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This study compared physiological and productive parameters in ¾ Holstein × ¼ Gir dairy cows diagnosed or not with subclinical hypocalcemia (SCH) during early lactation. Nonlactating, multiparous cows (n = 32) were enrolled in this experiment 21 d prior to expected date of calving. Cows were maintained in a single pen with ad libitum access to corn silage before calving and received a limit-fed prepartum concentrate. Cow body weight (BW) and body condition score (BCS) were recorded weekly, and blood samples were collected on days −21, −14, −9, −6, and −3 relative to expected calving. After calving (day 0), cows were managed in a single pen with ad libitum access to a total mixed ration, and were milked twice daily. Cow BW and BCS were recorded upon calving and then weekly. Milk production was recorded daily and milk samples collected weekly until 30 d in milk (DIM). Blood was collected during the first 5 DIM, and at 6, 9, 16, 23, and 30 DIM. Cows were classified with SCH when mean total serum Ca during the first 5 DIM was ≤2.125 mmol/L. Cows diagnosed with SCH (n = 11) had less (P ≤ 0.04) mean BCS (2.85 vs. 3.07; SEM = 0.07) and less concentrations of serum insulin (0.396 vs. 0.738 ppmol/L; SEM = 0.115) and insulin-like growth factor I (35.9 vs. 57.9 ng/mL; SEM = 4.2), and these outcomes were noted since 21 d prior to expected calving. Cows diagnosed with SCH had greater (P < 0.01) serum concentrations of cortisol at calving (30.2 vs. 22.4 ng/mL; SEM = 2.0), serum haptoglobin at 3 and 6 DIM (0.453 vs. 0.280 mg/mL on day 3 and 0.352 vs. 0.142 mg/mL on day 6; SEM = 0.046), and tended (P = 0.09) to have greater mean concentrations of nonesterified fatty acids from calving to 30 DIM (0.368 vs. 0.304 μEq/L; SEM = 0.026). No differences were detected (P ≥ 0.41) for cow BW and milk production. Cows diagnosed with SCH had less (P = 0.05) mean concentrations of milk total solids (13.2 vs. 13.8 %; SEM = 0.21), tended to have less (P ≤ 0.10) mean concentrations of milk fat (4.34 vs. 4.81 %; SEM = 0.20), protein (3.31 vs. 3.45 %; SEM = 0.05), and lactose (4.45 vs. 4.55 %; SEM = 0.04), and had greater (P = 0.02) milk somatic cell count during the initial 14 DIM (504 vs. 140 cells/μL; SEM = 90). Collectively, Holstein × Gir cows diagnosed with SCH upon calving had altered periparturient physiological parameters denoting reduced energy nutritional, increased milk somatic cell count, and less concentration of milk components during early lactation compared with normocalcemic cows. [ABSTRACT FROM AUTHOR]

The effects of high stocking density during the dry period on dairy cow physiology, behaviour and welfare were investigated. Holstein Friesian cows (n = 48, calving over a seven month period) were dried-off 60 ± 4 d before their expected calving date, and allocated to either high (H) or low (L) stocking density groups. Cows were housed in cubicles from dry-off to 21 d before calving and then moved to straw yards until calving. In cubicle pens, H and L cows had 0.5 vs. 1.0 feed yokes/cow and 1.0 vs. 1.5 cubicles/cow, respectively, and in straw yards, 0.3 m vs. 0.6 m linear feed-face space and 6 m2 vs. 12 m2 lying space, respectively. Video observations of feeding behaviour during the 3 h after feed delivery (3 d/week) and agonistic interactions at the feed-face during peak feeding (2 d/week) were made. Daily lying proportion was measured using an accelerometer device throughout the dry period. Concentrations of faecal glucocorticoid metabolites (FGCM) at dry-off, d7 and d35 after dry-off and d21 and d7 before calving and the change in energy metabolites (glucose, NEFA, BHB) from dry-off to d7 before calving were measured. H cows were less likely to start feeding within 5 min of feed delivery and spent less time feeding compared to L cows, but they engaged in displacements more frequently and spent more time standing in the feed alley. Irrespective of the treatment groups, FGCM concentrations significantly increased from dry-off to d7 after dry-off and remained higher during the dry period. Stocking density did not affect daily lying proportion, energy metabolites during the dry period and milk yield during subsequent lactation. This study found that whilst high stocking density during the dry period increased competition at the feed-face and altered feeding behaviour, it did not affect stress responses, energy metabolism or subsequent milk yield. [ABSTRACT FROM AUTHOR]

This experiment compared milk production, milk composition, and physiological responses in lactating dairy cows supplemented with or without a mixture of condensed tannins, encapsulated cinnamaldehyde, curcumin, capsaicin, and piperine. Thirty-six lactating, multiparous, pregnant ¾ Holstein × ¼ Gir cows were maintained in a single drylot pen with ad libitum access to water and a total-mixed ration and were milked twice daily (d –7 to 84). On d 0, cows were ranked by days in milk (86 ± 3 d), milk yield (27.8 ± 1.0 kg), body weight (BW; 584 ± 10 kg), and body condition score (BCS; 3.04 ± 0.06) and assigned to receive (SUPP; n = 18) or not (CON; n = 18) 30 g/cow daily (as-fed basis) of Actifor Pro (Delacon Biotechnik GmbH; Steyregg, Austria). From d 0 to 84, SUPP cows individually received (as-fed basis) 15 g of Actifor Pro mixed with 85 g of finely ground corn through self-locking headgates before each milking of the day. Each CON cow concurrently received 85 g (as-fed basis) of finely ground corn through self-locking headgates. Throughout the experimental period (d –7 to 84), cows from both treatments were administered 500 mg of sometribove zinc at 14-d intervals and were monitored daily for morbidity, including clinical mastitis. Individual milk production was recorded daily, whereas milk samples were collected weekly for analysis of milk composition. Cow BW, BCS, and blood samples were also collected weekly. Cows receiving SUPP gained more BCS (P = 0.05) and had greater (P = 0.04) milk yield during the experiment compared with CON cows (0.22 vs. 0.07 of BCS, SEM = 0.05; 29.5 vs. 27.9 kg/d, SEM = 0.5). Milk composition did not differ (P ≥ 0.15) between SUPP and CON cows; hence, SUPP cows also had greater (P ≤ 0.02) production of fat-corrected and energy-corrected milk. Incidence of clinical mastitis did not differ (P ≥ 0.49) between SUPP and CON cows. No treatment differences were also detected (P ≥ 0.21) for serum concentrations of glucose and serum urea N. Mean serum haptoglobin concentration during the experiment was greater (P = 0.05) in CON vs. SUPP cows. Cows receiving SUPP had less (P ≤ 0.04) serum cortisol concentrations on d 21 and 42, and greater (P ≤ 0.05) serum concentrations of insulin-like growth factor-I on d 7, 35, and 63 compared with CON cows (treatment × day interactions; P ≤ 0.02). Collectively, supplementing phytogenic feed ingredients improved nutritional status and milk production of lactating ¾ Holstein × ¼ Gir cows. [ABSTRACT FROM AUTHOR]

This study (1) investigated the effect of dietary transition at dry off on the behavior and physiology of Holstein dairy cows and (2) evaluated the efficacy of utilizing reductions in dietary nutrient density and milking frequency to mediate the dry-off process. Forty-eight cows were dried off over a 5-d period approximately 60 d before their expected calving dates. At the start of dry off (d 1), cows were randomly assigned to 1 of 2 total mixed rations that differed in nutrient density: higher nutrient density (HND; n = 24) and lower nutrient density (LND; n = 24). During dry off, cows were milked 1×/d on d 1, 2, and 3 and a final time on d 5. Milk yield, feeding behavior, rumination, lying behavior, and reticulorumen pH were monitored electronically and feed samples were collected to determine feed sorting. Blood samples, body condition scores, and body weights were taken periodically. Across treatments, milk yield was reduced by approximately 10 kg/d during dry off, with cows fed the LND diet producing 0.9 kg less milk at the time of dry off compared with cows fed the HND diet. Cows fed the LND diet consumed 2.2 kg less dry matter per day, fed at a slower rate, spent 15.7 min more feeding, and sorted to a greater extent for the smaller, more nutrient dense components of the diet compared with cows fed the HND diet. Despite sorting activity, cows fed the LND diet ruminated 3.3 min more per kilogram of dry matter consumed and had a mean reticulorumen pH 0.07 units higher compared with cows fed the HND diet. Following the start of dry off, cows spent approximately 5% more of their free time lying down. Dietary transition and dry off similarly affected the energy balance and inflammatory response of cows, although these parameters varied by day after the start of dry off. The results of this study indicate that the LND diet more effectively reduced milk production before dry off compared with the HND diet while not substantially altering cow physiology. [ABSTRACT FROM AUTHOR]

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The effects of 50% or 100% of a herbage diet of plantain on milk production and urinary nitrogen (N) concentration were measured in two experiments for late (autumn 2015) and early (spring 2015) lactation dairy cows. Three groups of 12 mixed age Friesian × Jersey dairy cows were offered a perennial ryegrass-white clover pasture, or pure plantain or 50% perennial ryegrass-white clover and 50% pure plantain by ground area (50–50 pasture–plantain). Urine N concentration was lower in both experiments (P< .001) for plantain (2.4 and 2.2 g N/L) and 50–50 pasture–plantain (3.6 and 3.4 g N/L) than pasture (5.4 and 4.7 g N/L). Cows on plantain or 50–50 pasture-plantain produced at least as much milk as those on pasture in both experiments. Plantain may offer environmental benefits to dairy systems by reducing the N concentration of urine deposited on the soil from grazing cows. [ABSTRACT FROM PUBLISHER]

