ABSTRACT The aim of this study was to determine the semen quality, sexual behaviour and testosterone (T) levels in Saint Croix rams under semi-desert climate conditions. Sixteen rams (70.6 ± 12.5 kg; 24.1 ± 0.3 months old) were randomly divided into a grazing group (GG, n = 8) and a supplemented group (supplemented individually with 1 kg.d−1 of concentrate (156 g CP.kg−1 DM and 2.5 Mcal EM.kg−1 DM). SG, n = 8). Each group grazed on buffel, grass. Every two weeks, semen was collected, and sexual behaviour traits were evaluated. SG rams had greater body weight (P < 0.0001) and greater semen quality than the GG rams. SG rams had greater values for reaction time and lateral approaches than GG rams (P < 0.0001). No interaction was found between treatment and month for T concentration (P < 0.05); the SG rams had greater values during most of the months, but GG rams had greater values during September. Month had a significant effect on T concentration (P < 0.05) with the highest values in autumn. It can be concluded that Saint Croix rams are able to adapt to adverse environmental conditions and that supplementary feed prior to the mating season improves ram sexual behaviour.

中文翻译：

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墨西哥半沙漠地区圣克罗伊公羊繁殖参数和性行为的年度变化

摘要 本研究的目的是确定半沙漠气候条件下圣克罗伊公羊的精液质量、性行为和睾酮 (T) 水平。16 只公羊（70.6 ± 12.5 kg；24.1 ± 0.3 个月大）被随机分为放牧组（GG，n = 8）和补充组（单独补充 1 kg.d-1 浓缩物（156 g CP.kg） -1 DM 和 2.5 Mcal EM.kg-1 DM).SG，n = 8)。每组都在野牛、草地上吃草。每两周收集一次精液，并评估性行为特征。SG 公羊比 GG 公羊具有更大的体重 (P < 0.0001) 和更高的精液质量。SG rams 的反应时间和横向方法比 GG rams 具有更高的值（P < 0.0001）。在治疗和月份之间没有发现 T 浓度的相互作用（P < 0.05）；SG 公羊在大部分月份的价值更高，但 GG 公羊在 9 月的价值更高。月份对 T 浓度有显着影响（P < 0.05），秋季最高。可以得出结论，圣克罗伊公羊能够适应不利的环境条件，并且在交配季节之前补充饲料可以改善公羊的性行为。