Analysis of productive performance of different Holstein x Gir genetic groups in Brazil

Revista Brasileira de Zootecnia

Facó, Olivardo³  Martins Filho, Raimundo²  Lôbo, Raimundo Nonato Braga¹  Moura, Arlindo de Alencar Araripe² 

[1] Embrapa Caprinos, Sobral;UFC;UFC, Fortaleza

关键词: crossbreeding;    epistatic interactions;    heterosis;    lactation length;    milk yield   IntroduçãoA produtividade dos sistemas de produção de leite em áreas de clima tropical é caracteristicamente baixa em todo o mundo;    quando comparada aos sistemas de clima temperado;   

DOI  :  10.1590/S1516-35982002000800010

学科分类：兽医学

来源: Universidade Federal de Vicosa

【 摘 要 】

Total milk yield per lactation (PL), milk yield in 305 days (PL305) and lactation length (DL) were estimated based on records of the Brazilian Association of Girolando Breeders (3,574 lactations). Milk production was recorded monthly and 10.8% of the herds were raised under an extensive feeding system, 67.9% under a semi-intensive feeding system and 21.3% under an intensive feeding system. Data were analyzed through the least square method by GLM procedure (SAS, 1996). Preliminary analysis indicated a high interaction between genetic group and feeding system. Thus, the performance of genetic groups was evaluated within each feeding system. Genetic effects of additive difference between (g) Holstein and Gir breeds, dominance (d) and additive x additive epistatic interactions (gg) were also studied. It was observed that, in some cases, the effects of epistatic interactions should be taken into account. Moreover, increasing the proportion of Holstein-Friesian genes did not have any significant effect on milk yield when herds were raised under poor management conditions. However, as such conditions improved, crosses with higher proportion of Holstein tended to show better performance.

【 授权许可】

CC BY-NC