Despite its low NDF digestibility, sugarcane is an option for feeding dairy cattle in tropical regions. We evaluated the effect of sugarcane silages inoculated with Lactobacillus hilgardii CCMA 0170 (LH; an epiphytic bacteria isolated from sugarcane) or with L. buchneri NCIMB 40788 (LB; a commercial strain isolated from temperate grasses) on dairy cow performance and feeding behavior. The microbial inoculums were previously grown in the laboratory to obtain 5 log cfu/g of fresh forage. Nine tons of each inoculated silage and a noninoculated control silage (CON) were harvested from the same field and stored for at least 35 d in experimental 20 × 2.1 × 0.4 m bunker silos. Fifteen Holstein cows in late lactation (336 ± 175 days in milk at the start of the experiment) received the treatments in five 3 × 3 Latin squares with 21-d periods. The diets contained 20% of DM of sugarcane silage and 41% of DM of corn silage. Milk yield was increased from 18.0 kg/d for CON to18.8 kg/d for LH, but LB did not elicit a detectable increase in milk yield (18.1 kg/d). The daily yields of fat, protein, lactose, and total solids were increased by LH. Daily DMI and total tract apparent digestibility of nutrients did not differ among treatments. Both inoculated silages reduced acetate and increased butyrate proportions in ruminal VFA, but only LH silage reduced the acetate to propionate ratio (3.0 vs. 3.3). First meal duration was shorter for CON compared to LH and LB. The proportion of daily intake between 0700 and 1300 h tended to be increased, and the proportion between 1900 and 0700 h was reduced by LH. The inoculation of sugarcane silage with Lactobacillus hilgardii affected rumen fermentation profile and feeding behavior of late lactation dairy cows, increasing the yield of milk solids. [ABSTRACT FROM AUTHOR]

Herbage feeding with only little input of concentrates plays an important role in milk production in grassland dominated countries like Switzerland. The objective was to investigate the effects of a solely herbage-based diet and level of milk production on performance, and variables related to the metabolic, endocrine and inflammatory status to estimate the stress imposed on dairy cows. Twenty-five multiparous Holstein cows were divided into a control (C+, n = 13) and a treatment group (C−, n = 12), according to their previous lactation yield (4679-10 808 kg) from week 3 ante partum until week 8 post-partum (p.p.). While C+ received fresh herbage plus additional concentrate, no concentrate was fed to C− throughout the experiment. Within C+ and C−, the median of the preceding lactation yields (7752 kg) was used to split cows into a high ( HYC+, HYC−)- and low-yielding ( LYC+, LYC−) groups. Throughout the study, HYC+ had a higher milk yield (35.9 kg/d) compared to the other subgroups (27.2-31.7 kg/d, p < 0.05). Plasma glucose (3.51 vs. 3.72 mmol/l) and IGF-1 (66.0 vs. 78.9ng/ mL) concentrations were lower in HYC−/ LYC− compared to HYC+/ LYC+ cows (p < 0.05). Plasma FFA and BHBA concentrations were dramatically elevated in HYC− (1.1 and 1.6 mmol/l) compared to all other subgroups (mean values: 0.5 and 0.6 mmol/l, p < 0.05). Saliva cortisol, plasma concentrations of serum amyloid A ( SAA), haptoglobin (Hp), beta-endorphin ( BE) and activity of alkaline phosphatase ( AP) were not different between C+ and C−. In conclusion, herbage-fed high-yielding cows without supplementary concentrate experienced a high metabolic load resulting in a reduced performance compared to cows of similar potential fed accordingly. Low-yielding cows performed well without concentrate supplementation. Interestingly, the selected markers for inflammation and stress such as cortisol, Hp, SAA, BE and AP gave no indication for the metabolic load being translated into compromised well-being. [ABSTRACT FROM AUTHOR]

This experiment was conducted to compare conventional (CON; 21 d) and shortened (SH; 10 d) close-up period, and evaluate the effect of shortened close-up period combined with feeding different metabolizable protein (MP) levels on dry matter (DM) intake, metabolic status, and performance of dairy cows. Forty-eight multiparous Holstein cows with similar parity, body weight (BW), and previous lactation milk yield were divided into 2 groups. The first group (n = 24) received the far-off diet from -60 to -21 d (CON), and the second group (n = 24) received same far-off diet from -60 to -10 d (SH) relative to expected parturition. Cows were then moved to individual stalls and randomly allocated to 1 of 3 close-up diets: low MP diet (LMP; MP = 79 g/kg of DM), medium MP diet (MMP; MP = 101 g/kg of DM), or high MP diet (HMP; MP = 118 g/ kg of DM). Treatments were used in a 2 × 3 factorial arrangement with 2 lengths of close-up period (CON and SH) and 3 levels of MP (LMP, MMP, and HMP). All diets were fed for ad libitum intake during the closeup period. After calving, all cows received the same fresh cow diet. We found no interaction between closeup period length and MP levels for traits, except for postpartum serum fatty acids and β-hydroxybutyrate (BHB). The concentrations of postpartum serum fatty acids and BHB were higher on LMP than MMP and HMP diets in SH group. The cows of the SH group tended to produce less colostrum in the first milking than cows in CON group. The length of close-up period did not affect pre- and postpartum DM intake or energy balance of cows during the last week of prepartum, but cows of the CON group had greater BW changes during the last 3 wk before parturition than cows in SH group. Cows fed MMP and HMP diets consumed 1.2 and 1 kg more DM than for those fed LMP prepartum, respectively. The concentrations of prepartum BHB and Ca were higher for SH cows than CON group cows. Except for blood urea N concentration, no other blood metabolite in prepartum was affected by dietary MP. We found no effects of close-up period length or MP levels in the close-up diet on urinary pH, purine derivative excretion, and microbial N flow. Postpartum, milk yield was not affected by close-up period length, but cows in CON group tended to have higher 4% fatcorrected milk yield, had higher milk fat content and yield, had greater BW and body condition score loss, and higher energy negative balance than cows in the SH group. Cows fed MMP diet ate 1.8 kg more DM and yielded 3.37 kg more milk than those fed the LMP diet. Milk fat, protein, and lactose content, milk urea N, and somatic cell count were not affected by MP levels, but the yield of milk protein and lactose were higher on MMP diet than on LMP diet. Concentrations of postpartum serum fatty acids and BHB were decreased by shortening the close-up period length, but glucose, cholesterol, and triglyceride were similar between closeup groups. During the postpartum period, serum fatty acids, BHB, aminotransferase, and Ca concentrations were decreased by increasing the MP levels in the closeup diet. It appears from this data set that multiparous cows will benefit from a shortened close-up period, and feeding a moderate MP diet could improve DM intake, milk yield, and metabolic status of periparturient dairy cows. [ABSTRACT FROM AUTHOR]

The heart rate variability (HRV) parameters of dairy cows were monitored during parlour (PARL) and the later installed automatic (AMS) milking on a small-scale commercial dairy farm in Hungary. The aim of the study was to assess stress in relation to the type of milking and the frequency of human interaction. Parlour milking involved regular moving and crowding of the animals with frequent human interaction, which were much less frequent in automatic milking. The first phase of the study was conducted prior to the changeover [n = 27] and the second two months afterwards [n = 19 (of the cows from the first phase)]. Heart rate (HR) was recorded by the Polar RS800 CX recording system. HRV parameters indicative of sympathovagal balance were calculated for periods of lying and standing in the barn, waiting before milking and milking, respectively. Morning and evening faecal glucocorticoid concentrations were also measured. Fear of humans was tested by an avoidance distance test. Baseline HRV parameters showed no difference (P > 0.05) between the two systems. In the periods before, during and after milking a higher sympathetic tone was detected in cows in the PARL phase. Mean faecal glucocorticoid concentrations were higher at the time of parlour milking. The avoidance distance did not differ between the two phases. The results suggest that automatic milking might be less stressful for cows than parlour milking, possibly due to the shorter duration of restraint after milking and the less frequent human interaction. [ABSTRACT FROM AUTHOR]

Currently, there is a trend in management practices to feed a high concentrate diet to sustain a high level of milk production. The objective of this study was to identify the differences between primiparous (PP) and multiparous (MP) dairy cows fed a high-concentrate diet on feed intake and behavior, rumen pH and rumen fermentation, blood metabolites, inflammation, and milk production and efficiency. Twenty-four PP (DIM =114±20; 43.2±10.6 kg/d of milk; mean±SD) and fifty-four MP (DIM =99±30; 53.2±13.6 kg/d of milk) cows were fed a high-concentrate diet consisting of 35% forage and 65% concentrate mix. The study lasted for 24 d, which consisted of 14 d of environmental adaptation followed by 10 d of data collection. Rumen pH was measured via rumenocentesis for all cows and reticuloruminal pH was measured for a subset of animals (4 PP and 10 MP) using indwelling oral-administered sensors. The PP cows had greater sorting against long particles during the daytime, but greater sorting in favor of long particles at night. The dry matter intake (DMI) between 0 and 4 h after the morning feeding was not affected by parity, whereas PP cows had greater DMI from 4 to 6 h post-feeding and MP cows had greater DMI from 6 to 24 h post-feeding. Total 24-h intake was greater (25.1 vs. 22.4 kg/d) in MP than in PP. Rumen pH and fermentation profile were not affected by parity. Duration of rumen pH <5.8 measured 750 and 570±231 min/d for PP and MP cows, respectively, which indicates that cows experienced rumen acidosis with respective coefficients of variation measuring approximately 8.2% and 10.8%, respectively. Primiparous cows produced less milk (−6.3 kg/d), 3.5% fat corrected milk (−4.2 kg/d), milk protein (−0.160 kg/d), and lactose (−0.230 kg/d). The PP cows, despite lower production, had greater concentrations in plasma of cholesterol, ß-hydroxy-butyrate (BHBA), and blood urea nitrogen and a trend for greater triglyceride than MP cows. Primiparous cows also had lower feed efficiency compared with MP (1.88 vs. 2.03). We conclude from these results that under conditions of the present study, PP dairy cows responded with lower feed efficiency and greater concentration of cholesterol, BHBA, and urea nitrogen in the blood. [ABSTRACT FROM AUTHOR]

