Estimated genetic parameters for all genetically evaluated traits in Canadian Holsteins

Area of Science:

• Animal Genetics
• Dairy Science
• Quantitative Genetics

Background:

• Sustainable dairy production requires genetic improvement for high-quality traits.
• Breeding programs rely on genetic parameters like heritability and genetic correlations.
• Canadian Holstein cows are a key population for dairy genetic research.

Purpose of the Study:

• Estimate population genetic parameters and trends for 67 traits in Canadian Holstein cows.
• Provide updated and novel genetic parameter estimates for use in breeding programs.
• Inform the development and refinement of selection indexes for dairy cattle.

Main Methods:

• Utilized a large dataset of approximately 500,000 records from 1980 to 2019.
• Employed bivariate linear animal models under a Bayesian approach for parameter estimation.
• Conducted analyses across 2,211 bivariate trait combinations.

Main Results:

• High heritability estimates were found for fat percent (0.69) and protein percent (0.66), and stature (0.47).
• Low heritabilities (0.01) were observed for disease traits (lameness, toe ulcer) and calf survival.
• Strong genetic correlations were found between gestation length, calf size, and calving ease; other traits showed no genetic relationship.

Conclusions:

• The study provides essential genetic parameter estimates for Canadian Holstein cows, including novel data.
• These estimates are crucial for enhancing dairy cattle breeding programs and selection indexes.
• Understanding genetic correlations aids in predicting correlated responses and incorporating new traits into selection strategies.