Genetic Evaluation for Herd Life in Canada

• Published in: Journal of dairy science 1998-02, Vol.81 (2), p.550-562
• Main Authors: Jairath, L., Dekkers, J.C.M., Schaeffer, L.R., Liu, Z., Burnside, E.B., Kolstad, B.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; BODY CONFORMATION; Breeding; BREEDING VALUE; BULLS; CANADA; Cattle - genetics; Classical genetics, quantitative genetics, hybrids; conformation; CORRELATED TRAITS; DAIRY CATTLE; DIRECT SIRE COMPARISONS; EQUATIONS; Female; Fundamental and applied biological sciences. Psychology; genetic evaluation; Genetic Variation; GENETICS; Genetics of eukaryotes. Biological and molecular evolution; herd life; Lactation - genetics; LACTATION NUMBER; LONGEVITY; Male; MATHEMATICS; Models, Genetic; PREDICTED DIFFERENCE; PRODUCTION POSSIBILITIES; PRODUCTIVE LIFE; SELECTION INDEX; SIRE EVALUATION; TRENDS; TYPE SCORE; Vertebrata
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(98)75607-3

Methods were developed for the national genetic evaluation of herd life for Canadian Holstein sires. The genetic evaluations incorporate information from survival (direct herd life) and information from conformation traits that are related to herd life (indirect herd life) after adjustment for production in first lactation to remove the effect of culling for production. Direct genetic evaluations for herd life were based on survival in each of the first three lactations, which was analyzed using a multiple-trait animal model. Sire evaluations thus obtained for survival in each of the first three lactations were combined based on their economic weights into an overall sire evaluation for direct herd life. Sire evaluations for indirect herd life were based on an index of sire evaluations for mammary system, feet and legs, rump, and capacity. A multiple-trait sire model based on multiple-trait across country evaluation methodology was used to combine direct and indirect genetic evaluations for herd life into an overall genetic evaluation for herd life. Sire evaluations for herd life were expressed in estimated transmitting ability as the number of lactations and represent expected differences among daughters in functional herd life (number of lactations); the average functional herd life was set equal to three lactations. Estimated transmitting abilities were normally distributed and ranged from 2.31 to 3.43 lactations.