Productivity of Cinta Senese and Large White x Cinta Senese pigs reared outdoor on woodlands and indoor. 1. Growth and somatic development

Twenty-nine Cinta Senese (CS), 12 Large White (LW) and 29 LWxCS pigs were reared indoor and group fed on commercial mixtures in pens averaging 6 animals according to genetic type and sex. Seventeen CS and 16 LWxCS pigs were reared outdoor on woodland pastures (Quercus ilex, Castanea sativa) with minimum commercial mixtures supplementation. Both males and females were castrated. Since the age of 100 days morphological measures were recorded bimonthly (height at rump, body length, chest girth, width at shoulder, width at rump). To perform a statistical analysis, factors such as regression on age and allometric relationship on weight were taken into consideration, together with the fixed effect of genetic type x rearing system. In the indoor system, CS pigs reached 140 kg of live weight 30 and 100 days later than LWxCS and LW pigs, respectively. Moreover, CS conversion index was worse than that of LW pigs (i.e. 4.54 vs. 3.77 feed/gain) and CS backfat thickness was higher. During spring and summer, the outdoor system worsened the growth of backfat in both genetic types, as a consequence of scarce feed availability. However, cross pigs showed higher growth rate than CS breed. Allometric relationships analysis pointed out that CS pigs were taller, narrower at shoulder and at rump and shorter than LW pigs. Moreover, CS breed had higher chest girth than LW and the difference became more evident at higher weights. Crossbred pigs showed intermediate behaviour compared to parental breeds. Outdoor reared Cinta Senese pigs differed from those indoor in the evolution of body proportion, due to older age at a given weight and to the grazing activity. No differences were found with respect to for width values at rump, but outdoor CS pigs presented higher growth for width at shoulder and for chest girth. Thus, the outdoor system seems to intensify the development of the body forepart in Cinta Senese breed, already emphasised in this breed.