Carpenter B B, Forrest D W, Sprott L R, Rocha A, Hawkins D E, Beverly J R, Hawkins H E, Parish N R
Department of Animal Science, Texas A&M University, College Station 77843.
J Anim Sci. 1992 Jun;70(6):1795-800. doi: 10.2527/1992.7061795x.
Three experiments were conducted with Santa Gertrudis (SG) or F1 (Gelbvieh x SG or Red Angus x SG) bulls to assess factors that influence copulatory activity and fertility of Bos indicus-influenced genotypes. In Exp. 1, 3-yr-old SG bulls (n = 20) with sexual experience and 20-mo-old virgin SG bulls (n = 34) were allotted in a split-plot design (age, bull within age group, test day, and heifer treatment). Number of mounts (Mt), intromissions (I), and ejaculations (E) were measured 14 d apart during two 30-min serving capacity (SC) tests. Estrus was either induced via progesterone+estradiol cypionate (PE) injections or synchronized with Syncro-Mate B (SMB). There were more (P less than .05) I and E on Test d 2 than on Test d 1. Heifers treated with SMB received more (P less than .001) Mt, I, and E than did heifers treated with PE. Sixteen 20-mo-old bulls from Exp. 1 were allotted to breeding pastures at a bull:heifer ratio of 4:119 +/- 3 for 50 d in Exp. 2. Breeding pasture treatments either included or excluded low-SC bulls. Neither pregnancy rate nor least squares mean day of conception differed between treatments. Experiment 3 evaluated copulatory activity with a 2 x 2 factorial arrangement (breed and test day) in 14- to 16-mo-old SG (n = 45) and F1 (n = 16) bulls. The F1 bulls had more Mt, I, and E than did the SG bulls (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)
进行了三项试验，使用圣格鲁迪牛（SG）或F1代牛（格尔维牛×SG或红安格斯牛×SG）公牛，以评估影响受印度瘤牛影响的基因型交配活动和繁殖力的因素。在试验1中，采用裂区设计（年龄、年龄组内的公牛、试验日和小母牛处理），将有性经验的3岁SG公牛（n = 20）和20月龄的处女SG公牛（n = 34）进行分配。在两次30分钟的配种能力（SC）测试期间，每隔14天测量一次爬跨次数（Mt）、插入次数（I）和射精次数（E）。发情期通过注射孕酮+环丙孕酮（PE）诱导，或与同步伴侣B（SMB）同步。试验第2天的I和E比试验第1天更多（P < 0.05）。用SMB处理的小母牛比用PE处理的小母牛接受了更多（P < 0.001）的Mt、I和E。试验1中的16头20月龄公牛在试验2中以1:4:119 ± 3的公牛与小母牛比例分配到繁殖牧场50天。繁殖牧场处理包括或排除低SC公牛。各处理之间的妊娠率和最小二乘平均受孕日没有差异。试验3采用2×2析因设计（品种和试验日）评估了14至16月龄的SG（n = 45）和F1（n = 16）公牛的交配活动。F1公牛的Mt、I和E比SG公牛更多（P < 0.05）。（摘要截短至250字）
