Brazil has the third bovine herd of the world in number of animals. Among the specialized dairy breed the Holstein is the most representative in terms of milk production, with productions that get to reach values similar to the observed at developed countries. According to the Brazilian Holstein Herd Book, 104.382 animals was in milking recording in 1999, with average of milk yield of 6.799 kg (2X and 305 days) and of 7.532 kg the mature age (2X and 305 days). About 84,0 % of the Holstein dairy herds are located in the states of São Paulo, Paraná and Minas Gerais. The selection based on the estimates of the genetic values of the sires for trait used as selection criteria cause the increase of the inbreeding rates, because relatives animals has similar genetic value allowing the relatives co-selection to be frequent. Several algorithms that allow the estimate of the inbreeding coefficient are being used when the pedigrees of all the animals should be used ( Vanraden and Hoeschele, 1990 ; Meuwissen and Luo, 1992 ; Miglior et al., 1992 ; Bijma, 2000). Due the difficulty to have the complete genealogy registrations, Vanraden and Hoeschele (1990) and Bijma (2000) developed a algorithm to estimate the inbreeding rate with data lost. A negative action of the inbreeding about the production of milk has been reported by literature (Hodges et al., 1979 ; Hudson and Van Vleck, 1984 ; Shorts et al., 1992 ; Vanraden et al., 1992 ; Bijma, 2000). This study had as objectives to estimate the genetics parameters of milk yield and the inbreeding rate in Holstein herds maintained in the Southeast region of Brazil
Proceedings of the World Congress on Genetics Applied to Livestock Production, Volume 2002. Session 1, , 1.87, 2002
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