0) more milk if treated with B+C and 3.4 kg/d (95% CI: 1.7 to 5.1) more milk if treated with 5 d of PG compared with their respective controls. This response was not seen in animals with blood glucose ≥2.2 mmol/L at enrollment and there was no interaction between treatments. These results indicate that extended PG treatment is beneficial in decreasing blood BHB concentrations in more severely affected animals. Additionally, both B+C treatment and extended PG treatment improved milk yield in animals with low blood glucose at the time of ketosis diagnosis. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
41. The effects of periparturient administration of flunixin meglumine on the health and production of dairy cattle.
- Author
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Newby, N. C., Leslie, K. E., Dingwell, H. D. Putnam, Kelton, D. F., Weary, D. M., Neuder, L., Millman, S. T., and Duffield, T. F.
- Subjects
- *
DAIRY cattle , *PARTURITION grounds , *MILK yield , *PLACEBOS , *HIGH temperatures - Abstract
Research on the assessment and management of pain in cows following difficult or assisted calving is still limited, especially on the effects of analgesics intended to mitigate this pain. The purpose of this study was to assess the effects of flunixin meglumine on the health and production of Holstein cows after calving. In total, 34 flunixin-treated and 38 placebo-treated animals were enrolled in a precalving treatment trial. A total of 633 animals given flunixin and 632 animals administered a placebo were enrolled in a postcalving treatment trial. In both cases, animals were randomly assigned to treatment, and researchers were blind to treatment condition until after analysis. A total of 1,265 animal records were analyzed for milk production for the first 14 d in milk and health outcomes for the first 30 d in milk. Animals treated with flunixin meglumine before calving had a significantly increased risk of stillbirth. Animals treated immediately after calving had increased odds of having a retained placenta and, in turn, increased risk of a high temperature, decreased milk production, and an increased risk of developing metritis. The administration of flunixin meglumine within 24 h of parturition is not recommended in dairy cattle. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
42. Short communication: Association of lying behavior and subclinical ketosis in transition dairy cows.
- Author
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Kaufman, E. I., LeBlanc, S. J., McBride, B. W., Duffield, T. F., and DeVries, T. J.
- Subjects
- *
ACETONEMIA , *CATTLE diseases , *COW diseases , *MILK fever in animals , *BOVINE mastitis , *CATTLE - Abstract
The objective of this study was to characterize the association of lying behavior and subclinical ketosis (SCK) in transition dairy cows. A total of 339 dairy cows (107 primiparous and 232 multiparous) on 4 commercial dairy farms were monitored for lying behavior and SCK from 14 d before calving until 28 d after calving. Lying time, frequency of lying bouts, and average lying bout length were measured using automated data loggers 24 h/d. Cows were tested for SCK 1×/wk by taking a blood sample and analyzing for β-hydroxybutyrate; cows with β-hydroxybutyrate ≥1.2 mmol/L postpartum were considered to have SCK. Cases of retained placenta, metritis, milk fever, or mastitis during the study period were recorded and cows were categorized into 1 of 4 groups: healthy (HLT) cows had no SCK or any other health problem (n = 139); cows treated for at least 1 health issue other than SCK (n = 50); SCK (HYK) cows with no other health problems during transition (n = 97); or subclinically ketotic plus (HYK+) cows that had SCK and 1 or more other health problems (n = 53). Daily lying time was summarized by week and comparisons were made between HLT, HYK, and HYK+, respectively. We found no difference among health categories in lying time, bout frequency, or bout length from wk -2 to wk +4 relative to calving for first-lactation cows. Differences in lying time for multiparous cows were seen in wk +1, when HYK+ cows spent 92 ± 24.0 min/d more time lying down than HLT cows, and during wk +3 and +4 when HYK cows spent 44 ± 16.7 and 41 ± 18.9 min/d, respectively, more time lying down than HLT cows. Increased odds of HYK+ were found to be associated with higher parity, longer dry period, and greater stall stocking density in wk -1 and longer lying time during wk +1. When comparing HYK to HLT cows, the same variables were associated with odds of SCK; however, lying time was not retained in the final model. These results suggest that monitoring lying time may contribute to identifying multiparous cows experiencing SCK with another health problem after calving, but may not be useful in the early detection of SCK. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
43. Association of rumination time with subclinical ketosis in transition dairy cows.
- Author
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Kaufman, E. I., LeBlanc, S. J., McBride, B. W., Duffield, T. F., and DeVries, T. J.
