Inbreeding depression on beef cattle traits: Estimates, linearity of effects and heterogeneity among sire-families
2008
Gama Luis T | Carolino Nuno
<p>Abstract</p> <p>Records from up to 19054 registered cows and 10297 calves in 155 herds of the Alentejana cattle breed were used to study the effects of individual (F<sub>i</sub>) and maternal (F<sub>m</sub>) inbreeding on reproductive, growth and carcass traits, as well as assessing the importance of non-linear associations between inbreeding and performance, and evaluating the differences among sire-families in the effect of F<sub>i </sub>and F<sub>m </sub>on calf weight at 7 months of age (W7M). Overall, regression coefficients of performance traits on inbreeding were small, indicating a minor but still detrimental effect of both F<sub>i </sub>and F<sub>m </sub>on most traits. The traits with the highest percentage impact of F<sub>i </sub>were total number of calvings through life and calf weight at 3 months of age (W3M), followed by longevity and number of calves produced up to 7 years, while the highest effect of F<sub>m </sub>was on W3M. Inbreeding depression on feed efficiency and carcass traits was extremely small and not significant. No evidence was found of a non-linear association between inbreeding and performance for the traits analyzed. Large differences were detected among sire-families in inbreeding depression on W7M, for both F<sub>i </sub>and F<sub>m</sub>, encouraging the possibility of incorporating sire effects on inbreeding depression into selection decisions.</p>
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