Genetic parameters for sex-specific traits in beef cattle

Area of Science:

• Animal Genetics
• Quantitative Genetics
• Beef Cattle Breeding

Background:

• Understanding genetic relationships between growth, reproductive, and carcass traits is crucial for efficient beef cattle breeding.
• Heritability estimates provide insights into the genetic basis of these traits.
• Genetic correlations reveal how selection for one trait might influence another.

Purpose of the Study:

• To estimate genetic parameters for female growth and reproductive traits and male carcass traits in beef cattle.
• To determine the genetic correlations between these traits across sexes.
• To inform selection strategies in beef cattle breeding programs.

Main Methods:

• Utilized data from 3,593 beef heifers and 4,079 paternal half-sib steers.
• Estimated heritability for female traits (e.g., adjusted weights, age at puberty, calving rate/difficulty).
• Estimated heritability and genetic correlations for male carcass traits (e.g., hot carcass weight, fat percentage, marbling score, tenderness).

Main Results:

• Heritability estimates varied, with higher values for carcass traits (e.g., marbling score .71) and moderate values for female traits (e.g., age at puberty .47).
• Positive genetic correlations were found between heifer weights and several steer carcass traits (e.g., hot carcass weight, fat percentage).
• Calving rate and difficulty showed complex genetic correlations with carcass traits, including fatness and tenderness.

Conclusions:

• Selection for certain traits in one sex can lead to unintended consequences in the other sex.
• Genetic correlations highlight potential antagonistic relationships between reproductive and carcass traits.
• Balanced selection strategies are necessary to optimize overall breeding goals in beef cattle.