Pinheiro V G, Souza A F, Pegorer M F, Satrapa R A, Ereno R L, Trinca L A, Barros C M
Department of Pharmacology, University of Sao Paulo State, Botucatu, Sao Paulo, Brazil.
Theriogenology. 2009 Feb;71(3):519-24. doi: 10.1016/j.theriogenology.2008.08.018. Epub 2008 Oct 11.
The objective was to evaluate the effects of temporary calf removal (TCR), eCG administration, or both, in a progesterone-based protocol. Suckled Nellore cows (40-80 d postpartum, n=443) with body condition scores from 2.0 to 3.5 (5-point scale) on three farms were all given a synchronizing protocol (PEPE). At the start (designated Day 0), cows were given an intravaginal device (1.0 g of progesterone) and 2.5mg of estradiol benzoate (EB) im. On Day 8, the device was removed and cows were given PGF(2 alpha) (150 microg of D-cloprostenol im), followed in 24h by 1.0mg EB im, and 30-36 h thereafter, fixed-time AI. The design was a 2 x 2 factorial; main effects were TCR (54-60 h; from device removal to FTAI) and eCG treatment (300 IU im, concurrent with PGF(2 alpha)). Transrectal ultrasonography was done on Days -10 and 0 to detect anestrus (absence of a CL at both examinations) and approximately 30 d after FTAI (pregnancy diagnosis). Data were analyzed by logistic regression. The following variables did not significantly affect pregnancy rates: farm, postpartum interval, cyclicity, inseminators, and semen (sire). Overall, 77% of the cows were deemed anestrus. Pregnancy rates were similar (P>0.05) among treatment groups: Control (54/108=50.0%), TCR (44/106=41.5%), eCG (63/116=54.3%), and TCR+eCG (49/113=43.4%). Pregnancy rate was higher in multiparous than primiparous cows (186/360, 51.7% vs. 24/83, 28.9%, P<0.01), but was not significantly affected by cyclicity status or body condition score. In conclusion, temporary calf removal, eCG, or both, did not significantly increase pregnancy rate to timed-insemination in a progesterone-based synchronization protocol in postpartum Nellore cows with acceptable body condition.
目的是评估在基于孕酮的方案中，临时去除犊牛（TCR）、注射eCG或两者同时使用的效果。在三个农场中，选取产后40 - 80天、体况评分为2.0至3.5（5分制）的哺乳内罗尔母牛（n = 443头），全部给予同步化方案（PEPE）。在开始时（指定为第0天），给母牛放置阴道内装置（1.0 g孕酮）并肌肉注射2.5 mg苯甲酸雌二醇（EB）。在第8天，取出装置，给母牛注射PGF(2α)（150 μg氯前列醇钠肌肉注射），24小时后肌肉注射1.0 mg EB，此后30 - 36小时进行定时人工授精（AI）。设计为2×2析因试验；主要因素为TCR（54 - 60小时；从装置取出到定时人工授精）和eCG处理（300 IU肌肉注射，与PGF(2α)同时使用）。在第 - 10天和第0天进行经直肠超声检查，以检测发情间期（两次检查均无黄体）以及定时人工授精后约30天（妊娠诊断）。数据采用逻辑回归分析。以下变量对妊娠率无显著影响：农场、产后间隔、周期性、输精员和精液（种公牛）。总体而言，77%的母牛被判定处于发情间期。各处理组的妊娠率相似（P>0.05）：对照组（54/108 = 50.0%）、TCR组（44/106 = 41.5%）、eCG组（63/116 = 54.3%）和TCR + eCG组（49/113 = 43.4%）。经产母牛的妊娠率高于初产母牛（186/360，51.7%对24/83，28.9%，P<0.01），但不受周期性状态或体况评分的显著影响。总之，在体况良好的产后内罗尔母牛基于孕酮的同步化方案中，临时去除犊牛、注射eCG或两者同时使用，均未显著提高定时输精的妊娠率。
