Evaluation of Canadian Holstein-Friesian Sires on Disposal Reasons of Their Daughters

Abstract

Data were lactations of 82,971 Canadian Holstein-Friesian cows by 4778 sires recorded from 1975 to 1978 and included final disposal codes. Progeny were required to have 1st lactation records and were grouped according to whether they had the opportunity to complete 1, 2 or 3 lactations. Henderson''s Method I technique was used to estimate sire, herd and error variances within opportunity group for culling for low production, sickness and all undesirable causes. Variances were low, and many were negative. Heritabilities ranged from 0 to 0.13. Best linear unbiased prediction techniques were used to estimate sire proofs for disposal reasons. Sire proofs were not distributed normally. Sire proofs were correlated between opportunity groups within disposal reason. All correlations were positive and ranged from 0.21 to 0.82. Correlations were greatest between contiguous opportunity groups and lowest between proofs on early opportunity groups and proofs on cows that were close to maturity, indicating that 1st opportunity group proofs for disposal are not accurate predictors of longevity. Routine evaluation of sires on disposal reasons is not recommended.