Figueiredo R A, Barros C M, Pinheiro O L, Soler J M
Departamento de Farmacologia, Instituto de Biociências - UNESP Botucatu-SP, Brazil.
Theriogenology. 1997 Jun;47(8):1489-505. doi: 10.1016/s0093-691x(97)00156-8.
The most common beef cattle raised in Brazil is the Nelore breed (Bos indicus). Information obtained by ultrasonography on follicular growth in Bos taurus cattle has been accumulating rapidly. However, there are few publications to date on follicular development in Bos indicus breeds. The follicular dynamics in Nelore heifers and cows during natural or prostaglandin (PG)-induced estrous cycle were studied. From the detection of estrus onward, all animals were examined daily by ultrasonography for one (n = 35) or two (n = 10) consecutive estrous cycles. The follicular dynamic in Nelore cattle was characterized by the predominance of 2 follicular waves in the cows (83.3%, n = 18, P < 0.05) and 3 waves in the heifers (64.7%, n = 16, P < 0.05). Most of the cattle observed over 2 consecutive estrous cycles presented the same pattern of follicular waves in the first and second cycle, and only 30% showed variation in the number of waves from one cycle to the other. Most of the follicular parameters analyzed were not affected by PG treatment or age but were altered by follicular waves. Consequently, data on cows and heifers were combined according to the number of follicular waves. The ovulatory follicle was larger than the other dominant follicles (P < 0.05), and the ovulatory wave was shorter than the preceding waves (P < 0.05). The interovulatory interval was longer in animals showing 3 waves than those exhibiting 2 waves (P < 0.05). Maximum diameter of the dominant follicle (around 11 mm) and of the corpus luteum (CL, approximately 17 mm) were smaller than those reported for European breeds. In conclusion, the results demonstrate that although the dominant follicle and corpus luteum are smaller than in European breeds, the follicular dynamics in Nelore cattle were similar to those observed in European breeds and were characterized by 2 or 3 follicular waves for cows and heifers, respectively, during the natural or prostaglandin-induced estrous cycle.
巴西饲养的最常见肉牛品种是内罗尔牛（印度瘤牛）。通过超声检查获得的关于欧洲牛卵泡生长的信息一直在迅速积累。然而，迄今为止，关于印度瘤牛品种卵泡发育的出版物很少。本研究对内罗尔小母牛和母牛在自然发情周期或前列腺素（PG）诱导的发情周期中的卵泡动态进行了研究。从检测到发情开始，所有动物每天通过超声检查连续一个（n = 35）或两个（n = 10）发情周期。内罗尔牛的卵泡动态特征为，母牛中以2个卵泡波为主（83.3%，n = 18，P < 0.05），小母牛中以3个卵泡波为主（64.7%，n = 16，P < 0.05）。在连续两个发情周期观察到的大多数牛在第一和第二周期呈现相同的卵泡波模式，只有30%的牛在两个周期之间的卵泡波数量有所变化。分析的大多数卵泡参数不受PG处理或年龄的影响，但受卵泡波的影响。因此，根据卵泡波的数量将母牛和小母牛的数据合并。排卵卵泡比其他优势卵泡大（P < 0.05），排卵波比前一波短（P < 0.05）。出现3个卵泡波的动物的排卵间期比出现2个卵泡波的动物长（P < 0.05）。优势卵泡的最大直径（约11毫米）和黄体（CL，约17毫米）的最大直径小于欧洲品种的报道值。总之，结果表明，尽管内罗尔牛的优势卵泡和黄体比欧洲品种小，但在内罗尔牛中，自然发情周期或前列腺素诱导的发情周期中，卵泡动态与欧洲品种相似，其特征分别为母牛和小母牛有2个或3个卵泡波。
