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Phenotypic and Genetic Trends for Growth and Milk Traits of Guzera Breed in Dual Purpose Herds
Breeding programs of dairy breeds in Brazil have focused their goals on milk production, where Guzerá is considered as dual purpose breed and is widely used for milk and beef production. The breeding programs for beef and dairy traits have been conducted separately, and so are genetic evaluations. Despite that data banks are genetically connected. Selection decisions are taken based on the results published in the summaries. This study aimed to verify the phenotypic and genetic trends for cows’ milk and beef performance in the selected herds. Records of milk production and weight traits were used to estimate predicted transmit ability (PTA) for 305-d milk, fat and protein production, as well as for weaning and yearling weight, and post-weaning daily gain. PTA were regressed on birth year for obtaining genetic trends. Despite low, positive genetic trends were found for both traits.
Keywords:
Animal breeding
Production systems
Zebu cattle