Body condition score (BCS) is strongly correlated with energy reserves. The ease, rapidity of scoring, and high intra- and inter-observer repeatability make it a widely used herd management tool in bovine practice and in scientific studies. Loss or gain of BCS, rather than a single BCS measurement, is frequently used to monitor energy balance in dairy cows. It is unknown if the difference between 2 BCS measures taken at different moments (ΔBCS) would demonstrate inter-observer agreement similar to that of a single BCS measurement. The objective of this study was to compare interobserver agreement of BCS and ΔBCS in dairy cows when multiple observers perform data collection. An observational study was conducted between April and September 2015; 3 observers independently assessed BCS of 73 Holstein cows from 1 commercial dairy herd. Body condition score assessments of the animals were performed between 1 and 20 d in milk (early lactation; exam 1) and again between 41 and 60 d in milk (peak of milk production; exam 2). Quadratic weighted kappa (κw) was computed to quantify agreement between observers for single BCS measurements and ΔBCS. For single BCS measurements, κw of 0.79 (95% CI: 0.69, 0.85) and 0.84 (95% CI: 0.77, 0.89) were obtained for exam 1 and exam 2, respectively. Such values would be interpreted as strong agreement and are consistent with the available literature on BCS repeatability. When computing agreement for ΔBCS, a κw value of 0.49 (95% CI: 0.32, 0.63) was obtained, suggesting moderate agreement between observers. These findings suggest that studies investigating single BCS measures could use many observers with a high degree of accuracy in the results. When ΔBCS is the parameter of interest, more reliable results would be obtained if one observer conducts all assessments. [ABSTRACT FROM AUTHOR]

The purpose of the paper is to investigate the impact of physiological and environmental factors on milk productivity by using artificial intelligence (AI). The model will be useful for the user to decide the best cow treatment in order to gain the best milk production. The research starts with a literature review and an early survey of cattle physiological, environment factors and milk productivity. The next step is measuring the environment data (temperature, wind speed, noise level and relative humidity) and measuring the physiological aspect (heart rate, body temperature) correlated with the milk productivity in 500 pairs of data. All the data are collected and stored into the database and then trained and validated using Back Propagation Neural Network (BPNN) with Genetic Algorithm (GA) optimization. The initial BPNN architectures are selected in 2 hidden layers, delta bar delta learning rule, sigmoid transfer function and epoch 10000. The sensitivity analysis of all independent factors with temperature, relative humidity, core body temperature and heart rate in milk production are successfully presented. Finally, the research successfully increases cow milk production at an average = 0.96 kg/day. [ABSTRACT FROM AUTHOR]

Cows are often shown at dairy shows with overfilled udders to achieve a better show placing. However, it is unclear to what degree "over-bagging" affects the health and well-being of show cows. The goal of this study was to assess the effect of a single prolonged milking interval (PMI) of 24 h on the measurable signs of health and well-being in dairy cows in early and mid-lactation and to assess the effect of a nonsteroidal anti-inflammatory drug (NSAID) on well-being during a PMI. Fifteen Holstein cows were studied in early lactation (89.5 ± 2.7 d in milk) and were given an NSAID or physiological saline in a crossover design. Ten cows were studied again in mid-lactation (151.6 ± 4.0 d in milk). Data on clinical signs of cows' health, behavior, and well-being were collected at 1 or 2 h intervals before and during a PMI of 24 h. Data from the last 6 h of a 12 h milking interval were compared with the last 6 h of the PMI. Compared with that of a cow in the last 6 h of a 12-h milking interval, the behavior of cows in early lactation (saline group) changed during the last 6 h of the PMI: we observed decreased eating time (22.4 vs. 16.2 min/h), increased ruminating time (13.3 vs. 25.0 min/h), and increased hind limb abduction while walking (score 41.7 vs. 62.6) and standing (31.2 vs. 38.9 cm). Udder firmness was increased (2.9 vs. 4.5 kg) during this period and more weight was placed on the hind limbs (46.4 vs. 47.0%). We also found pathological signs at the end of the PMI: all cows showed milk leaking, and 10 of 15 cows developed edema in the subcutaneous udder tissue. Somatic cell count was significantly increased from 12 h to 72 h after the PMI. Administration of an NSAID had no influence on measured variables, except that the occurrence of edema was not significantly increased during PMI in the flunixin group (10 of 15 and 6 of 15 cows for the saline and flunixin groups, respectively). In the cows in mid-lactation, different variables were not significantly changed in the PMI compared with baseline values (e.g., eating and ruminating time, occurrence of edema, and abduction). We conclude that the cows' health and well-being were compromised by a single PMI of 24 h, because their behavior changed and pathological signs were recorded. Administration of an NSAID had a slight effect on cows' well-being during a PMI. The stage of lactation had more effect on the cows' health and well-being, because fewer variables were changed in mid-lactation. [ABSTRACT FROM AUTHOR]

Cashew nut shell liquid (CNSL) and castor oil (CO) are considered functional oils since they present antitumor, antioxidant, gastroprotective, and antibiotic properties. The objective of this study was to evaluate the effects a commercial blend of functional oils (CNSL and CO) and monensin supplementation on nutrient intake and total tract apparent digestibility, ruminal fermentation, milk yield and composition, N utilization, microbial protein synthesis, and blood metabolites of dairy cows. Twenty-four multiparous Holstein cows (150.2 ± 61.4 days in milk, 619 ± 76 kg of BW and 29.1 ± 4.0 kg/d of milk yield, mean ± SD) were used in a replicated 3 × 3 Latin square experimental design, in which six ruminally cannulated cows were used to assess ruminal fermentation. The animals were randomly assigned to one of the following three treatments: control (CON; without additive); 500 mg/kg DM of functional oil (FO; commercial blend of CNSL and CO), and 22 mg/kg DM of monensin sodium (MON). The treatments did not affect either nutrient intake or digestibility of diets. Both feed additives provided an increase in ruminal propionate molar proportion compared to CON. In addition, FO increased ruminal propionate concentration when compared to MON and CON. Although both additives increased (P < 0.01) milk and protein yields, MON had lower milk fat concentration compared to CON, not differing from FO. Monensin and FO increased milk nitrogen excretion. Neither rumen microbial N synthesis nor blood glucose concentration were changed by the supplements. Finally, FO decreased (P < 0.001) blood urea concentration compared to CON or MON, besides increasing milk yield without altering nutrient intake; thus, it might be an alternative to monensin in lactating cow diets. [ABSTRACT FROM AUTHOR]

Differing soya bean particle sizes may affect productive performance and ruminal fermentation due to the level of fatty acid ( FA) exposure of the cotyledon in soya bean grain and because the protein in small particles is more rapidly degraded than the protein in large particles, which influence ruminal fibre digestion and the amounts of ruminally undegradable nutrients. The objective of this experiment was to investigate the effects of raw soya bean particle size on productive performance, digestion and milk FA profile of dairy cows. Twelve Holstein cows were assigned to three 4 × 4 Latin squares with 21-day periods. At the start of the experiment, cows were 121 days in milk ( DIM) and yielded 30.2 kg/day of milk. Cows were fed 4 diets: (i) control diet ( CO), without raw soya bean; (ii) whole raw soya bean ( WRS); (iii) cracked raw soya bean in Wiley mill 4-mm screen ( CS4); and (iv) cracked raw soya bean in Wiley mill 2-mm screen ( CS2). The inclusion of soya beans (whole or cracked) was 200 g/kg on dry matter ( DM) basis and partially replaced ground corn and soya bean meal. Uncorrected milk yield and composition were not influenced by experimental diets; however, fat-corrected milk ( FCM) decreased when cows were fed soya bean treatments. Soya bean diets increased the intake of ether extract ( EE) and net energy of lactation ( NEL), and decreased the intake of DM and non-fibre carbohydrate ( NFC). Ruminal propionate concentration was lower in cows fed WRS than cows fed CS2 or CS4. Cows fed cracked raw soya bean presented lower nitrogen in faeces than cows fed WRS. The milk of cows fed WRS, CS2 and CS4 presented higher unsaturated FA than cows fed CO. The addition of raw soya bean in cow diets, regardless of the particle size, did not impair uncorrected milk yield and nutrient digestion, and increased the concentration of unsaturated FA in milk. Cows fed cracked raw soya bean presented similar productive performance to cows fed whole raw soya bean. [ABSTRACT FROM AUTHOR]

