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Humans and dogs commonly share the same domestic environment. Europe, and Italy specifically, have a substantial and growing dog population. Potentially zoonotic parasites may be harbored even by dogs receiving regular veterinary care. Thus, transmission of zoonotic or potentially zoonotic parasites to owners and their families should not be underestimated. Frequently, endoparasite infections occur as a subclinical infection and clinicopathological alterations have been documented including anemia, hypoalbuminemia, and eosinophilia. The aim of this large retrospective secondary data study was to analyze coprological endoparasite results and putative risk factors obtained from owned dogs, through a 9-year-period (2011-2019). Possible associations between diagnosed endoparasites and sex, age, seasonality, and year of examination were evaluated. Additionally, parasitological diagnoses were combined to complete blood count parameters and biochemical profiles, when available, to check for any possible hematological alteration from parasitism. A total of 1,972 dogs were evaluated for endoparasites using common fecal diagnostic tests over a 9-year period. The overall proportion of endoparasite-positive animals was 10%. The most common endoparasites detected were Cystoisospora spp. (3%), Toxocara canis (2.8%), Giardia duodenalis (1.6%), and Trichuris vulpis (1.2%). Of these parasites detected, Toxocara poses the greatest zoonotic risk, while Giardia species are considered to have a low potential to be zoonotic. There was no significant diagnostic trend across the years through the study period. Dogs were more frequently diagnosed endoparasite-positive when young and during cold seasons compared to the baselines of mature dogs and warm seasons. The clinicopathological profiles indicated that parasitized dogs had mild hematological alterations. The frequency of detected potentially zoonotic endoparasites in this study highlights that the risk should not be underestimated. Parasitic infection was found to be mostly dependent on age and season. Having this information may help clinicians to develop anthelmintic protocols to reduce the risk of transmission., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Morandi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Smallholder dairy farmers (SDF) in developing countries often have limited understanding on the importance of cow comfort. We conducted a randomized controlled trial with 124 cows on 114 Kenyan SDF to determine the status of cow comfort, to assess compliance to farm-specific cow comfort recommendations, and to evaluate the impacts of the farm-specific interventions on cow comfort. On the first farm visit, stall dimensions and characteristics (e.g. stall base hardness and hygiene) were measured and categorized as adequate, marginal or inadequate/absent based on cow size. Where measurements were not adequate, farm-specific cow comfort recommendations were provided in written and oral form to the randomly allocated intervention group of farms (n = 74). On the second farm visit two months later, the same measurements were taken, and percent compliance to the recommendations was evaluated. A discomfort index was arithmetically calculated based on the stall base hardness (scale was 1-3 for soft to hard) and hygiene (scale was 1-5 for clean to dirty). Multivariable linear regression models were used to determine specific associations with the discomfort index. On the first visit, the mean stall base hardness and stall hygiene scores were 1.7 and 2.3, respectively, for a mean discomfort index of 4.0. Intervention farmers were given 3.9 comfort recommendations, on average, and complied with 2.1 recommendations, significantly improving the discomfort index at visit two to 3.3. The overall compliance to the recommendations was 49.0%. In a final model, the interaction between intervention group and visit number was significantly associated with discomfort index, indicating that after adjusting for baseline discomfort indices, the intervention led to better cow comfort. Specifically, bedding type and neck rail positioning were significantly associated with discomfort index. We concluded that farmers can substantially improve cow comfort on SDF by providing recommendations to them. Farm advisors should include cow comfort recommendations to SDF., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest in all aspects of this study., (Copyright © 2023. Published by Elsevier Ltd.)

There is a growing interest in protein supplementation of dairy-cow diets using leguminous shrubs. The study objective was to ascertain the association between diet supplementation with Calliandra calothyrsus and Sesbania sesban and milk production in dairy cattle on commercial smallholder farms. This trial involved 235 cows from 80 smallholder dairy farms in Kenya randomly allocated to 4 intervention groups: (1) receiving Calliandra and Sesbania and nutritional advice; (2) receiving reproductive medicines and advice; (3) receiving both group 1 and 2 interventions; and (4) receiving neither intervention. Farm nutritional practices and management data were collected in a questionnaire, and subsequent physical examinations, mastitis tests, and milk production of cows on the farm were monitored approximately monthly for 16 months. Descriptive and univariable statistical analyses were conducted, and multivariable mixed-model regression was used for identification of factors associated ( P < 0.05) with daily milk production. The mean milk production was 6.39 liters/cow/day (SD = 3.5). Feeding Calliandra/Sesbania to cows was associated ( P < 0.0005) with an increase in milk produced by at least 1 liter/cow/day with each kg fed. Other variables positively associated with ln daily milk production in the final model included feeding of Napier grass, amount of silage and dairy meal fed, body condition score, and appetite of the cow. Other variables negatively associated with ln daily milk production in the final model included amount of maize germ fed, days in milk, sudden feed changes, pregnancy, and subclinical mastitis. In conclusion, our field trial data suggest that use of Calliandra / Sesbania through agroforestry can improve milk production in commercial smallholder dairy farms in Kenya. Agroforestry land use systems can be adopted as a way for dairy farmers to cope with feed shortages and low crude protein in farm-available feeds for their cows., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this paper., (Copyright © 2020 D. N. Makau et al.)

