Smith B A, Brinks J S, Richardson G V
Dept. of Anim. Sci., Colorado State University, Fort Collins 80523.
J Anim Sci. 1989 Nov;67(11):2881-5. doi: 10.2527/jas1989.67112881x.
Reproductive and growth data were obtained on 779 and 564 yearling beef heifers and bulls, respectively, that had sires with yearling scrotal circumference data at the San Juan Basin Research Center, Hesperus, CO. Partial regression coefficients of reproductive and growth traits on inbreeding (FXC) and age of the individual and adjusted scrotal circumference of sire (SCSI) were obtained. Growth and reproductive traits of heifers and growth and breeding soundness traits of bulls were analyzed. Separate analyses for each sex were performed, but least squares models were similar. Models included fixed effects of breed, birth year (BY), age of dam (AOD) and the covariates FXC, age (day of birth in heifer analyses) and SCSI. Scrotal circumference of sire was adjusted for age, FXC, AOD and BY using values obtained in a separate analysis. Seminal traits improved as age increased, and there was a seasonal effect present for age of puberty. Inbreeding had a detrimental effect on reproductive traits. Partial regression coefficients for the reproductive traits on SCSI were: age of puberty, -.796 d/cm; age of first calving, -.826 d/cm; julian day of first calving, -.667 d/cm; julian day of second calving, .597 d/cm; most probable producing ability, .132 %/cm; percent sperm motility, -.74 %/cm; percent primary sperm abnormalities, .08 %/cm; percent secondary sperm abnormalities, .92 %/cm; percent normal sperm, -1.28 %/cm; total breeding soundness examination score, .28 units/cm and scrotal circumference, .306 cm/cm. A heritability of .39 was obtained for scrotal circumference.
分别在科罗拉多州赫斯珀斯的圣胡安盆地研究中心，获取了779头一岁肉用小母牛和564头一岁肉用公牛的繁殖与生长数据，这些牛的父亲有一岁时的阴囊周长数据。获得了繁殖和生长性状对近亲繁殖（FXC）、个体年龄以及父亲调整后的阴囊周长（SCSI）的偏回归系数。分析了小母牛的生长和繁殖性状以及公牛的生长和繁殖健全性状。对每个性别进行了单独分析，但最小二乘模型相似。模型包括品种、出生年份（BY）、母牛年龄（AOD）的固定效应以及协变量FXC、年龄（小母牛分析中的出生日期）和SCSI。使用在单独分析中获得的值，对父亲的阴囊周长进行了年龄、FXC、AOD和BY的调整。精液性状随年龄增加而改善，青春期年龄存在季节效应。近亲繁殖对繁殖性状有不利影响。SCSI对繁殖性状的偏回归系数为：青春期年龄，-.796天/厘米；首次产犊年龄，-.826天/厘米；首次产犊儒略日，-.667天/厘米；第二次产犊儒略日，.597天/厘米；最可能生产能力，.132%/厘米；精子活力百分比，-.74%/厘米；初级精子异常百分比，.08%/厘米；次级精子异常百分比，.92%/厘米；正常精子百分比，-1.28%/厘米；总繁殖健全性检查评分，.28单位/厘米；阴囊周长，.306厘米/厘米。阴囊周长的遗传力为.39。
