GROWTH, CARCASS AND MEAT QUALITY PERFORMANCE OF CROSSBRED PIGS WITH GRADED PROPORTIONS OF MEISHAN GENES

Growth, carcass and meat quality traits were measured in 2 different e xperimental herds on male and female pigs produced from matings betwee n Pietrain boars and 12 genetic types of sows with graded proportions of Large White (LW) and Meishan (MS) genes. Growth records (from 30-10 0 kg liveweight) were obtained on ad libitum feeding on a total of 1 6 40 pigs, among which 1 200 were submitted to carcass evaluation and me at quality measurements. Genetic type mean performance essentially var ied according to the relative proportions of MS and LW genes in the da m and could hence be characterized by a single parameter, difference i n crossbreeding (DELTA(MS)c-LW), which measures the difference between MS and LW breeds used as dam breeds. Differences in crossbreeding wer e unfavourable to MS for all growth and carcass traits. Average estima tes of DELTA(MS)c-LW were -71 +/- 16 g/d; 0.21 +/- 0.07; -2.4 +/- 0.3% ; -9.0 +/- 0.5% for average daily gain (ADG) feed conversion ratio, ki lling out percentage and estimated carcass lean content (% M), respect ively. However, significant herd differences were observed for ADC and %M. The 2 herd estimates were -51 +/- 16 g/d and -92 +/- 30 g/d for A DG, -7.3 +/- 0.6% and -10.7 +/- 1.5%, for %M. Conversely, differences in crossbreeding for meat quality traits were in favour of MS, with an advantage of 1.1 +/- 0.4 point in meat quality index over LW, ie one third of a phenotypic standard deviation.