Department of Animal Biosciences, University of Guelph, ON, Canada, N1G 2W1.
Department of Animal Sciences, University of Florida, Gainesville 32611.
J Dairy Sci. 2019 Dec;102(12):11701-11717. doi: 10.3168/jds.2019-17025. Epub 2019 Sep 20.
Two retrospective studies examining data of 7,500 lactating cows from a single herd were performed with the objective of evaluating the long-term effects of clinical disease during the early postpartum period on milk production, reproduction, and culling of dairy cows through 305 days in milk (DIM). In the first study, data regarding health, milk production, reproduction, and culling of 5,085 cows were summarized. Cows were classified according to incidence of clinical problem (metritis, mastitis, lameness, digestive problem, or respiratory problem) during the first 21 DIM (ClinD21). During 305 d of lactation, cows that had ClinD21 produced, on average, 410 kg less milk, 17 kg less fat, and 12 kg less protein compared with cows that did not have ClinD21 (NoClinD21). Although the interval to first breeding was not different between groups of interest, pregnancy rate through 305 DIM was lower in cows that had ClinD21 [adjusted hazard ratio (AHR) = 0.81]. When individual breedings were analyzed, cows that had ClinD21 presented lower rates of pregnancy per breeding for breedings performed before 150 DIM, reduced numbers of calving per breeding for breedings performed before 200 DIM, and greater number of pregnancy losses for all breedings performed through 305 DIM. The rate of culling from calving through 305 DIM was higher in cows that had a single ClinD21 (AHR = 1.79) and in cows that had multiple ClinD21 (AHR = 3.06), which resulted in a greater proportion of cows leaving the herd by 305 DIM (NoClinD21 = 22.6%; single ClinD21 = 35.7%; multiple ClinD21 = 53.8%). In the second study, data regarding postpartum health and 305-d yields of milk, fat, and protein were collected from 2,415 primiparous cows that had genomic testing information. Genomic estimated breeding values (EBV) were used to predict 305-d yields of milk, fat, and protein. Genomic EBV and predicted yields of milk, fat, and protein did not differ between cows that had ClinD21 and those that did not have ClinD21. In contrast, the observed 305-d yields of milk, fat, and protein were reduced by 345, 10, and 10 kg, respectively, in cows that had ClinD21 compared with cows that did not have ClinD21. We conclude that clinical disease diagnosed and treated during the first 21 DIM has long-term effects on lactation performance, reproduction, and culling of dairy cows, which contribute to detrimental consequences of health problems on sustainability of dairy herds. Replication of our studies in multiple herds will be important to confirm our findings in a larger population.
进行了两项回顾性研究，以评估单一群落中 7500 头泌乳奶牛的早期产后临床疾病对奶牛产奶量、繁殖和淘汰率的长期影响，直至 305 天泌乳日（DIM）。在第一项研究中，总结了 5085 头奶牛的健康、产奶量、繁殖和淘汰数据。根据奶牛在最初 21 天 DIM 期间（ClinD21）发生临床问题（子宫炎、乳腺炎、跛行、消化问题或呼吸问题）的发生率对奶牛进行分类。在 305 天的泌乳期内，患有 ClinD21 的奶牛的产奶量平均减少了 410 公斤，脂肪减少了 17 公斤，蛋白质减少了 12 公斤，而没有 ClinD21 的奶牛则没有这种情况（NoClinD21）。尽管两组奶牛的首次配种间隔时间没有差异，但患有 ClinD21 的奶牛的妊娠率在 305 天 DIM 时较低[调整后的风险比（AHR）=0.81]。当分析个体配种时，患有 ClinD21 的奶牛在 150 DIM 之前的配种中妊娠率较低，在 200 DIM 之前的配种中每头产犊数减少，在 305 DIM 之前的所有配种中妊娠损失数增加。从分娩到 305 DIM 的淘汰率在患有单一 ClinD21 的奶牛（AHR=1.79）和患有多种 ClinD21 的奶牛（AHR=3.06）中较高，这导致更多的奶牛在 305 DIM 时离开牛群（NoClinD21=22.6%；单一 ClinD21=35.7%；多种 ClinD21=53.8%）。在第二项研究中，从 2415 头具有基因组测试信息的初产奶牛中收集了产后健康和 305 天牛奶、脂肪和蛋白质产量的数据。基因组估计育种值（EBV）用于预测 305 天牛奶、脂肪和蛋白质的产量。患有 ClinD21 的奶牛与没有 ClinD21 的奶牛的基因组 EBV 和预测产量的牛奶、脂肪和蛋白质没有差异。相比之下，与没有 ClinD21 的奶牛相比，患有 ClinD21 的奶牛的 305 天牛奶、脂肪和蛋白质实际产量分别减少了 345、10 和 10 公斤。我们得出结论，在最初的 21 天 DIM 中诊断和治疗的临床疾病对奶牛的泌乳性能、繁殖和淘汰率有长期影响，这对奶牛群的可持续性造成了健康问题的不利后果。在多个牛群中复制我们的研究将很重要，以在更大的人群中证实我们的发现。
