Relationships among some Physical and Chemical Parameters of Full- Versus Limited-Fed Yorkshire Pigs Slaughtered at Different Live Weights

Abstract

An experiment was designed using 30 Yorkshire pigs to study the influence of slaughter weight and feed restriction on carcass cut-out data and to relate these physical measurements to the chemically‐determined proximate components. As slaughter weight increased from 79 to 102 kg., the percent of all lean cuts decreased significantly, while that of fat cuts and back-fat thickness increased significantly. Absolute amounts of both fat and lean cuts increased with slaughter weight. Feed restriction significantly increased most of the lean parameters studied and reduced the fat measurements. It increased percent of head and reduced the percent of offal (gastrointestinal tract minus contents, head, respiratory tract and all other internal organs). Correlations between leaf fat and empty body weight and between leaf fat and carcass extractable fat were higher than between back fat and the same parameters. Therefore, leaf fat may be a more satisfactory index of true body fat than is back fat, although the best index still is the carcass extractable fat, for which the correlation with the empty body fat was 0.99. The offal proximate chemical components were highly correlated with those of the carcass and the empty body. A knowledge of the chemical composition of the offal alone is, therefore, a good reflection of the chemical composition of the empty body. Percent of extractable fat in the empty body, carcass, or offal were positively correlated with fat measures and negatively correlated with all lean measures and with the protein and water. Percents of water and protein were positively correlated with the lean parameters and negatively correlated with all fat characteristics. The saturated fatty acids were positively related to all fat measures and to average daily gain and gross energy of the body and negatively correlated with all lean measures and water and protein. The reverse was true for the unsaturated fatty acids. Also, some strong inverse relationships were found between some unsaturated and saturated fatty acids. The chilled dressing percent was poorly correlated with nearly all physical and chemical measures and, therefore, should not be regarded as a satisfactory index of physical or chemical parameters. Copyright © 1966 American Society of Animal Science. Used by permission. R E L A T I O N S H I P S A M O N G S O M E P H Y S I C A L A N D C H E M I C A L P A R A M E T E R S O F F U L L V E R S U S L I M I T E D F E D Y O R K S H I R E P I G S S L A U G H T E R E D A T D I F F E R E N T L I V E W E I G H T S G. M. ]~ABATUNDE, W. G. POI~D, L. D. V A N V L E C K , G. H. K R O E N I N G , 1 J. T. REID, J . R . S T O U F F E R AND G. H. W E L L I N G T O N 2 Cornell University, '~ Ithaca, New York I T is well established that feed restriction, when imposed at the right stage of growth of the pig, tends to increase the proportion of lean cuts in relation to fat. Most reports have dealt primarily with physical factors such as growth rate, feed efficiency, back-fat thickness, loin-eye area, percent lean cuts and carcass length. Only a few reports (McMeekan and Hammond, 1939; McMeekan, 1940; Zobrisky et al., 1958) have included a more detailed analysis. Similarly, only a few reports (Lu et al., 1958; Zobrisky et al., 1954, 1958; Gnaedinger et al., 1963; Doornenbal, 1961) have described relationships between physical and chemical measurements of the pig. The purposes of this investigation were to study (1) influences of slaughter weight and feed restriction on physical characteristics of the pig carcass and (2) relationships between physical carcass measures and chemical components of the body.