Queensland Alliance for Agriculture and Food Innovation, Centre for Animal Science, The University of Queensland, Brisbane, Queensland, Australia.
The University of Queensland, Gatton, Queensland, Australia.
Theriogenology. 2014 Apr 1;81(6):805-12. doi: 10.1016/j.theriogenology.2013.12.020. Epub 2013 Dec 27.
Normal range for scrotal circumference in Australian beef bulls was established using more than 300,000 measurements of breed, management group, age, liveweight, and scrotal circumference. The data used were derived from Australian bull breeders and two large research projects in northern Australia. Most bulls were within 250 to 750 kg liveweight and 300 to 750 days of age. The differences between breeds and variances within breeds were higher when scrotal circumference was predicted from age rather than liveweight, because of variance in growth rates. The average standard deviation for predicted scrotal circumference from liveweight and age was 25 and 30 mm, respectively. Scrotal circumference by liveweight relationships have a similar pattern across all breeds, except in Waygu, with a 50 to 70 mm range in average scrotal circumference at liveweights between 250 and 750 kg. Temperate breed bulls tended to have higher scrotal circumference at the same liveweight than tropically adapted breeds. Five groupings of common beef breeds in Australian were identified, within which there were similar predictions of scrotal circumference from liveweight. It was concluded that liveweight and breed are required to identify whether scrotal circumference is within normal range for Australian beef bulls that experience a wide range of nutritional conditions.
使用超过 30 万次的品种、管理组、年龄、活重和阴囊围度测量值，确定了澳大利亚肉牛的阴囊围度正常范围。所使用的数据来自澳大利亚公牛饲养者和澳大利亚北部的两个大型研究项目。大多数公牛的活重在 250 至 750 公斤之间，年龄在 300 至 750 天之间。由于生长速度的差异，从年龄而不是活重来预测阴囊围度时，品种之间的差异和品种内的方差更大。从活重和年龄预测的阴囊围度的平均标准偏差分别为 25 和 30 毫米。除了在 Waygu 品种中，所有品种的活重与阴囊围度的关系都呈现出相似的模式，在 250 至 750 公斤的活重范围内，平均阴囊围度的范围为 50 至 70 毫米。温带品种公牛在相同活重下的阴囊围度往往高于热带适应品种。在澳大利亚，确定了五个常见的肉牛品种分组，在这些分组中，可以根据活重相似地预测阴囊围度。结论是，需要根据活重和品种来确定澳大利亚肉牛的阴囊围度是否在正常范围内，因为这些牛经历了广泛的营养条件。