- Subjects
- *
RUMINATION (Digestion) , *ACETONEMIA , *RUMEN (Ruminants) , *DAIRY cattle , *LIVESTOCK diseases , *HOLSTEIN-Friesian cattle , *MILK yield - Abstract
The objective of this study was to characterize the relationship between rumination and subclinical ketosis (SCK) in transition dairy cows. A study was conducted on 4 commercial dairy farms in eastern Ontario, Canada. A total of 339 Holstein dairy cows (107 primiparous and 232 multiparous) were monitored for rumination activity and SCK from 14 d before calving until 28 d after calving. Rumination was recorded daily using an automated monitoring system. A blood sample was taken from the coccygeal vein of each cow for measurement of β-hydroxybutyrate (BHB) once weekly throughout the 6-wk observation period. Cows with BHB ⩾1.2 mmol/L in any of the 4 postpartum samples were considered to have SCK. Cases of retained placenta, metritis, milk fever, or mastitis during the study period were also recorded. Cows were categorized into 1 of 4 groups: healthy cows (HLT) that had no SCK or any other recorded health problem (n = 139); cows treated for at least one health issue other than SCK (HLT+; n = 50); cows with SCK (hyperketonemia; HYK) with no other health problems during transition (n = 97); or cows (HYK+) that had SCK and one or more other health problems (n = 53). Daily rumination time was summarized by week and comparisons were made between HLT and HYK and HYK+. From 2 wk before calving (wk -2) to 4 wk after calving (wk +4), there was no difference in rumination time (409 ± 9.8 min/d) among HLT, HYK, and HYK+ cows in their first lactation. Multiparous cows in HLT spent an average of 459 ± 11.3 min/d ruminating from wk -2 to wk +4. Multiparous HYK cows ruminated 25 ± 12.8 min/d less than HLT cows, whereas HYK+ cows ruminated 44 ± 15.6 min/d less than HLT cows. The largest differences in rumination time between HLT and HYK+ cows were seen during wk -1, +1, and +2, when HYK+ cows ruminated 48 ± 17.2, 73 ± 16.0, and 65 ± 19.4 min/d less than HLT cows, respectively. In multiparous cows, increased odds of HYK were associated with greater milk yield in the previous lactation, greater loss of body condition over the transition period, greater stall stocking density in wk -1, and reduced rumination time in wk -1. Increased odds of HYK+ were associated with higher parity, longer dry period, greater stall stocking density in wk -1, and reduced rumination time in wk +1. These results suggest that rumination monitoring across the transition period might contribute to identification of SCK and other health problems in multiparous cows. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
44. Effect of administration of recombinant bovine somatotropin on health and performance of lactating dairy cows diagnosed with hyperketonemia.
- Author
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Gohary, K., Leslie, K. E., Ford, J., Capel, M., LeBlanc, S. J., and Duffield, T. F.
