Morphological characterization of follicle deviation in Nelore (Bos indicus) heifers and cows
Morphological characterization of follicle deviation in Nelore (Bos indicus) heifers and cows
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DOI：
10.1016/j.theriogenology.2004.08.017
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发表时间：
2005-06-01
期刊：
影响因子：
2.8
通讯作者：
Barros, CM
中科院分区：
文献类型：
--
作者：
Sartorelli, ES;Carvalho, LM;Barros, CM
卵泡直径偏差被定义为波出现后最大卵泡和下一个最大卵泡之间生长率差异变化的开始，被认为是卵泡选择的关键组成部分。欧洲品种的牛(Bos Taurus)的卵泡选择已被广泛研究，但在Zebu品种(Bos Indus)中尚未得到严格的研究。本研究的目的是确定和比较Nelore小母牛(n=8)和非哺乳期奶牛(n=11)与发情周期的第一个排卵后波(波1)相关的偏差的形态特征。从排卵当天(第0天)开始，每隔12h用经直肠超声分别追踪3个最大的卵泡(F1~F3)，连续6d。在个体动物中，通过目测F1、F2和有时F3的直径轮廓(观察偏差)并使用F1和F2之间的直径差异或有时F3的直径差异(计算偏差)的分段回归分析来数学地确定偏差。在母牛和小母牛之间，F1代达到3朗姆时的平均出现天数(排卵后约1d)和偏离期间的F1生长速度(约1.4 mm/d)没有显著差异。用观测方法和计算方法确定小母牛和母牛的偏差起点的结果没有显著差异。两种方法的平均直径偏差，小母牛在排卵后2.8d，F1达5.7 mm，奶牛在排卵后2.4d，F1达6.1 mm。总之，无论用什么方法来确定偏差，Nelore小母牛和非哺乳期奶牛在偏差开始时的第1波的出现以及未来优势卵泡的生长速度和直径是相似的。与荷斯坦牛相比，Nelore牛第1波的出现似乎晚了约1d，未来优势卵泡的直径在偏差开始时要小约2圈。(C)2004 Elsevier Inc.保留所有权利。
Follicle diameter deviation is defined as the beginning of the differential change in growth rates between the largest and next largest follicles subsequent to wave emergence and is considered a key component of follicle selection. Follicle selection has been extensively studied in European breeds of cattle (Bos taurus) but has not been critically studied in Zebu breeds (Bos indicus). The objectives of the present study were to determine and compare the morphological characteristics of deviation associated with the first post-ovulatory wave (Wave 1) of the estrous cycle in Nelore heifers (n = 8) and nonlactating cows (n = 11). Beginning on the day of ovulation (day 0), the three largest follicles (F1-F3, respectively) were individually tracked every 12 h for 6 d using transrectal ultrasonography. In individual animals, deviation was determined graphically using visual inspection of the diameter profiles of F1, F2 and sometimes F3 (observed deviation) and mathematically using segmented regression analysis of the diameter differences between F1 and F2 or sometimes F3 (calculated deviation). Mean day of emergence of Wave 1 when F1 reached >3 rum (approximately 1 d after ovulation) and growth rate of F1 during deviation (approximately 1.4 mm/d) were not significantly different between heifers and cows. The results of determining the beginning of deviation within heifers and cows using the observed and calculated methods were not significantly different. Averaged over both methods, diameter deviation occurred 2.8 d after ovulation when F1 reached 5.7 mm in heifers, and 2.4 d after ovulation when F1 reached 6.1 mm in cows. In conclusion, the emergence of Wave 1 and growth rates and diameters of the future dominant follicles at the beginning of deviation were similar in Nelore heifers and nonlactating cows, regardless of the methods used to determine deviation. Relative to Holstein cattle, emergence of Wave 1 appeared to occur about 1 d later and diameter of the future dominant follicle at the beginning of deviation was about 2 turn smaller in Nelore. (C) 2004 Elsevier Inc. All rights reserved.