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Milk samples collected from dairy cattle suspected of having mastitis were submitted to the Microbiology Laboratory of the Animal Health Diagnostic Laboratory, Michigan State University, for bacteriologic culture. A total of 2778 isolates, from the years 1994 to 2000, were isolated, identified, and subjected to in vitro antimicrobial susceptibility testing(More)
Two groups of dairy herds (16 herds/group) were studied to determine the relationship between the prevalence of mastitis in a herd and mean herd blood concentrations of vitamins A and E, beta-carotene, and selenium (Se). One group had a Dairy Herd Improvement Association 12-month mean herd somatic cell count (SCC) of less than or equal to 150,000 cells/ml.(More)
The objectives of this study were to determine the efficacy of intramuscular administration of ceftiofur to reduce the incidence of case-related death and culling following severe clinical mastitis in lactating dairy cattle. A total of 104 cows with severe clinical mastitis (systemic signs) were enrolled in the study and randomly assigned to one of two(More)
Six primiparous Holstein cows were fed a Se-deficient diet, beginning at least 90 days before their first calving, and 6 other primiparous cows were given the same diet plus a supplement of 2 mg of Se/cow/d as sodium selenite. All cows were fed their diets for the duration of the experimental period. One uninfected quarter of each cow was injected with 25(More)
The biggest challenge for host immune defense against mastitis-causing bacteria in dairy cows is to quickly recruit large enough numbers of opsonizing molecules and mature neutrophils into milk such that intramammary pathogens are cleared before they multiply significantly and the inflammatory response gets out of control. Currently, this challenge is best(More)
Ten Holstein heifers were fed a selenium-deficient (SeD) diet (0.04 mg of Se/kg on a total ration dry-matter basis) 3 months before calving and throughout their first lactation. A selenium-supplemented (SeS) diet (2 mg of Se/head/d) was fed to a group of 10 heifers. In about the 14th week of lactation, the cows were challenge-exposed to Escherichia coli by(More)
Methods to enhance mammary resistance to bacterial infection and to reduce the effects of existing infections without the use of antimicrobial agents are becoming more attractive, primarily because of increasing pressure from consumers and regulatory agencies to decrease the risk of drug residues in milk. Because of the difficulty in obtaining satisfactory(More)
Eighteen dairy herds were studied, 12 with a 12-month Dairy Herd Improvement Association herd mean somatic cell count (SCC) less than or equal to 150,000 cells/ml (low SCC) and 6 with a 12-month mean SCC greater than 700,000 cells/ml (high SCC). At the outset of the study, quarter samples for bacteriologic culture were collected (in duplicate) from all(More)
  • R J Erskine
  • 1993
Increasing evidence presents a relationship between nutrition and mammary resistance to infection. The role of nutrition in mammary resistance has been best defined for antioxidants. To optimize this interaction, rations should be balanced and formulated for lactational stage. Although supplementation of nutrients with antioxidant function may enhance(More)
Holstein cows (n = 555) from four Michigan dairy farms were randomly assigned to receive bovine somatotropin (bST) or to serve as untreated controls. Bovine somatotropin (500 mg) was administered every 14 d beginning at 63 to 69 d of lactation and continuing until approximately 21 d prior to dry-off or until the cow was removed from the herd. Trial(More)