THERAPEUTIC AND PROPHYLACTIC EFFECT OF PREPARTUM ANTIBIOTIC INFUSION IN HEIFERS

Prepartum bacteriologic examination of secretions from 42 dairy heifer s 12-14 weeks prepartum revealed a total of 24 Staphylococcus aureus i nfected quarters, 53 Staphylococcus species infected quarters, and 20 Streptococcus species infected quarters. Prepartum intramammary therap y of primigravid dairy heifers with two commercially available dry cow antibiotics (penicillin-novobiocin or cephapirin) resulted in cure ra tes of 94 %, 97 %, and 100 % for S. aureas Staphylococcus species, and Streptococcus species intramammary infections (IMI), respectively. No protective effect was observed for dry cow treatment of uninfected qu arters of heifers for any of the antibiotic preparations. No antibioti c was detectable in heifer secretions collected at parturition indicat ing that antibiotic concentrations may have fallen below protective le vels prior to parturition.