Effects of feeding strategies, genotypes, sex, and birth weight on carcass and meat quality traits under organic pig production conditions

Nutrient supply in organic pig production is characterized by limited amino acids (AA) availability due to the preferable use of home-grown feedstuffs and restrictions on purchased feedstuffs. This can cause large variations in the quality of diets, carcasses, and pork. The objective of two feeding trials was to assess the interactions between feeding regimes, genotype, and birth weight on carcass and pork quality. A control regime was compared with two feeding regimes that were partly (only in the finishing phase (FIN)) or both in the growing and finishing phase (GRO+FIN) restricted to home-grown feedstuffs, thus differing in AA supply. Using an isocaloric ration, individually housed pigs differing in genotype (Experiment 1) or birth weight (Experiment 2) were allocated to the three feeding regimes.The highest daily live weight gain, the best feed conversion, and the highest values for performance traits and meat composition were achieved by Du×DL pigs, while the highest carcass yield was achieved by Pi×(DL×DE) pigs. In Experiment 1, performance traits were significantly higher in the control feeding regime than in the GRO+FIN treatment, with the feeding regime FIN being intermediate. Lean meat percentage was significantly lower in the GRO+FIN feeding regime than in the control while the fat area was not influenced by feeding regime. Intramuscular fat content was higher under the GRO+FIN feeding regime without AA supplementation than in the control. In Experiment 2, birth weight showed no significant effect on carcass yield, carcass traits and meat composition, but affected growth rate. Performance traits were highest in the control, while meat composition was best in the GRO+FIN treatment, confirming results of Experiment 1. Exclusion of AA supplementation in the feeding regime reduced growth but increased intramuscular fat content (IMF). The feeding regime was the main source of variation for intramuscular fat content in the longissimus muscle. Organic pig production can yield high quality pork, but information on feed, feed intake, and pig characteristics is important to steer the production process.