The objective ofthis study was to evaluate the effect of the halothane genotypes (heterozygousand dominant homozygous) and intensive rearing systems (indoor, wood shavingsbedding and outdoor) on growth performance, carcass and meat yield. Ninety sixcastrated male pigs were used for the trial. Identification of the halothanegenotype was determined in blood samples using the DNA-test, based on the polymerasechain reaction (PCR) for amplification of the critical region of the ryanodinereceptor and subsequent restriction of the amplified fragment by restrictionfragment lengh polymorfism technique (RFLP). Growth and finishing performancewere evaluated by weight gain, feed intake and feed efficiency. Carcass qualitywas evaluated by backfat and muscle depth, meat percentage through HennessyGrading Probe and carcass weight. Twenty four hours after slaugther, ham andloin weight were recorded and the loin eye area was evaluated. The growth performancewas similar for the two genotypes. The heterozygous pigs for the halothane genehad higher percentage of fat-free lean and less fat in the carcass. Outdoorreared pigs showed lower average daily gain and worst efficiency than pigs rearedindoor. Carcasses of pigs reared under wood shavings bed had less fat-free leanand greater backfat thickeness. The interaction between halothane genotypesand rearing systems had no significant effect on any trait studied.