Although many studies on the frequency of endoparasites in dogs and cats in Canada have been reported, seasonal and/or annual patterns are often not evaluated. The frequency and risk factors of endoparasite infections from fecal samples of cats and dogs submitted to the Veterinary Teaching Hospital of the Atlantic Veterinary College, University of Prince Edward Island-Canada were determined, using univariable and multivariable logistic regression analyses. Investigated predictors of endoparasitism available in the 2000-2017 database included sex, age, geographic origin and seasonality. A total of 15,016 dogs and 2,391 cats were evaluated for endoparasite status using specific diagnostic tests: direct smear, Baermann, and/or 33 % zinc sulfate solution in a standardized centrifugal flotation method. Overall, twelve and eight parasite genera were detected in dogs and cats, respectively. The overall proportional infection was 14.6 %, and the cat population showed a higher frequency of positivity to parasites compared to the dog population (P < 0.001). The most frequent genera recovered in the whole population (dogs and cats), were Giardia duodenalis (5.2 %), Cystoisospora spp. (3.3 %) and Toxocara spp. (3.2 %). Endoparasitism levels were diagnosed more in feces submitted from young, female intact dogs from PEI compared to the baselines of mature, sterilized male dogs from other provinces, respectively, and diagnoses occurred more often in autumn months than in winter months. There was no significant diagnostic trend across the years for the individual parasites models. The frequency of detected potentially zoonotic parasites in this study highlights the veterinary public health and One Health context of parasitic infections in pets. Although the presented results are not from a random sample and therefore frequency results should be interpreted with caution, the model relationship results may still be relevant. In addition, results are of value to estimate parasite impact and to assist researchers, veterinarians and pet-owners with suitable information to control parasites., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The growth rate of female calves on dairy farms is one of the crucial factors which influence age at first calving, affecting lifetime lactation productivity of a dairy cow. Diets with adequate crude protein are necessary to support calf growth. The study objective was to determine the effects of nutritional advice and diet supplementation with Calliandra calothyrsus and Sesbania sesban on average daily weight gain in dairy calves on semi-commercial smallholder dairy farms in Kenya. This trial involved 155 calves from 73 smallholder dairy farms, in Kenya, randomly selected and allocated to either intervention or control groups. The intervention group received nutritional advice and seedlings of Calliandra calothyrsus and Sesbania sesban, while the control group did not receive these interventions. Every 1-2 months for 16 months, data on farm nutritional practices and management were collected in a questionnaire, and physical examinations were done to monitor weight and health status. Descriptive and univariable statistical analyses were conducted, and multivariable mixed linear regression models were used for identification of factors associated (P < 0.05) with the natural log transformation of weight gain of calves on a given farm, controlling for clustering of visits within calves. Feeding at least 0.2 kg/day (wet weight) of Calliandra or Sesbania to calves <6 months old resulted in 33.2% increase in daily weight gain, while controlling for confounding by breed and sex of the calf. For calves ≥6 months, there was a significant interaction between amount of hay fed and if calves were also fed on Calliandra or Sesbania. When no Calliandra or Sesbania supplementation was provided, the mean weight gain was low and relatively constant even with increasing amounts of hay. When Calliandra or Sesbania supplement was added to the diet, the mean weight gain increased from 0.17 kg to 0.48 kg when hay was fed at 1 and 5 kg, respectively, while controlling for confounding by amount of maize silage fed and the prevailing season. In conclusion, supplementation of calf diets with at least 0.2 kg/calf/day of Calliandra or Sesbania is beneficial for faster weight gains., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Our study aimed to evaluate farmers' compliance in implementing recommendations of farm-specific cow comfort changes, and the effects of these changes on lying time, stall cleanliness and cow cleanliness using a randomized controlled trial carried out on 100 smallholder dairy farms in Kenya, with 62 and 11 farms remaining in the intervention and control groups, respectively. On the first farm visit, data loggers were attached on lactating cows to determine lying time and questionnaires utilized to collect baseline data. Three days later, stall design and management recommendations were given to the intervention group of farmers orally and in written form. After an average of 39 ± 7 days, data loggers were re-attached, compliance was assessed, and a post-intervention questionnaire was administered to the intervention group on the third visit. Three days subsequent to the first and third visits, data loggers were removed from all cows. Data were analysed in Stata 14.2® using proportion tests and Kruskal-Wallis rank tests to compare cleanliness scores and lying time, respectively. Interaction effects between treatment groups and visits were assessed using multivariable mixed linear and logistic regression models. While 46 of the 62 intervention farmers (74%) made at least one recommended change to cow comfort, 63% of the 324 overall recommendations were implemented. The odds of a recommendation being implemented were significantly higher when:1) major recommendations were given relative to minor recommendations (OR = 6.28); 2) recommendations were related to floor characteristics (floor softness and flatness) in comparison to recommendations related to stall design (OR = 3.14). The odds of compliance were lower on: 1) farms where the farm-hands received the recommendations compared to farms that had the female principal farmer receive the recommendations (OR = 0.01); 2) farms that had recommended changes related to roof, alley and sharps fixes relative to stall design fixes (OR = 0.13). Post-intervention, stall, udder and upper hind-leg cleanliness scores improved significantly (p < 0.0001, p = 0.021 and p = 0.017, respectively) in the intervention farms but not in the control farms. There was no significant difference in lying times between intervention and control farms, with 0.6 and 0.2 h/day increases being recorded in the intervention and control groups, from the 10.9 and 10.4 h/day at baseline, respectively. Giving farm-specific cow comfort recommendations to smallholder dairy farmers in Kenya, and providing them with a participatory role in the formulation and implementation of improvement recommendations ensured good acceptance and a high degree of implementation, and led to a subsequent improvement in cow comfort and cleanliness., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background and Aim: The welfare of animals kept in livestock production systems has raised concerns around the world. Adult dairy cattle require adequate rest and spend approximately 12 h/day lying down. This cross-sectional study aimed to determine the stall factors and management practices affecting cows' lying time, stall cleanliness, and cows' cleanliness (udder and upper leg), in smallholder dairy cows in Meru County of Kenya., Materials and Methods: A total of 106 milking cows from 73 farms were assessed for daily lying time and cleanliness. Data loggers were used to record the lying time of cows for 3 days. Stall, udder, and upper leg cleanliness were assessed using a 5-score system: 1 (very clean) to 5 (very dirty). Management information was acquired using a questionnaire that was administered face-to-face to the farmers in their native Kimeru language. Univariable and multivariable linear and logistic regression models were fit to determine factors associated with cows' lying time and dichotomized stall and cows' own cleanliness, respectively., Results: The mean daily lying time was 10.9±2.2 h, and the mean stall cleanliness score was 2.4±1.0. The mean average cleanliness scores of the udder and upper legs were 1.9±0.7 and 2.5±1.1, respectively. Overall, 35% of the stalls were categorized as dirty (>2.5), whereas 13% and 47% of the cows had udder and leg cleanliness scores >2.5, respectively. From the final multivariable models (p<0.05), daily lying time increased by 1.0 h for cows older than 5.25 years versus younger cows. Conversely, lying time decreased by 1.0 h with stall cleanliness scores >2.5 and by 1.6 h with poorly positioned neck rails. In an interaction term, addition of new bedding at least once a day without removing stall manure at least once a day decreased the daily lying time of the cows by 1.5 h, whereas failure to add new bedding at least once a day but removing stall manure at least once a day decreased the lying time of the cows by 1.2 h. Farm-level risk factors for stall dirtiness (>2.5) included delayed cleaning of the alley (odds ratio [OR]=6.6, p=0.032), lack of bedding (OR=4.9, p=0.008), and standing idle and/or backward in the stall (OR=10.5, p=0.002). Stalls categorized as dirty (OR=2.9, p=0.041) and lack of bedding (OR=2.7, p=0.065) were cow- and farm-level risk factors for dirtiness of the udder (>2.5), respectively, whereas the stall being dirty (OR=2.3, p=0.043) was the only risk factor (cow level) for dirtiness of the upper legs (>2.5)., Conclusion: It was recommended that farmers should pay attention to the specific factors identified regarding the stall design (e.g., neck rail position) and bedding/manure management that impact the cleanliness of cows and their lying time.

Calf growth is an important determinant of dairy herd productivity, particularly in countries where the dairy industry is expanding, such as Kenya. Our objective was to determine factors associated with weight gain in randomly selected dairy calves and heifers in smallholder dairy farms (SDF) in Kenya. A cross-sectional study on a census of 321 calves and heifers (dairy calves and heifers up to 36 months of age), sampled from 200 randomly selected SDF in Naari, Kenya, formed the study population. Youngstock management was recorded using a questionnaire. Biodata were obtained through subsequent physical examination and heart girth measurement. Descriptive statistical analyses were conducted, and mixed model regression was used for identification of factors associated (p < 0.05) with the natural log transformation of estimated average daily weight gain (ADG). Median and mean ADG of the youngstock were 360 and 443 (s.d. = 375) g day -1 , respectively. In the final model, ADG was highest in pre-weaned calves and declined with age. Supplementing with quality hay during the dry season at least weekly was associated with increased ADG. There was an interaction between breed and historical disease on ADG such that disease was associated with decreased ADG in Bos taurus breeds, while ADG in Bos indicus breeds was not affected by disease. There was a significant interaction between education levels of the husband and wife caretakers; when the man's education was low (having less than or equal to primary school), ADG was highest when the woman had not completed primary school, but was lower when the woman had completed primary, secondary or tertiary education, possibly because such women worked off-farm more often. General growth performance of animals on these farms was lower than benchmarked standards recommended for optimum dairy production but within previously reported ranges for the East African region. Supplementation of diets (with hay and/or concentrates) is recommended for optimum growth in calves and heifers, especially in the dry season. If nutritional management of Bos taurus youngstock is not improved, crosses of Bos indicus could be better suited for the current nutritional management systems in SDF in Meru having calf disease problems. Interventions to support educating women (the primary caretakers of the cattle) and men in the community on calf management should be initiated, preferably with shared on-farm responsibilities. Training in better management, even for learned farmers, would be critical to better calf growth., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Aim: The study was to evaluate the relationship between the first service conception (FSC) and milk urea nitrogen (MUN) in smallholder dairy farms under heat and humidity stress., Materials and Methods: Dairy cows from 43 dairy farms giving birth between November 2014 and April 2015 (n=295) contributed to the study. All cows were sampled monthly to measure milk compositions, and we collected additional farm data from farmers through a questionnaire. The first service during the first 120 days of lactation was the outcome of interest in this study. Multivariable logistic regression determined significant associations with FSC., Results: The overall FSC was 22% and the mean MUN concentration was 11.55 mg/dl. The final FSC model included MUN concentration, the season of breeding, and protein energy ratio (PE ratio) in the diet. The odds of FSC were reduced by approximately 10% for each mg/dl higher MUN on the day of the milk sample that was nearest to the artificial insemination (AI) day. The odds of FSC were nearly 3 times higher when the first insemination occurred in winter compared to summer first services. Taking into account the nutritional factors, the odds of FSC were nearly 70% higher with an increase in PE ratio of 10 g of crude protein/Mcal from the mean of 35.90 g., Conclusion: This study of smallholder dairy farmers in the hot and humid climate of Thailand confirmed that season, nutritional management, and MUN concentration were associated with FSC. MUN appears to be a useful indicator to monitor the effects of diet on reproductive performance from this study.

