In semiarid conditions, feed is often scarce and variable with underfeeding being common; these factors can potentially induce fertility reductions in both sexes. Sexually active bucks are able to very efficiently fertilize out-of-season goats, but we do not know whether underfeeding would reduce the ability of bucks to fertilize goats during these periods. Two experiments were conducted to determine (i) testicular size and change of odor intensity of undernourished bucks exposed to long days and (ii) the ability of these bucks to stimulate reproductive activity in seasonally anestrous goats. In experiment 1, bucks (n = 7) were fed 1.5 times the normal maintenance requirements from September to May and formed the well-fed group. Another group of bucks (n = 7) were fed 0.5 times the maintenance requirements and formed the undernourished group. All bucks were subjected to artificially long days from 1 November to 15 January; this period was followed by a natural photoperiod until 30 May. Body weight, scrotal circumference and male odor intensity changes were determined every 2 weeks. In experiment 2, two groups of female goats (n = 26 each) were exposed to well-fed (n = 2) or undernourished bucks (n = 2) on 31 March. Ovulations and pregnancy rates were determined by transrectal ultrasonography. In experiment 1, a treatment by time interaction was detected for BW, scrotal circumference and odor intensity changes (P < 0.001). The BWs of well-fed bucks were greater than those of the undernourished bucks from October to May (P < 0.01), as were the scrotal circumferences from December to March (P < 0.05) and odor intensities from February to May (P < 0.05). In experiment 2, the proportions of females that ovulated at least once (100% v. 96%) or those that were diagnosed as pregnant (85% v. 77%; P > 0.05) did not differ significantly between the goats exposed to well-fed or undernourished bucks. The interval between the introduction of bucks and the onset of estrous behavior was shorter in goats exposed to well-fed bucks compared to the interval for those goats exposed to undernourished bucks (2.5 ± 0.2 v. 9.5 ± 0.6 days; P < 0.05). We conclude that undernourishment reduces the testicular size and odor intensity responses in bucks exposed to long days, but that undernourished bucks are still able to stimulate reproductive activity in seasonally anestrous goats, as is also the case for well-fed bucks.

在半干旱条件下，饲料通常稀少且多变，饲喂不足是常见的现象。这些因素都可能导致两性生育力下降。有性活动的雄鹿能够非常有效地给过季的山羊施肥，但是我们不知道喂食不足是否会降低雄鹿在这段时期内给山羊施肥的能力。进行了两个实验，以确定（i）长时间营养不良的雄鹿的睾丸大小和气味强度的变化，以及（ii）这些雄鹿刺激季节性无情山羊的生殖活动的能力。在实验1中，从9月到5月，给雄鹿（n = 7）喂食了正常维护需求的1.5倍，并组成了喂饱的组。另一群雄鹿（n= 7）被喂食0.5倍维持需求的食物，并组成了营养不足的人群。从11月1日至1月15日，所有雄鹿都被人为地长时间休假；在此期间之后是自然光周期，直到5月30日。每2周测定一次体重，阴囊周长和雄性气味强度变化。在实验2中，两组雌性山羊（Ñ = 26每个）暴露于精心喂养（Ñ = 2）或营养不良雄鹿（Ñ = 2）3月31日。通过经直肠超声检查排卵和妊娠率。在实验1中，通过时间交互作用检测到体重，阴囊周长和气味强度变化（P<0.001）。10月至5月，饲喂雄鹿的体重指数高于营养不足的雄鹿的体重指数（P <0.01），12月至3月的阴囊周长（P <0.05）和2月至5月的气味强度（P <0.05） ）。在实验2中，至少排卵一次的女性比例（100％对96％）或被诊断出怀孕的女性比例（85％对77％；P> 0.05）暴露于饱食或营养不良的雄性山羊之间没有显着差异。相比于暴露于营养不良雄鹿那些山羊的间隔引入雄鹿和的发情行为的发作之间的间隔是在暴露于精心喂养雄鹿山羊较短（2.5±0.2 v 9.5±0.6天; P <0.05）。我们得出的结论是，营养不足会减少长时间暴露的雄鹿的睾丸大小和气味强度反应，但营养不足的雄鹿仍然能够刺激季节性无情山羊的生殖活动，而饲喂雄鹿的情况也是如此。