Including nonadditive genetic effects in mating programs to maximize dairy farm profitability

Area of Science:

• Animal breeding and genetics
• Quantitative genetics
• Genomic selection

Background:

• Traditional breeding programs primarily focus on additive genetic effects.
• Nonadditive genetic effects, including dominance and heterozygosity, can significantly influence complex traits in livestock.
• Integrating nonadditive effects into mating strategies may optimize genetic gain and economic returns.

Purpose of the Study:

• To compare the efficacy of mating programs utilizing additive genetic effects alone versus those incorporating nonadditive genetic effects (dominance and heterozygosity).
• To evaluate the impact of different genetic models on progeny performance, inbreeding, and economic profit in Holstein cattle.

Main Methods:

• Estimation of additive and dominance marker effects and regression on average heterozygosity using 632,003 SNPs in 7,902 (calving interval) and 7,510 (production) Holstein cows.
• Computation of expected progeny values incorporating nonadditive effects for hypothetical progeny.
• Development of an economic index to assess mating scenarios based on trait values and profit.

Main Results:

• Mating programs incorporating dominance and heterozygosity effects outperformed models with only additive effects.
• Significant increases in milk, fat, and protein yields (up to 38 kg, 1.57 kg, and 1.21 kg, respectively) and decreased calving interval (up to 0.70 d) were observed.
• Reduced progeny inbreeding (0.25–1.57 percentage points) and increased profit (A$8.42 per mating) were associated with models including nonadditive effects.

Conclusions:

• Nonadditive genetic effects significantly enhance progeny performance and economic outcomes in cattle breeding.
• The benefits of nonadditive effects are primarily realized in the immediate generation and do not accumulate over time.
• Continuous updating of genomic predictions and mating allocation strategies is crucial for sustained benefits from nonadditive genetic effects.