Aim: This study was undertaken to determine the household, calf management, and calf factors associated with the occurrence of Eimeria, Cryptosporidia, and diarrhea in pre-weaned calves reared in smallholder dairy farms in Mukurwe-ini Sub-County of Nyeri County, Kenya. In addition, the study also evaluated factors associated with average daily weight gain in the same pre-weaned calves., Materials and Methods: A total of 112 newborn calves (63 males and 49 females) on 111 farms (1 set of twins) were followed for 2 months between June 2013 and August 2013. Two calves were lost to follow-up. A pre-tested questionnaire was used to collect data on household characteristics and calf management practices in the 111 selected farms. On the first visit to the farm (within 7 days of the birth of the calf), blood samples were collected from the jugular vein to assess the level of maternal immunity acquired by the calf, by determining the serum total protein and selenium concentration. At 4 and 6 weeks of age, fecal samples from the calves were collected to assess the presence of Cryptosporidia and Eimeria oocysts. Every 2 weeks for 2 months, the calves and their environments were examined, their 2-week consumption and health history were recorded, and weights were estimated with a weight tape. Each of the factors was evaluated in a univariable regression model and only those found to be significant (p≤0.20) were included in a multivariable model. Elimination of non-significant factors was done in the multivariable model through a backward elimination procedure so that only those variables which were confounders, and/or significant at (p≤0.05) remained in the final model., Results: About 37% (41/110) of the calves experienced diarrhea at least once during the 2-month study period. The overall period prevalence of Eimeria and Cryptosporidia was 42.7% (47/110) and 13.6% (15/110), respectively. Low serum protein was associated with 1.8 and 2.4 times the odds of Eimeria and Cryptosporidia infections, respectively. Lack of supervision of calf birth and low serum total protein were both associated with 1.3 times the odds of diarrhea incidence. Dirty calf pens, feeding <5 L of milk/day, and infection with Eimeria were associated with 0.105, 0.087, and 0.059 kg, respectively, reduced average daily weight gain of the calves., Conclusion: In the Kenyan context, calf diarrhea risk could be reduced through better supervision of parturition and colostrum provision. Specifically, the risk of Eimeria and Cryptosporidia infections could be reduced by optimizing the passive transfer of immunity to the newborn calves. Average weight gains of calves could be improved by good colostrum provision, pen hygiene, and preventing Eimeria infections.

There is limited field-based research and recommendations on the effect of cattle feeding management practices on smallholder dairy farms (SDF) for the growing dairy industry in Kenya. This controlled trial aimed to determine the effect of feeding locally produced dairy meal (DM) on early lactation daily milk production (DMP) on Kenyan SDF, controlling for other factors associated with DMP. Privately owned, recently calved cows (n=111) were randomly assigned to one of three groups of feeding recommendations for DM (meeting predicted DM requirements by: (1) 100%; (2) 50%; or (3) feeding by the farmer's discretion). DM was provided for free to groups 1 and 2 to ensure they had sufficient DM to feed to the recommendations. Data collection on cow and farm characteristics occurred biweekly for a 60-day period post-calving starting in June 2013. A repeated measures multivariable linear regression model was used on the DMP outcome variable. With variability in DM consumption within feeding groups due to variability in DMP, actual DM fed was assessed as an independent variable rather than assigned feeding groups. DMP was positively associated with each kg/day of DM fed (0.53kg/day), cow weight (0.13kg/day), feeding DM in the month prior to calving (1.42kg/day), and feeding high protein forage (0.41kg/day), and was negatively associated with having mastitis (-0.30kg/day). In interaction terms, taller cows had higher DMP than shorter cows, whereas heifers (first parity cows) had similar DMP regardless of height. Also, thin cows (2+ parity with body condition score<2.5 out of 5) produced less milk (1.0kg/day less) than cows with a better body condition score at calving,whereas thin heifers produced more milk (2.0kg/day more) than heifers in better body condition-this association is possibly due to a small unrepresentative sample size of heifers. In conclusion, feeding DM in the month prior to calving, improving body condition in cows prior to calving, and enhancing dietary DM and high protein forage were positively associated with DMP in early lactation on Kenyan SDF. In addition there was an association between, taller cows and increased DMP, evidence supporting the importance of educating farmers on good genetic selection and heifer management. These findings will help with future management recommendations for higher DMP on SDF., (Copyright © 2016 Elsevier B.V. All rights reserved.)

A new portable x-ray fluorescence (XRF) screening tool was evaluated for its effectiveness in arsenic (As) quantification in human finger and toe nails ([Formula: see text]). Nail samples were measured for total As concentration by XRF and inductively coupled plasma-mass spectrometry (ICP-MS). Using concordance correlation coefficient (CCC), kappa, diagnostic sensitivity (Sn) and specificity (Sp), and linear regression analyses, the concentration of As measured by XRF was compared to ICP-MS. The CCC peaked for scaled values of fingernail samples, at 0.424 (95% CI: 0.065-0.784). The largest kappa value, 0.400 (95% CI:  -0.282-1.000), was found at a 1.3 μg g(-1) cut-off concentration, for fingernails only, and the largest kappa at a clinically relevant cut-off concentration of 1.0 μg g(-1) was 0.237 (95% CI:  -0.068-0.543), again in fingernails. Analyses generally showed excellent XRF Sn (up to 100%, 95% CI: 48-100%), but low Sp (up to 30% for the same analysis, 95% CI: 14-50%). Portable XRF shows some potential for use as a screening tool with fingernail samples. The difference between XRF and ICP-MS measurements decreased as sample mass increased to 30 mg. While this novel method of As detection in nails has shown relatively high agreement in some scenarios, this portable XRF is not currently considered suitable as a substitute for ICP-MS.

Animal studies and epidemiological evidence suggest an association between prenatal exposure to drinking water with elevated nitrate (NO3-N) concentrations and incidence of congenital anomalies. This study used Geographic Information Systems (GIS) to derive individual-level prenatal drinking-water nitrate exposure estimates from measured nitrate concentrations from 140 temporally monitored private wells and 6 municipal water supplies. Cases of major congenital anomalies in Kings County, Nova Scotia, Canada, between 1988 and 2006 were selected from province-wide population-based perinatal surveillance databases and matched to controls from the same databases. Unconditional multivariable logistic regression was performed to test for an association between drinking-water nitrate exposure and congenital anomalies after adjusting for clinically relevant risk factors. Employing all nitrate data there was a trend toward increased risk of congenital anomalies for increased nitrate exposure levels though this was not statistically significant. After stratification of the data by conception before or after folic acid supplementation, an increased risk of congenital anomalies for nitrate exposure of 1.5-5.56 mg/L (2.44; 1.05-5.66) and a trend toward increased risk for >5.56 mg/L (2.25; 0.92-5.52) was found. Though the study is likely underpowered, these results suggest that drinking-water nitrate exposure may contribute to increased risk of congenital anomalies at levels below the current Canadian maximum allowable concentration.

