EFFECTS OF DIETARY PROTEIN LEVEL AND SEX ON SWINE PERFORMANCE AND CARCASS TRAITS

Abstract

One group of pigs containing equal numbers of boars, barrows, and gilts, with an average initial weight of 22.5 kg, was given a growing ration (17% protein) until slaughter at an average weight of 88.6 kg. A similar group received the growing ration to a body weight of 50 kg, and then a finishing ration (13% protein) until slaughter.No statistically significant (P > 0.05) treatment differences were found for any performance traits studied. However, significant differences (P < 0.05) among sexes were found for all performance traits except daily feed consumption. Boars exceeded barrows by 7% and gilts by 5% in average daily gain. Boars required 16% less feed per unit of gain than barrows. Pigs fed the higher level of protein had less carcass backfat and smaller live backfat probe measurement than those fed at the lower level. Gilts exceeded boars and barrows in longissimus dorsi area. Both boars and gilts were superior to barrows in percent lean in the ham face.No apparent important treatment by sex interactions were observed.