ARS | Publication request: Effects of dry cow treatment of beef cows on pathogenic organisms, milk somatic cell counts, and calf growth during the subsequent lactation

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 1, 2007
Publication Date: December 1, 2007
Citation: Lents, C., Wettemann, R., Paape, M.J., Looper, M.L., Buchanan, D. Effects of dry cow treatment of beef cows on pathogenic organisms, milk somatic cell counts, and calf growth during the subsequent lactation . American Society of Animal Science. 86:748-755.

Interpretive Summary: Milk production of cows account for about 60% of the variation in weaning weights of calves. Mastitis, a bacterial infection of the mammary gland, causes reduced milk yield and subsequent decreases in body weights of calves. Minimal information exists on antibiotic treatment of the mammary gland of beef cows. Personnel from Oklahoma State University and ARS scientists from Beltsville, MD and Booneville, AR, conducted an experiment to determine effects of intramammary treatment with antibiotics at the time of weaning on udder health and calf growth following the subsequent calving. Treatment of nonlactating beef cows with antibiotics improved udder health and increased body weight gain of calves during the next calving cycle. This information is of interest to livestock producers, extension personnel, and agricultural professionals who advise producers on livestock management practices.

Technical Abstract: Spring calving Angus and Angus x Hereford multiparous cows were utilized to determine effects of intramammary treatment with penicillin G procaine (200,000 IU) and novobiocin (400 mg) at the time of weaning on udder health and calf growth following the subsequent calving. Cows were stratified by age and breed, and assigned randomly to receive intramammary treatment (n = 99) at weaning or untreated controls (n = 97). Quarter milk samples were collected at weaning and at 8 to14 d after calving. Milk samples were analyzed for somatic cell counts (SCC) and mastitis causing bacteria. Dry cow treatment decreased (P = 0.005) the number of cows infected after calving. Treatment decreased (P = 0.04) the number of cows that developed new infections and reduced (P = 0.03) the number of quarters with mastitis causing bacteria after calving, that were infected at weaning. Somatic cell counts after calving were greatest (P = 0.008) for cows infected with Staphylococcus aureus. Treatment did not alter (P = 0.19) SCC of quarters after calving that were infected with s. aureus at weaning, but reduced (P = 0.002) SCC after calving of quarters that were infected with coagulase-negative staphylococci at weaning. Weight of calves during early lactation was increased (P = 0.006) if cows with intramammary infection were treated at weaning. Treatment of non-infected cows at weaning increased (P = 0.008) adjusted 205 d weaning weights of calves after the subsequent lactation when compared with untreated non-infected cows. We conclude that treatment of beef cows at weaning with intramammary antibiotics decreased intramammary infections after calving, improved udder health during the subsequent lactation, and increased BW gain of calves.