Efficacy of prepartum intramammary lactating cow treatment in dairy heifers

Mastitis in prepartum dairy heifers has been recognized as a significant economic problem for the dairy industry. Intramammary infusion of cephapirin sodium was completed in 20 treatment animals and the results were compared to 25 non-treated control animals. Bacteriological data from the quarter milk samples were used to determine and compare initial infection rates and cure rates following calving between treatment and control groups. Comparisons were also made between groups for differences in reproductive performance, milk yield, somatic cell count and milk ketone concentration. Milk yield did not differ between groups for either DHIA monthly average kg/day, 305 day actual milk yield or 305 day mature equivalent yield (305ME). The average weekly milk weights (kg/d) between groups were different (P\u3c.0001). Reproductive performance between groups was not significantly different. Milk ketone concentration did not differ at weeks 1 or 2. Somatic cell count score (SCS) at 200 days in milk were not different between groups, but the treatment group exhibited a trend towards lower cell counts (P\u3c.10). SCS in the treatment group tended to be lower (P\u3c.09) during the average of the first 3 DHIA test periods. Prepartum treatment of dairy heifers significantly improved cure rates in the treatment group (P\u3c.003), moderately reduced SCC throughout lactation, and did not affect milk yield. While there were no significant differences between treatment groups in milk ketone concentration, evidence suggests that infections caused by major mastitis pathogens may increase metabolic stress on primiparous heifers. Further research in the use of prepartum lactating cow antibiotics in heifers is needed