Abstract
TEN litters each of four female and four male castrates of Danish Landrace were physically divided into blood, bristles, entrails, bones, skin, subcutaneous fat and muscle. After grinding and mixing each fraction was analysed for dry matter, protein, fat, ash, calories, carbon, calcium and phosphorus. Also the muscle was analysed for amino acids. The average live weight at slaughter was 90 kilograms. The weight without contents of the digestive tract averaged 80.8 kilograms. Of this 42.0% was dry matter. The dry matter contained 41.1% protein, 51.1% fat, 7.7% ash and 7,080 kcal per kg corresponding to 13.9 kg protein, 17.4 kg chemical fat, 2.6 kg ash and 240,000 kilocalories. The carcass weighed 68.2 kg and contained 59.017o muscle, 16.7% subcutaneous fat, 7.21/o skin and 16.6% bones. Of the total content of the pigs the muscle contained: 55.0ofo of the protein, 29.8% of the chemical fat, 38.0% of the calories, 0.4 of the calcium and 17.0% of the phosphorus. In the individual experiments many statistically significant differences were found between litters and between sexes both in the anatomical and in the chemical composition. Multiple regression analyses within litter and sex showed that the anatomical composition of the pigs was independent of the feed composition, whereas, the chemical composition was significantly influenced by feed composition, i.e., the energy concentration in the pigs increased with increasing energy concentration in the diets. A number of correlation and regression analyses show that the fat content in the different anatomical fractions are highly correlated. When, e.g., the amount of subcutaneous fat fell by 1 kg, percent fat in muscle fell by 0.7. The fat content in muscle influences juiciness, flavor, aroma and tenderness. Till now the primary goal of the breeding work has been to decrease the content of subcutaneous fat in the pigs which will automatically cause a decrease in the muscle fat, thus to some degree decreasing the muscle quality. Therefore, if juiciness, flavor, aroma and tenderness cannot be improved by addition of fat, technically, it may be of interest in the future to breed pigs with a desired fat content in the muscle. Simultaneous with selection of that type of pigs it may be necessary to select for a lower content of subcutaneous fat. Copyright © 1973. American Society of Animal Science . Copyright 1973 by American Society of Animal Science.