- Subjects
- *
RECOMBINANT bovine somatotropin , *PHYSIOLOGICAL effects of somatotropin , *DAIRY cattle , *ACETONEMIA , *MILK yield , *3-Hydroxybutyric acid , *PLACEBOS , *CATTLE - Abstract
The effect of administering recombinant bovine somatotropin (rbST) to cows with hyperketonemia during the early postpartum period on health, metabolic parameters, milk production, and early reproductive performance was evaluated in a double-blinded clinical trial. Cows from 8 dairy herds in New York State were tested weekly between 3 and 16 d in milk for elevated serum β-hydroxybutyrate. Cows were enrolled in the study when blood β-hydroxybutyrate was ≥1.3 mmol/L for the first time. Enrolled cows were randomly assigned to a treatment (n = 273) or placebo control (n = 270) group. Treated cows were given 325 mg of rbST subcutaneously on the day of enrollment and again 14 d later. Control cows received the same regimen except the syringe contained only the carrier without somatotropin. After enrollment, blood samples were collected weekly for 4 wk and submitted to the laboratory to be analyzed for selected metabolites. Risk ratios for clinical diseases subsequent to treatment were calculated using Poisson regression. Continuous data were analyzed using linear mixed models. Time to first insemination was assessed with survival analysis. In the 42 d following the first administration of rbST, incidence risks of displaced abomasum, clinical ketosis, metritis, clinical mastitis, and lameness were not different between treatment groups. Cows treated with rbST had a slightly lower body condition score 28 d after enrollment compared with control cows. In the 4 wk following enrollment, serum nonesterified fatty acids and aspartate amino-transferase were slightly higher for treated than control cows, respectively. Serum glucose, calcium, haptoglobin, and β-hydroxybutyrate were similar between groups. Treatment had no effect on resolution of hyperketonemia in any of the 4 wk after enrollment. Milk production in either of the 2-wk periods after each treatment was not different between treated and control cows. Furthermore, milk production was not different between groups from enrollment to 98 d in milk (42.6 ± 0.6 and 42.1 ± 0.7 kg/d for treatment and control groups, respectively). Treatment had no effect on time to first insemination (83 and 74 d in milk for treatment and control groups, respectively; hazard ratio = 0.72) or first insemination pregnancy risk (27 and 29% for treatment and control groups, respectively; risk ratio = 0.92). Based on the current results, it is not recommended to use a low dose of rbST as therapy for cows with hyperketonemia. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
45. Short communication: Limit feeding affects behavior patterns and feeding motivation of dairy heifers.
- Author
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Greter, A. M., Miller-Cushon, E. K., McBride, B. W., Widowski, T. M., Duffield, T. F., and DeVries, T. J.
- Subjects
- *
HEIFERS , *DAIRY cattle feeding & feeds , *DAIRY cattle behavior , *DAIRY farming research , *DAIRY industry research - Abstract
The study objective was to assess the effects of limit feeding dairy heifers on behavior patterns and feeding motivation. Ten Holstein heifers (291.6 ± 39.2 d of age, weighing 324.2 ± 61.2 kg; mean ± SD) were exposed to each of 2 dietary treatments, in a random order, over 2 successive 26-d treatment periods (14-d adaptation period and a 12-d data collection period) using a crossover design: (1) a high-forage total mixed ration (TMR), provided ad libitum (CON) and (2) a low-forage TMR, limit-fed at 2.05% body weight (LF). Heifers were fed daily at 1100 h and motivation to access a low-nutritive feedstuff (straw) was assessed using a push-door apparatus at 2 time points: 3 h after feed delivery (1400 h) and 21 h after feed delivery (0800 h). The amount of weight pushed, weight pushed as percentage of body weight, and latency to access the push door were recorded on 3 different days for each heifer at each time point on each treatment. When fed CON, heifers had greater dry matter intake (12.9 vs. 7.2 kg/d), greater feeding time (209.3 vs. 82.4 min/d), greater ruminating time (452.2 vs. 318.3 min/d), and slower rates of intake (0.06 vs. 0.09 kg of dry matter/min) than when fed LF. Heifers fed LF pushed more weight as a percentage of body weight at 3 h (4.5 vs. 1.9%) and 21 h (9.3 vs. 2.8%) after feed delivery. At both 3 and 21 h after feed delivery, latency to access the door was shorter for the LF heifers compared with the CON heifers (65 vs. 145 s). These results indicate that, in addition to decreasing feeding time, limit feeding increases motivation of heifers to access a low-nutritive feedstuff, possibly due to lack of satiety resulting from lack of physical fill or insufficient time spent foraging. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
46. Use of a direct-fed microbial product as a supplement during the transition period in dairy cattle.
- Author
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AlZahal, O., McGill, H., Kleinberg, A., Holliday, J. I., Hindrichsen, I. K., Duffield, T. F., and McBride, B. W.
