Heifers infected with coagulase-negative staphylococci in early lactation have fewer cases of clinical mastitis and higher milk production in their first lactation than noninfected heifers
Heifers infected with coagulase-negative staphylococci in early lactation have fewer cases of clinical mastitis and higher milk production in their first lactation than noninfected heifers
复制标题
DOI：
10.3168/jds.2009-2897
复制
发表时间：
2010-05-01
影响因子：
3.5
通讯作者：
De Vliegher, S.
中科院分区：
文献类型：
--
作者：
Piepers, S.;Opsomer, G.;De Vliegher, S.
乳房内感染(IMI)在新生的小母牛中比以前认为的更常见，但它们与未来生产性能的相关性很少被研究。在本研究中，探讨了新鲜小母牛的IMI状态与它们随后的乳房健康、产奶量和第一次哺乳时的淘汰之间的关系。从20个奶牛群的191头小母牛中采集1~4d乳样(DIM)和5~8DIM乳样进行细菌学培养和体细胞计数(SCC)分析。每个月的牛奶记录数据包括混合牛奶的SCC和试验日产奶量(MY)，从最初的285dim或直到淘汰。农民记录的临床乳房炎病例可用。数据分析采用混合模型和生存分析。大约80%的新鲜小母牛(79.8%)至少有一个培养阳性季度。最常见的病原菌为凝固酶阴性葡萄球菌(CNS)(72%)，其次为七叶素阳性链球菌(4.6%)和金黄色葡萄球菌(3.5%)。在第一次和第二次采样之间，四分之一水平的总体几何平均体细胞数从348,000个/毫升下降到116,000个/毫升。感染CNS的小母牛在前285天的平均体细胞数(84,000个/毫升)高于未感染的小母牛(53,000个/毫升)和感染主要病原体的小母牛(195,000个/毫升)。感染主要病原体的小母牛在第一次哺乳期间的日均体重(18.3 kg)明显低于未感染的小母牛(21.3 kg)。感染中枢神经系统的小母牛的产奶量高于未感染的小母牛，这至少可以部分解释为，与未感染的小母牛相比，感染了中枢神经系统的小母牛在第一次哺乳期间的临床乳房炎发病率显著降低(发病率风险为3.6%比21.0%)。我们的结论是，尽管中枢神经系统导致了产犊期间小母牛的大部分IMI，但它们不应该成为一个严重担忧的理由。
Intramammary infections (IMI) in recently calved dairy heifers are more common than was formerly believed but their relevance for future performance has been studied only rarely. In the present study, the association between the IMI status of fresh heifers and their subsequent udder health, milk production, and culling in first lactation was explored. Quarter milk samples were collected between 1 and 4 d in milk (DIM) and between 5 and 8 DIM from 191 dairy heifers in 20 dairy herds for bacteriological culturing and somatic cell count (SCC) analysis. Monthly milk recording data including composite milk SCC and test-day milk yield (MY) were obtained for the first 285 DIM or until culling. Farmer-recorded clinical mastitis cases were available. Data were analyzed using mixed models and survival analysis. Approximately 80% of the fresh heifers (79.8%) had at least one culture-positive quarter. Coagulase-negative staphylococci (CNS) were the most frequently isolated pathogens (72%), followed by esculin-positive streptococci (4.6%) and Staphylococcus aureus (3.5%). Overall geometric mean SCC at quarter level decreased between the first and second samplings from 348,000 to 116,000 cells/mL. Heifers infected with CNS had an intermediate average test-day SCC (84,000 cells/mL) during the first 285 DIM compared with noninfected heifers (53,000 cells/mL) and heifers infected with major pathogens (195,000 cells/mL). Heifers infected with major pathogens had a much lower average daily MY (18.3 kg) during first lactation compared with noninfected animals (21.3 kg). That CNS-infected heifers out-produced their noninfected counterparts could be at least partially explained by their significantly lower incidence of clinical mastitis (incidence risk 3.6 vs. 21.0%) during first lactation compared with noninfected heifers. We conclude that although CNS cause the majority of IMI in heifers around calving, they should not be a reason for serious concern.