Abulaiti Adili, Riaz Umair, Naseer Zahid, Ahmed Zulfiqar, Hua Guohua, Yang Liguo
Key Laboratory of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China.
International Joint Research Center for Animal Genetics, Breeding and Reproduction, Wuhan 430070, China.
Animals (Basel). 2022 May 7;12(9):1208. doi: 10.3390/ani12091208.
The follicular dynamics is used as a reliable indicator for reproductive management in livestock. However, the follicular dynamics (follicle wave emergence, estrus cycle length, diameter of dominant follicle, follicular growth and atretic phases) during the estrous cycle of crossbred (Nili Ravi-Jianghan) buffalo is still unexplored. Therefore, the present study aimed to observe the follicular dynamics in estrous cycle of crossbred buffaloes at different physiological stages (pubertal; n = 28, sexual mature; n = 22 and postpartum; n = 18). In the present study, the follicular dynamics were ultrasonically examined at 12 h intervals throughout an estrous cycle during the breeding season. The results indicate that about 86.76% (59/68) crossbred buffaloes, irrespective of physiological stage, exhibited two follicular waves in estrous cycle with an average estrus cycle length was 20.7 ± 0.4 days. The estrus cycle length was significantly shorter (p < 0.05) in pubertal buffaloes (19.4 ± 0.4 days) compared with sexual mature (21.5 ± 0.3 days) and postpartum (21.9 ± 0.4 days) buffaloes. The first follicular wave emerged on same day during one- (pubertal vs. postpartum), two- (pubertal vs. mature vs. postpartum) or three-wave (mature vs. postpartum) estrous cycle buffaloes. The maximum diameter of dominant follicle (DF) in pubertal, sexually mature and postpartum crossbred buffaloes was 9.6 ± 2.0 mm, 10.6 ± 0.5 mm and 12.6 ± 0.7 mm with growth rate of 1.08 ± 0.04 mm/day, 0.92 ± 0.04 mm/day, and 0.9 ± 0.07 mm/day, respectively. In conclusion, similar to other buffalo breeds, Nili Ravi-Jianghan crossbred buffaloes showed the two-wave follicular pattern dominantly with an average duration of ~20 days estrous cycle. The observed follicular dynamics can be used as a reliable indicator for synchronization and fixed-time artificial insemination (FTAI) programs to improve the fertility of crossbred buffaloes.
卵泡动态被用作家畜繁殖管理的可靠指标。然而，杂交（尼里拉菲-江汉）水牛发情周期中的卵泡动态（卵泡波出现、发情周期长度、优势卵泡直径、卵泡生长和闭锁阶段）仍未得到充分研究。因此，本研究旨在观察不同生理阶段（青春期；n = 28，性成熟；n = 22，产后；n = 18）杂交水牛发情周期中的卵泡动态。在本研究中，在繁殖季节的整个发情周期内，每隔12小时对卵泡动态进行超声检查。结果表明，约86.76%（59/68）的杂交水牛，无论生理阶段如何，在发情周期中表现出两个卵泡波，平均发情周期长度为20.7±0.4天。与性成熟（21.5±0.3天）和产后（21.9±0.4天）水牛相比，青春期水牛的发情周期长度显著缩短（p < 0.05）（19.4±0.4天）。在单波（青春期与产后）、双波（青春期与成熟与产后）或三波（成熟与产后）发情周期的水牛中，第一个卵泡波在同一天出现。青春期、性成熟和产后杂交水牛优势卵泡（DF）的最大直径分别为9.6±2.0毫米、10.6±0.5毫米和12.6±0.7毫米，生长速率分别为1.08±0.04毫米/天、0.92±0.04毫米/天和0.9±0.07毫米/天。总之，与其他水牛品种相似，尼里拉菲-江汉杂交水牛主要表现出双波卵泡模式，平均发情周期持续约20天。观察到的卵泡动态可作为同步化和定时人工授精（FTAI）计划的可靠指标，以提高杂交水牛的繁殖力。