- Subjects
- *
MICROBIAL products , *DAIRY cattle feeding & feeds , *ANIMAL nutrition , *DAIRY farming , *DAIRY industry - Abstract
Two studies were conducted. The objective of the first study was to assess the effects of a direct-fed microbial (DFM) product on dry matter intake, milk yield, milk components, disease incidence, and blood metabolites in dairy cattle. The objective of the second study was to assess the effects of DFM on apparent total-tract nutrient digestibility (ATTD). One hundred twenty primiparous and multiparous Holstein cows housed in a tiestall facility at the University of Guelph were used in study 1, and a subset (21) of the same cows participated in study 2. Cows were blocked by anticipated calving date (6 blocks) and then randomly assigned within parity to receive either a DFM supplement (Chr. Hansen Ltd., Milwaukee, WI) or placebo (control). The DFM supplement provided cows with 5.0 x 109 cfu/d of 3 strains of Enterococcus faecium and 2.0 x 109 cfu/d of Saccharomyces cerevisiae. The DFM supplement was mixed with 0.5 kg of ground dry corn and top-dressed during the morning feeding. The placebo supplement contained the corn only. Individual feed intakes and milk yields were recorded daily. The experiment commenced 3 wk before calving and ended 10 wk postcalving. Milk samples for component analysis were collected on 3 d per week and pooled by week. Body weights and body condition scores were assessed 1 d before enrollment in the study (wk -3), postcalving (wk 1), and at the end of wk 3, 6, and 9. Blood samples were collected before calving (wk-3) and the end of wk 1 and 3. Study 1 showed that treatment had no effect on average dry matter intake or milk yield (kg/d) over the duration of the experiment. The changes in body weights and body condition scores and net energy balance over the duration of the experiment did not differ due to treatment. Treatment had no effect on plasma concentrations of β-hydroxybutyrate, non-esterified fatty acids, glucose, or haptoglobin. Study 2 investigated the effects of DFM on ATTD of starch and neutral detergent fiber (NDF) using insoluble NDF and lignin as internal markers. Study 2 used 21 cows (block 6) from the cows that participated in study 1 while the cows were between 60 and 70 d in milk. Cows receiving DFM had lower fecal starch content (0.88 ± 0.10 vs. 1.39 ± 0.25) and greater ATTD for starch (98.76% ± 0.28 vs. 97.87% ± 0.24) compared with those receiving placebo, and the AATD of NDF did not differ. Additionally, we detected no difference between internal markers for the measurement of ATTD. In conclusion, we were unable to detect a change in overall dry matter intake, milk yield, or milk and blood parameters with DFM supplementation. However, our results demonstrated that DFM can have a positive effect on total-tract starch digestibility. More studies are needed to investigate the effects of DFM and their modes of action under multiple management conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
47. Effect of prepartum administration of recombinant bovine somatotropin on health and performance of lactating dairy cows.
- Author
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Gohary, K., Leblanc, S. J., Lissemore, K. D., Overton, M. W., Von Massow, M., and Duffield, T. F.
