Comparison of boars and castrates for bacon production 2. Composition of muscle and subcutaneous fat, and changes in side weight during curing

Abstract

Sixty-four commercial hybrid male pigs given different levels of feeding between 27 and 87 kg live weight were used to determine whether quality differences between boars and castrates, when used for bacon production, are true castration effects or due to the greater leanness of boars. At the same carcass composition as castrates, boars had: a higher proportion of water inm. longissimus; a higher proportion of water and lower proportion of lipid in both layers of backfat at last rib; and slightly lower curing gain as the result of a greater loss of tissue water during curing. A separate study on the composition of backfat in lighter weight pigs also revealed a higher proportion of water and lower proportion of lipid in boar backfat compared with that of castrates or gilts, and in both studies a higher proportion of fat-free dry matter in boar backfat indicated greater synthesis of connective tissue protein. Subjective assessment of backfat firmness and whiteness revealed no important castration effects that were independent of carcass composition. The leanest group of boars (average 12 mm P₂) had the lowest score for firmness. Fatty acid composition of outer and inner backfat layers was determined more by the rate of fat deposition than by castration.