Animal Research Centre, Directorate General of Veterinary Services, Royal Court Affairs, P.O. Box: 64, P.C: 111, Muscat, Oman.
Animal Research Centre, Directorate General of Veterinary Services, Royal Court Affairs, P.O. Box: 64, P.C: 111, Muscat, Oman.
Theriogenology. 2022 Feb;179:230-236. doi: 10.1016/j.theriogenology.2021.12.007. Epub 2021 Dec 6.
This study examines the effect of advancing the breeding season on the reproductive performance of dromedary camels under an intensive management system. Using a synchronization protocol, timed natural mating in female camels was carried out either in September (2 months ahead of the natural breeding season, n = 182) or December (peak breeding season, n = 115). The ovarian responses (size of the dominant follicle at the time of mating and ovulation), pregnancy rate, and pregnancy losses were evaluated using ultrasonography. Blood samples were collected after mating to assess progesterone concentrations by RIA. The libido of male camels (n = 13) was evaluated objectively. Results showed that the percentage of female camels with an optimal sized follicle (11-17 mm) for breeding at the time of mating was lower in September compared to December (81.9 vs 91.3%, P = 0.03). The libido of male camels was lower in September than in December (P <0.001). The ovulation rate (86.3 vs 93.9%, P = 0.04), size of the ovulated follicle (12.7 ± 0.1 vs 13.7 ± 0.2 mm, P <0.001), pregnancy rates on Day 14 (47.8 vs 72.2%, P <0.001) and Day 90 (38.5 vs 60.9%, P <0.001) after mating was lower in September compared to December. However, pregnancy loss was not affected between months (15.7 vs 19.5%, P = 0.3). Among pregnant camels, the progesterone concentrations on Days 6, 8, 10, 12 and 14 after mating were lower in September as compared to December (P <0.001). In non-pregnant camels, the progesterone concentrations on Days 6, 8 and 10 after mating were also lower in September as compared to December (P <0.001). In conclusion, advancing the breeding season by two months, significantly affects the reproductive performance of dromedary camels, yet, acceptable pregnancy rates can be achieved.
本研究考察了在集约化管理系统下，提前繁殖季节对单峰驼繁殖性能的影响。通过同步方案，对雌性单峰驼进行定时自然交配，时间分别为 9 月（比自然繁殖季节提前 2 个月，n=182）或 12 月（繁殖高峰期，n=115）。使用超声评估卵巢反应（交配时主导卵泡的大小和排卵）、妊娠率和妊娠损失。交配后采集血液样本，通过 RIA 评估孕酮浓度。客观评估了 13 头雄性单峰驼的性欲。结果表明，9 月时，适合繁殖的最佳大小卵泡（11-17mm）的雌性单峰驼比例低于 12 月（81.9%对 91.3%，P=0.03）。9 月时，雄性单峰驼的性欲低于 12 月（P<0.001）。排卵率（86.3%对 93.9%，P=0.04）、排卵卵泡大小（12.7±0.1 对 13.7±0.2mm，P<0.001）、交配后 14 天（47.8%对 72.2%，P<0.001）和 90 天（38.5%对 60.9%，P<0.001）的妊娠率低于 12 月。然而，妊娠损失在各月之间没有差异（15.7%对 19.5%，P=0.3）。在妊娠单峰驼中，交配后第 6、8、10、12 和 14 天的孕酮浓度 9 月低于 12 月（P<0.001）。在非妊娠单峰驼中，交配后第 6、8 和 10 天的孕酮浓度 9 月也低于 12 月（P<0.001）。总之，将繁殖季节提前两个月会显著影响单峰驼的繁殖性能，但仍能获得可接受的妊娠率。
