A note on the growth and backfat thickness of the Hampshire, Duroc and L63X H genotypes

Data of 1790, 394 and 315 pigs of both sexes of the Hampshire and Duroc bre eds and the L63 x Hampshire hybrid, respectively were compared for growth a nd backfat thickness. The animals were born in 1991 and 1992 and were submi tted to field performance test at the "Lage" animal breding centre in the p rovince of Pinar del Rio. The traits analysed were: final liveweight(FW), w eight for age (WFA), average daily gain (ADG) and total backfat thickness ( BT). Data were analysed through a mixed model which considered the sources of variation: genotype, sire:genotype, year and trimester of birth and thei r interaction and sex. The final weight and average daily gain were adjuste d to age at selection through a linear regression analysis and the backfat thickness using a linear regression on final weight (92.6 kg). The genotype and interaction significantly affected all traits while the effect of sex was not significant on backfat thickness. There was a remarkable superiorit y of the L63x Hampshire hybrid in all traits except in ADG due to the adjus tment. The adjusted means obtained were 92.9, 91.3 and 95.0 kg for FW; 0.41 6, 0.414 and 0.444 kg for WFA; 0.470, 0.464 and 0.458 kg for ADG and 41.5, 41.8 and 40.3 for BT in the Hampshire, Duroc and L63 x Hampshire genotypes, respectively.