GENETIC CORRELATIONS BETWEEN TEST STATION AND ON-FARM PERFORMANCE TRAITS IN LARGE WHITE AND FRENCH LANDRACE PIG BREEDS

Genetic correlations between test station and on-farm performance trai ts were estimated in Large White (LW) and French Landrace (LF) pig bre eds using a restricted maximum likelihood procedure applied to a bivar iate individual animal model. Traits recorded in test stations were av erage daily gain (ADG1), average backfat thickness (BT90), feed conver sion ratio (FCR) measured on candidates to selection, average daily ga in (ADG2), dressing percentage (DP), estimated carcass lean content (E CLC) and meat quality index (MQI) measured on slaughtered sibs. On-far m traits were age (A100) and average backfat thickness (BT100) at 100 kg. Test station data involved records on 7068 and 3392 candidates, 33 32 and 1735 slaughtered sibs for LW and LF breeds, respectively. On-fa rm data consisted of records from 16670 (LW) and 8244 (LF) pigs of bot h sexes. Genetic correlations between A100 and ADG1 or ADG2 varied bet ween -0.50+/-0.05 and -0.67+/-0.03. BT100 was strongly related to BT90 (0.91+/-0.03 and 0.91+/-0.05 in LW and LF breeds, respectively) and E CLC (-0.84+/-0.05 and -0.70+/-0.07 in LW and LF breeds, respectively). Strongly favourable genetic correlations were also obtained between F CR and A100 (0.32+/-0.04 in LW; 0.54+/-0.06 LF) or BT100 (0.45+/-0.04 and 0.51+/-0.06 in LW and LF breeds, respectively). MQI was almost ind ependant of A100, but unfavourably related to BT100 in both breeds. Th ese results tend to indicate that genotype X environment interactions in French national breeding programmes are limited for backfat depth, but remain significant for growth rate.