Perry R C, Corah L R, Cochran R C, Beal W E, Stevenson J S, Minton J E, Simms D D, Brethour J R
Dept. of Anim. Sci. and Ind., Kansas State University, Manhattan 66506-0201.
J Anim Sci. 1991 Sep;69(9):3762-73. doi: 10.2527/1991.6993762x.
Twenty-eight Hereford x Angus cows (4 yr of age) were used to determine the effects of pre- and postpartum dietary energy on performance and reproductive function in suckled beef cows. The experiment was designed as a 2 x 2 factorial with cows receiving either 70 (L) or 150% (H) of NRC recommended level of dietary energy before and(or) after parturition, resulting in four treatment combinations (L-L, L-H, H-L, H-H). Prepartum diets were fed for approximately 110 d, and postpartum diets were fed until either 10 d after the second postpartum ovulation or 150 d postpartum for those cows that failed to ovulate. Cows receiving low compared with high levels of energy before calving lost more (P less than .01) weight, body condition, subcutaneous fat, and longissimus muscle area before parturition and had calves with lighter (P less than .01) birth weights. Cows receiving low compared with high levels of energy postpartum lost more (P less than .01) weight, body condition, and longissimus muscle area after parturition. Low levels of energy before and after parturition decreased (P less than .01) milk production and calf weight at 70 d of age. Rates of cervical and uterine involution were unaffected by dietary energy treatments. Cows receiving high levels of energy prepartum had increased (P less than .01) mean concentrations and pulse frequency of LH in serum after parturition, and cows receiving high levels of energy postpartum had increased (P less than .05) pulse frequency of LH. Low levels of energy postpartum decreased (P less than .01) appearance rate of small (5.0 to 7.9 mm) and large (greater than or equal to 10 mm) follicles, and low levels of energy prepartum decreased (P less than .02) appearance rate of large follicles based on transrectal ultrasonography. Cows receiving high levels of energy prepartum had shorter (P less than .02) intervals from parturition to ovulation, and a higher (P less than .01) percentage of the cows that received high levels of energy postpartum ovulated by 150 d postpartum. In summary, prepartum level of dietary energy influenced birth weight and weight gain of calves, milk production, concentrations and pulse frequency of LH in serum, appearance rate of large follicles, and the interval to first ovulation. Postpartum level of dietary energy influenced milk production, weight gain of calves, pulse frequency of LH, appearance rate of small and large follicles, and the percentage of cows that ovulated after parturition.
选用28头4岁的赫里福德×安格斯母牛，以确定产前和产后日粮能量对哺乳肉用母牛生产性能和繁殖功能的影响。试验设计为2×2析因试验，母牛在分娩前和（或）分娩后分别采食相当于美国国家研究委员会（NRC）推荐能量水平的70%（低能量，L）或150%（高能量，H），从而形成4种处理组合（L-L、L-H、H-L、H-H）。产前日粮饲喂约110天，产后日粮一直喂到第二次产后排卵后10天，对于未排卵的母牛则喂到产后150天。与产前采食高能量水平的母牛相比，采食低能量水平的母牛在分娩前体重、体况、皮下脂肪和背最长肌面积损失更多（P<0.01），所产犊牛出生体重更轻（P<0.01）。与产后采食高能量水平的母牛相比，采食低能量水平的母牛在分娩后体重、体况和背最长肌面积损失更多（P<0.01）。产前和产后低能量水平降低了（P<0.01）70日龄时的产奶量和犊牛体重。日粮能量处理对子宫颈和子宫复旧率没有影响。产前采食高能量水平的母牛产后血清中促黄体素（LH）的平均浓度和脉冲频率升高（P<0.01），产后采食高能量水平的母牛LH脉冲频率升高（P<0.05）。产后低能量水平降低了（P<0.01）直径小（5.0至7.9毫米）和大（大于或等于10毫米）卵泡的出现率，产前低能量水平降低了（P<0.02）经直肠超声检查的大卵泡出现率。产前采食高能量水平的母牛从分娩到排卵的间隔时间更短（P<0.02），产后采食高能量水平的母牛在产后150天内排卵的比例更高（P<0.01）。总之，产前日粮能量水平影响犊牛出生体重和体重增加、产奶量、血清中LH浓度和脉冲频率、大卵泡出现率以及首次排卵间隔时间。产后日粮能量水平影响产奶量、犊牛体重增加、LH脉冲频率、小卵泡和大卵泡出现率以及产后排卵母牛的比例。
