Agricultural Sciences Faculty, Grande Dourados Federal University, Dourados, MS, Brazil.
J Anim Breed Genet. 2012 Dec;129(6):488-500. doi: 10.1111/j.1439-0388.2012.00992.x. Epub 2012 Mar 13.
Buffaloes are generally raised in Brazil without milk-recording programs, and thus without genetic evaluations of any of their traits. This study evaluated the economic impacts of three different selection strategies on buffalo populations and the evolution of genetic trends, genetic variances and inbreeding coefficients resulting from each of them. The selection strategies used were as follows: (i) random selection; (ii) phenotypic selection; and (iii) progeny testing (PT). As the numbers of herds enrolled in milk-recording programs increased, phenotypic selection and PT strategies increased both monetary benefits and genetic trends. The extra costs of implementing milk recording (MR) and PT procedures were exceeded by the income resulting from better buffalo performance. Progeny testing is known to result in beneficial genetic trends and the use of artificial insemination promoted better distributions of genetic material into herds that were not enrolled in milk-recording programs. Phenotypic selection and PT increased mean milk production--a key factor in profitability. Inbreeding levels remained stable with phenotypic selection, even as the numbers of MR herds increased. Increases in the numbers of sires that were evaluated reduced the mean inbreeding coefficient in PT. Increasing the number of herds enrolled in milk-recording programs resulted in increased numbers of sires needed for PT, but this did not increase the inbreeding coefficient. In summary, phenotypic selection and PT strategies appear to be economically viable for buffalo husbandry in south-eastern Brazil under current (2007-2008) economic conditions and should be encouraged.
水牛在巴西通常未经泌乳记录方案(即没有任何性状的遗传评估)而被饲养。本研究评估了三种不同选择策略对水牛群体的经济影响,以及由此产生的遗传趋势、遗传方差和近交系数的演变。所使用的选择策略如下:(i)随机选择;(ii)表型选择;和(iii)后裔测验(PT)。随着参加泌乳记录方案的牛群数量的增加,表型选择和 PT 策略提高了货币收益和遗传趋势。实施泌乳记录(MR)和 PT 程序的额外成本被更好的水牛表现带来的收益所超过。PT 已知会导致有利的遗传趋势,并且人工授精的使用促进了未参加泌乳记录方案的牛群中遗传物质的更好分布。表型选择和 PT 提高了平均奶产量——这是盈利能力的关键因素。随着参加 MR 牛群数量的增加,近交水平保持稳定。经过评估的种公牛数量的增加降低了 PT 中的平均近交系数。参加泌乳记录方案的牛群数量的增加导致需要进行 PT 的种公牛数量增加,但这并没有增加近交系数。总之,在当前(2007-2008 年)经济条件下,表型选择和 PT 策略似乎在巴西东南部的水牛养殖中具有经济可行性,应该得到鼓励。