EFFECT OF DIFFERENT SELECTION CRITERIA FOR LITTER SIZE, GROWTH PERFORMANCE AND CARCASS TRAITS IMPROVEMENT OF THE PIGS IN SERBIA

VIDOVIC, V., D. LUKAC, V. VISNJIC, A. STOISAVLJEVIC and M. STUPAR, 2015. Effect of different selection criteria for litter size, growth performance and carcass traits improvement of the pigs in Serbia. Bulg. J. Agric. Sci., 21: 687–692 Four pig breeds, Landrace and Yorkshire (as dam lines) and Duroc and Pietrain (as terminal, sire lines) were studied on commercial farms during 2000 - 2011. Altogether, 13584 litters with a total of 154344 progeny of both sexes, from 43 boars and 4824 sows were analyzed. Also, analysis of genetic change study included 426 sows of Duroc and 247 Pietrain, totally 2557 litters and 22760 piglets then, in each breed of 14 boars, total 28. The difference between the number of live born piglets and piglets alive on the day fifth was significant, which means that future feeding regimens of sows must be optimized. The selection efficiency of number of live born piglets was on average 0.25 per generation. Even different size of heritability the ge netic variation of analyzed traits was similar from the beginning to the last selected generation. Carcase quality was analyzed for 144 pigs of different weights and sex. The average weight of animals at the end of the fattening period was 103 kg ± 2.6 kg. Weight of bone was not significantly different between Landrace, Yorkshire and Duroc pigs, while bones in Pietrain pigs were much lighter. This indicates the slower growth of Pietrain pigs, which required an extra fattening period of 24 to 32 days compared to the other breeds. When just growth was compared, Pietrain pig growth was significantly less compared with their peers of other breeds. Even that, selection gain was significant to all breeds. At Landrace and Yorkshire selection improved gain for 42 days. Significantly slower was on Duroc, only 19 days and highest at Pietrain, 44 days. At the end of the study, the content of meat in the carcasses was, on average, 57.6% in Landrace and Yorkshire pigs and 59.7% in Duroc pigs (this was not significantly different). Pietrain carcasses contained 62.3% meat, which was significantly more than in the other breeds. After 11 years of breeding according to the chosen selection criteria, intramuscular fat content in the final carcasses was: 0.8% in Pietrain, 2.6% in Duroc, 2.0% in Landrace and 1.8% in Yorkshire pigs.