A total of 2,484 lactations in 760 Polish Holstein-Friesian cows were analysed. Calculations were made of length of life, length of productive life, total number of days in milk, number of calvings, ratio of days in milk to length of productive life, lifetime milk yield (kg), daily yield at the peak of lactation (kg) and lactation persistency as the percentage difference between daily milk production in the 2nd and 10th month in milk. The cows were divided into three groups according to lactation persistency (decrease in production): group I - up to 30%, group II - 30.1-50% and group III - over 50%. Lactation persistency significantly influenced (P≤0.01) length of life and efficiency of milk production in the analysed cow population. Cows with yield over 30 kg at the peak of lactation followed by a moderate decrease (40%) lived longest (over 6 years) and produced the most milk (nearly 28,000 kg). Yield of primiparous cows at the peak of lactation and its course were found to have a significant effect on length of life and lifetime milk production. The long period of high peak yield (over 30 kg of milk) in the primiparous cows in group I (with the best lactation persistency) in the long term proved to be detrimental, as these cows had the shortest productive life (2.3 lactations on average) and lifetime milk yield about 4,000 kg lower than in the cows in groups II and II (with the poorer lactation persistency). [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of blood and milk zinc concentration on milk somatic cell count and occurrence of subclinical mastitis cases. The study was performed on thirty Holstein cows approximate same body weight, ages 3 to 5 years, with equally milk production. Blood samples were taken after morning milking from the caudal vein. Milk samples were taken before morning milking. Zinc concentration was determined from blood and milk by inductively coupled plasma mass spectrometry. 37.67% cows have zinc blood serum concentration below 7μmol/l, and 63.33% cows have zinc blood serum concentration higher then 13μmol/l. Also 30% cows have somatic cell count lower then 400.000/ml which indicate absence of subclinical mastitis, but 70% cows have somatic cell count higher than 400.000/ml which indicate subclinical mastitis. Results indicate that cows with level of zinc in blood serum higher then 13µmol/l have lower somatic cell count. Cows with lower zinc blood serum concentration then 7μmol/l have high somatic cell count and high incidence of subclinical mastitis. According to results in this research there is no significant effect of milk serum zinc concentration on somatic cell count in dairy cows. [ABSTRACT FROM AUTHOR]

The study was conducted to investigate the effect of α-tocopherol acetate and zinc on body condition, energy metabolites and milk production in Karan Fries cows. Sixteen pregnant Karan Fries cows were selected two months before expected date of calving. The experimental animals were randomly divided in to two groups namely control group (eight cows) and treatment group (eight cows). Treatment group cows were supplemented with a-tocopherol acetate @ 1000 IU/day/cow and zinc @ 60 ppm/day/cow. Blood samples were collected on the days -60, -45, -30, -15, -7, 0, +7, +15, +30, +45 and +60 with respect to expected date of calving. The body weight and body condition score of all the experimental animals was recorded on the day of blood collection. After calving milk yield of the experimental animals was recorded till 60 days in milk. At parturition, body weight and body condition score differ significantly (P<0.001) in treatment group than control group (448.00 vs. 416.33 Kg and 4.42 vs. 4.17, respectively). The overall mean (±SEM) of plasma glucose was found to be significantly (P<0.001) higher in treatment group as compared to control group (62.39±1.23 vs. 57.44±1.59 mg/dl). The overall mean of non-esterified fatty acids was found to be significantly (P<0.001) lower in treatment group as compared to control group (197.10±3.38 vs. 239.21±3.48 μM/L). The overall mean of milk yield was found significantly (P<0.001) higher in treatment group as compared to control group (20.48±1.16 vs. 16.94±1.38 Kg/day i.e. 20.90%). The results of this study indicated that supplementation of antioxidants like α-tocopherol acetate and zinc have beneficial effects on milk production along with improved body condition and metabolic status of the animals. [ABSTRACT FROM AUTHOR]

The objective of the present study was to determine the effects of feeding pelletized broccoli byproducts (PBB) on milk yield and milk composition in dairy cows. In Trial 1, an in vitro gas test determined the optimal replacement level of PBB in a concentrate mixture in a mixed substrate with Chinese wild ryegrass hay (50:50, w/w) at levels of 0, 10%, 20%, 30%, or 40% (dry matter basis). When the concentrate was replaced by PBB at a level of 20%, no adverse effects were found on the gas volume or its rate constant during ruminal fermentation. In trial 2, 24 lactating cows (days in milk = 170.4±35; milk yield = 30±3 kg/d; body weight = 580 ±13 kg) were divided into 12 blocks based on day in milk and milk yield and randomly allocated to two dietary treatments: a basic diet with or without PBB replacing 20% of the concentrate mixture. The feeding trial lasted for 56 days; the first week allowed for adaptation to the diet. The milk composition was analyzed once a week. No significant difference in milk yield was observed between the two groups (23.5 vs 24.2 kg). A significant increase was found in milk fat content in the PBB group (p<0.05). Inclusion of PBB did not affect milk protein, lactose, total solids or solids-not-fat (p>0.05). These results indicated that PBB could be included in dairy cattle diets at a suitable level to replace concentrate mixture without any adverse effects on dairy performance. [ABSTRACT FROM AUTHOR]

The main objective of this experiment was to study the γ-glutamyl transferase (GGT) activity in milk during lactation and its relationship with metabolic status of dairy cows, milk yield, milk composition, and cheesemaking properties. The study was performed in a tied stall barn and involved 20 lactations from 12 healthy multiparous Italian Friesian dairy cows. During lactation starting at d 10, milk samples were collected weekly and analyzed for composition, somatic cells count, titratable acidity, and milk coagulation properties. The GGT activity was measured in defatted samples. Blood samples were collected weekly to assess biochemical indicators related to energy, protein, and mineral metabolism, markers of inflammation and some enzyme activities. The lactations of each cow were retrospectively categorized into 2 groups according to their milk GGT activity value through lactation. A median value of GGT activity in the milk of all lactations was calculated (3,045 U/L), and 10 lactations with lower GGT activity were classified as low while 10 lactations with greater GGT activity were classified as high. The average value of milk GGT activity during lactation was 3,863 and 3,024 U/L for high and low, respectively. The GGT activity decreased in early lactation and reached minimum values in the second month (3,289 and 2,355 U/L for high and low, respectively). Thereafter GGT activity increased progressively, reaching values in late lactation of 4,511 and 3,540 U/L in high and low, respectively. On average, milk yield was 40.81 and 42.76 kg/d in high and low, respectively, and a negative partial correlation with milk GGT activity was observed. A greater milk protein concentration was observed in high (3.39%) compared with low (3.18%), and a positive partial correlation with milk GGT activity was observed. Greater titratable acidity in high than that in low (3.75 vs. 3.45 degrees Soxhlet-Henkel/50 mL, respectively) was also observed. Plasma glucose was greater in cows of high than in low group, while plasma urea was lower in the high than in the low group. No relationship between plasma GGT and milk GGT activity was observed. Our results show an important effect of lactation stage on milk GGT activity. The individual effect observed from consecutive lactations and the relationship between milk GGT activity and milk protein concentration in healthy cows could open prospects for GGT as a future tool in improving milk protein content. [ABSTRACT FROM AUTHOR]

Considering the clinical benefits derived from the extensive morphological data existing in relation to the vascularisation of the udder in various milk cow breeds, our study focused on assessing the venous vascularisation of the udder in buffalo cows. Ten adult female buffalo cow udders were sampled, their vascularisation highlighted by arterial injection of a coloring agent, then fixed in a 2% formalin solution for 24 hours. The venous vascular system was identified by stratigraphic dissection under a magnifying glass and examined. We have identified common venous trunks for the homolateral anterior and caudal quarters and perforating veins going through the median septum. In 7 out of 10 examined udders, teat and parenchyma veins merged into a venous circle for each caudal quarter, both of them merging caudally with the greater venous circle at the base of the udder. 5 out of 10 samples also presented secondary venous circles around each anterior quarter. The results of the present study indicate a proportionally better developed venous vascularisation of the caudal quarters in the buffalo cow, correlated with a higher milk production at this level; a superior number of veins and a higher occurrence of venous circles at this level illustrate this aspect. However, the udder presents a unified venous drainage, as superficial veins of homolateral quarters merge, and the median suspensory ligament is traversed by perforating veins. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of two different forage sources on mammary gland growth, mammary cell turnover and activity in early lactation dairy cows. Twelve early lactation cows were randomly assigned to a CS (33.8% corn straw as sole forage) or MF diet (3.7% Chinese wildrye + 28.4% alfalfa hay + 26.5% corn silage as mixed forage). All cows were fed from Week -3 to Week 8, and mammary biopsies were taken on 16 days postpartum. Mammary cell proliferation and apoptosis were determined by immunohistology, and genes expression in mammary were detected by real-time PCR. Results showed that cell proliferation, gene expression of milk proteins and proteins involved in the synthesis of milk components did not differ between two dietary treatments (P > 0.05). However, cows fed the MF diet had a higher IGF-1 receptor (IGF-1R) expression (P = 0.02), and lower rate of cell apoptosis (P = 0.003) relative to cows fed the CS diet. Collectively, these results suggest that the mammary secretory activity probably was not affected by the dietary treatments, but high quality and mixed forages led to the increased expression of IGF-1R and a larger number of cells in mammary glands, which may be responsible for the higher milk production in early lactation dairy cows. The forage system is critically important to lactation performance in dairy cows. Our results suggested that the expression of IGF-1R in the mammary glands and the number of mammary cells is significantly affected by forage system, and this is closely related to the milk production in early lactation cows. This research provided the basis for better understanding of the molecular mechanisms of lactation regulation. [ABSTRACT FROM AUTHOR]