We aimed to describe the management and productivity of this group of smallholder dairy farmers in Kenya at the beginning of an intervention program and to document relevant observed changes in the 3rd year of the intervention. A 3-year intervention program, focused on management of animal health and nutrition, and milk quality, was implemented by one Kenyan and two Canadian non-governmental organizations (one university based) to help improve the milk production and livelihoods of Kenyan smallholder dairy farmers (primarily women). Thirty farmers were enrolled and completed questionnaires at the start and end of the project. Focus groups were also conducted to obtain qualitative information on livelihood effects from the program. In 2004, 70% of the eligible youngstock (more than 15 months of age) were pregnant, and cows had a long average days-in-milk of 240 days. External parasites, poor hygiene, and long claws were not uncommon among cows, and 37% and 20% of the farms reported clinical intestinal parasitism and diarrhea in youngstock. In 2006, there were significant improvements in the proportion of farms planting high-protein forages, farms using better milking procedures, and on-farm milk storage methods. The reported mastitis incidence rate fell from 0.55 to 0.20 cases/cow-year (p < 0.01), and the average number of cows and youngstock significantly increased from 1.5 and 0.9 to 2.9 and 2.6, respectively. There were reported improvements in the livelihoods among the member families. The partnership-based intervention program significantly improved management and productivity of this group of smallholder dairy farmers in rural Kenya, leading to reported livelihood benefits.

Using a randomized controlled trial design, a randomly allocated intervention group of 15 cows received a slow-release bolus that delivered 100 days of monensin. The negative control group of 15 cows received a placebo bolus that was identical to the monensin bolus, except without the monensin. Two weeks after bolus administration, all cows were challenged with a 2 ml subcutaneous injection of a live tachyzoite suspension. Whole blood and serum samples were collected from each cow every week for the first month post-challenge, and then every 2 weeks for the next 2 months. The extracted DNA from whole blood was tested for the Nc-5 gene fragment of Neospora caninum using a quantitative real time polymerase chain reaction. Serum was tested for antibodies to N. caninum using the IDEXX ELISA. Cows treated with monensin boluses had a significantly lower humoral immune response than cows treated with placebo boluses at one time point post-challenge (week 4 post-challenge). However, when adjusting for repeated measures within cows, the P value for this humoral difference was 0.098. No DNA for N. caninum was detected in either group, likely due to study design features., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Objective: To determine the relationship between the risk of type 1 diabetes (T1D) and daily intake of drinking water and dietary components, including nitrate, nitrite, and nitrosamines, during the year prior to diagnosis., Methods: Controls (n = 105) were matched by age at diagnosis and sex to T1D cases (n = 57) newly diagnosed during 2001-2004. Food consumption was assessed using a food frequency questionnaire. Locally available samples of foods were tested for nitrate, nitrite, and nitrosamine concentrations. Water consumption was determined through an additional questionnaire, and water samples were taken from homes and tested for routine chemical components, including nitrate., Results: After controlling for age, age, sex, and daily energy intake, nitrate intake from food sources showed a non-significant positive trend (odds ratios and 95% confidence intervals for quartiles = 1.00, 1.63 (0.58, 4.63), 1.71 (0.54, 5.40), 3.02 (0.78, 11.74); p for trend = 0.13). Nitrite and nitrosamine intake were not related to T1D risk (p for trend = 0.77 and 0.81, respectively). When food and water components were combined, zinc and calcium intakes were marginally and inversely related to T1D risk (p for trend = 0.07 and 0.06, respectively). After further model adjustment of possible confounders and significant risk factors, an increased intake of caffeine marginally increased the risk of T1D (p = 0.07)., Conclusion: Dietary components from both food and water sources may influence the risk of developing T1D in young persons.

Our objective was to investigate effects of seropositivity for bovine leukemia virus (BLV), Type 1 bovine viral-diarrhea virus (BVDV), Mycobacterium avium subspecies paratuberculosis (MAP), and Neospora caninum (NC), and their possible interactions, on reproductive efficiency (specifically, first-service conception [FSC], and calving interval [CI]) in dairy cows. The sample population included up to 30 randomly selected animals from 179 randomly selected farms in five provinces in Canada, from which 23 farms did not meet the inclusion criteria for the final dataset. Serum samples were tested for antibodies against the stated pathogens using commercially available diagnostic tests. A Cox proportional hazards model with shared (herd-level) frailty was utilized to analyze the CI data. In this model, BLV-seropositive cows had a 7% lower rate of conception compared to seronegative cows (P=0.06). Mixed logistic regression models of CI>484 days, CI>534 days, and CI>584 days were built to explore factors of long CIs. These cut-offs were selected to represent calving-to-conception intervals of >200 days, >250 days, and >300 days. BLV-seropositive cows had higher odds of having a CI>484 days compared to BLV-seronegative cows, and BLV serostatus interacted with lactation number in this model, with 1st lactation seropositive cows being more likely to have a CI>484 days than older seropositive cows. NC-seropositive cows had a 1.27 times higher odds of exhibiting a CI>484 days, a 1.37 times higher odds of a CI>534 days, and a 1.54 times higher odds of a CI>584 days, compared to NC-seronegative cows. Neither BVDV nor MAP seropositivity showed any significant effect in these models. For the FSC models, a first service was classified successful (pregnancy=1) if it was the cow's last service and she calved 270-290 days later. A mixed logistic regression model of FSC revealed an interaction between NC and BVDV-seropositivity at the herd level, with odds ratios of 0.64, 1.06 and 0.85 for NC-seropositive cows (compared to NC-seronegative cows) in BVDV-seronegative, BVDV-seropositive and BVDV-missing herds, respectively. BLV and MAP seropositivity had no significant impact on FSC. All models controlled for herd-clustering effects, and included parity, linear score of somatic cell counts, peak milk, and province to control for confounding. The overall FSC was 51%, the average CI was 393 days, and 18%, 9% and 5% of lactations had CI>484 days, >534 days, and >584 days, respectively.

Our objective was to determine cow- and herd-level risk factors associated with seropositivity for Neospora caninum in a large number of randomly selected Canadian dairy herds, controlling for important confounding variables and co-infections with bovine leukemia virus (BLV), bovine viral diarrhea virus (BVDV) and Mycobacterium avium subspecies paratuberculosis (MAP). Serum samples were obtained from 30 randomly selected cows, where available, in 240 herds using monthly milk testing, within 6 of 10 provinces, and these samples were tested for antibodies against BLV, MAP and N. caninum using commercially available ELISA test kits. Five unvaccinated cattle >6 months old from each herd were tested for antibodies to BVDV using virus neutralization. Most herd-level predictors were obtained through personal interviews with questionnaires administrated to each farm manager. A mixed logistic-regression model was built using N. caninum serostatus at the cow-level as the outcome variable, with herd as a random effect and province as a fixed effect. A BLV seropositive cow was 1.50 times more likely to be seropositive for N. caninum than a BLV-seronegative cow, and this was the only cow-level variable to remain in the final model. Regarding herd-level variables, with "no on-farm dogs" as the baseline, "presence of dogs but not known to eat placentas and/or fetuses" increased the odds of seropositivity for N. caninum by a factor of 1.66. For "presence of dogs known to eat placentas and/or fetuses", the odds ratio (OR) was 2.75, demonstrating a dose-response relationship. "Using embryo transfer" (OR=0.69), "asking for a BVDV-negative test before introducing an animal" (OR=0.30), "using monensin in dry cows" (OR=0.71), and "heifers having nose-to-nose contact with calves" (OR=0.73) were all dichotomous variables negatively associated with seropositivity for N. caninum. "Number of milk cows on the farm" (OR=0.99), and "area (acres) used for forage production" (OR=0.99) were continuous variables negatively associated with N. caninum seropositivity., (Copyright 2009 Elsevier B.V. All rights reserved.)

