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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.)

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.)

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.

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.

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.

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.

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.

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.

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.

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.

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 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.

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)