(Co)variances between cattle postpartum body weight and dairy traits in a pastoral system in Chile
Héctor Uribe1*, y Humberto González1
In Chile, the genetic parameters of dairy cow body weight have not been estimated due to lack of data. The objective of this study was to determine variance components of milk yield traits and postpartum body weight. Data were obtained from a dairy research farm in southern Chile. A multi-trait animal mixed repeatability model was used and genetic parameters were estimated using the VCE software. Heritability estimates for yields of milk, milk fat and protein, and postpartum body weight were 0.26 ± 0.011, 0.30 ± 0.011, 0.27± 0.012 and 0.43 ± 0.047, respectively. Genetic correlations for postpartum body weight and yields of milk, milk fat and protein were 0.34, 0.40 and 0.38, respectively. Phenotypic correlations were also positive and generally 10% lower than genetic correlations. It is concluded that the correlations between postpartum body weight and milk yield traits are positive and not very high. The genetic selection to favour yield would increase cow’s body weight.
Key words: genetic correlation; milk solids; body weight; pastoral; heritability
1 Departamento de Producción Animal, Facultad de Ciencias Agronómicas, Universidad de Chile, Avenida Santa Rosa 11315, La Pintana, Santiago, Chile..
* Autor para correspondencia E-mail: [email protected]