Our objective was to determine the risk factors associated with the seroprevalence of Mycobacterium avium subspecies paratuberculosis (MAP) in a large number of randomly selected Canadian dairy herds, controlling for important confounding variables and co-infections with bovine leukemia virus (BLV), bovine viral diarrhea virus (BVDV) and Neospora caninum (NC). Serum samples from 30 randomly selected cows, where available, in 315 herds from seven provinces were tested for antibodies against BLV, MAP and NC using commercially available enzyme-linked immunosorbant assay (ELISA) test kits, while five unvaccinated cattle >6 months old from each herd were tested for antibodies to BVDV. We used a zero-inflated negative-binomial (ZINB) multivariable model to determine simultaneously the risk factors associated with the count of MAP-seropositive cows in a herd, and the odds of herds having no MAP-seropositive cows as compared to having one or more MAP seropositive cows in a herd. The following factors were significantly positively associated with the count of MAP-seropositive cows: "more than one cow in the maternity pen", "group-housing for pre-weaned calves in winter", "open heifers purchased during the last 12 months", "beef cattle direct (nose-to-nose) contact", "BVDV-seropositive herds (> or = 1 animal with > or = 1:64 titer)" and "BVD vaccination not done properly in calves" (i.e. after 6 months old, animals were not boostered 2-4 weeks after their first killed vaccine, or not given modified live vaccine), with count ratios of 1.7, 2.0, 2.3, 1.9, 1.4 and 1.8, respectively. The variable "BVDV vaccination (modified live) done properly in calves" (i.e. received another modified live vaccination after 6 months as well) was associated with 0.4 times fewer MAP-seropositive cows.

Our study objective was to determine the ability of milk urea-nitrogen concentrations ([MUN]) to predict fecal nitrogen concentrations ([Fecal N]) in commercial dairy herds. A total of 83 dairy herds were each visited 3 times within 48 h after a monthly herd milk test. For each farm visit, forages were sampled for nutrient analyses, which were entered into a computerized ration evaluator, and fecal samples were taken per rectum from each of 6 cows (2 early-, 2 mid-, and 2 late-lactation). Fecal samples were pooled, mixed, and analyzed for nitrogen content. Fecal nitrogen concentrations were compared with the routinely measured nutritional parameters from the ration evaluation, and the herd average [MUN] for the previous milk test date using mixed linear regression analyses. Total protein supplied in the ration was significantly positively associated with [Fecal N], but herd average [MUN] was not associated (P > 0.10) with [Fecal N].

The objective of this study was to estimate the annual losses from Mycobacterium avium subspecies paratuberculosis (MAP) for an average, MAP-seropositive, Canadian dairy herd. A partial-budget simulation model was developed with 4 components of direct production losses (decreased milk production, premature voluntary culling, mortality, and reproductive losses). Input values were obtained primarily from a national seroprevalence survey of 373 Canadian dairy farms in 8 of 10 provinces. The model took into account the variability and uncertainty of the required input values; consequently, it produced probability distributions of the estimated losses. For an average Canadian dairy herd with 12.7% of 61 cows seropositive for MAP, the mean loss was $2992 (95% C.I., $143 to $9741) annually, or $49 per cow per year. Additional culling, decreased milk production, mortality, and reproductive losses accounted for 46%, 9%, 16%, and 29% of the losses, respectively. Canadian dairy producers should use best management practices to reduce these substantial annual losses.

Objective: The objective of this study was to determine if the consumption of certain foods during the year prior to diagnosis of type 1 diabetes mellitus (T1D) was associated with the risk of developing T1D in children and youth residing in Prince Edward Island, Canada., Methods: Cases (n = 57) consisted of newly diagnosed patients with T1D during 2001 to 2004. Controls (n = 105) were randomly selected from the province's population, and matched to cases by age at diagnosis and sex. Food consumption in cases and controls was assessed using two previously validated food frequency questionnaires, and a survey was developed to collect information on potential environmental and genetic risk factors., Results: The median age at diagnosis was nine years, and 67% of cases were male. After controlling for the matched variables and four significant environmental and genetic risk factors (family members with T1D, the number of infections during the first two years of life, place of residence, and father's education) in the final logistic regression model, the consumption of regular soft drinks (OR = 2.78, 95% CI = 1.21, 6.36) and eggs (OR = 2.50, 95% CI = 1.09, 5.75) were significant risk factors of T1D, when consumed once per week or more often., Conclusion: Diet may play a role in the development of T1D. However, further research is needed to confirm these observed associations.

The performance of flow cytometry (FC) was compared with immunofluorescence microscopy (IM) for detection of Giardia duodenalis in bovine feces. Samples from 36 adult dairy cows and 208 dairy calves were collected. Flow cytometry test characteristics were calculated using continuous, ordinal, and dichotomized results. Spearman correlation coefficients comparing the results of the 2 tests were 0.47 and 0.68 for cows and calves, respectively. Using IM as indicative of presence or absence of G. duodenalis cysts in each sample, likelihood ratios of FC results with 0, 1, and > or = 2 gated events indicated that samples with 1 gated event were likely to be positive in the cows but not in the calves. Immunofluorescence microscopy detected G. duodenalis in 69.7% and 48.1% of cows and calves, respectively. When dichotomizing the FC results at a cut-off point of 1 or 2 gated events, 46.3% and 19.9% of the cow and 51.9% and 35.1% of the calf samples, respectively, were classified as G. duodenalis-positive. Relative to IM, the sensitivity in the cows was 0.59 and 0.28, respectively, and 0.76 and 0.64, respectively, in the calves. At a cut-off point of 1, 65.7% and 73.1% of the cow and calf samples, respectively, were correctly classified in FC, and at a cut-off point of 2, 49.3% and 78.4% were correctly classified in the cows and calves, respectively. Flow cytometry was less sensitive than IM. Possible reasons and research needed to improve FC for G. duodenalis detection are discussed.

Our objective of this study was to investigate the relationship between milk urea-nitrogen concentrations ([MUN]) and first-service breeding success (FSBS) in a large number of commercial dairy herds, using various timings on [MUN]. All commercial dairy herds in Prince Edward Island on monthly milk testing (n=198) formed the sampling frame. Milk components, [MUN], 24-h milk production, and breeding data for all cows from these farms were gathered electronically from a central database. A first service between 1 June 1999 and 31 May 2000 was classified successful (FSBS=1) if it was the cow's last service and she calved 270-290 d later. Mixed logistic-regression modeling was used to determine the association between FSBS (the outcome variable) and the [MUN] closest to first service, controlling for other possible confounders and clustering effects of cows within the study herds. The final dataset included 2787 successful and 3015 unsuccessful first services. A change in [MUN] on the test closest to first service from 10 to 20 mg/dL was associated with a 13.9% reduction in the odds of FSBS (controlled for parity, milk production and days in milk).

