RESEARCH ON THE MULTITRAIT ASSESSMENT OF THE GENETIC MERIT FOR MILK AND MEAT PRODUCTION IN THE ROMANIAN FRIESIAN USING A BLUP SIMPLIFIED MODEL

The paper objective was to assess the genetic merit for milk and meat production using a sample of 16 Romanian Friesian bulls and a BLUP simplified model as well as the contemporary comparison method. The bulls' 730 daughters (half-sisters) registered during the 305 days first lactation 3,034.89 kg milk with 22.86 % variation coefficient, 3.79 % fat with 6.06 % variation and 115.72 kg fat with 23.49 % variation. The 249 sons (half-brothers) recorded 138.05 kg atthe age of 6 months with 19.31 % variation coefficient, 293.41kg at the age of 12 months with 4.33 % variation, and 881.97 g/day daily gain with 3.14% variation. The heritability was 0.505 for milk yield, 0.741 for fat %, 0.567 for milk fat, 0.524 for the weight at 6 months, 0.642 for the weight at 12 months and 0.372 for daily gain. The genotypic correlations have been -0.245 between milk yield and fat % and 0.465 between milk and fat yield, -0.287 between the weight at 6 months and 12 months and 0.850 between the weight at 12 months and daily gain. Breeding value varied from 637.6 and -68.1 for milk yield and between 26.26 and -2.07 for milk fat. The breeding value precision ranged between 92 and 58 in case of milk traits. Breeding value varied between 48.6 and - 27.8 for the weight at 12 months and between 168.2 and 2.2. for daily gain. The accuracy of the breeding value for meat traits ranged between 76 and 60. Rank correlations between bull ranking for milk traits were 0.377** between milk fat and fat %, 0.974** between milk yield and fat yield. Rank correlations between bull ranking for meat traits were 0.766** between the weight at 6 months and at 12 months and 0.847** between the weight at 12 months and daily gain. The rank correlation between bull hierarchy by BLUP and contemporary comparison was 0.563 significantly for P=0.05 and P=0.01. As a conclusion, the high accuracy of BLUP model recommends it to be used for breeding value assessment. The position occupied by bulls in their ranking by BLUP was similar in some cases with the one set up by contemporary comparison. Some Friesian bulls could improve both milk and meat production but most of them have the best impact on the growth of milk yield.