Sires genetic evaluations using complete or partial projected lactation records: 3. Reliabilities and genetic gains

Revista Brasileira de Zootecnia

Martinez, Mário Luiz³  Melo, Cláudio Manoel Rodrigues de²  Oliveira, Antonio Ilson Gomes de¹  Freitas, Rilke Tadeu Fonseca de¹  Verneque, Rui da Silva³  Gonçalves, Tarcisio de Moraes¹ 

[1] UFLA;USP;Embrapa Gado de Leite

关键词: genetic evaluation;    Gyr cattle;    model animal;    partial projected lactation;    reliabilities;    restricted maximum likelihood     IntroduçãoO uso de registros de lactação em progresso na avaliação do mérito genético de touros pode reduzir o tempo requerido para a decisão de quais animais devem ser selecionados;   

DOI  :  10.1590/S1516-35982000000300012

学科分类：兽医学

来源: Universidade Federal de Vicosa

【 摘 要 】

- Records of 4595 lactations from 2254 cows, daughters of 145 sires and 1,618 dams of the Gyr breed, assigned to 18 herds, with calving from 1980 to 1997 were used to study the viability of using production from projected partial lactations, on the evaluation. From 91, 151, 211 or 241 days of lactation, 10, 30, 50 or 70% of the lactations were projected, for the duration of the observed lactation and 305 days of lactation. The estimates of genetic parameters were determined using the MTDFREML system. Independent of the traits, the herd-year, season of calving and age of calving with linear and quadratic parameters were included in the model as fixed effects, and considering the animal, permanent environment and error as random effects. The mean of the obtained reliabilities using the estimation productions (PE) ranged from 0.60 to 0.67, and the average was obtained using P305 equal to 0.60. The annual genetic gain for the selection of the sire using the PE was, on the average, 24.27% higher than the annual genetic gain of P305, when the lactations were projected for the length of the observed lactation, and 25.65% higher, when the lactations were projected for P305. The recorded reliabilities as well as the annual genetic gain estimated in the genetic evaluations using the PE were similar to those obtained for the production of milk up to 305 days.

【 授权许可】

CC BY-NC