Extended Ceftiofur Therapy for Treatment of Experimentally-Induced Streptococcus uberisMastitis in Lactating Dairy Cattle

Abstract

Streptococcus uberis is an important cause of mastitis in dairy cows throughout the world, particularly during the dry period, the period around calving, and during early lactation. Strategies for controlling Strep. uberis mastitis are poorly defined and are currently inadequate. Objectives of the present study were to evaluate efficacy of ceftiofur, a new broad-spectrum cephalosporin antibiotic, for treatment of experimentally induced Strep. uberis intramammary infections (IMI) in lactating dairy cows during early lactation and to determine whether extended therapy regimens enhanced efficacy of ceftiofur. Efficacy of extended ceftiofur intramammary therapy regimens was investigated in 37 mammary quarters of 23 dairy cows that developed clinical mastitis following experimental infection with Strep. uberis during early lactation. Cows that developed clinical mastitis during the challenge period were allocated randomly to 3 groups representing 3 different ceftiofur treatment regimens: 2-d (n = 7 mammary quarters), 5-d (n = 16 mammary quarters), and 8-d (n = 14 mammary quarters) treatment regimens. For all groups, 125 mg of ceftiofur hydrochloride was administered via intramammary infusion. A bacteriological cure was defined as an experimentally infected quarter that was treated and was bacteriologically negative for the presence of Strep. uberis at 7, 14, 21, and 28 d posttreatment. Percentage of Strep. uberis IMI eliminated was 43, 88, and 100% for the 2-, 5-, and 8-d ceftiofur treatment regimens, respectively. Both the 5- and 8-d ceftiofur extended therapy treatment regimens had significantly higher bacterial cure rates than the standard 2-d ceftiofur treatment regimen. The bacterial cure rate of the 8-d ceftiofur extended therapy group was marginally better (P = 0.052) than the 5-d ceftiofur extended therapy group. Results of this study indicate that ceftiofur therapy was effective for eliminating Strep. uberis experimental IMI, and 5- and 8-d extended ceftiofur therapy regimens were more effective than the standard 2-d treatment.

Effects of Escherichia coli- and Staphylococcus aureus-induced mastitis in lactating cows on oocyte developmental competence

“…In addition, SCC was determined (by Z1 Coulter counter, Coulter Electronics, Luton, UK) in three sequential aseptic milk samples taken from each of the four mammary quarters once a week before the experiment was begun, as described previously (Younis et al 2003, Leitner et al 2006. Bacterial examination was performed according to the International Dairy Federation procedures using accepted standards for bacteriological typing (Oliver et al 2004). …”

Innate immune response to intramammary infection with Serratia marcescens and Streptococcus uberis

“…Similar to S. marcescens infections, IMI's caused by S. uberis are predominantly subclinical and can persist for long periods of time in a chronic state [21,22,40]. Currently recommended antibiotic therapy in the USA for S. uberis IMI remains sub-optimal as two-day treatment with pirlimycin was recently reported to eliminate only 58% of infections [38].…”

Bovine Streptococcus uberis Intramammary Infections and Mastitis

“…Oliver et al [88,90] investigated the effect of time using the third-generation cephalosporin ceftiofur to treat S. uberis mastitis for two, five, and eight days. Bacterial cure rates for naturally-occurring, subclinical cases were to 17, 56, and 67%, resp.…”

“…Several studies demonstrated that the extension of the therapy is advantageous [85,[87][88][89][90]. Oliver et al [88,90] investigated the effect of time using the third-generation cephalosporin ceftiofur to treat S. uberis mastitis for two, five, and eight days.…”