Canaza-Cayo Ali William, Lopes Paulo Sávio, da Silva Marcos Vinicius Gualberto Barbosa, de Almeida Torres Robledo, Martins Marta Fonseca, Arbex Wagner Antonio, Cobuci Jaime Araujo
Facultad de Ciencias Agrarias, Universidad Nacional del Altiplano, Puno 21001, Perú .
Animal Science Departament, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil .
Asian-Australas J Anim Sci. 2015 Oct;28(10):1407-18. doi: 10.5713/ajas.14.0620.
A total of 32,817 test-day milk yield (TDMY) records of the first lactation of 4,056 Girolando cows daughters of 276 sires, collected from 118 herds between 2000 and 2011 were utilized to estimate the genetic parameters for TDMY via random regression models (RRM) using Legendre's polynomial functions whose orders varied from 3 to 5. In addition, nine measures of persistency in milk yield (PSi) and the genetic trend of 305-day milk yield (305MY) were evaluated. The fit quality criteria used indicated RRM employing the Legendre's polynomial of orders 3 and 5 for fitting the genetic additive and permanent environment effects, respectively, as the best model. The heritability and genetic correlation for TDMY throughout the lactation, obtained with the best model, varied from 0.18 to 0.23 and from -0.03 to 1.00, respectively. The heritability and genetic correlation for persistency and 305MY varied from 0.10 to 0.33 and from -0.98 to 1.00, respectively. The use of PS7 would be the most suitable option for the evaluation of Girolando cattle. The estimated breeding values for 305MY of sires and cows showed significant and positive genetic trends. Thus, the use of selection indices would be indicated in the genetic evaluation of Girolando cattle for both traits.
2000年至2011年间，从118个牛群中收集了276头种公牛的4056头吉罗兰多奶牛女儿的首次泌乳期总计32817条测定日产奶量（TDMY）记录，用于通过随机回归模型（RRM）、使用阶数从3到5的勒让德多项式函数来估计TDMY的遗传参数。此外，还评估了9种产奶持久性指标（PSi）以及305天产奶量（305MY）的遗传趋势。所使用的拟合质量标准表明，分别采用阶数为3和5的勒让德多项式来拟合遗传加性效应和永久环境效应的RRM是最佳模型。通过最佳模型获得的整个泌乳期TDMY的遗传力和遗传相关性分别在0.18至0.23和 -0.03至1.00之间变化。持久性和305MY的遗传力和遗传相关性分别在0.10至0.33和 -0.98至1.00之间变化。使用PS7将是评估吉罗兰多牛的最合适选择。种公牛和母牛305MY的估计育种值显示出显著的正遗传趋势。因此，在吉罗兰多牛这两个性状的遗传评估中应使用选择指数。
