犊牛早期断奶对母牛产后乏情的影响与机理研究

Effects of early weaning on postpartum anestrus of cow

选择产后 5 0～ 6 0d膘情体况相当 ,未发情的健康荷杂母牛 2 0头 ,等数随机分为两组 ,试验组实施犊牛断奶 ,对照组不进行断奶仍按日常管理饲养。试验开始后每隔 7d颈静脉采血 ,直至发情 ,发情当日采血 1次。用放射免疫分析法测定血清中雌二醇、促卵泡素、促黄体素、孕酮和促乳素激素含量。结果表明 :1)母牛产后至第一次发情时间试验组 (6 9.0± 7.0 4)d与对照组 (98.8± 2 4.6 3)d差异极显著 (p <0 .0 1)。 2 )母牛发情前 ,促卵泡素、雌激素、孕酮平均含量试验组 [(10 .2± 1.0 7)× 10 -11mol·s-1·mL-1、(38.49± 7.15 ) pg·mL-1、(0 .0 34± 0 .0 0 1) pg·mL-1]与对照组 [(8.90± 0 .75 )× 10 -11mol·s-1·mL-1、(30 .0 8± 2 .96 ) pg·mL-1、(0 .0 44± 0 .0 0 1) pg·mL-1]之间差异显著 (p <0 .0 5 ) ,促黄体素和促乳素平均含量两组间差异不显著。 3)哺乳影响母牛产后乏情不是高浓度的促乳素 。

health crossbred Cows (Hostein×Chinese Yellow Cattle), postpartum 50～60 d and anestrus,were selected and divided into the experimental group(10)and the control group(10).The cows in the experimental group were weaned and collected blood from jugular vein 10 mL for each,7d interval till estrus,then the serum was isolated ,the treatment for the control group was the same, but without weaning.The levels of FSH, LH, E 2, P 4and PRL in the serum of cows were determined by RIA. The results were as follows: 1) The postpartum anestrus length of cows in the experimental group and control group were (69.0±7.04) d and (98.8±24.63) d respectively(p<0.01). 2) The average concentration of FSH and E 2 of cows before estrus in the experimantal group was significantly high than that in the control group[(10.2±1.07)×10 -11 mol·s -1 ·mL -1 , (38.49±7.15) pg·mL -1 vs(8.90±0.75)×10 -11 mol·s -1 ·mL -1 ,(30.08±2.96) pg·mL -1 ], but the average concentration of P 4of cows before estrus in control group was significantly high than that in the experimental group[(0.044±0.001) pg·mL -1 vs (0.034±0.001) pg·mL -1 ]. The average concentration of LH and PRL of cows before estrus was no sharp difference between the experimental and the control group. 3) The reason of postpartum anestrus is not PRL but Suckle stimulation.