Paul C. Bartlett

Comparison of Prevalence and Antimicrobial Susceptibilities of Campylobacter spp. Isolates from Organic and Conventional Dairy Herds in Wisconsin

ABSTRACT The prevalence and antimicrobial susceptibilities of Campylobacter spp. isolates from bovine feces were compared between organic and conventional dairy herds. Thirty organic dairy herds, where antimicrobials are rarely used for calves and never used for cows, were compared with 30 neighboring conventional dairy farms, where antimicrobials were routinely used for animals for all ages. Fecal specimens from 10 cows and 10 calves on 120 farm visits yielded 332 Campylobacter isolates. The prevalence of Campylobacter spp. in organic and conventional farms was 26.7 and 29.1%, and the prevalence was not statistically different between the two types of farms. Campylobacter prevalence was significantly higher in March than in September, higher in calves than in cows, and higher in smaller farms than in large farms. The rates of retained placenta, pneumonia, mastitis, and abortion were associated with the proportion of Campylobacter isolation from fecal samples. The gradient disk diffusion MIC method (Etest) was used for testing susceptibility to four antimicrobial agents: ciprofloxacin, gentamicin, erythromycin, and tetracycline. Two isolates were resistant to ciprofloxacin, and none of isolates was resistant to gentamicin or erythromycin. Resistance to tetracycline was 45% (148 of 332 isolates). Tetracycline resistance was found more frequently in calves than in cows (P = 0.042), but no difference was observed between organic and conventional farms. When we used Campylobacter spp. as indicator bacteria, we saw no evidence that restriction of antimicrobial use on dairy farms was associated with prevalence of resistance to ciprofloxacin, gentamicin, erythromycin, and tetracycline.

Metritis complex in Michigan Holstein-Friesian cattle: incidence, descriptive epidemiology and estimated economic impact

Abstract Twenty-two Michigan dairy herds participating in a computerized herd health program were studied to determine the incidence and epidemiologic characteristics of metritis. Of 3773 lactations studied, 18% of the cows developed metritis at least once during the lactation. Metritis was reported most frequently immediately following calving. No clear pattern of association with age or season was demonstrated. A estimate was made of the extra cost associated with a cow treated for metritis. After including the effect on reproductive efficiency, milk production, cost of medication and losses due to culling, the total cost estimate was

Prevalence and indicators of post partum fatty infiltration of the liver in nine commercial dairy herds in The Netherlands

106.00 for a lactation with metritis.

Cystic follicular disease in Michigan Holstein-Friesian cattle: Incidence, descriptive epidemiology and economic impact

Abstract A field study was performed with 218 dairy cows in nine dairy herds in order to investigate the prevalence of post partum fatty infiltration of the liver and its relationship to subsequent body condition scores, blood variables and milk production. The mean concentration of triacylglycerols in the liver was 61.2 mg/g wet liver tissue. The prevalence of fatty liver (more than 50 mg triacylglycerol in 1 g wet liver tissue) was 54.1%. Serum non-esterified fatty acids, urea and blood glucose concentrations appeared to be significant indicators of hepatic lipidosis between 6 and 17 days post partum (R2=0.33). High milk production and large losses of body condition score in early lactation were significant indicators of hepatic lipidosis from a retrospective point of view (R2=0.22). Single body condition scores were not significantly related to the concentration of triacylglycerol in the liver. It was concluded that, according to the classification used, fatty liver seems to be fairly common in early lactating dairy cows. Although correlation coefficients were too low to enable a precise and accurate description of liver triacylglycerol content, we found some biologically explicable variables in commercial herds that were significantly related to the liver triacylglycerol content.

Repeated insemination in Michigan Holstein-Friesian cattle: Incidence, descriptive epidemiology and estimated economic impact.

Abstract Data collected from the Food Animal Health Resource Management System (FAHRMX) Dairy Herd Health Network between 1981 and 1984 were used to study the incidence, descriptive epidemiology and economic impact of cystic follicular disease. Complete records were available for 2847 lactations of Holstein-Friesian cows from 21 Michigan herds. The lactational incidence rate of cystic follicular disease was 12.8%. The condition was more common in older cattle, with a bimodal peak incidence between 30 an 40 days post-partum and between 190 and 220 days post-partum. The economic loss for the average lactation with cystic follicles was estimated at approximately

Disease surveillance and referral bias in the veterinary medical database

137 considering the effects on reproduction, culling, medical costs and labor. Lactations with cystic follicles produced an average of

Human Mycobacterium bovis infection and bovine tuberculosis outbreak, Michigan, 1994-2007.

98 more 305 mature equivalent milk than lactations without cystic follicles.

Influence of Antibiotic Selection on Genetic Composition of Escherichia coli Populations from Conventional and Organic Dairy Farms

Twenty-two Michigan dairy herds participating in a computerized herd-health program were studied to determine the incidence and epidemiologic characteristics of repeat-breeder syndrome. A cow with repeat-breeder syndrome was defined as having been inseminated three or more times within the same lactation. Repeat-breeder syndrome was observed in 24% of 3,309 lactations. Cost components associated with unsuccessful inseminations included costs of delayed conception, extra inseminations, extra veterinary service and losses due to culling. Lactations with repeat-breeder syndrome were associated with a loss of approximately

Association of Group B Streptococcus Colonization and Bovine Exposure: A Prospective Cross-Sectional Cohort Study

385. An estimated extra cost of

Comparison of Antimicrobial Susceptibility of Staphylococcus aureus Isolated from Bulk Tank Milk in Organic and Conventional Dairy Herds in the Midwestern United States and Denmark

140 was associated with a second insemination,