Evaluation of Canadian Holstein-Friesian sires on disposal reasons of their daughters.

Data were lactations of 82,971 Canadian Holstein-Friesian cows by 4,778 sires recorded from 1975 to 1978 and included final disposal codes. Progeny were required to have first lactation records and were grouped according to whether they had the opportunity to complete one, two, or three 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 .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 .21 to .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 first opportunity group proofs for disposal are not accurate predictors of longevity. Routine evaluation of sires on disposal reasons is not recommended.