Changes in carcass and meat traits during the montanera finishing period of Iberian pigs

Iberian pigs are usually slaughtered at an average body weight (BW) of 160 kg. The free-range, acorn-feeding montanera starts at an average weight of 100 kg, lasts for 2.5-3 months, and pigs gain around 60 kg during this period. During this extensive finishing, the weight gain is mostly based on subcutaneous and intramuscular fat accretion, but other changes in carcass and meat composition may occur as well. This study (made in TREASURE project) evaluated the changes in carcass and meat composition occurred in Iberian pigs between the end of premontanera (pre-finishing period) and the end of montanera, as assessed in animals slaughtered at 110 and 160 kg BW, respectively. Castrate male Iberian pigs (n=45) were randomly assigned to 2 treatments (2 slaughter times) and raised on concentrate up to 110 kg BW. At this point, 15 pigs were slaughtered, and the remaining 30 pigs were finished in montanera with acorns and grass and were slaughtered at an average BW of 158 kg. Carcass and several meat traits were evaluated in both cases. In general, carcass fat (subcutaneous and intramuscular) increased significantly during the finishing period, with the exception of loin weight and area and the outer backfat layer, that remained unchanged after the finishing period. Hip height and ham length did not change, but carcass length increased significantly after finishing. In relation to meat colour, only the b index (blue to yellow) was significantly greater in finished pigs. Regarding backfat fatty acid profiles, PUFA and SFA decreased and MUFA increased significantly after the montanera finishing period, but C18:3 remained unchanged. In conclusion, pre-finishing Iberian pigs (at 110 kg BW) had similar muscle accretion, hip height, outer backfat layer thickness and C18:3 proportion than the finished ones. The BW gain during montanera was essentially based on fat deposition, and finishing increased the proportion of MUFA and decreased that of PUFA and SFA. Funded by European Union’s H2020 RIA program (grant agreement no. 634476).