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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Genetics and Animal Breeding » Research » Publications at this Location » Publication #132738
Title: ESTIMATES OF GENETIC PARAMETERS AND AN EVALUATION OF GENOTYPE X ENVIRONMENT INTERACTION FOR WEANING WEIGHT IN NELLORE CATTLE

Author
item DE SOUZA, JULIO - BRAZIL
item GADINI, CLAUDIA - BRAZIL
item DA SILVA, LUIS - BRAZIL
item RAMOS, ALCIDES - BRAZIL
item EUCLIDES FILHO, KEPLER - BRAZIL
item DE ALENCAR, MAURICIO - BRAZIL
item FERRAZ FILHO, PAULO - BRAZIL
item Van Vleck, Lloyd

Submitted to: Archivos Latinoamericanos De Produccion Animal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2003
Publication Date: 11/1/2003
Citation: DE SOUZA, J.C., GADINI, C.H., DA SILVA, L.O.C., RAMOS, A.A., EUCLIDES FILHO, K., DE ALENCAR, M.M., FERRAZ FILHO, P.B., VAN VLECK, L.D. ESTIMATES OF GENETIC PARAMETERS AND AN EVALUATION OF GENOTYPE X ENVIRONMENT INTERACTION FOR WEANING WEIGHT IN NELLORE CATTLE. ARCHIVOS LATINOAMERICANOS DE PRODUCCION ANIMAL. 2003. 11(2):94-100.

Interpretive Summary: A common question breeders have is whether the genetic evaluation of a bull tested in one region is valid in a different region. One answer to this question is suggested by the correlation between expression of a sire's genes in the two regions. As a rule of thumb, if the correlation is above 0.80, then selection for use in one region based on progeny in another region should be okay. This study compared evaluations of Nelore bulls with progeny in 8 regions in Brazil. The correlations of genetic expression in pairs of regions varied from -0.03 to 1.00. All except one of the correlations was less than 0.80, although many were in the range of 0.50 to 0.76. These results suggest an important genotype by environment interaction and that selection of bulls of the Nellore breed would be most effective if based on progeny performance in the region where the bull is to be used.

Technical Abstract: Records of 105,645 Nellore calves born from 1977 to 1994 in eight different regions of Brazil were used to estimate genetic parameters for weaning weight (kg). The objective of this study was to estimate genetic and environmental parameters and evaluate genotype x environment interaction for weaning weight in Nellore calves in eight different regions of Brazil. Estimates were obtained using MTDFREML with a sire model. Mathematical model included random effects of sire and dam, and fixed effects of sex, month and year of birth, herd, and age of dam at calving. Estimates of phenotypic variances were 375, 431, 431, 407, 409, 400, 413, and 336 for the eight different regions and 420 over all regions. Estimates of heritability were, respectively, 0.22, 0.26, 0.16, 0.29, 0.34, 0.38, 0.37, 0.26, and 0.26. Heritability estimates for weaning weights from two trait analyses with measurements in different regions considered as different traits varied from 0.17 to 0.38 and estimated genetic correlations among weaning weights in different regions varied from -0.03 to 1.00. Spearman rank correlations between EPDs for weaning weight from different regions were calculated to verify whether sires ranked differently in different regions. The correlations ranged from 0.25 to 1.00 between pairs of regions. Estimates of heritability suggest that mass selection can result in genetic gain under a breeding program that utilizes weaning weight as a selection criterion. The apparent importance of genotype x environment interaction detected by this study suggests a need to choose sires appropriate for the region where they will be used, since relative performance of progeny of a sire appears to change from one region to another.