- Subjects
- *
RECOMBINANT bovine somatotropin , *BOVINE somatotropin , *DAIRY cattle , *RECOMBINANT proteins , *SOMATOTROPIN - Abstract
A double-blind, randomized clinical trial was conducted in 5 commercial dairy herds in southern Ontario with 1,362 cows enrolled to evaluate the effect of prepartum administration of recombinant bovine somatotropin (rbST) on health and performance. Cows were randomly assigned to receive either 325 mg of sometribove zinc suspension (n = 680) or a placebo injection (n = 682; control) subcutaneously every 14 d until calving. Treatments started 28 to 22 d before expected calving, with a maximum of 3 treatments per cow. Serum samples taken at the time of enrollment, 1 wk before calving, and weekly for 3 wk after calving were analyzed for nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), glucose, aspartate aminotransferase, calcium, and haptoglobin. Diseases were recorded by farm staff. Incidences of clinical ketosis, clinical mastitis, displaced abomasum, metritis, retained placenta, milk fever, and lameness were similar between groups. Body condition score was lower for treated than for control cows at 3 wk after calving (3.13 and 3.17, respectively). Serum NEFA tended to be higher for treated than for control cows by 0.01 mmol/L. Overall BHBA was not different between groups, but BHBA for treated cows was higher in wk 1 after calving (750 and 698 μmol/L, respectively) and tended to be higher in wk 2 after calving (779 and 735 μmol/L, respectively). Incidence of hyperketonemia was similar between groups. Treated cows had higher serum glucose compared with control cows (2.8 and 2.7 mmol/L, respectively). We detected no differences in serum aspartate aminotransferase, calcium, or haptoglobin between groups. Milk yield was recorded daily for each cow for 63 d, and did not differ between groups (37.1 ± 0.5 kg and 36.7 ± 0.5 kg, respectively) but we detected a tendency for treated cows to produce 0.8 kg/d more milk than control cows in wk 1 after calving. We observed no difference between groups in the time from calving to first insemination or the probability of pregnancy at the first insemination. Groups did not differ in the proportion of anovular cows at 53 ± 3 d in milk based on serum progesterone measured from a subset of cows (38.0 and 34.3%, respectively, for treated and control groups). We found no difference between groups in dry matter intake from 21 d before calving to 63 d after calving in a subset of cows (17.4 ± 0.4 and 17.5 ± 0.4 kg/d, respectively). Based on results of the current study, biweekly (every 14 d) administration of rbST before calving to prevent disease and enhance performance is not recommended. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
48. The effect of meloxicam on pain sensitivity, rumination time, and clinical signs in dairy cows with endotoxin-induced clinical mastitis.
- Author
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Fitzpatrick, C. E., Chapinal, N., Petersson-Wolfe, C. S., Devries, T. J., Kelton, D. F., Duffield, T. F., and Leslie, K. E.
- Subjects
- *
ALGOMETRY , *LIPOPOLYSACCHARIDES , *ENDOTOXINS , *NONSTEROIDAL anti-inflammatory agents , *ESCHERICHIA coli - Abstract
The objectives of this study were to (1) evaluate the use of a pressure algometer and an automated rumination monitoring system to assess changes in pain sensitivity and rumination time in response to endotoxin-induced clinical mastitis and (2) evaluate the effect of the nonsteroidal antiinflammatory drug meloxicam on pain sensitivity and rumination time, as well as other clinical signs, in dairy cattle with endotoxin-induced clinical mastitis. Clinical mastitis was induced in 12 primiparous and 12 multiparous lactating dairy cows by intramammary infusion of 25 µg of Escherichia coli lipopolysaccharide (LPS) into 1 uninfected quarter. Immediately after, half the cows were injected subcutaneously with meloxicam (treated group) and half with the same volume of a placebo solution (control group). Pain sensitivity was assessed by measuring the difference in pressure required to elicit a response on the control and challenged quarter using an algometer 3 d before, immediately before, and at 3, 6, 12, and 24 h after LPS infusion and either meloxicam or placebo injection. Rumination was continuously monitored from 2 d before to 3 d after LPS infusion using rumination loggers. Udder edema, body temperature, somatic cell score, and dry matter intake were also monitored to evaluate the occurrence and the duration of the inflammation after LPS infusion. In control animals, the difference in the pressure applied to the control and challenged quarters (control -- challenged quarter) increased by 1.1 ± 0.4 kg of force 6 h after LPS infusion compared with the baseline, suggesting an increase in pain sensitivity in the challenged quarter. Neither the LPS infusion nor the meloxicam treatment had an effect on daily rumination time. However, the rumination diurnal pattern on the day of LPS infusion showed an overall deviation from the baseline pattern. Cows spent less time ruminating in the hours following LPS infusion and more time ruminating later in the day. Meloxicam did not alter somatic cell score or dry matter intake. However, meloxicam-treated animals had less udder edema and a lower body temperature in the hours following LPS infusion compared with control animals. In conclusion, pressure algometers and rumination loggers show promise as tools to detect mastitis and monitor recovery on farm. Further, meloxicam has a beneficial effect in relieving pain and decreasing udder edema and body temperature in LPS-induced clinical mastitis. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
49. Herd-level association of serum metabolites in the transition period with disease, milk production, and early lactation reproductive performance.
