Carcass composition and growth performance of swine as influenced by nutrition

Abstract

Three levels of feed intake, full, j/4 and 1/2 were used by Ellis and Zeller (1931) to study the level of Intake effect upon carcass composition. Pigs weighing 68 pounds initially were fed to 200, pounds and then slaughtered. Pull fed pigs had 35.7 percent carcass fat as compared to 34.5 and 28.7 for the 3/4 and 1/2 fed pigs, respectively. The period of time of the middle 1950's produced con siderable interest in ration supplementation with antibiotics and their influence upon growth performance and consequently body composition. Vitamin and/or antibiotic supplementation failed to cause differences in carcass water, protein and fat in a study conducted by Hanson et (1955). The control pigs did have more protein, more water and less fat than any other lots since they were 20 days older at slaughter and thus fattened less rapidly. The authors did note a significant effect of ration upon ash content due to antibiotic. A report by Perry et al. (1953) indicated that antibiotic-fed hogs contained significantly more carcass fat and significantly less carcass protein and water than carcasses from the control animals. Antibiotic supplementation and its influence upon carcass composition was reported by Clawson ^ al. (1955). Carcass water was slightly lower and carcass fat slightly higher in antibiotic fed pigs but not significantly different from the Three sets of protein levels (12 vs. 16, 1? vs. 22 and 17 vs. 26 percent) were studied by Carroll et (1936). The average differences in the carcass water, fat, protein and ash were significantly different between compared groups of pigs. These authors noted that changes in carcass composition were greater for a given change of protein level at the lower levels of dietary protein. An experiment was conducted by Kropf ^ (1959) to study the effect of protein level and quality upon body composition of pigs. Experimental diets were (1) 16 percent protein with balanced essential amino acids (2) 16 percent protein with poorly balanced essential amino acids and (3) 12 percent protein with balancsd essential amino acids. Pig slaughter weights were 85, 145 and 205 pounds. The experi mental design involved stratification such that the effect of sex, stage of slaughter and treatment could be evaluated. Percentages of water and fat were determined on the composite carcass and also on the Longissimus dorsi. The 16 percent protein diet with balanced amino acids resulted in signifi cantly more carcass water and protein and Longissimus dorsi protein. Percent fat was significantly less in both tissues from pigs fed this diet. There were no significant differ ences between rations 2 and 3 except upon Longissimus dorsi protein content. The known inverse relationship between car cass water and fat was obvious from these data. intramuscular fat of the Longissimus dorsi and backfat thick ness. This agrees with Henry et (1963) •who suggested that marbling is not Influenced by the amount of backfat since a correlation coefficient of only 0.08 was detected between these same measurements. However, Bat...