RESEARCH ON MEAT PRODUCTION PARAMETERS IN STEER FATTENING AND THEIR IMPORTANCE FOR SIRES BREEDING VALUE ESTIMATION IN ROMANIA

The paper presents the genetic and phenotypic parameters for meat production characters using the results in progeny testing based on 1,705 half brothers offspring of 105 Friesian bulls from Romania. The live traits taken into account were weight at the age of 180 and 365 days, and weight daily gain during the period of fattening starting at the age of 2.5 months and ending at the age of 12-15 months of the steers. Taking into account that the fattening was made in 28 herds and the peculiarities of half sibs families, it was used a linear mathematical model for nested (hierarchical) classification. Weight at the age of 180 days registered 138.85 +/- 6.04 kg, weight at the age of 365 days was 293.41 +/- 1.04 kg in average and daily gain 881.977 +/- 4.24 g/head/day. Heritability was h(2)= 0.524 for weight at the age of 180 days, h(2)= 0.642 for weight at the age of 365 days and h(2)= 0.372 for daily gain. The correlations between weight at the age of 180 days and weight at the age of 365 days was rG = -0.287 and r(P) = -0.189, between weight at the age of 180 days and weight daily gain r(G) = -0.307 and r(F) = -0.726, and between weight at the age of 365 days and weight daily gain r(G) = 0.850 si r(F) = 0.771. The meat production traits are closely related one to each other. Weight daily gain is substantially influenced by environmental factors. In practice, farmers should pay attention to live weight at various fattening stages and improve all the environment conditions in order to reach the weight daily gain as planned. In the breeding programmes, live characters are the most important ones and the steers month of birth needs to be corrected in order to precisely detemine sire position in the breeding pyramid.