The primary purpose of this research was to determine associations among seropositivity for bovine leukemia virus (BLV), bovine viral diarrhea virus (BVDV), Mycobacterium avium ssp. paratuberculosis (MAP), and Neospora caninum (NC) and each of 3 outcome variables (305-d milk, fat, and protein production) in Canadian dairy cattle. Serum samples from up to 30 randomly selected cows from 342 herds on monthly milk testing were tested for antibodies against BLV (IDEXX ELISA; IDEXX Corporation, Westbrook, ME), MAP (IDEXX or Biocor ELISA; Biocor Animal Health, Inc., Omaha, NE), and NC (IDEXX or Biovet ELISA; Biovet Inc., St. Hyacinthe, Quebec, Canada). Up to 5 unvaccinated cattle over 6 mo of age were tested for virus-neutralizing antibodies to the Singer strain of type 1 BVDV. Dairy Herd Improvement records were obtained electronically for all sampled cows. Linear mixed models with herd and cow as random variables were fit, with significant restricted maximum likelihood estimates of outcome effects being obtained, while controlling for potential confounding variables. Bovine leukemia virus seropositivity was not associated with 305-d milk, 305-d fat, or 305-d protein production. Cows in BVDV-seropositive herds (at least one unvaccinated animal with a titer > or =1:64) had reductions in 305-d milk, fat, and protein of 368, 10.2, and 9.5 kg, respectively, compared with cows in BVDV-seronegative herds. Mycobacterium avium ssp. paratuberculosis seropositivity was associated with lower 305-d milk of 212 kg in 4+-lactation cows compared with MAP-seronegative 4+-lactation cows. Neospora caninum seropositivity in primiparous cows was associated with lower 305-d milk, fat, and protein of 158, 5.5, and 3.3 kg, respectively, compared with NC-seronegative primiparous cows. There were no interactions among seropositivity for any of the pathogens and their effects on any of the outcomes examined, although the low MAP seroprevalence limited this analysis. Results from this research will contribute to understanding the economic impacts of these pathogens and justify their control.

The aims of this study were to evaluate the performance and agreement of various commercial and in-house Neospora caninum antibody assays used in dairy cattle in North America, and to investigate reproducibility of two assays performed in different laboratories. From 1998 to 2005, three enzyme linked immunosorbent assays (ELISAs, a competitive ELISA-VMRD Inc., an indirect ELISA-Biovet Inc., and another indirect ELISA-Herdchek IDEXX Corp.), two indirect fluorescent antibody tests (IFATs, VMRD Inc., and in-house USDA) and one N. caninum agglutination test (NAT, in-house USDA) were utilized to test 397 randomly selected dairy cattle serum samples from 34 herds in eastern Canada for antibodies to N. caninum. The manufacturers' recommended cut-off values were used to evaluate test performance and agreement between tests. One IFAT (VMRD Inc.) performed well (sensitivity and specificity: 0.97 and 0.97, respectively) using reference sera (n = 452), therefore, results from this IFAT on the 397 samples could subsequently be used as the reference standard to calculate test characteristics for the other assays. Only 11% of the 397 sera were found to be N. caninum-positive with the IFAT. Prevalence-adjusted bias-adjusted kappa (PABAK) ranged from 0.06 to 0.99. Positive agreement was moderate to very good (P(pos) = 0.25-0.96). Negative agreement was very good for all assays (P(neg) > 0.94) except NAT (P(neg) = 0.66). Sensitivity was > or =0.89 for all assays except the NAT, which had a significantly lower sensitivity (0.66). Specificity was high (>0.94) for all assays except for one indirect ELISA (specificity = 0.52). This indirect ELISA did not perform satisfactorily when used in 1998, but an improved version of the ELISA performed as one of the best assays in 2004. Reproducibility of the competitive ELISA was excellent, but the reproducibility of the indirect ELISA that was improved was low (concordance correlation coefficient = 0.90 and 0.36, respectively). The performance characteristics observed for most assays in this study make them useful for screening antibodies to N. caninum in cattle.

A province-wide, cross-sectional seroprevalence and agroecological risk factor study of Mycobacterium avium subspecies paratuberculosis (MAP), Neospora caninum (NC), Bovine leukemia virus (BLV), and Bovine viral diarrhea virus (BVDv) genotypes 1 and 2 (BVDv1 and BVDv2) infection in dairy cattle herds in Alberta was conducted. Among adults, the seroprevalence of MAP, NC, and BLV was 9.1%, 18.5%, and 26.9%, respectively. For MAP, based on a herd test cutpoint of 2 or more seropositive cows, 58.8% of herds were infected. Herd-level seroprevalence for NC and BLV was 98.7% and 86.7%, respectively, based on a herd-test cutpoint of 1 seropositive cow. Among unvaccinated dairy heifers, the seroprevalence for BVDv1 and BVDv2 infection was 28.4% and 8.9%, respectively, while herd-level infection was 53.4% and 19.7%. Seroprevalence for MAP varied moderately by agroecological region, whereas that for NC, BLV, and BVDv1 and BVDv2 did not. For MAP, aridity and soil pH (correlated features of the region) were also important.

Recent international developments in the area of infectious disease control and nontariff trade barriers, along with possible zoonotic concerns, have provoked a revival of interest in Johne's disease in Canada and elsewhere. The bacterium causing Johne's disease, Mycobacterium avium subspecies paratuberculosis, is distributed worldwide and causes chronic granulomatous enteritis, also known as paratuberculosis, in domestic and exotic ruminants, including cattle. The subclinical form of this disease results in progressive weight loss, reduced milk production, lower slaughter value, and premature culling, with possible impacts on fertility and udder health. Eventually, infection can lead to the clinical form that manifests as chronic diarrhea, emaciation, debilitation, and eventual death. Currently, available tests to detect infected animals produce many false-negative results and some false-positives, particularly in subclinically infected animals, thus making their interpretation and utilization challenging in control programs. The objective of this 2-part review is to critically review the literature about Johne's disease in dairy cattle for bovine practitioners in Canada. Part I covers the clinical stages, pathophysiology, diagnosis, and prevalence of infection in Canada, while Part II discusses impacts, risk factors, and control programs relevant to Canadian dairy farms. By reviewing the scientific literature about Johne's disease, control of the disease could be pursued through informed implementation of rational biosecurity efforts and the strategic use of testing and culling.

Of 1204 dairy cows and 1425 beef cows sampled, 60.8% and 10.3% were seropositive for Bovine leukemia virus, 4.5% and 1.7% were seropositive for Mycobacterium avium subspecies paratuberculosis, and 8.3% and 9.1% were seropositive for Neospora caninum, respectively, while 28.1% of dairy herds had unvaccinated animals with titres > or = 1:64 for Bovine viral diarrhea virus.

In spatial analyses of causes or health effects of environmental pollutants, small units of analyses are usually preferred for internal environmental homogeneity reasons but can only be done when fine resolution data are available for most units. Objectives of this study were to determine which land use practices were spatially associated with ground water nitrate concentrations across Prince Edward Island (PEI), Canada, and which spatial aggregation is the preferred unit of analyses. Nitrate concentrations were determined for 4855 samples from private wells. Validated field-by-field land use data were available. Average nitrate concentration and percentage of area for the 14 major land use categories in PEI were determined for each of three spatial aggregations: watersheds based on topography and hydrology; freeform polygon boundaries based on similar neighboring nitrate concentrations; and 500-m buffer zones around each well. Results showed that the percentages of potato, grain, and hay coverage were positive predictors of ground water nitrate concentrations. Percentage of blueberry was a marginally significant negative predictor in the watershed and freeform polygon models, and percentage of residential coverage was a positive predictor in the freeform polygon and buffer zone models. Spatial autocorrelation was present in the freeform polygon and buffer zone models even after land use was taken into account. In conclusion, analyses based on watersheds produced the best predictive model with the percentages of land cover of potato, hay, and grain being significantly associated with ground water nitrate concentrations, and the percentages of blueberry, clear-cut woodland, and other agriculture being marginally significant.

