Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/4/1999
Publication Date: N/A
Citation: Paape, M.J., Duenas, M.I., Wetemann, R., Douglass, L.W. 1999. Incidence of mastitis in beef cows after intramuscular administration of oxytetracycline. Journal of Animal Science. 79:1996-2005.
Interpretive Summary: Results indicate that the prevalence of mastitis in beef cows is high. On average, 43% of the cows and 14% of the quarters were infected at calving, and increased to 53% and 25% at weaning. Further, the incidence of mastitis and the number of blind quarters increased with parity. As the number of infected and blind quarters increased, weaning weight of calves decreased. Reducing the incidence of mastitis and the number of blind quarters in bee cows should be considered as a management tool to increase calf weaning weight.
Technical Abstract: Effects of the number of infected mammary quarters, number of blind or dry mammary quarters, type of intramammary pathogen, and parity on calf weaning weight, milk somatic cell counts, milk components and intramammary infection were studied after antibiotic treatment at post-calving and subsequent weaning on 115 purebred Hereford cows. Oxytetracycline was administered intramuscularly following collection of quarter milk samples. Percentage of infected cows and quarters averaged 43.4 and 16.4% at calving and increased to 53.7 and 29.7% at weaning. Calves from cows with 1 or 2 blind quarters or with 3 to 4 infected quarters weighed less than calves with no blind quarters or with no infected quarters. Infections by Staphylococcus aureus and coagulase negative staphylococci were the most common and accounted for 67 and 78% of the infections. Percentages of infected cows and quarters, infections caused by S. aureus, and blind quarters increased with parity. No differences were found among antibioti treatments for any of the response variables studied.