Objectives were to estimate variance components and genetic parameters for daily milk yields of Brazilian Holstein cattle, using an autoregressive TD multiple lactations (AR) animal model. Data consisted of 377 465 TD records produced by 27 080 cows, sired by 1,371 bulls and calving from 1993 to 2004. The AR animal model gave smaller residual and higher genetic variances than other models previously used to fit TD yields. Medium to high heritability estimates suggest opportunities for larger genetic gain by selection. Results from this study confirm the potential of using TD yields to replace the lactation model to estimate breeding values of Holstein cows in Brazil. Further studies are needed to evaluate other traits (fat and protein yields) along with comparisons with other modelling approaches e.g., the RR model.

C. N Costa, J. Vasconcelos, Jaime A Cobuci, G. Thompson, J. Carvalheira

Proceedings of the World Congress on Genetics Applied to Livestock Production, Volume , , 01.53, 2006
Download Full PDF BibTEX Citation Endnote Citation Search the Proceedings

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.