Pérez-Torres Libia, Rubio Ivette, Corro Manuel, Cohen Abraham, Orihuela Agustín, Galina Carlos S, Pablos J Luis
Facultad de Ciencias Agropecuarias, Universidad Autónoma del Estado de Morelos, Morelos 62210, México.
J Reprod Dev. 2015;61(3):199-203. doi: 10.1262/jrd.2014-114. Epub 2015 Feb 28.
The aim of this study was to establish if pre-synchronization would enhance the number of animals cycling prior to conventional breeding at 45 days irrespective of the length of calf separation. Multiparous Bos indicus cows were allotted in four groups (n = 10). Control group (C) dams remained with their calves; groups G24, G48 and G72, which were partially weaned for 24, 48 and 72 h, respectively, were estrus synchronized using a controlled internal drug. These procedures were performed at 25 days and again at 45 days postpartum. The number of follicles, presence of a corpus luteum and back fat thickness (BFT) were determined by ultrasound. The proportion of cows with estrus and ovulation at day 25 postpartum was statistically different between the control and treated groups, with the values being 20, 60, 50 and 70 for the control, G24, G48 and G72 groups respectively (P < 0.05). At days 45 postpartum, the proportion of cows with estrus and ovulation was different in group G48 compared with the other groups (P <0.05). The average BFT and body condition score for the four experimental groups in the two periods were similar (P >0.05). Animals with a higher proportion of follicles from 17 to 21 mm, BFT values above 3.5 mm and a regular body condition were significantly different regardless of whether the dams remained with their calves or were separated, regardless of the length of this event. It can be concluded that (1) a pre-synchronization program at day 25 could trigger the onset of ovarian activity and facilitate a breeding program at day 50 and (2) temporary weaning enhances the effect of a pre-synchronization program.
本研究的目的是确定预同步是否会增加45天常规配种前发情的动物数量，而不考虑犊牛分离的时长。经产印度瘤牛被分为四组（n = 10）。对照组（C）的母牛与犊牛待在一起；G24、G48和G72组分别进行24、48和72小时的部分断奶，使用一种可控的体内药物进行发情同步。这些操作在产后25天进行一次，产后45天再进行一次。通过超声测定卵泡数量、黄体的存在情况和背部脂肪厚度（BFT）。产后25天发情和排卵的母牛比例在对照组和处理组之间存在统计学差异，对照组、G24组、G48组和G72组的该比例分别为20%、60%、50%和70%（P < 0.05）。产后45天，G48组发情和排卵的母牛比例与其他组不同（P <0.05）。两个时期四个实验组的平均BFT和体况评分相似（P >0.05）。无论母牛是与犊牛待在一起还是分开，无论分离时长如何，卵泡直径在17至21毫米的比例较高、BFT值高于3.5毫米且体况正常的动物都存在显著差异。可以得出结论：（1）产后25天的预同步程序可触发卵巢活动的开始，并有助于在第50天进行配种计划；（2）临时断奶可增强预同步程序的效果。
