Phenotypic plasticity of composite beef cattle performance using reaction norms model with unknown covariate

Author(s)

Santana, Jr., M. L. ^{[1, 2]} ; Eler, J. P. ^[2] ; Cardoso, F. F. ^[3] ; Albuquerque, L. G. ^[4] ; Ferraz, J. B. S. ^[2]

Affiliation

^[1] Univ Fed Mato Grosso, Inst Ciencias Agr & Tecnol, Grp Melhoramento Anim Mato Grosso, BR-78735901 Rondonopolis, MT - Brazil

^[2] Univ Sao Paulo, Fac Zootecnia & Engn Alimentos, Grp Melhoramento Anim & Biotecnol, BR-13635970 Pirassununga, SP - Brazil

^[3] Embrapa Pecuaria S, BR-96401970 Bage, RS - Brazil

^[4] Univ Estadual Paulista, Fac Ciencias Agr & Vet, BR-14884900 Jaboticabal, SP - Brazil

• Document type: Journal article
• Source: ANIMAL; v. 7, n. 2, p. 202-210, FEB 2013.
• Web of Science Citations: 16

Abstract

The objective of the present study was to determine the presence of genotype by environment interaction (G X E) and to characterize the phenotypic plasticity of birth weight (BW), weaning weight (WW), postweaning weight gain (PWG) and yearling scrotal circumference (SC) in composite beef cattle using the reaction norms model with unknown covariate. The animals were born between 1995 and 2008 on 33 farms located throughout all Brazilian biomes between latitude -7 degrees and -31 degrees, longitude -40 degrees and -63 degrees. The contemporary group was chosen as the environmental descriptor, that is, the environmental covariate of the reaction norms. In general, higher estimates of direct heritability were observed in extreme favorable environments. The mean of direct heritability across the environmental gradient ranged from 0.05 to 0.51, 0.09 to 0.43, 0.01 to 0.43 and from 0.12 to 0.26 for BW, WW, PWG and SC, respectively. The variation in direct heritability observed indicates a different response to selection according to the environment in which the animals of the population are evaluated. The correlation between the level and slope of the reaction norm for BW and PWG was high, indicating that animals with higher average breeding values responded better to improvement in environmental conditions, a fact characterizing a scale of G X E. Low correlation between the intercept and slope was obtained for WW and SC, implying re-ranking of animals in different environments. Genetic variation exists in the sensitivity of animals to the environment, a fact that permits the selection of more plastic or robust genotypes in the population studied. Thus, the G X E is an important factor that should be considered in the genetic evaluation of the present population of composite beef cattle. (AU)

• FAPESP's process: 09/05072-4 - Genotype-environment interaction in composite beef cattle and prospection of possible breed compositions more appropriate for different productive environments
• Grantee: Mário Luiz Santana Júnior
• Support Opportunities: Scholarships in Brazil - Doctorate