Section of Epidemiology, Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
J Dairy Sci. 2010 Apr;93(4):1551-60. doi: 10.3168/jds.2009-2599.
The objective of this study was to estimate the effects of different types of clinical mastitis (CM) on the probability of conception in New York State Holstein cows. Data were available on 55,372 artificial inseminations (AI) in 23,695 lactations from 14,148 cows in 7 herds. We used generalized linear mixed models to model whether or not a cow conceived after a particular AI. Independent variables included AI number (first, second, third, fourth), parity, season when AI occurred, farm, type of CM (due to gram-positive bacteria, gram-negative bacteria, or other organisms) in the 6 wk before and after an AI, and occurrence of other diseases. Older cows were less likely to conceive. Inseminations occurring in the summer were least likely to be successful. Retained placenta decreased the probability of conception. Conception was also less likely with each successive AI. The probability of conception associated with the first AI was 0.29. The probability of conception decreased to 0.26, 0.25, and 0.24 for the second, third, and fourth AI, respectively. Clinical mastitis occurring any time between 14 d before until 35 d after an AI was associated with a lower probability of conception; the greatest effect was an 80% reduction associated with gram-negative CM occurring in the week after AI. In general, CM due to gram-negative bacteria had a more detrimental effect on probability of conception than did CM caused by gram-positive bacteria or other organisms. Furthermore, CM had more effect on probability of conception immediately around the time of AI. Additional information about CM (i.e., its timing with respect to AI, and whether the causative agent is gram-positive or gram-negative bacteria, or other organisms) is valuable to dairy personnel in determining why some cows are unable to conceive in a timely manner. These findings are also beneficial for the management of mastitic cows (especially those with gram-negative CM) when mastitis occurs close to AI.
本研究旨在估计不同类型的临床型乳房炎（CM）对纽约州荷斯坦奶牛受孕概率的影响。数据来自 7 个牛场的 14148 头奶牛的 23695 个泌乳期的 55372 次人工授精（AI）。我们使用广义线性混合模型来模拟特定 AI 后奶牛是否受孕。自变量包括 AI 次数（第一次、第二次、第三次、第四次）、胎次、AI 发生的季节、牛场、AI 前后 6 周内 CM 的类型（由革兰氏阳性菌、革兰氏阴性菌或其他病原体引起）以及其他疾病的发生情况。年龄较大的奶牛受孕概率较低。夏季发生的 AI 受孕可能性最小。胎衣不下降低了受孕的概率。随着 AI 的进行，受孕的可能性也越来越小。第一次 AI 相关的受孕概率为 0.29。第二次、第三次和第四次 AI 的受孕概率分别降低至 0.26、0.25 和 0.24。AI 前 14 天至 AI 后 35 天期间发生的任何时间的 CM 都与受孕概率降低有关；最大的影响是在 AI 后一周内发生的革兰氏阴性 CM 导致受孕概率降低 80%。一般来说，革兰氏阴性菌引起的 CM 对受孕概率的影响大于革兰氏阳性菌或其他病原体引起的 CM。此外，CM 对 AI 前后的受孕概率影响更大。CM 的更多信息（即，其与 AI 的时间关系，以及病原体是革兰氏阳性菌还是革兰氏阴性菌或其他病原体）对于奶牛养殖人员确定为什么某些奶牛不能及时受孕很有价值。这些发现对于管理接近 AI 时发生的乳腺炎奶牛（特别是患有革兰氏阴性 CM 的奶牛）也很有益。
