USE OF PROGENY TESTING IN BEEF-CATTLE - PREDICTION OF GENETIC GAIN INA NELORE CATTLE-BREEDING PROGRAM

Genetic gains predicted for selection, based on both individual perfor mance and progeny testing, were compared to provide information to be used in implementation of progeny testing for a Nelore cattle breeding program. The prediction of genetic gain based on progeny testing was obtained from a formula, derived from methodology of Young and weller (J. Genetics 57: 329-338, 1960) for two-stage selection, which allows prediction of genetic gain per generation when the individuals under t est have been pre-selected on the basis of their own performance. The application of this formula also allowed determination of the number o f progeny per tested bull needed to maximize genetic gain, when the to tal number of tested progeny is limited.