High ambient temperatures have severe adverse effects on biological functions of high-yielding dairy cows. The metabolic adaption to heat stress was examined in 14 German Holsteins transition cows assigned to two groups, one heat-stressed (HS) and one pair-fed (PF) at the level of HS. After 6 days of thermoneutrality and ad libitum feeding (P1), cows were challenged for 6 days (P2) by heat stress (temperature humidity index (THI) = 76) or thermoneutral pair-feeding in climatic chambers 3 weeks ante partum and again 3 weeks post-partum. On the sixth day of each period P1 or P2, oxidative metabolism was analyzed for 24 hours in open circuit respiration chambers. Water and feed intake, vital parameters and milk yield were recorded. Daily blood samples were analyzed for glucose, β-hydroxybutyric acid, non-esterified fatty acids, urea, creatinine, methyl histidine, adrenaline and noradrenaline. In general, heat stress caused marked effects on water homeorhesis with impairments of renal function and a strong adrenergic response accompanied with a prevalence of carbohydrate oxidation over fat catabolism. Heat-stressed cows extensively degraded tissue protein as reflected by the increase of plasma urea, creatinine and methyl histidine concentrations. However, the acute metabolic heat stress response in dry cows differed from early-lactating cows as the prepartal adipose tissue was not refractory to lipolytic, adrenergic stimuli, and the rate of amino acid oxidation was lower than in the postpartal stage. Together with the lower endogenous metabolic heat load, metabolic adaption in dry cows is indicative for a higher heat tolerance and the prioritization of the nutritional requirements of the fast-growing near-term fetus. These findings indicate that the development of future nutritional strategies for attenuating impairments of health and performance due to ambient heat requires the consideration of the physiological stage of dairy cows. [ABSTRACT FROM AUTHOR]

The objective of this study was to estimate genetic and phenotypic parameters for linear type traits, as well as milk yield (MY), fat yield (FY) and protein yield (PY) in 18,831 Holstein cows reared in 495 herds in Brazil. Restricted maximum likelihood with a bivariate model was used for estimation genetic parameters, including fixed effects of herd-year of classification, period of classification, classifier and stage of lactation for linear type traits and herd-year of calving, season of calving and lactation order effects for production traits. The age of cow at calving was fitted as a covariate (with linear and quadratic terms), common to both models. Heritability estimates varied from 0.09 to 0.38 for linear type traits and from 0.17 to 0.24 for production traits, indicating sufficient genetic variability to achieve genetic gain through selection. In general, estimates of genetic correlations between type and production traits were low, except for udder texture and angularity that showed positive genetic correlations (>0.29) with MY, FY, and PY. Udder depth had the highest negative genetic correlation (-0.30) with production traits. Selection for final score, commonly used by farmers as a practical selection tool to improve type traits, does not lead to significant improvements in production traits, thus the use of selection indices that consider both sets of traits (production and type) seems to be the most adequate to carry out genetic selection of animals in the Brazilian herd. [ABSTRACT FROM AUTHOR]

Background: Alterations in energy demands during different physiological states of dairy cows predispose them to metabolic disorders. Insulin as a main metabolic hormone has a key role to maintain homeorhesis in dairy cows. Insulin resistance phenomenon can expose these animals to metabolic dysfunctions. Information regarding insulin resistance at each physiological state of high producing dairy cows can assist veterinarians to control and prevent the metabolic disorders at herd levels. Materials, Methods & Results: This research was carried out at winter 2014 on 25 multiparous Holstein dairy cows from a high producing industrial dairy farm. The total mixed rations were formulated and prepared for all animals according to National Research Council (NRC) requirements. At this farm, a dry period of 60 days has been considered. Milk production was about 10,000 kg for year, an average of 3.6 of milk fat %, and 3.3 of milk protein %. All the animals were clinically healthy and body condition score (BCS) was estimated based on 0 to 5 system. Cattle were divided into 5 equal groups containing early, mid and late lactations, far-off and close-up dry periods. A blood sample was taken immediately after catheterization, and dextrose 50% was administered at 500 mg/kg, 10 mL/kg/h, subsequently. Blood samples were collected from all cows through the fixed catheter prior to and 1, 2, 3 and 4 h after dextrose 50% infusion in plain tubes. After sera separation, glucose and insulin were detected in all samples. Significant and rapid elevation of serum glucose and insulin concentrations were seen in all studied animals at 1st h after dextrose administration (P < 0.05). Decreasing the glucose level near to base line levels was seen at h 4 in late lactation and far-off dry cows. The glucose level at this time was remained significantly higher than h zero in other groups (P < 0.05). In early, mid and late lactation and close-up dry cows, insulin levels at h 4 were remained significantly higher than base line values (P < 0.05). Discussion: Cows during the early far-off dry period are experiencing relatively low metabolic demands as fetal growth is just beginning to accelerate and cows are no longer lactating. Fetal and uterine tissues are insulin-independent and so as energy demands increase with days of pregnancy, maternal peripheral tissues will become more insulin resistant in order to support fetal growth. These changes in the role of insulin have effects on energy metabolism in dry cows. Although pregnant dairy cows had essentially the same basal insulin levels as the lactating and non-pregnant non-lactating dairy cows, the amount of insulin secreted during infusion of glucose or propionate was higher in pregnant cows than in the lactating and non-pregnant non-lactating cows. The significant increasing patterns of insulin and glucose were seen after dextrose infusion in early lactation dairy cows (P < 0.05). In the mid-lactation group the glucose at 4th h was significantly remained at higher levels than base line values. These findings indicate the presence of insulin resistance in early and mid lactation dairy cows. It was reported that insulin clearance rates had a tendency to decrease during the postpartum period. The reduced clearance of glucose observed at post partum was due to a greater degree of insulin resistance which gave rise to more pronounced net lipolysis from the adipocytes. These qualitative changes in metabolism occurring during lactation are necessary to support a homeostatic state. Despite the presence of high concentrations of insulin, high levels of glucose were seen in early and mid-lactation and close-up dry cows. The insulin resistance was found in early and mid lactation and close-up dry cows. It could be concluded that high energy demands to lactogenesis and suffering from the negative energy balance are the main reasons of insulin resistance in high producing Holstein dairy cows. [ABSTRACT FROM AUTHOR]

In this study, 288 milk samples were collected randomly from individual farms in Qazvin province from March to February 2012, Iran. Samples were analysed for Aflatoxin M1 (AFM1) by ELISA; also the Aflatoxin B1 (AFB1) contamination in animal feed was determined at the same time as the sampling of raw milk. One hundred and sixty-three samples (56.59%) were found to contain AFM1 at various levels; the presence of AFM1 was detected in a concentration ranging between 0.01 and 0.22 ppb. In 113 (69.32%) of the 163 milk samples, AFM1 levels were found to be higher than the maximum tolerable limit (0.05 ppb) accepted by the European union/Codex Alimentarius Commission. The mean AFM1 contamination levels in milk in summer and winter were 0.08 and 0.18 ppb, respectively. The AFB1 contamination level in the winter feed (2.27 ± 1.76) was higher than from summer (0.83 ± 0.60) (P< 0.05). [ABSTRACT FROM AUTHOR]

This summer study evaluated the effect of providing additional fans (cooling) in the resting area within a free-stall dairy barn that had fans and sprinklers in the feeding area and paddock availability. Thirty cows were divided into two homogenous groups and kept in two pens: one had the resting area equipped with two fans (FAN) while no fans were added to the other resting area (CON). Microclimatic parameters, rectal temperature (RT), breathing rate (BR), milk yield, and milk pH traits were recorded. Time budgeting and the behaviour of the cows (time spent in the feeding area, standing and lying in other areas) were also recorded using digital video technology. Two slight-to-moderate heat waves were observed. During the hottest period the daily maximum temperature recorded was 33.5 °C and the daily maximum THI was 81.6. During this period, the BR and RT increased only slightly in both groups, with lower BR (n.s.) in FAN compared with CON. Milk yield was better maintained (n.s.) in FAN compared with CON during the hottest period. The FAN cows showed a greater ( P < 0.05) lying time in the free stalls (9.5 and 8.6 h/day in FAN and CON, respectively), whereas CON cows made greater ( P < 0.05) use of the paddock during evening and late evening hours. Consequently, the total daily lying time was 13.5 h/day in both groups. In conclusion, the results suggest that using fans in the resting area improves cow comfort, which increases use of the resting area. The lying time results also suggest that the benefits of providing ventilation in the resting area might be more evident in barns where there is no paddock. [ABSTRACT FROM AUTHOR]

The evaluation of red bean hulls ( RBH) as a non-forage fiber source on ruminal mat formation, chewing activity and milk production was determined using two experiments. In experiment 1, four non-lactating, rumen-cannulated Holstein cows were offered a control diet of 60.1% forage, and an RBH diet of 51.6% forage and 9.4% RBH. Although the neutral detergent fiber ( NDF) intake was higher with the RBH diet than the control diet, the physically effective NDF (pe NDF) intake was lower. The rumination period tended to be longer with the RBH diet than with the control diet and the ruminal mat was formed even when the RBH diet was consumed. Ruminal fermentation parameters were not affected by treatment. In experiment 2, 40 lactating cows were fed a control diet of 53.4% forage or an RBH diet of 50.3% forage and 8.1% RBH. Dry matter intake, chewing activity and milk production were not affected by diet. Cows sorted against NDF in the control diet, but not in the RBH diet. It is concluded that normal ruminal function can be maintained because the ruminal mat was stratified and rumination activity was not reduced even when a low pe NDF diet that contained RBH was given to dairy cows. [ABSTRACT FROM AUTHOR]

