Canalization analysis of birth weight in Bruna dels Pirineus beef cattle1

Abstract

Although heteroskedasticity has been a main topic of interest in beef cattle during recent decades, the current availability of canalization models provided new insights for animal breeding programs. Within this context, birth BW (BWT) was analyzed in the Bruna dels Pirineus beef cattle breed by implementing canalization models that accounted for heterogeneous residual variances due to systematic, permanent environmental effects and additive genetic effects. Analyses were performed on BWT data from 8,130 calves born in 12 commercial breeding herds contributing to the yield recording scheme of the Bruna dels Pirineus breed. Analytical models accounted for direct additive genetic, permanent environmental, and 4 systematic effects (i.e., age of the dam, sex of the calf, birth type, and herd-year-season), and the same effects were evaluated as potential sources of variation in the residual term. Their relevance was checked by the deviance information criterion (DIC), and only residual additive genetic, permanent environmental, birth type, and herd-year-season remained in the operational model, all of them originating relevant reductions in the DIC parameter. Bruna dels Pirineus calves showed a moderate heritability of 0.30 (95% high posterior density, 0.19 to 0.40) for BWT; additional additive genetic variability was revealed in the residual term, this being positively correlated with the direct additive genetic component (0.44; 95% high posterior density, 0.37 to 0.54). Genetic trends were evaluated on both sources of additive genetic variance, and relevant patterns were identified in several herds. Although this breed did not evidence a homogeneous genetic trend for the whole population, herd-specific positive and negative trends were revealed, suggesting the plausibility of genetic selection for canalization on BWT in beef cattle breeds. These results must be viewed as a contribution to the canalization research field, providing relevant information for the breeding scheme of the Bruna dels Pirineus breed, as well as important insights about the genetic background of BWT for the beef industry worldwide.

The milk yield of dams and its relation to direct and maternal genetic components of weaning weight in beef cattle

“…Table 4 presents the heritability estimates of the direct and maternal additive genetic effects for all traits and their correlation. The heritability of direct BW was high compared with the results from Fina et al (2013) in Bruna dels Pirineus beef cattle breed (0.30).…”

“…Males were heavier than females throughout lactation, as their birth weight was 2.8 kg higher (P=0.035), and they differed by 5.4 kg at 90 days (P=0.002), and by 8.4 kg at 150 days (P=0.028). Similarly, Fina et al (2013) found higher birth weights in males of Bruna dels Pirineus breed, and Fries and Ruvinsky (1999) reported a sex influence on birth weight and W150 in beef cattle breeds.…”

Parámetros genéticos en la varianza residual de variables de comportamiento en toros de lidia

“…Tabla II. Estimaciones de heredabilidad (sobre la diagonal) y correlaciones genéticas (bajo la diagonal) para las notas de tienta y de lidia evaluadas (Heritability estimates (on the diagonal) and genetic correlations (below the diagonal) for the groping and dealing notes evaluated Neves et al (2011) reportaron estimaciones en el intervalo de 0.0042 a 0.099 y un valor promedio de 0.022; Fina et al (2013) evaluando el peso al nacer en bovinos Pirineus publicaron h 2 de 0.44 para varianza residual. Estos estudios afines, respaldan la existencia de efectos genéticos aditivos en la varianza residual.…”

“…En diversas especies de interés zootécnico se ha reportado evidencia de variabilidad genética en la varianza residual de características productivas; lo cual abre la posibilidad de controlar la varianza ambiental, y su posible disminución, a través de selección (SanCristobal-Gaudy et al, 2001;Ibáñez-Escriche et al, 2008;Mulder et al, 2009;Neves et al, 2011;Blasco et al, 2017;Iung et al, 2017). La selección para reducir la varianza, denominada canalización ambiental, se enfoca hacia un fenotipo optimo y homogeneidad en la producción (Gutiérrez et al, 2006;Mulder et al, 2008;Fina et al, 2013); este tipo de selección ocurre en poblaciones naturales como un mecanismo de adaptación y evolución a los cambios ambientales (Wagner et al, 1997).…”

Selection for environmental variance of litter size in rabbits

“…Most of this evidence is indirect, because it comes from analyses of databases and not from experiments designed to assess the genetic determination of environmental variance (litter size in sheep [10] and pigs [11], birth weight and stillbirth in pigs [12], weight in snails [13], birth weight in mice [14], uterine capacity in rabbits [15], weight in poultry [16] and beef cattle [17], milk yield of dairy cattle [18], and weight in trout [19] and salmon [20]). Other evidence of the existence of a genetic component for environmental variance comes from a few experiments on inbred lines of Drosophila melanogaster [1] and from only two selection experiments on birth weight, in rabbits [21] and mice [22].…”