Mammary Pathogens and Their Relationship to Somatic Cell Count and Milk Yield Losses in Dairy Ewes

作者：Carlos Gonzalo, A. Ariznabarreta, Juan Antonio Carriedo, F. San Primitivo · 发表于：Journal of Dairy Science · 年份：2002 · DOI：10.3168/jds.s0022-0302(02)74214-8 · 被引用次数：172 · 研究领域：Milk Quality and Mastitis in Dairy Cows、Microbial infections and disease research、Probiotics and Fermented Foods

A total of 9592 samples of half udder milk were collected monthly throughout lactation for bacteriological and somatic cell count (SCC) study from 1322 Churra ewe lactations from seven separate flocks enrolled in the recording scheme of the National Association of Spanish Churra Breeders in the Castile-Le6n region of Spain. Statistical analyses were carried out from a mixed model with random factor half udder or ewe for repeated measures. Test of significance of fixed effects of this mixed model showed significant effects of organisms, flock, parity, lactation stage, and birth type on SCC. Special reference must be made to novobiocin-sensitive coagulase-negative staphylococci, which represented more than 50% of the isolates and which elicited SCC geometric means of around 106/ml. In addition, the analysis of 4352 monthly test-day records for milk yield, SCC, and bacteriology showed that the ewes that were uninfected and infected by minor pathogens had the lowest SCC and the highest milk yields, whereas those infected by major pathogens had high SCC and milk yield losses between 8.8 and 10.1% according to the uni- or bilateral character of the infection. Finally, ewes infected by novobiocin-sensitive coagulase-negative staphylococci elicited SCC values similar to those of infections by major pathogens and milk yield losses ranging between those caused by minor and major pathogens. As a result, emphasis should be put on prevention of subclinical mastitis, particularly mastitis ...