Logroño Joaquín Chiozza, Rearte Ramiro, Corva Santiago Gerardo, Domínguez Germán Ariel, de la Sota Rodolfo Luzbel, Madoz Laura Vanina, Giuliodori Mauricio Javier
Instituto de Investigaciones en Reproducción Animal (INIRA), Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata (FCV-UNLP), La Plata B1900AVW, Argentina.
Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Ciudad Autónoma de Buenos Aires C1033AAJ, Argentina.
Animals (Basel). 2021 Aug 3;11(8):2294. doi: 10.3390/ani11082294.
The main aim of this study was to assess the associations between the timing of lameness clinical case occurrence in lactation with productive and reproductive performances in grazing Holstein cows. A cohort study was carried out on a dataset with records from a commercial dairy herd (Buenos Aires, Argentina) for cows that calved and were dried off from January 2010 through June 2017. The first recorded event of lameness per lactation was considered for the study. Criteria for lactation inclusion included not having uterine diseases, mastitis, or anovulatory cysts during the studied risk period (i.e., up to 200 DIM). Therefore, a total of 7156 out of 20,086 lactations were included in the statistical analysis. The association between lameness case occurrence in lactation (cows not lame (LG0) vs. lame cows between parturition and first service (LG1) vs. lame cows between first service and first pregnancy (LG2)) with productive (i.e., accumulated milk yield to 150 DIM (MILK150) and 300 DIM (MILK305)) and reproductive performances (hazard of insemination and pregnancy) was analyzed with linear regression models and proportional hazard regression models, respectively. Lame cows produced 161 and 183 kg less MILK150 and MILK305 than non-lame herd mates, respectively. Moreover, LG1 cows produced 216 kg less MILK150 and 200 kg less MILK305 than LG0 cows, and LG2 cows also produced 58 kg less MILK150 and 158 kg less MILK305 than LG0 cows. The LG1 cows had a lower hazard of service than LG0 cows (HR = 0.43, 95%CI = 0.39-0.47). Furthermore, LG1 cows had a lower hazard of pregnancy than LG0 cows (HR = 0.52, 95%CI = 0.46-0.59) and took longer to get pregnant than LG0 cows (median [95%CI], 139 [132-144] vs. 101 [99-103]). Moreover, LG2 cows had a much lower hazard of pregnancy than LG0 cows (HR = 0.08, 95%CI = 0.05-0.12) and much longer calving to first pregnancy interval than LG0 cows (188 [183-196] vs. 101 [99-103]). In conclusion, cows that become lame in early lactation produce less milk and have lower hazards of insemination and pregnancy than herd mates that are healthy or become lame later in lactation. In addition, cows that become lame immediately after the voluntarily waiting period have the poorest reproductive performance (i.e., they have the lowest hazard of pregnancy and the longest calving to pregnancy interval).
本研究的主要目的是评估泌乳期跛行临床病例发生时间与放牧荷斯坦奶牛生产性能和繁殖性能之间的关联。对一个商业奶牛场（阿根廷布宜诺斯艾利斯）2010年1月至2017年6月产犊并干奶的奶牛记录数据集进行了队列研究。本研究考虑了每个泌乳期首次记录的跛行事件。纳入泌乳期的标准包括在研究的风险期（即至200天泌乳期）内没有子宫疾病、乳腺炎或无排卵囊肿。因此，20086次泌乳中有7156次被纳入统计分析。用线性回归模型和比例风险回归模型分别分析了泌乳期跛行病例发生情况（未跛行奶牛（LG0）与分娩至首次配种期间跛行奶牛（LG1）与首次配种至首次怀孕之间跛行奶牛（LG2））与生产性能（即至150天泌乳期（MILK150）和300天泌乳期（MILK305）的累计产奶量）和繁殖性能（授精和怀孕风险）之间的关联。跛行奶牛的MILK150和MILK305分别比未跛行的同群奶牛少产161千克和183千克。此外，LG1奶牛的MILK150比LG0奶牛少产216千克，MILK305比LG0奶牛少产200千克，LG2奶牛的MILK150也比LG0奶牛少产58千克，MILK305比LG0奶牛少产158千克。LG1奶牛的配种风险低于LG0奶牛（风险比（HR）=0.43，95%置信区间（CI）=0.39 - 0.47）。此外，LG1奶牛的怀孕风险低于LG0奶牛（HR = 0.52，95%CI = 0.46 - 0.59），且怀孕所需时间比LG0奶牛长（中位数[95%CI]，139[132 - 144]天对101[99 - 103]天）。此外，LG2奶牛的怀孕风险远低于LG0奶牛（HR = 0.08，95%CI = 0.05 - 0.12），且分娩至首次怀孕间隔远长于LG0奶牛（188[183 - 196]天对101[99 - 103]天）。总之，泌乳早期跛行的奶牛比健康或泌乳后期跛行的同群奶牛产奶量少，授精和怀孕风险低。此外，在自愿等待期后立即跛行的奶牛繁殖性能最差（即怀孕风险最低，分娩至怀孕间隔最长）。