Enzyme-linked immunosorbent assays (ELISAs) are used in Johne's disease (JD) control programs as a first screening for presence of the disease in a herd. A high sensitivity of the ELISA is therefore important, yet the commonly used ELISAs have relatively low sensitivity. The inclusion of an absorption phase, although improving specificity, potentially decreases sensitivity. Sera and feces of 383 adult dairy cows in 8 herds were used to compare the test characteristics of an absorbed and a nonabsorbed indirect ELISA for the detection of JD. The absorbed ELISA is based on a protoplasmic antigen, whereas the nonabsorbed uses a lipoarabinomannan-based antigen. The potential advantage of the nonabsorbed ELISA is that it may be less specific and more sensitive. Two herds certified free of JD were used to compare the specificity of the ELISAs. The other herds used to compare sensitivity were either infected with Mycobacterium avium subsp. paratuberculosis or had unknown status. Using fecal culture as a gold standard, the diagnostic specificity for the absorbed and nonabsorbed ELISAs were 98.4% and 87.9%, respectively. The diagnostic sensitivity was 72.4% and 65.5% for the absorbed and the nonabsorbed ELISA, respectively. Furthermore, a comparison using a fecal DNA probe as the comparison standard resulted in both ELISAs having a sensitivity of 61.9%. Agreement between the 2 ELISAs was moderate, with a kappa statistic of 0.58. The nonabsorbed ELISA did not have a higher sensitivity and had a lower specificity than the absorbed ELISA. Therefore, in this population, there was no advantage gained with using the nonabsorbed ELISA.

The purpose of this research was to determine the effects of seropositivity for exposure to bovine leukemia virus (BLV), bovine viral diarrhoea virus (BVDV), Mycobacterium avium subspecies paratuberculosis (MAP) and Neospora caninum (NC) on overall and reason-specific culling in Canadian dairy cattle. Serum samples from, approximately, 30 randomly selected cows from 134 herds were tested for antibodies against BLV, MAP and NC using commercially available ELISA test kits, while 5 unvaccinated cattle over 6 months of age were tested for antibodies to bovine viral diarrhoea virus (BVDV). For analyzing the time (in days) to culling of cows after the blood testing, a two-step approach was utilized, non-parametric (Kaplan-Meier survival graphs) visualization and then semi-parametric survival modelling (Cox proportional hazards model), while controlling for confounding variables and adjusting for within herd clustering. For all reasons of culling, MAP-seropositive cows had a 1.38 (1.05-1.81, 95% C.I.) times increased hazard of culling compared to MAP-seronegative cows. Seropositivity for the other pathogens was not associated with an increased risk of overall culling. Among cows that were culled because of either decreased reproductive efficiency or decreased milk production or mastitis, MAP-seropositive cows were associated with 1.55 (1.12-2.15, 95% C.I.) times increased hazard compared to MAP-seronegative cows. Among cows that were culled because of reproductive inefficiency, NC-seropositive cows had a 1.43 (1.15-1.79, 95% C.I.) times greater hazard than NC-seronegative cows. Among cows that were culled because of decreased milk production, cows in BVDV-seropositive herds had a 1.86 (1.28-2.70, 95% C.I.) times increased hazard compared to cows in BVDV-seronegative herds. BLV-seropositive cows did not have an increased risk of reason-specific culling as compared to BLV-seronegative cows. No significant interaction on culling among seropositivity for the pathogens was detected, but only a limited number of cows tested seropositive for multiple pathogens. Results from our research will help in better understanding the economic impacts of these pathogens and justification for their control.

Blood was drawn from 1530 dairy cows in 51 herds. For antibodies against bovine leukemia virus, Mycobacterium avium subspecies paratuberculosis, and Neospora caninum, 37.4%, 2.7%, and 5.6% of cows were test positive, respectively, while 29.2% of herds had unvaccinated animals with > or = 1:64 for bovine viral diarrhea virus.

The prevalence of Mycobacterium avium ssp. paratuberculosis (Mptb) in culled dairy cattle in Eastern Canada and Maine was determined to be 16.1% (95% confidence interval 13.8 to 18.3%) based on a systematic random sample of abattoir cattle. Mesenteric lymph nodes and ileum from 984 cows were examined by histologic and bacteriologic methods. Histological testing was far less sensitive than bacteriologic methods for detecting infected cattle. A seasonal pattern of positive cows was also detected, with the highest proportion of cows being Mptb-positive in June (42.5%). Overall, body condition score was not associated with prevalence of Mptb isolation.

The objectives of this study were: 1) to determine if bulk tank milk urea nitrogen (BTMUN) and whole herd weighted average of the individual cow MUN levels (WHMUN) were equivalent measurements of herd MUN status; and 2) to determine the seasonal variation in BTMUN concentrations in Prince Edward Island (PEI) dairy herds. For BTMUN-WHMUN correlation testing, bulk tank milk samples from 176 herds were tested for MUN once every 1 to 2 wk between September 1999 and August 2002, as part of routine BTM testing for milk components. During this 3-year period, all herds had all milking cows tested for MUN once a month at the same lab. The WHMUN levels (weighted for milk production) were calculated for each month, and were compared to BTMUN levels using a concordance correlation coefficient (CCC) and a graphic procedure. Tests were only compared if they occurred on the same date, producing a final dataset of 669 comparisons. The BTMUN had good (but not perfect) correlation with WHMUN (CCC = 0.91). This high reliability extended to both the pasture and non-pasture seasons, various milk sampling protocols, and all herd sizes seen in PEI. For evaluating the seasonal variation of BTMUN, the 3 y worth of data (24 803 observations) were divided into 15 seasonal categories, 5 seasons per year (early, mid, and late pasture, and early and late stable). Using linear mixed modelling, significantly (P < 0.05) higher BTMUN values were found during the mid and late pasture seasons of 2000, likely because the precipitation was unusually high during this period, enhancing pasture growth.

The ELISA tests that are available to detect an infection with Mycobacterium avium subsp. paratuberculosis (MAP) have a limited validity expressed as the sensitivity (Se) and specificity (Sp). In many studies, the Se and Sp of the tests are treated as constants and this will result in an underestimation of the variability of the true prevalence (TP). Bayesian inference provided a natural framework for using information on the test variability (i.e., the uncertainty) in the estimates of test Se and Sp when estimating the TP. Data from two prevalence studies for MAP using an ELISA in several regions in two locations were available for the analyses. In location 1, all cattle of at least 3 years of age were sampled in approximately 90 randomly sampled herds in each of the four regions of the country. In location 2, in 30 randomly sampled herds in each of three regions, approximately 30 randomly selected cows were sampled. Information about the unknown test Se and Sp and MAP prevalence was incorporated into a Bayesian model by joint prior probability distributions. Posterior estimates were obtained by combining the actual likelihood with the prior distributions using Bayes' formula. The corrected cow-level TP (proportion of infected cows in a herd) was low, 5.8 and 3.6% in locations 1 and 2, respectively. Certain regions within a location differed significantly in herd-level TP (proportion of infected herds). The herd-level TP was 54.3% in location 1 (95% credible interval (CI) 46.1, 63.3%) and 32.9% in location 2 (95% CI: 14.4, 73.3%). The variation in the herd-level TP estimate for location 2 was more than three times as large as the variation in location 1 mainly because of the relatively small number of investigated herds in location 2. In future prevalence studies for MAP, sample size calculations should be based on a very low cow-level prevalence. Approximately 50 and 90% of the herds in the current study had an estimated cow-level TP below 4 and 10%, respectively.

