tilmicosin and Escherichia-coli-Infections

A new, extended long-acting tilmicosin (TLAe) preparation was tested against intramammary ceftiofur (CEF) using a non-inferiority trial model during dry-cow therapy (DCT) in a farm with high bovine population density and deficient hygiene application.. To evaluate the possibility that TLAe administered parenterally can achieve non-inferiority status compared to CEF administered intramammary for DCT.. TLAe and CEF had overall cure rates of 57% and 53% (. This study is the first successful report of parenteral DCT showing comparable efficacy as CEF, the gold-standard. The extended long-term pharmacokinetic activity of TLAe explains these results.

Topics: Animals; Anti-Bacterial Agents; Cattle; Cattle Diseases; Cephalosporins; Delayed-Action Preparations; Escherichia coli; Escherichia coli Infections; Female; Injections, Subcutaneous; Mastitis, Bovine; Staphylococcal Infections; Staphylococcus aureus; Streptococcal Infections; Streptococcus; Tylosin

The objective of this study was to compare the efficacy of an intramammary infusion, containing tilmicosin phosphate, to an infusion of a negative control intramammary placebo for preventing new intramammary infections (IMI) during the dry period. Cows were enrolled from 24 dairy herds from three geographical regions of Canada. Data from 248 cows and 938 bacteriologically negative quarters at drying-off are summarized. Overall, the rate of new IMI during the dry period was 16.7% of quarters. The new infection rates for quarters that received intramammary tilmicosin compared with the intramammary placebo were 14.4 and 19.4%, respectively. The majority of new IMI was caused by coagulase-negative staphylococci (49%) and environmental streptococcal organisms (26.8%). The probability for quarters to develop new IMI in the dry period was significantly increased when cows had higher milk production before drying-off (P = 0.04), when cows had longer dry periods (P = 0.02), and when dry cows were housed in tie-stall barns (P = 0.002). Higher parity cows and those that had a linear score somatic cell count (SCC) above 4 on the last DHI test were also at increased risk for new IMI (P < 0.10). Administration of intramammary tilmicosin appears to be an efficacious therapy for prevention of new IMI; however, there is currently no approved intramammary formulation of this product available. Use of blanket dry cow antibiotic therapy compared to selective dry cow therapy, as well as the importance of identifying risk factors and managing the environment of dry cows are discussed.

Topics: Animals; Anti-Bacterial Agents; Canada; Cattle; Cell Count; Escherichia coli Infections; Female; Klebsiella Infections; Lactation; Logistic Models; Macrolides; Mammary Glands, Animal; Mastitis, Bovine; Milk; Parity; Placebos; Risk Factors; Staphylococcal Infections; Streptococcal Infections; Tylosin