Genotype×Environment Interactions in Growth Performance of Brahman Crossbred Cattle in Bangladesh

The objective was to evaluate the effects of genotype×environment interaction on growth traits of Brahman crossbred cattle.The animals were reared in two environments viz., Central Cattle Breeding Station (on-station) and farmer's herd (on-farm) where management system was respectively intensive and semi-intensive in nature.Birth weight was very similar across environments.Average body weight at different ages was greater in on-station herd than in on-farm herd (p<0.01).Body weight was 23.0, 25.4, 41.5 and 27.5 kg greater at 6, 9, 12 and 18 month in on-station herd than in the on-farm herd, respectively.Significant interaction between sire×environment in most of the growth traits (p<0.001) was observed.Heritability estimates for growth traits were greater in on-station herd (ranged from 0.29-0.47)than in on-farm herd (ranged from 0.48-0.50).Genetic correlations of the same growth trait between two environments showed a decreasing tendency with the increase in age of animal (from 0.74±0.05at 3 months to 0.57±0.05at 24 months).These results demonstrate that effects of G×E in Brahman crossbred cattle are large between two types of management system indicating that breeding bull selection and use should be carried out within environment basis.