Coulter G H, Kozub G C
J Anim Sci. 1984 Aug;59(2):432-40. doi: 10.2527/jas1984.592432x.
The effect of high (HED) and medium energy diets (MED), fed to Hereford (H) and Angus (A) bulls from 6 through 24 mo of age, on scrotal circumference (SC), paired testes weight (PTW), epididymal sperm reserves (ESR) and seminal traits were examined. Over 3 yr, 120 bulls were involved. Angus exceeded H for both SC and PTW. Hereford bulls in yr 2 had smaller SC than in yr 1 or 3 but the response for A was consistent. Year affected PTW. In yr 2 Hereford bulls fed HED had 75% fewer ESR than MED-H bulls (9.3 vs 37.2 X 10(9]. Comparably treated A bulls had similar ESR numbers (29.2 vs 33.4 X 10(9]. In yr 3, epididymal sperm reserves of HED-H were depressed by 35% compared with MED-H (23.1 vs 35.7 X 10(9], whereas HED-A had 14% fewer ESR than did MED-A bulls (28.6 vs 33.1 X 10(9]. It was not obvious why H bulls were more susceptible to the effects of HED. Seminal quality of HED bulls was inferior to that of MED bulls, particularly with respect to progressive motility and the incidence of sperm in which a crater defect of the head was present at 2 yr of age. In yr 2 all seminal traits were severely depressed in 2-yr-old HED-H. Feeding HED to young H and A bulls reduced their reproductive potential.
研究了从6月龄到24月龄给赫里福德（H）和安格斯（A）公牛饲喂高能日粮（HED）和中能日粮（MED）对阴囊周长（SC）、双侧睾丸重量（PTW）、附睾精子储备（ESR）和精液性状的影响。在3年多的时间里，共有120头公牛参与。安格斯公牛的SC和PTW均超过赫里福德公牛。第2年的赫里福德公牛SC比第1年或第3年小，但安格斯公牛的反应是一致的。年份影响PTW。在第2年，饲喂HED的赫里福德公牛的ESR比饲喂MED的公牛少75%（9.3×10⁹ 对比37.2×10⁹）。同等处理的安格斯公牛的ESR数量相似（29.2×10⁹ 对比33.4×10⁹）。在第3年，与饲喂MED的赫里福德公牛相比，饲喂HED的公牛附睾精子储备降低了35%（23.1×10⁹ 对比35.7×10⁹），而饲喂HED的安格斯公牛的ESR比饲喂MED的公牛少14%（28.6×10⁹ 对比33.1×10⁹）。赫里福德公牛为何对HED的影响更敏感尚不清楚。饲喂HED的公牛精液质量低于饲喂MED的公牛，尤其是在2岁时的精子前向运动能力和头部有火山口样缺陷的精子发生率方面。在第2年，2岁的饲喂HED的赫里福德公牛所有精液性状都严重下降。给年轻的赫里福德和安格斯公牛饲喂HED会降低它们的繁殖潜力。