Abstract: Previous work has hypothesised that cows in low body condition become lame. We tested this in a prospective longitudinal study. Body condition score (BCS), causes of lameness and milk yield were collected from a 600-cow herd over 44-months. Mixed effect binomial models and a continuous outcome model were used to investigate the associations between lameness, BCS and milk yield. In total, 14,320 risk periods were obtained from 1137 cows. There were 1510 lameness treatments: the most common causes of lameness were sole ulcer (SU) (39%), sole haemorrhage (SH) (13%), digital dermatitis (DD) (10%) and white line disease (WLD) (8%). These varied by year and year quarter. Body condition was scored at 60-day intervals. BCS ranged from 1 to 5 with a mean of 2.5, scores were higher in very early lactation but varied widely throughout lactation; approximately 45% of scores were <2.5. The key finding was that BCS<2.5 was associated with an increased risk of treatment for lameness in the following 0–2 months and >2–4 months for all causes of lameness and also specifically for SU/WLD lameness. BCS<2.5 was associated with an increased risk of treatment for SH in the following 0–2 months but not >2–4 months. There was no such association with DD. All lameness, SU/WLD, SH and DD were significantly more likely to occur in cows that had been lame previously, but the effect of BCS was present even when all repeat cases of lameness were excluded from the analysis. Milk yield was significantly higher and fell in the month before treatment in cows lame with SU/WLD but it was not significantly higher for cows that were treated for DD compared with non-lame cows. These findings support the hypothesis that low BCS contributes to the development of horn related claw lameness but not infectious claw diseases in dairy cows. One link between low BCS and lameness is a thin digital cushion which has been proposed as a trigger for claw horn disease. Cows with BCS 2 produced more milk than cows with BCS 2.5, however, this was only approximately 100kg difference in yield over a 305-day lactation. Given the increased risk of lameness in cows with BCS 2, the direct costs of lameness and the small variability in milk yield by BCS, preventing cows from falling to BCS<2.5 would improve cow welfare and be economically beneficial. [Copyright &y& Elsevier]

Metabolizable protein (MP) supply and amino acid balance were manipulated through selection of highly digestible rumen-undegradable protein (RUP) sources. Effects on production efficiency and N utilization of early post-partum dairy cows were determined. Forty-two multiparous and 16 primiparous Holstein cows were assigned to the diets in a randomized complete block design immediately after parturition with 3-wk experimental periods, and then were fed a ration for 120 days in milk. Diets were formulated to provide 3 concentrations of dietary RUP (LRUP 6.65, MRUP 7.72 and HRUP 8.79% of dry matter (DM)) while rumen- degradable protein remained constant (11.3% of DM). Diets contained 26.30% alfalfa hay, 12.60% corn silage, 9.50% sugar beet pulp and 51.5% concentrate in DM basis. Ingredients within the diets were equal across treatments except for fish meal and corn gluten meal that partially replaced with steam rolled barley and soybean meal. Dry matter intake linearly increased by the treatments. Milk yield, Fat corrected milk (FCM) and protein content and yield increased significantly when cows were fed the diets with greater RUP, but milk fat and lactose was not different between treatments. Body weight (BW) changes was improved with intake of high RUP but Body condition score (BCS) changes had significant difference and improved by increasing RUP in the diet. The efficiency of N use increased linearly. Milk urea N and predicted urinary N increased linearly when cows were fed higher amounts of RUP, but differences between the control treatment and high RUP diets were not significant. Fecal N and N balance did not have significant difference. Total tract digestibility of DM and crude protein (CP) intakes increased significantly with greater RUP. In general, increasing amounts of MP and RUP improved productive performance and BCS status of fresh cows and enhanced digestibility of DM and CP. [ABSTRACT FROM AUTHOR]

In this study, the incomplete gamma function, an exponential function, a mixed-log function and a polynomial function were evaluated to describe the lactation curve in Moroccan Holstein-Friesian dairy cows. Data from 1990 to 1999, comprising 77130 monthly milk yields of 6029 dairy cows in 280 dairy herds, were used. Edits were carried out by considering the lactation length (<305 d), days in milk (DIM) at which the first test-day was recorded (>5 d and <50 d) and the interval between two consecutive recordings (<60 d). The models were compared based on the mean square error, the adjusted coefficient of determination and the estimated difference between actual and predicted milk yields. The estimated mean square errors of the models were slightly equal differing only in the first decimal for the incomplete gamma function (33.8) and for the other three models (33.7). The adjusted coefficient of determination was estimated to be 0.18 in the exponential function, mixed-log function and polynomial function but 0.91 for the incomplete gamma function. The estimated difference between actual and predicted milk yields was zero for all the models. It was concluded that all models provided an acceptable level of accuracy in describing the shape of the lactation curve for Moroccan Holstein-Friesian dairy cows, but Wood model is observed to be the most suitable. [ABSTRACT FROM AUTHOR]

Successful pasture-based milk production systems pivot on balancing dairy cows' feed requirements with seasonal and annual fluctuations in pasture production. In order to maximise cow production from grazing dairy systems, it is necessary to reach an efficient utilization of grazed grass for feeding cows and the development of appropriate grazing management systems designed to maximize daily pasture dry matter intake (PDMI) per cow and per hectare, while maintaining high sward quality over the grazing season by keeping high pasture levels of crude protein, water soluble carbohydrates and digestibility of organic matter and low levels of acid and neutral detergent fibers in the swards. To maximize PDMI, cows need to consume plants that have characteristics that allow rapid consumption and lead to fast rates of passage through the rumen. This review considers the role of sward factors which affect the short-term feed budget of cows at pasture and, therefore, condition cow feed requirements at grazing and influence on PDMI. Furthermore, it highlights the relevance that have for the development of pasture-based milk production systems the study of the species of grasses and / or legumes that integrate the pastures, the changes on sward structure, the seasonality in grass production, the pasture chemical constituents, the sward botanical composition, the grass feeding value, the digestibility of pastures, the intensity of sward defoliation, and the importance of sward height and herbage mass in relation to maximizing PDMI. The amount of herbage consumed is the major determinant of cow production but it is yet one of the most difficult aspects of forage quality to predict. In this review, three methods for PDMI calculation are presented as faecal output/diet digestibility method, sward difference method and the grazing-behaviour method. Also, three equations for PDMI estimation are described considering different sward and animal variables. [ABSTRACT FROM AUTHOR]

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The milking machine can transmit infection onto teats and disturb normal teat health. Milking-time tests allow advisors to quantify the degree to which the milking machine might be contributing to the risk of new intra-mammary infection. Cows' teat size and position have changed as have milk flow rates. Milk yields have been rising faster than unit attachment times. Milk flow rate has been shown to be positively associated with risk of new intra-mammary infection. Vacuum traces collected during milking can illustrate problems with biphasic milk flow or over milking and pressure records can help assess liner function. Lightweight data logging equipment is now available with excellent software to assist with interpretation. [ABSTRACT FROM AUTHOR]

Analysis was made of the relationship between conformation traits and lifetime production efficiency of the cows that first calved in 2000 and represented the active population in the Pomorze and Kujawy regions of Poland. The CORR Pearson procedures of SAS package were used in the statistical calculations. It was found that there is a statistically significant relationship, weak or low on the Guilford scale, between conformation traits and lifetime production efficiency of the cows, which is slightly higher for milk yield than for longevity. The type and conformation traits appear to be more suitable than the detailed traits for predicting the lifetime production efficiency of cows. Lifetime performance was most strongly related to the overall score and udder score (r = 0.22), followed by the scores for type and conformation and legs and feet (r = 0.13), and detailed traits such as udder width and dairy character (r = 0.14). The highest positive effect on longevity was exerted by udder score and legs and feet (r = 0.11) and among detailed traits by udder placement (r = 0.14) and fore udder attachment (r = 0.10). [ABSTRACT FROM AUTHOR]

Ferulic acid (FRA), a phenolic compound with antioxidant and anticancer activities, naturally occurs in plants as a lignin precursor. Many veins of research have been devoted to releasing FRA from the lignin complex to improve digestibility of ruminant feeds. Thus, the objective of this research was to investigate the transfer of a given dosage of the free form of FRA into the milk of dairy cattle. Six mid- to late-lactation Holstein cows at the Cornell Research Farm (Harford, NY) were given 14-d adaptation to diet and stall position. Ad libitum access to a total mixed ration based on haylage and maize silage (31.1% neutral detergent fiber containing 5.52 mg of FRA/g) was provided during the study. A crossover design was implemented so that each cow alternated weekly between FRA-dosed and control. On d 1, jugular cannulas and urine catheters were placed in all cows. On d 2, FRA-dosed cows received a single dosage of 150 g of pure FRA powder at 0830 h via their fistula (n = 4) or a balling gun for nonfistulated cows (n = 2). Plasma, urine, feces, feed, orts, milk, and rumen fluid were sampled intensively for the next 36 h and analyzed for FRA concentration. On d 8, the cows crossed over and the experiment was repeated. When compared with the control, FRA administration did not have an effect on dry matter intake, milk yield, milk fat yield, milk protein yield, somatic cell count, or neutral detergent fiber content of orts and feces. The concentration of FRA in the feces did not change as a result of FRA dosage. As expected, FRA concentration increased dramatically upon FRA dosage and decreased over time until returning to basal levels in rumen fluid (4 h after dosage), plasma (5.5 h after dosage), urine (10 h after dosage), and milk (14 h after dosage). Baseline values for FRA in urine and rumen fluid were variable among cows and had an effect on FRA concentration in FRA-dosed cows. From this study, it is observed that orally ingested FRA can be transported into the milk and that the physiological transfer of FRA occurs from rumen to milk within 6.5 h or the first milking after dosage. Ferulic acid may affect the functionality of milk due to its antioxidant, anticancer, and antibacterial activities. Future research will be required to elucidate whether FRA in milk is bioavailable and bioactive, and to evaluate the complete sensory and microbiological effects of increased FRA and FRA degradation products in milk. [ABSTRACT FROM AUTHOR]

