Farrell P B, Presicce G A, Brockett C C, Foote R H
Department of Animal Science, Cornell University, Ithaca, NY, USA.
Theriogenology. 1998 Mar;49(4):871-9. doi: 10.1016/S0093-691X(98)00036-3.
Two experiments were conducted to evaluate semen quality of bulls housed under controlled conditions at a large AI facility and relate results to fertility. In Experiment 1 semen was collected from six 6-yr-old bulls twice daily at 3- to 4-d intervals for 3 d. In Experiment 2 eleven 6- to 11-yr-old bulls were used. Extensive breeding information was available and semen was collected as in Experiment 1 but replicated 4 times. Standard semen analysis and computer-assisted sperm analysis (CASA) with the Hamilton Thorne IVOS, model 10 unit, were performed on 36 first and second ejaculates in Experiment 1 and on 44 first ejaculates in Experiment 2. Sixteen fields (2 chambers with 8 fields per chamber) were examined per sample. In Experiment 1 the correlation between estimated sperm concentration by spectrophotometry and CASA was 0.91 (P < 0.01). Among bulls the range in the percentage of motile spermatozoa was 52 to 82 for CASA versus 62 to 69 for subjective measurements made by highly experienced technicians. Thus, CASA, with high repeatability, provided a more discriminating estimate of the percentage of motile sperm cells than did the subjective procedure. Bull effect was much greater than any other variable in the experiments. Chamber differences were small and so the results for the 2 chambers with 8 fields each were combined. One to five CASA values were correlated with bull fertility, defined as 59-day nonreturn rates corrected for cow and herd effects. The percentage of motile spermatozoa accounted for a small fraction of the total variation in fertility (r2 = 0.34). However higher r2 values (0.68 to 0.98) were obtained for 2 to 5 variables used in the multiple regression equations. The results are promising, and further testing will determine more precisely which of these CASA variables are most useful in estimating bull fertility potential.
进行了两项实验，以评估大型人工授精机构在可控条件下饲养的公牛的精液质量，并将结果与生育力相关联。在实验1中，从6头6岁的公牛身上，每隔3至4天每天采集两次精液，共采集3天。在实验2中，使用了11头6至11岁的公牛。有丰富的繁殖信息可用，精液采集方式与实验1相同，但重复了4次。对实验1中的36份首次和第二次射精以及实验2中的44份首次射精进行了标准精液分析和使用汉密尔顿·索恩IVOS 10型仪器的计算机辅助精子分析（CASA）。每个样本检查16个视野（2个腔室，每个腔室8个视野）。在实验1中，通过分光光度法估计的精子浓度与CASA之间的相关性为0.91（P < 0.01）。在公牛中，CASA检测的活动精子百分比范围为52%至82%，而经验丰富的技术人员进行的主观测量结果为62%至69%。因此，具有高重复性的CASA对活动精子细胞百分比的估计比主观方法更具区分性。在实验中，公牛效应比任何其他变量都大得多。腔室差异很小，因此将每个有8个视野的2个腔室的结果合并。1至5个CASA值与公牛生育力相关，公牛生育力定义为校正母牛和牛群效应后的59天不返情率。活动精子百分比在生育力的总变异中占一小部分（r2 = 0.34）。然而，在多元回归方程中使用的2至5个变量获得了更高的r2值（0.68至0.98）。结果很有前景，进一步的测试将更精确地确定这些CASA变量中哪些在估计公牛生育潜力方面最有用。