- Author
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Chapinal, N., LeBlanc, S. J., Carson, M. E., Leslie, K. E., Godden, S., Capel, M., Santos, J. E. P., Overton, M. W., and Duffield, T. F.
- Subjects
- *
MILK yield , *LACTATION , *LACTATION in cattle , *FATTY acid content of milk , *COMPOSITION of milk - Abstract
The objective was to identify herd-level indicators expressed as a proportion of sampled animals with increased nonesterified fatty acids (NEFA) or β -hydroxybutyric acid (BHBA), or decreased calcium in wk -1 and wk +1 relative to calving that were associated with herd-level incidence of retained placenta, metritis and displaced abomasum, milk production, and probability of pregnancy at the first artificial insemination (AI). Fifty-five Holstein freestall dairy herds in the United States and Canada were visited weekly. Blood was collected from 2,365 cows around parturition, and serum concentrations of NEFA, BHBA, and calcium were determined. Different cow-level metabolite thresholds associated with detrimental health or productivity in previous studies were used to classify animals into high- and low-risk metabolite concentration groups. For wk -1 and wk +1 relative to calving, a herd-level threshold was determined as the proportion of sampled animals in the high-risk metabolite concentration groups with the strongest association with increased incidence of disease, milk loss, or decreased pregnancy at the first AI. The odds of displaced abomasum after calving were higher in herds that had ≥ 25% of the animals with BHBA ≥ 1,400 μ mol/L in wk +1 [odds ratio (OR) = 2.1; 95% confidence interval (CI) = 1.0-4.2)] or ≥ 35% of the animals with calcium ≤ 2.1 mmol/L in wk +1 (OR = 2.4; CI = 1.3-4.3). Herd-level thresholds of ≥ 15% of the cows with BHBA ≥ 800 μ mol/L in wk -1 and ≥ 15% of the cows with calcium ≤ 2.1 mmol/L in wk +1 were associated with milk loss (±SE) of 4.4 ± 1.7 and 3.8 ± 1.4 kg/d per cow, respectively. When only multiparous cows were considered, herds with ≥ 30% of the multiparous cows with NEFA ≥ 0.5 mEq/L in wk -1 were associated with a 3.0 ± 1.5 kg/d per cow milk loss. The odds of pregnancy at first AI were lower in herds that had ≥ 5% of the cows with calcium ≤ 2.1 mmol/L in wk -1 (OR = 0.7; CI = 0.5-1.0), or ≥ 30% of the cows with NEFA ≥ 1.0 mEq/L (OR = 0.6; CI = 0.4-0.9) or ≥ 25% of the cows with calcium ≤ 2.1 mmol/L in wk +1 (OR = 0.7; CI = 0.5-0.9). When only multiparous cows were considered, the odds of pregnancy at first AI were lower in herds that had ≥ 50% of multiparous cows with NEFA ≥ 0.5 mEq/L in wk -1 (OR = 0.5; CI = 0.2-0.9). In conclusion, several herd-level thresholds for the proportion of cows with increased NEFA or BHBA, or decreased calcium in the week before and after calving were associated with higher risk of displaced abomasum, milk loss at the first Dairy Herd Improvement Association test, and decreased pregnancy at first AI. The association found between precalving BHBA and milk production is promising due to the availability of several cow-side tests for measuring BHBA. Some of the herd-level associations differed from the previously described cow-level associations, suggesting the potential of interpreting periparturient metabolic challenges at the herd level, where changes in diet and management are generally implemented. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
