Performances of Italian pig breeds fed diets for commercial hybrids

The effects of specific diets for commercial hybrids were investigated on 6 Casertana (CA), 11 Mora Romagnola (MR), 14 Large White x Mora Romagnola (LM) and 9 Borghigiana (BO), a hybrid of Large White and Nera Parmigiana. Diets were formulated assuming that requirements of breeds were similar and did not differ from those used for the hybrid pigs bred in the Experimental Station. Feeds were prepared weekly and made up of meal and pellets (when ≤60 kg l.w.; CP 20.7; ED 3610 kcal/kg) or meal (when 60<l.w.≤90 kg; CP 19.5; ED 3662 kcal/kg; and when >90 kg l.w.; CP 17.5; ED 3720 kcal/kg). All animals had an under-skin trasponder and were fed with an automatic feeder for calculation of average daily gain (ADG) and feed conversion index (FCI). BO and LM reached the final weight (199 kg and 210 kg) more rapidly than CA and MR (200 kg and 193 kg); differences between sexes were observed for BO only. ADG were calculated for 5 groups based on l.w. of animals: ≤60 kg, 60<kg≤90, 90<kg≤120, 120<kg≤160, >160 kg. Differences were analysed with a bifactorial model (breed x group) with interaction. When l.w. ≤60 kg, ADG of LM was statistically lower than CA and MR (P<0,001); in the other groups, BO and LM showed higher values than other breeds; when 120<l.w.≤160 kg, CA showed higher ADG although not statistically different from others. On the whole trials, the two hybrid types showed better ADG. The CA and MR consumed more than BO and LM; FCI was 4.2 and 4.3 vs. 3.5 and 3.7 respectively. Performances of the hybrids were not different from those of commercial hybrids; CA and MO confirmed to be prone to adipogenesis and showed a poor growth rate if compared with other types. Nevertheless they represent a valuable genetic reserve to utilise for recovering some properties of meat or fat, actually lost due to the selective programs.