Department of Animal Physiology, Federal University of Agriculture, (FUNAAB), Abeokuta, P.M.B 2240, Nigeria.
Department of Animal Production and Health, FUNAAB, Abeokuta, Nigeria.
Trop Anim Health Prod. 2024 Oct 28;56(8):364. doi: 10.1007/s11250-024-04215-4.
Comprehensive understanding of reproductive hormones and environmental cues with their relationship is essential for efficient production in livestock sectors involving either assisted or natural reproductive methods. This study evaluated the effects of age and seasonal-associated changes in the blood concentrations of testosterone and follicle stimulating hormone (FSH) of male Kalahari Red (KR) and Kalawad (KW)-crossbred goats. Based on a 2 × 3 × 4 factorial arrangement, a total of 42 bucks (KR n = 21 and KW n = 21) were allotted into three age groups (> 1 ≤ 2 years, > 2 ≤ 3 years and > 3 ≤ 4 years) with seven KR bucks and seven KW bucks each per age group; reared under different seasons (early rainy, late rainy, early dry and late dry). The animals were managed semi-intensively, kept in an open-ventilated pen and subjected to same nutritional regime throughout the one-year experimental period. Follicle stimulating hormone and testosterone concentrations were analyzed in serum samples. Data obtained reproductive hormones were subjected to three-way Analysis of Variance using SAS 1999. Results show that breed had a significant effect (p < 0.05) on both serum FSH and testosterone concentrations. The highest FSH (0.49 ± 0.02 ng/mL, 0.45 ± 0.01 ng/mL, 0.41 ± 0.1 ng/mL and 0.47 ± 0.07 ng/mL) mean values (P > 0.05) were observed in KR in September, October, November and May, respectively while the highest (2.6 ± 0.02 ng/mL) testosterone concentration in KW (p < 0.05) was obtained in December. Testosterone had irregular patterns between breeds and months of sampling. FSH was at peak (p > 0.05) in KR during the late rainy season at all ages while the values of FSH concentration in KW were not significantly different at all ages and seasons. The highest (2.05 ± 0.11 ng/mL) serum testosterone mean value in KW peaked (p < 0.05) age > 3 ≤ 4 years during the late rainy season. Testosterone concentration was lower and steady at all ages during rainy seasons in KR but started fluctuating during the early dry season. The least mean (0.62 ± 0.07 ng/mL and 0.68 ± 0.05 ng/mL) were recorded (p > 0.05) in KW during the late dry season at age > 2 ≤ 3 and > 3 ≤ 4 years respectively. In KR and KW goat breeds raised under tropical condition, the high seasonal variations were responsible for the fluctuations in the reproductive hormones which resultantly altered or lowered the sexual activity of the animals at certain season(s).
全面了解生殖激素及其与环境线索的关系对于涉及辅助或自然生殖方法的牲畜部门的高效生产至关重要。本研究评估了年龄和季节性变化对雄性卡拉哈里红（KR）和卡拉瓦德（KW）杂交山羊血液中睾酮和卵泡刺激素（FSH）浓度的影响。基于 2×3×4 析因设计，总共 42 只公山羊（KR n=21，KW n=21）被分配到三个年龄组（>1≤2 岁、>2≤3 岁和>3≤4 岁），每个年龄组有 7 只 KR 公山羊和 7 只 KW 公山羊；在不同季节（早雨季、晚雨季、早旱季和晚旱季）下饲养。动物被半集约化管理，饲养在通风良好的围栏中，并在整个一年的实验期间接受相同的营养方案。在血清样本中分析卵泡刺激素和睾酮浓度。用 SAS 1999 对获得的生殖激素数据进行三因素方差分析。结果表明，品种对血清 FSH 和睾酮浓度均有显著影响（p<0.05）。KR 在 9 月、10 月、11 月和 5 月的 FSH 平均值（0.49±0.02ng/mL、0.45±0.01ng/mL、0.41±0.1ng/mL 和 0.47±0.07ng/mL）最高（p>0.05），而 KW 的最高（2.6±0.02ng/mL）睾酮浓度（p<0.05）则在 12 月获得。睾酮在品种和采样月份之间呈不规则模式。在所有年龄组中，FSH 在 KR 的晚雨季达到高峰（p>0.05），而 KW 的 FSH 浓度值在所有年龄组和季节均无显著差异。KW 在晚雨季的 FSH 浓度达到峰值（p<0.05），年龄为>3≤4 岁，而 KW 的睾酮平均峰值（2.05±0.11ng/mL）出现在晚雨季，年龄为>3≤4 岁。KR 在雨季的所有年龄段，睾酮浓度均较低且稳定，但在早旱季开始波动。KW 在晚旱季的年龄分别为>2≤3 岁和>3≤4 岁时，记录到的平均睾酮浓度最低（0.62±0.07ng/mL 和 0.68±0.05ng/mL）（p>0.05）。在热带条件下饲养的 KR 和 KW 山羊品种中，季节性变化较大是导致生殖激素波动的原因，这导致动物在某些季节（或季节）的性活动发生变化或降低。
