Optimization of a genomic breeding program for a moderately sized dairy cattle population

Area of Science:

• Animal Breeding and Genetics
• Dairy Science
• Genomic Selection

Background:

• Genotyping bull calves is typically limited to elite sires due to costs and logistical challenges.
• Expanding sire pools requires significant investment in calf acquisition, housing, and identification.
• Genomic selection offers potential for increased accuracy and efficiency in breeding programs.

Purpose of the Study:

• To economically optimize a genomic breeding program for bull calf selection in the Israeli Holstein population.
• To determine the optimal number of bull calves to genotype for maximizing profit and genetic gain.
• To evaluate the impact of genomic information on profitability and selection response.

Main Methods:

• Economic optimization via simulation of a genomic breeding program.
• Utilized a population of 120,000 milk-recorded cows and their potential bull progeny.
• Simulated pseudo-phenotypes based on genetic evaluations and incorporated costs of genotyping, calf acquisition, and salvage value.

Main Results:

• Optimal economic returns were achieved by genotyping 1,620-1,750 bull calves.
• However, 95% of optimal profit was attainable with only 240-300 genotyped calves.
• Genomic selection increased annual response to selection and absolute profits compared to non-genomic methods.

Conclusions:

• Genomic selection in dairy cattle breeding programs significantly enhances both genetic gain and economic profitability.
• A reduced number of genotyped bull calves, around 240-300, can achieve near-optimal economic outcomes.
• Inbreeding had a negligible impact on genetic gain and profits within the studied genomic selection framework.