Heat stress generates a significant economic impact for the dairy industry in arid and semi-arid regions of the world, so that heat abatement is an important issue for dairy producers. The objective of this study was to evaluate effects of two short-term cooling periods on physiological and productive status of lactating Holstein cows during hot ambient temperatures. Thirty-nine multiparous cows were blocked by milk yield and assigned to one of three treatments including: control group (C), cows cooled before milking time (0500 and 1700 h daily, 1 h cooling); AM group, cows cooled at 1000 h and before milking (2 h cooling); and AM + PM group, cows cooled at 1100, 1500 and 2200 h, as well as before milking (4 h cooling). The cooling system was placed in the holding pen which the cows were moved through for cooling. Respiratory rate, and temperatures of thurl and right flank, were lower ( P < 0.05) in cows from the AM + PM group than AM and C cows during the morning and afternoon. However, udder temperature was higher in the AM + PM group compared to AM and C groups during the afternoon, although lower than the AM group during the morning. Rectal temperature was similar in all groups. Thyroxin concentrations tended ( P < 0.10) to be lower in AM + PM relative to the AM and C groups. The AM + PM group had higher ( P < 0.05) milk production than C (18.70 vs. 17.43 kg, respectively), and AM + PM cows had a trend ( P < 0.10) to increased milk energy output vs. the C and AM groups (13.75 vs. 13.18 and 13.15 Mcal, respectively). Protein and fat in milk, body condition score, glucose, cholesterol, triglycerides and triiodothyronine were similar among the groups. Four hours of cooling with spray and fans during severe summer temperatures only modestly improved milk yield of lactating Holstein cows. [ABSTRACT FROM AUTHOR]

The molecular mechanisms regulating the physiological adaptation of tissues important for nutrient partitioning and metabolism in lactating cows are still not completely understood. The aim of our study was to identify tissue-specific regulatory mechanisms necessary to accommodate metabolic changes associated with different genetic potential for milk performance. For this purpose, we analyzed mRNA expression of genes involved in energy metabolism of segregating F2beef type cows with a combined genetic dairy and beef background (Charolais × German Holstein cross, CH×GH) in contrast to purebred German Holstein (GH) dairy cows. Three groups of cows differing in milk performance were examined using quantitative real-time PCR in liver, mammary gland, and skeletal muscle. Our results describe substantial tissue-specific differences in mRNA transcription profiles between cow groups in relation to their genetic potential for milk performance and highlight genes exhibiting specific, partially yet-unknown functions in dairy and beef type cows, e.g., upregulation of PCK2transcripts in the mammary gland and FBP2transcripts in skeletal muscle of dairy cows. Noticeably, PCCAand PPARGC1AmRNA abundance varied significantly across experimental groups in all three tissues, pointing to potential key gene functions in the metabolic adaptation relative to divergent milk production performance. Correlations of mRNA expression levels to milk performance traits indicate that gene transcriptional processes may play a regulatory role in liver, mammary gland, and skeletal muscle to enable cows with different genetic potential for milk performance to cope with metabolic lactation-associated challenges. [ABSTRACT FROM AUTHOR]

Traditional evaluations of cows with genotypes have been adjusted since April 2010 to be comparable with evaluations of bulls so that their value for estimation of single nucleotide polymorphism effects in genomic evaluation programs would be improved. However, that adjustment made them not comparable with traditional evaluations of nongenotyped cows. To create an adjustment for all cows with an evaluation based on US data, Mendelian sampling, which is the difference between predicted transmitting ability (PTA) and parent average (PA), was calculated for milk, fat, and protein yields and divided by a deregression factor. Standard deviations for the deregressed Mendelian sampling (DMS) were grouped by reliability with PA contribution removed (RELno PA). A multiplicative adjustment to reduce the DMS standard deviation for cows so that it would be the same as for bulls with similar RELno PA was represented as a linear function of RELno PA. Mean cow PA by birth year was subtracted from individual bull and cow PA to create within-year PA deviation groups, and mean DMS was calculated by PA deviation group. Means decreased for bulls and increased for cows with increasing deviation. The differences were fit by linear regression on PA deviation and used to adjust cow DMS. The adjustment reduced PTA of cows with a high PA and increased PTA of cows with a low PA but did not change estimated genetic trend because adjustment was within birth year. The adjustment also reduced variance of cow evaluations within birth year. Traditional evaluations of genotyped cows with a RELno PA of ≥55% were further adjusted so that the difference between those evaluations and direct genomic values calculated using only bulls as predictors was similar to that for bulls. The second adjustment was small compared with a 2010 adjustment and, therefore, had little effect on the comparability of evaluations for genotyped and nongenotyped cows. Cows with converted evaluations from other countries were excluded from the predictor population, and their converted evaluations were adjusted so that the difference between their mean PTA and direct genomic value was the same as the corresponding difference for bulls. For cows with converted evaluations, the adjustment amount differed depending on RELno PA (<55% or ≥55%). The new adjustment was implemented by USDA in April 2011 and permits a fairer comparison of estimated genetic merit between nongenotyped and genotyped cows. [ABSTRACT FROM AUTHOR]

The period of transition between late pregnancy and early lactation presents an important metabolic challenge to the high-yielding dairy cows. They need, especially for the high milk yield, more nutrients and energy supply than other animals. The aim of this study was to attempt at providing a complete picture of dynamics of selected biochemical blood parameters in dairy cows from late pregnancy to dry period, giving new and useful information about the guidelines for the management strategies during different physiological phases. The study was carried out on five clinically healthy dairy cows, breed Holstein Friesian, in good nutritional condition. All the experimental subjects were selected on the basis of their pregnancy and lactation status, so blood samples were collected two days before the expected parturition (Late gestation), during the post partum, in early lactation, during the 2nd 5th and 15th weeks after parturition, at the end of lactation and at the dry period. On each serum sample urea, creatinine, total proteins, albumin, total cholesterol, triglycerides, NEFA, β-hydroxybutyrate, total and indirect bilirubins, calcium, phosphorus and magnesium were determined. On all data, normally distributed (P<0.05, Koimogorov-Smirnov's Test), one-way Repeated Measure Analysis of Variance (ANOVA) was applied to evaluate the influence of the reproduction status on the considered parameters. A significant effect of the physiological phase was observed on urea, creatinine, total proteins, total cholesterol, triglycerides, NEFA, β-hydroxybutyrate, calcium and phosphorus. Our data confirm that the lactation period is the more sensible, by a metabolic point of view, for the high production dairy cow, so the information, provided in this paper, advance the continuous investigation in animal welfare and can be a useful tool in managing and preventing the deficiencies typical of high production ruminants. [ABSTRACT FROM AUTHOR]

The aim of the study was to investigate the effects of season, cow cleanliness and milking routine on bacterial and somatic cell counts of bulk tank milk. A total of 22 dairy farms in Lombardy (Italy) were visited three times in a year in different seasons. During each visit, samples of bulk tank milk were taken for bacterial and somatic cell counts; swabs from the teat surface of a group of cows were collected after teat cleaning and before milking. Cow cleanliness was assessed by scoring udder, flanks and legs of all milking cows using a 4-point scale system. Season affected cow cleanliness with a significantly higher percentage of non-clean (NC) cows during Cold compared with Mild season. Standard plate count (SPC), laboratory pasteurization count (LPC), coliform count (CC) and somatic cell count, expressed as linear score (LS), in milk significantly increased in Hot compared with Cold season. Coagulase-positive staphylococci on teat swabs showed higher counts in Cold season in comparison with the other ones. The effect of cow cleanliness was significant for SPC, psychrotrophic bacterial count (PBC), CC and Escherichia coli in bulk tank milk. Somatic cell count showed a relationship with udder hygiene score. Milking operation routine strongly affected bacterial counts and LS of bulk tank milk: farms that accomplished a comprehensive milking scheme including two or more operations among forestripping, pre-dipping and post-dipping had lower teat contamination and lower milk SPC, PBC, LPC, CC and LS than farms that did not carry out any operation. [ABSTRACT FROM AUTHOR]

