Alternative animal models with maternal effects and foster dams

Area of Science:

• Animal Genetics
• Quantitative Genetics
• Livestock Breeding

Background:

• Genetic evaluations traditionally focus on biological dams.
• The influence of foster dams on offspring's genetic merit is often overlooked.
• Accurate genetic evaluations require accounting for all significant maternal influences.

Purpose of the Study:

• To explore and present methods for integrating foster dam effects into animal model genetic evaluations.
• To demonstrate that incorporating foster dam effects requires only minor computational adjustments.
• To provide a framework for more comprehensive genetic predictions in livestock.

Main Methods:

• Discussed four alternative computational strategies for including foster dam effects.
• These methods involve modifications to existing animal models, such as fixed effects of breed-period and nested random effects.
• Utilized least squares contributions and solution vectors for breeding values, with one method employing Westell's rules for relationships and genetic groups.

Main Results:

• The proposed alternatives require minimal additional computational effort compared to standard models.
• Foster dam effects can be incorporated by adjusting equations for fixed and random effects or by expanding solution vectors.
• Westell's rules offer a method for calculating coefficients related to relationships and genetic groups for foster dams.

Conclusions:

• Integrating foster dam effects into genetic evaluations is computationally feasible with minor modifications to animal models.
• These approaches enhance the accuracy of breeding value predictions for direct and maternal traits.
• The presented methods provide practical solutions for livestock breeding programs seeking more precise genetic assessments.