Abstract In this study we evaluated the effect of feeding an immune modulatory feed additive (OmniGen-AF®; OMN) during the dry period through early lactation on postpartum health, subsequent lactational and reproductive performance of multiparous Holstein cows. We hypothesized that feeding OMN beginning in the dry period and through 150 days in milk (DIM) would improve milk yield and reproductive performance as a result of improved immune response. To test our hypothesis, 1392 multiparous pregnant Holstein cows of a commercial dairy herd were enrolled and randomly assigned at dry-off (47.6 ± 9.4 d before calving) to OMN (n = 706) or control (CON, n = 686) treatments. Both OMN and CON (placebo) supplements were fed once per day at a rate of 56 g/d per head from dry-off through 150 DIM. Cows were milked three times a day and daily milk yield was measured once per week, starting at the second week of lactation through 140 days in milk. Postpartum health disorders were monitored daily throughout the experiment. Cows were bred following a double OvSynch protocol after a 77-d voluntary waiting period (VWP). Final pregnancy status was assessed after supplementation ended at 230 DIM. Our results indicated that cows supplemented with OMN produced more milk than CON (40.8 kg/d vs. 40.1 kg/d; P

中文翻译：

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在干奶期和泌乳早期向经产荷斯坦奶牛饲喂免疫调节剂对健康、产奶和繁殖性能的影响

摘要 在本研究中，我们评估了在干奶期至泌乳早期饲喂免疫调节饲料添加剂 (OmniGen-AF®; OMN) 对经产荷斯坦奶牛产后健康、后续泌乳和繁殖性能的影响。我们假设从干奶期开始喂养 OMN 并在牛奶中持续 150 天 (DIM) 会由于免疫反应的改善而提高产奶量和繁殖性能。为了验证我们的假设，我们招募了商业奶牛群的 1392 头经产妊娠荷斯坦奶牛，并在干奶时（产犊前 47.6 ± 9.4 天）随机分配到 OMN（n = 706）或对照（CON，n = 686）处理。OMN 和 CON（安慰剂）补充剂从干燥到 150 DIM 每天以每头 56 克/天的速度喂食一次。奶牛每天挤奶 3 次，每周测量一次每日产奶量，从泌乳的第二周开始到 140 天的牛奶。在整个实验过程中每天监测产后健康障碍。在 77 天的自愿等待期 (VWP) 之后，奶牛按照双 OvSynch 协议进行繁殖。在 230 DIM 补充结束后评估最终妊娠状态。我们的结果表明，补充 OMN 的奶牛比 CON 产生更多的牛奶（40.8 kg/d vs. 40.1 kg/d；P