Shoup L M, Miller L M, Srinivasan M, Ireland F A, Shike D W
J Anim Sci. 2016 Dec;94(12):5105-5113. doi: 10.2527/jas.2016-0819.
Very little is known regarding the effects of cow exposure to toxic ergot alkaloids in late gestation and the subsequent, long-term effects on progeny. Therefore, the objectives were to determine the effects of grazing toxic endophyte-infected tall fescue () or novel endophyte-infected tall fescue during late gestation on cow BW, BCS, hair coat score (HCS), respiration rates, milk production, and reproduction and on growth performance and carcass characteristics of progeny. Eighty gestating, Angus × Simmental cows (age = 6.68 ± 0.32 yr; 588 ± 16 kg initial BW; initial BCS = 5.66 ± 0.28) were stratified by initial BW and allocated into 8 pasture groups (10 cows/group) with 4 groups per treatment. Each group was allotted to 1 of 2 grazing treatments: toxic endophyte-infected tall fescue ('Kentucky-31'; E+) or novel endophyte-infected tall fescue ('Jesup MaxQ'; NOV). Cows were placed on grazing treatments at 110 ± 6 d prepartum (May 28, 2014) and remained on treatment until the end of the calving period (October 8, 2014; 23 ± 6 d postpartum). Cow BW and BCS did not diverge ( ≥ 0.15) at any time point among grazing treatments. However, cows grazing E+ had increased ( < 0.05) respiration rates and HCS and reduced ( < 0.05) prolactin concentration compared with cows grazing NOV. Calf birth BW, Julian calving date, milk production, AI conception rate, and overall pregnancy rate did not differ ( ≥ 0.23) by grazing treatment. In a subsequent grazing period of the progeny, dam grazing treatment did not affect ( ≥ 0.14) respiration rates, HCS, or prolactin concentration of the progeny when all progeny grazed E+ pastures. However, progeny born to dams grazing NOV tended ( > 0.06 to ≤0.10) to have increased BW at 70 ± 6 d of age, 205 d (adjusted weaning BW), and throughout the postweaning calf grazing period. Despite a tendency for BW to differ throughout the postweaning calf grazing period, finishing phase performance and carcass characteristics of progeny did not differ ( ≥ 0.20) between dam grazing treatment. In conclusion, results indicate that by the time progeny enter the feedlot and are finished on a high-grain diet, any fetal programming effects are minimal.
关于母牛在妊娠后期接触有毒麦角生物碱的影响以及对后代随后的长期影响，人们了解甚少。因此，本研究的目的是确定妊娠后期放牧感染有毒内生真菌的高羊茅（‘肯塔基31’）或感染新型内生真菌的高羊茅（‘杰苏普MaxQ’）对母牛体重、体况评分、被毛评分（HCS）、呼吸频率、产奶量、繁殖性能以及后代生长性能和胴体特征的影响。80头妊娠的安格斯×西门塔尔母牛（年龄 = 6.68 ± 0.32岁；初始体重588 ± 16千克；初始体况评分 = 5.66 ± 0.28）按初始体重分层，分配到8个牧场组（每组10头母牛），每个处理4组。每组被分配到两种放牧处理中的一种：感染有毒内生真菌的高羊茅（‘肯塔基31’；E+）或感染新型内生真菌的高羊茅（‘杰苏普MaxQ’；NOV）。母牛在产前110 ± 6天（2014年5月28日）开始放牧处理，并一直持续到产犊期结束（2014年10月8日；产后23 ± 6天）。在任何时间点，放牧处理之间的母牛体重和体况评分均无差异（P≥0.15）。然而，与放牧NOV的母牛相比，放牧E+的母牛呼吸频率和HCS增加（P<0.05），催乳素浓度降低（P<0.05）。犊牛出生体重、儒略历产犊日期、产奶量、人工授精受胎率和总体妊娠率不受放牧处理的影响（P≥0.23）。在后代随后的放牧期，当所有后代都在E+牧场上放牧时，母代的放牧处理对后代的呼吸频率、HCS或催乳素浓度没有影响（P≥0.14）。然而，出生于放牧NOV母代的后代在70 ± 6日龄、205日龄（调整后的断奶体重）以及整个断奶后犊牛放牧期体重有增加的趋势（0.06<P≤0.10）。尽管在整个断奶后犊牛放牧期体重有差异的趋势，但母代放牧处理对后代育肥期性能和胴体特征没有影响（P≥0.20）。总之，结果表明，当后代进入饲养场并以高谷物日粮育肥时，任何胎儿编程效应都是最小的。
