Genomic evaluation for calf wellness traits in Holstein cattle

Area of Science:

• Animal Genetics
• Dairy Science
• Genomic Prediction

Background:

• Reducing calf morbidity and mortality is crucial for dairy farm financial sustainability and animal welfare.
• Zoetis has developed genomic predictions for key calf wellness traits: calf respiratory disease (RESP), calf scours (DIAR), and calf livability (DEAD).

Purpose of the Study:

• To evaluate the feasibility of direct genomic evaluation for calf wellness traits in Holstein dairy cattle.
• To assess the predictive accuracy and heritability of genomic predictions for calf respiratory disease, scours, and livability.

Main Methods:

• Utilized phenotype and pedigree data from commercial dairies, with over 1.9 million records for calf livability.
• Employed a single-step genomic best linear unbiased prediction (BLUP) approach with 45,425 SNPs, imputing low-density genotypes.
• Analyzed traits using a univariate threshold animal model, incorporating fixed and random effects.

Main Results:

• Estimated heritabilities for RESP, DIAR, and DEAD were 0.042, 0.045, and 0.060, respectively.
• Average reliabilities for genotyped animals were 41.9% (RESP), 42.6% (DIAR), and 47.3% (DEAD).
• Genomic predictions showed approximate normal distributions, with low to moderate genetic correlations to existing dairy wellness traits.

Conclusions:

• Direct genomic evaluation of calf wellness traits using a genomic threshold model is feasible.
• Genomic selection for calf wellness traits offers a viable strategy for dairy producers to reduce replacement costs and enhance profitability.
• The developed genomic predictions provide reliable insights for improving calf health and overall herd management.