The effect of sex and slaughter weight on intramuscular fat content and its relationship to carcass traits of pigs

Carcass quality and intramuscular fat content of castrates and gilts are compared and a possible dependence of intramuscular fat content on sex and slaughter weight is determined in the pig population of the Slovak Republic. A total of 129 pigs of three different genotypes were included in the experiment. After slaughter, the carcasses were weighed and backfat thickness was measured. On the next day, carcass dissection described by Walstra and Merkus (1995) was determined. Four prime cuts (shoulder, loin, ham and belly) were further dissected to meat, bones and fat with skin. Intramuscular fat content was analysed in a laboratory from the samples (100 g) of musculus longissimus dorsi. The results were statistically analysed using SAS/STAT and a linear model was used to find the dependence of intramuscular fat content. Correlation coefficients between carcass traits and intramuscular fat were also calculated. Sex of pigs, and particularly weight of lean meat and weight of fatty parts had a significant effect on intramuscular fat content (P < 0.0001 and P = 0.0022) while no effect of the genotype and slaughter weight was observed. Significant differences between castrates and gilts were found in almost all observed traits, e.g. average backfat thickness (29.01 vs. 25.56 mm), percentage of meat (52.77 vs. 57.68%), intramuscular fat content (2.49 vs. 2.00%). Generally, the intramuscular fat in the pig population is not sufficient (2.25%), therefore it would be desirable to include this trait in selection strategies in pig breeding.