50. Metabolic parameters in transition cows as indicators for early-lactation culling risk.
- Author
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Roberts, T., Chapinal, N., Leblanc, S. J., Kelton, D. F., Dubuc, J., and Duffield, T. F.
- Subjects
- *
CULLING of dairy cattle , *COW physiology , *PHYSIOLOGICAL effects of fatty acids , *LACTATION , *3-Hydroxybutyric acid , *HYPOCALCEMIA - Abstract
A retrospective cohort study was performed with the objective of determining whether the serum concentrations of nonesterified fatty acids (NEFA), β-hydroxybutyric acid (BHBA), or calcium were associated with the risk of culling within 60 d in milk (DIM) in Holstein cows, and to establish thresholds for each metabolite that were predictive of increased culling risk. Data from 5,979 cows in Ontario (Canada) and several US states were obtained from 4 previously reported studies. For each metabolite and each of 3 sampling weeks (-1, +1, and +2 relative to calving), an optimal threshold was calculated based on having the maximum combined sensitivity (Se) and specificity (Sp) and used to categorize the serum concentrations into high and low risk groups. Logistic regression models were built for each metabolite and each week of sampling, as well as considering together all metabolites in wk -1 and wk +1 relative to calving. Cow was considered the experimental unit and herd as a random effect. Considered separately, precalving NEFA ≥0.4 mmol/L [odds ratio (OR) = 1.8; 95% confidence interval (CI) = 1.4 to 2.2], NEFA ≥0.8 mmol/L in wk +1 relative to calving (OR = 2.0; 95% CI = 1.5 to 2.6) and NEFA ≥0.8 mmol/L in wk +2 (OR = 4.2; 95% CI = 1.9 to 9.4 for cows in lactation 2; OR = 2.1; 95% CI = 1.4 to 3.3 for cows in lactation ≥3) were each associated with an increased risk of culling within the first 60 DIM. Similarly, BHBA ≥0.7 mmol/L in wk -1 (OR = 1.8; 95% CI = 1.3 to 2.5), BHBA ≥1.2 mmol/L in wk +1 (OR = 1.8; 95% CI = 1.4 to 2.2), and BHBA ≥1.6 mmol/L in wk +2 (OR = 3.2; 95% CI = 1.6 to 6.4 for cows in lactation 2; OR = 2.3; 95% CI = 1.6 to 3.3 for cows in lactation ≥3) were each associated with an increased risk of culling within the first 60 DIM. Likewise, calcium ≤2.3 mmol/L in wk -1 (OR = 1.6; 95% CI = 1.2 to 2.2), calcium ≤2.2 mmol/L in wk +1 (OR = 1.5; 95% CI = 1.2 to 1.9), and calcium ≤2.3 mmol/L in wk +2 (OR = 2.3; 95% CI = 1.1 to 3.1) were each associated with an increased risk of culling within the first 60 DIM. When all metabolites were analyzed together, serum NEFA and calcium concentrations in wk -1 and serum NEFA concentration in wk +1 remained in the models. In conclusion, elevated serum NEFA and BHBA concentrations and lower serum calcium concentrations within 1 wk before calving through 2 wk after calving were associated with an increased risk of culling in early lactation. Measuring the concentration of selected metabolites around parturition may help to develop monitoring and intervention strategies to prevent early culling in transition dairy cows. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
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