Records representing data from 1,500 barren Holstein cows over an 8-yr period from a large commercial dairy farm in northern Mexico were analyzed to determine the effects of lactation number and season and year of initiation of lactation on milk production of cows induced hormonally into lactation and treated with recombinant bovine somatotropin (rbST) throughout lactation. Peak and 305-d milk yields were also assessed as predictors of total milk yield in cows induced into lactation. A significant quadratic relationship was found between 305-d milk yield and number of lactation [7,607 ± 145 and 9,548 ± 181 kg for first- and =6-lactation cows, respectively; mean ± standard error of the mean (SEM)] with the highest production occurring in the fifth lactation. Total milk yields of cows with =2 lactations were approximately 4,500 kg less than milk yields of adult cows (the overall average ± standard milk yield was 13,544 ± 5,491 kg per lactation and the average lactation length was 454 ± 154 d). Moreover, 305-d milk production was depressed in cows induced into lactation in spring (8,804 ± 153 kg; mean ± SEM) and summer (8,724 ± 163 kg) than in fall (9,079 ± 151 kg) and winter (9,085 ± 143 kg). Partial regression coefficients for 305-d milk yield and peak milk yield indicated an increment of 157 kg of milk per lactation per 1-kg increase in peak milk yield (r² = 0.69). Neither peak milk yield (r² = 0.18) nor 305-d milk yield (r² = 0.29) was accurate for predicting total milk yield per lactation. Year, parity, and season effects had significant influence on milk yield of cows induced into lactation and treated with rbST throughout lactation, and peak milk yield can assist in the prediction of 305-d milk yield but not total milk yield. This study also showed that hormonal induction of lactation in barren high-yielding cows is a reliable, practical, and affordable technique in countries where rbST treatment and prolonged steroid administration of dairy cows are legally permitted. [ABSTRACT FROM AUTHOR]

Thirty Danish Holstein cows were used to determine how cows in early lactation adapt to changes in protein to starch supply in order to manipulate metabolism to combat physiological imbalance. During weeks 4 through 6 of lactation, 10 cows were fed either a high protein to starch ratio (high) diet, 10 cows were fed a low protein to starch ratio (low) diet while 10 others continued on the control diet. During weeks 7 through 9 of lactation, all cows returned to the control diet. The diets were formulated to consist of 15.0%, 18.6% and 22.2% crude protein and 13.3%, 7.5% and 1.7% of starch for the low, control and high diets, respectively. Besides milk urea nitrogen, no other production or metabolic parameters were affected by treatment. In conclusion, manipulation of dietary protein to starch is not a potential strategy to combat physiological imbalance during early lactation. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of claw horn disruption lesions (CHDL; sole ulcers and white line disease) and body condition score (BCS) at dry-off on survivability, milk production, and reproductive performance during the subsequent lactation. An observational prospective cohort study was conducted on a large commercial dairy in Cayuga County, New York, from September 2008 until January 2009. A total of 573 cows enrolled at dry-off were scored for body condition and hoof trimmed; digits were visually inspected for the presence of CHDL. The BCS data were recategorized into a 3-level variable BCS group (BCSG), with cows with BCS <3 placed in BCSG 1 (n = 113), cows with BCS = 3 placed in BCSG 2 (n = 254), and cows with BCS >3 placed in BCSG 3 (n = 206). Cows in BCSG 2 were 1.35 and 1.02 times more likely to conceive than cows in BCSG 1 and 3, respectively. The cull/death hazard for BCSG 1 cows was 1.55 and 1.47 times higher than for cows in BCSG 2 and BCSG 3, respectively. Milk yield for cows in BCSG 2 (44.6 kg/d, 95% CI 43.4-45.8) was significantly greater than that for cows in BCSG 1 (41.5 kg/d, 95% CI 39.8-43.3). Cows with previous lactation days open ≤91 had 1.6 times higher odds of being classified into BCSG 1 at dry-off; cows with previous lactation mature-equivalent 305-d milk >14,054 kg had a similar 1.6 times higher odds of being classified into BCSG 1. Claw horn disruption lesions were found in 24.4% of the cows (n = 140) at dry-off. Cows without CHDL were 1.4 times more likely to conceive than cows with CHDL. Additionally, lesion cows were 1.7 times more likely to die or be culled than nonlesion cows. Absence of CHDL did not have a significant effect on milk yield. These findings highlight the importance of claw health and BCS at the end of lactation on future survival and performance. [ABSTRACT FROM AUTHOR]

This study investigated the effect of lameness, measured by serial locomotion scoring over a 12-mo period, on the milk yield of UK dairy cows. The data set consisted of 11,735 records of test-day yield and locomotion scores collected monthly from 1,400 cows kept on 7 farms. The data were analyzed in a multilevel linear regression model to account for the correlation of repeated measures of milk yield within cow. Factors affecting milk yield included farm of origin, stage of lactation, parity, season, and whether cows were ever lame or ever severely lame during the study period. Cows that had been severely lame 4, 6, and 8 mo previously gave 0.51 kg/d, 0.66 kg/d, and 1.55 kg/d less milk, respectively. A severe case of lameness in the first month of lactation reduced 305-d milk yield by 350 kg; this loss may be avoidable by prompt, effective treatment. Larger reductions can be expected when cases persist or recur. Evidence-based control plans are needed to reduce the incidence and prevalence of lameness in high yielding cows to improve welfare and productivity. [ABSTRACT FROM AUTHOR]

This study was undertaken to increase our understanding of the need of the mammary gland for the different types of AA and how the mammary gland alters its metabolism in response to a variable AA supply. Eight lactating Holstein cows (61±4 DIM) were used in a replicated 4 × 4 Latin square balanced for residual effects with 14-d periods. The diet was formulated to supply 100% of the net energy requirement and 72% of the metabolizable protein requirement. The 4 treatments were 1) abomasal infusions of water, 2) essential AA at 359g/d, 3) nonessential AA at 356g/d, and 4) essential AA at 359g/d+nonessential AA at 356g/d (total of 715g/d). The infusates had the same AA profile as casein with the exception that Met was increased to maintain a 3:1 ratio of digestible Lys to Met and because of solubility limitations all the Tyr was replaced by Phe and part of the Glu was replaced by Gln. Milk yield and milk protein yield were increased by the essential AA treatments compared with the other treatments. Mammary uptake of β-hydroxybutyrate plus lactate tended to increase with the essential AA treatments, whereas glucose mammary uptake tended to be higher with the nonessential AA treatments. With the essential AA treatments, the mammary uptake:milk protein output ratio for the group 1 AA (His, Met, Phe, Trp, and Tyr) did not differ from 1 but tended to increase; the ratio for the group 2 AA (Ile, Leu, Lys, and Val) did increase, significantly exceeding unity when essential AA were infused. These results indicate that the mammary gland alters differently its uptake of both AA and energy-yielding nutrients in response to the amount and profile of AA presented to it and that even under situations of protein deficiency nonessential AA supplementation does not enhance milk and milk protein synthesis. [ABSTRACT FROM AUTHOR]

This study examined the effects of primary growth (PG) and regrowth (RG) timothy-meadow fescue silages harvested at 2 stages of growth on feed intake, cell wall digestion and ruminal passage kinetics in lactating dairy cows. Four dairy cows equipped with rumen cannulas were used in a study designed as a 4 × 4 Latin square with 21-d periods. The experimental silages were offered ad libitum with 8 kg/d of concentrate. Ruminal digestion and passage kinetics were assessed by the rumen evacuation technique. Silages of PG were on average more digestible than RG silages. The concentration of neutral detergent fiber (NDF) and indigestible NDF (iNDF) increased and the concentration of digestible organic matter in dry matter (DM) of silages decreased with advancing maturity in PG and RG. Cows consumed more feed DM, energy, and protein and produced more milk when fed PG diets rather than RG diets. Delaying the harvest decreased DM intake and milk production in PG and RG. There were no differences between PG and RG in rumen pH, ammonia N, or total volatile fatty acid concentrations. The intake of N, omasal canal flow of total nonammonia N and microbial N, excretion of N in feces, and ruminal true digestibility of N were higher for PG than for RG diets. The efficiency of microbial N synthesis was not different between PG and RG. Intake and omasal canal flow of organic matter, NDF, and potentially digestible NDF (pdNDF) were higher in PG than in RG. Whole-diet digestibility of organic matter, NDF, or pdNDF in the rumen or in the total tract was not different between PG and RG despite the higher digestibility of PG silages measured in sheep. Rumen pool sizes of crude protein and iNDF were lower for PG diets, whereas the pool size of pdNDF was higher for PG diets than for RG diets. The rate of passage of iNDF was higher for PG diets than for RG diets, with no difference between them in rate of digestion or passage of pdNDF. The lower milk production in cows fed regrowth grass silages compared with primary growth silages could be attributed to the lower silage DM intake potential. Chemical composition of the silages, rumen fill, digestion and passage kinetics of NDF, or the ratio of protein to energy in absorbed nutrients could not explain the differences in DM intake between silages made from primary and regrowth grass. [ABSTRACT FROM AUTHOR]

Efficient reproductive performance is essential for optimal milk production and profitability of the dairy herd, whereas fertility is affected by multiple factors including nutrition. It is known that selenium may be effective on cyclicity and reproductive performance of the dairy cow, however there is also evidence for other trace minerals. A total of 44 dairy cows in the postpartum period, from commercial herds were divided into three groups Group I (n=16): Inactive ovaries: Absence of at least one luteal structure, accompanied with progesterone levels lower than 1 ng/ml.; Group II (n=12): Cystic ovaries: Presence and persistence of cystic structures with a diameter of over 2.5 cm.; Group III: Cyclic cows (n=16): Cyclic cows were selected according to ultrasonographic examination of luteal structure and serum progesterone analysis. Plasma Cu, Zn and Fe concentrations were measured at examinations performed ten days apart. Mean concentrations were calculated and compared between groups. No significant differences were observed in between group analysis and the trace element levels were normal when compared to the reference values. It was concluded that reproductive disorders (cystic ovaries, inactive ovaries) encountered in this observation did not result from a deficiency of the selected trace elements. [ABSTRACT FROM AUTHOR]