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Survival Rates of Tested Daughters of Sires in Artificial Insemination

Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada

ABSTRACT

Canadian Record of Performance records on 46,074 Ontario Holstein cows by 56 artificial insemination sires were from 1958 to 1971. All 2-yr-old records were between 1958 and 1967 to allow all cows enough time to complete 3-yr-old and 4-yr-old records by the end of 1972. Reasons for disposal were absent. Henderson's best linear unbiased prediction techniques were used with the minimum norm quadratic unbiased estimation method of estimating variance components in an iterative procedure to estimate variances for sire and error and to predict genetic values of sires for survival rate simultaneously. Fixed year and herd effects were also in the model. Proofs for survival rates were correlated with available milk and type score ratings to determine relationships among sire proofs as they affect sire selection. Heritability of survival through one lactation was .04 and for survival through two lactations was .08. Survival ability of cows can be improved by selecting and using bulls that have better than average milk and type proofs.