We determined the effects of non-nutritional factors such as breed, parity, days in milk (DIM), milk production, milk quality and milk components on milk urea nitrogen (MUN) concentration. A total of 177 dairy farms in Prince Edward Island containing 10,688 lactating dairy cows participated in the project. Individual-cow milk samples (n=68,158) were collected monthly from July 1999 to June 2000 from each farm. MUN was measured using a Fossomatic 4000 Milkoscan Analyzer at the PEI Milk Quality Laboratory. Descriptive statistics for MUN, parity, DIM, and test-day milk yield, fat and protein were calculated. Mixed linear-regression models were used; "cow" and "herd" were included as random effects to control for the effect of clustering of MUN test dates within cow, and clustering of cows within herd, respectively. The MUN was lower during the first month of lactation, peaked at 4 months of lactation, and decreased later in lactation. A positive relationship existed between MUN concentration and milk yield, while negative relationships with milk protein% and linear score were observed. A quadratic relationship existed between milk fat% and MUN concentration, with higher MUN occurring at mid-range fat percentages. The variation at the herd and cow levels in the model were 19.7 and 19.0%, respectively; while the variation at the test date level was 61.3%. The non-nutritional factors studied explained 13.3% of the variation in MUN.

The purpose of this study was to evaluate the reliability (precision and accuracy), and repeatability of an infrared method of determining milk urea nitrogen. The reference method used for the reliability assessment was a wet-chemistry, enzymatic determination of milk urea nitrogen. Reliability and repeatability, as measured by concordance correlation coefficients, were 0.97 and 0.99, respectively.

Our purpose was to determine direct production losses (milk loss, premature voluntary culling and reduced slaughter value, mortaliy loss, and abortion and reproductive loss) and treatmetn costs (veterinary services, medication cost, and extra farm labour cost) due to four infectious diseases in the maritime provinces of Canada: bovine viral diarrhoea (BVD), enzootic bovine leukosis (EBL), Johne's Disease (JD), and neosporosis. We used a partial-budget model, and incorporated risk and sensitivity analyses to identify the effects of uncertainty on costs. Total annual costs for an average, infected, 50 cow herd were: JD$ 2472; BVD$ 2421; neosporosis $ 2304; EBL$ 806. The stochastic nature of the proportion of infected herds and prevalence of infection within a herd were used to estimate probability distributions for these ex post costs. For all diseases, these distributions were right skewed. A sensitivity analysis showed the largest effect on costs was due to milk yield effects. For example, changing milk production loss from 0 to 5% for BVD increased the costs for the disease by 266%.

Bovine viral-diarrhoea (BVD), enzootic bovine leukosis (EBL), Johne's disease (JD), and neosporosis lower on-farm productivity, reduce export competitiveness, and increase consumer concerns regarding safety. Our purpose was to examine the relationship between 27 control practices and the estimated true seroprevalences for these four diseases for 2604 cattle in 90 dairy herds in the Maritimes provinces of Canada. Overall, 37.8, 20.4, 3.4, and 19.2% of all sampled cattle were truly exposed to the agents of BVD, EBL, JD, and neosporosis, respectively. The median within-herd true prevalences were 0, 9.3, 0, and 12.3%, respectively. Factor analysis reduced the 27 control practices to two highly correlated factors. Tobit-regression analyses determined that vaccination practices were associated with reduced prevalence of exposure for Bovine viral-diarrhoea and EBL. Also, farms that tended to purchase their dairy animals were associated with higher seroprevalence for Johnes' disease. Neither of these two factors was associated with the seroprevalence of Neospora caninum infection. The few routine biosecurity measures that were investigated in this study were generally not related to the seroprevalences of these farms.

Objective: To determine the value of a commercially available test for measurement of luteinizing hormone (LH) concentrations for its use in distinguishing between ovariectomized and sexually intact bitches., Design: Prospective longitudinal cohort study., Animals: 101 sexually intact bitches and 199 ovariectomized bitches, Procedure: A commercial test kit was used to assay serum samples for LH concentration. A kappa test was used to assess the consistency of test interpretations. Sensitivity, specificity, predictive values, and consistency of test interpretation in the sample population and in 2 theoretical populations of bitches with differing frequencies of ovarian removal were determined., Results: The test had excellent sensitivity (98%) but moderate specificity (78%) because of a high frequency of false-positive test results. This means that a single high serum LH concentration was not a reliable indicator of ovarian removal. However, a single low serum LH concentration was an excellent indicator that a bitch was sexually intact. The LH test results were positive within 10 days after ovarian removal and remained high in bitches from which ovaries had been removed > 5 years previously. Analysis of kappa values consistently revealed excellent agreement in test interpretation within and among evaluators and over a 6-hour time span., Conclusions and Clinical Relevance: A single low LH test result confirms the need for ovariectomy in bitches prior to adoption. The test is applicable to bitches that have been ovariectomized prior to puberty and probably applies over the lifespan of the animal.

The purpose of this study was to survey the seroprevalence of infection with the agents of production-limiting diseases in dairy cattle in New Brunswick, Nova Scotia, and Prince Edward Island. In 30 randomly selected herds per province, 30 cattle per herd were randomly selected and tested for antibodies to bovine leukemia virus (BLV) and Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis), while 5 unvaccinated cattle over 6 months of age were tested for antibodies to bovine viral diarrhea virus (BVDV). For BLV, 20.8% (15.8% to 27.0%) of cows were positive, and 70.0% (60.3% to 79.7%) of herds had at least one positive cow. In BLV-positive herds, the average BLV prevalence was 30.9% (24.8% to 37.2%). For M. paratuberculosis, 2.6% (1.8% to 3.9%) of cows were positive, and 16.7% (8.8% to 24.5%) of herds had at least 2 M. paratuberculosis-positive cows. In M. paratuberculosis-positive herds, the average M. paratuberculosis prevalence was 8.5% (6.9% to 10.1%). For BVDV, 46.1% (35.5% to 56.7%) of herds had at least 1 BVDV-positive animal with a titer greater than or equal to 1:64.

Survey responses from 75 randomly selected dairy producers on Prince Edward Island were summarized to obtain a demographic picture of the dairy industry in this province and to determine information management practices and demands for the future. The results indicate a preparedness for dairy production in the future.

The seroprevalence of Neospora caninum was compared among New Brunswick, Nova Scotia, and Prince Edward Island in 1998, 1989, and 1979. In 1998, the seroprevalence was lowest in Prince Edward Island, where it was the same as in 1989. Neospora caninum was present in 1979, but at a lower prevalence.

Twenty-two Costa Rican dairy herds were actively monitored for vesicular diseases between November 1991 and March 1992, in anticipation of the annual dry season occurrence of vesicular stomatitis (VS). Thirty-nine confirmed cases of VS were concentrated on nine farms, resulting in an average herd incidence rate of 11.1% of mature cattle for the affected farms, or 2.6% for all farms. Affected cattle were generally older (average age = 5.4 years), with seven-year-old cows having the highest age-specific incidence rate (6.5%). The New Jersey serotype of VS was diagnosed for all but four cases, primarily manifesting as teat vesicles. Cases had high acute and convalescent antibody titers for both major VS serotypes, New Jersey and Indiana, with significant titer increases after clinical disease. Screening and multiple variable regression analyses of 140 cow, farm, and ecologic variables revealed that clinical disease was significantly associated with cows being in lactation, and with higher acute antibody titers to serotype Indiana, but not with any predisposing diseases. Significant farm factors were the presence of poultry and a longer calving interval on the farm, but not higher rates of other diseases. According to a prior epidemiologic hypothesis, two ecologic factors were forced to be included into the farm model: the reported presence of sand flies, and a higher proportion of the farm being in forest land, with subsequent stepwise regression. The resulting model containing only the two forced variables was significant (P < 0.003) and correctly classified 78% of farms into the correct group, as compared with 79% for the final stepwise model.(ABSTRACT TRUNCATED AT 250 WORDS)