Revised Approaches to Estimate Lean of Pork Carcasses of Known Age or Days on Test2

Abstract

Carcass measurements for 185 market hogs representing two sexes and four body types, slaughtered at 91 to 132 kg, were examined as predictors of carcass composition. Dependent variables included weight of fatstandardized lean (FSL), percentage FSL in the standardized side, weight of FSL gained/day on test, and weight of FSL produced/day of age. The greatest degree of predictive accuracy in each equation occurred when longissimus muscle area and fat depth at the three-fourths location at the 10th rib were included as independent variables. Other important variables were hot carcass weight in the three equations predicting weight for FSL, age in the equation for FSL produced/ day of age, and initial weight on test and days on test for the prediction of FSL gained/day on test. Less accuracy was found when other back-fat thickness measurements or subjective scores of muscling or fatness were used as independent variables. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. SummaryCarcass measurements for 185 market hogs representing two sexes and four body types, slaughtered at 91 to 132 kg, were examined as predictors of carcass composition. Dependent variables included weight of fat-standardized lean (FSL), percentage FSL in the standardized side, weight of FSL gained/day on test, and weight of FSL produced/day of age. The greatest degree of predictive accuracy in each equation occurred when longissimus muscle area and fat depth at the three-fourths location at the 10th rib were included as independent variables. Other important variables were hot carcass weight in the three equations predicting weight for FSL, age in the equation for FSL produced/ day of age, and initial weight on test and days on test for the prediction of FSL gained/day on test. Less accuracy was found when other backfat thickness measurements or subjective scores of muscling or fatness were used as independent variables.

Prediction of live and carcass characteristics of market hogs by use of a single longitudinal ultrasonic scan

“…The gilts also had heavier LEANCUTS and BNLSCUTS, but this might be attributed in part to a slightly heavier CARCWTKG (1.40 kg). The advantage in leanness of gilts over barrows at equal weights is welldocumented (Grisdale et al, 1984;NPPC, 1988;Siemens et al, 1989;Gresham et al, 1992). Consistent with earlier studies (Mersmann, 1982;Gresham et al, 1986;Gresham et al, 1992) ultrasound fat estimates (CARCFAT) and muscle depth (CARC-MUSC) on the suspended carcass was greater than on the live animal (LIVEFAT and LIVEMUSC).…”

Estimates of Genetic Parameters for Carcass Measures of Body Composition and Growth in Swine

“…Carcass length (CL) was included in an initial model and was deleted in another model. Models with CL deleted showed essentially no reduction in R 2 or increase in the standard error of estimate (SEE, or residual standard deviation) from models that included CL, in agreement with Grisdale et al (1984) and Bereskin (1984).…”

“…Adams et al, (1972) reported an R 2 of .67 from a prediction equation that included ABF, LMA and CCWT to estimate WTCC compared with an R 2 of .45 from use of the same variables to estimate LCPC. Grisdale et al (1984) also reported a large decrease in the correlation (r) of actual with estimated percentage of carcass lean (r = .34) from the correlation of actual with estimated weight of carcass lean (r = .85). In addition, Bereskin (1984) (Grisdale et al, 1984).…”

“…Grisdale et al (1984) also reported a large decrease in the correlation (r) of actual with estimated percentage of carcass lean (r = .34) from the correlation of actual with estimated weight of carcass lean (r = .85). In addition, Bereskin (1984) (Grisdale et al, 1984).…”

Genetic analyses of growth, real-time ultrasound, carcass, and pork quality traits in Duroc and Landrace pigs: I. Breed effects

“…Carcass backfat thickness a t the first rib, last rib, last lumbar vertebra, and 10th rib, longissimus muscle area measured a t the 10th rib using the plastic grid method described by Boggs and Merkel(19841, and subjective scores of color, firmness, marbling in the longissimus muscle and ham muscle mass (on three-point integer scales), and length were evaluated 24 h postmortem on the right side of each carcass. Fat-standardized lean yield and lean gain per day of age were estimated as functions of carcass weight, 10th rib backfat thickness, longissimus muscle area, and age using equations described by Grisdale et al (1984).…”