Although the importance of postexercise nutrient ingestion timing has been investigated for glycogen metabolism, little is known about similar effects for protein dynamics. Each subject (n = 10) was studied twice, with the same oral supplement (10 g protein, 8 g carbohydrate, 3 g fat) being administered either immediately (EARLY) or 3 h (LATE) after 60 min of moderate-intensity exercise. Leg blood flow and circulating concentrations of glucose, amino acids, and insulin were similar for EARLY and LATE. Leg glucose uptake and whole body glucose utilization (D-[6,6-2H(2)]glucose) were stimulated threefold and 44%, respectively, for EARLY vs. LATE. Although essential and nonessential amino acids were taken up by the leg in EARLY, they were released in LATE. Although proteolysis was unaffected, leg (L-[ring-2H(5)]phenylalanine) and whole body (L-[1-13C]leucine) protein synthesis were elevated threefold and 12%, respectively, for EARLY vs. LATE, resulting in a net gain of leg and whole body protein. Therefore, similar to carbohydrate homeostasis, EARLY postexercise ingestion of a nutrient supplement enhances accretion of whole body and leg protein, suggesting a common mechanism of exercise-induced insulin action.

Live animal and carcass data were collected from market barrows and gilts (n = 120) slaughtered at a regional commercial slaughter facility to develop and test prediction equations to estimate carcass composition from live animal and carcass ultrasonic measurements. Data from 60 animals were used to develop these equations. Best results were obtained in predicting weight and percentage of boneless cuts (ham, loin, and shoulder) and less accuracy was obtained for predicting weight and ratio of trimmed, bone-in cuts. Independent variables analyzed for the live models were live weight, sex, ultrasonic fat at first rib, last rib, and last lumbar vertebra, and muscle depth at last rib. Independent variables for the carcass models included hot carcass weight, sex of carcass, and carcass ultrasonic measurements for fat at the first rib, last rib, last lumbar vertebra, and muscle depth at last rib. Equations were tested against an independent set of experimental animals (n = 60). Equations for predicting weight of lean cuts, boneless lean cuts, fat-standardized lean, and percentage of fat-standardized lean were most accurate from both live animal and carcass measurements with R2 values between .75 and .88. The results from this study, under commercial conditions, suggest that although live animal or carcass weight and sex were the greatest contributors to variation in carcass composition, ultrasonography can be a noninvasive means of differentiating value, especially for fat-standardized lean and weight of boneless cuts.

Live animal and carcass data were collected from market barrows and gilts (n = 119) to determine the accuracy and precision of using a single longitudinal scan, parallel to midline, in estimating body and carcass composition. Data from test pigs (n = 96) were used to develop prediction equations. Best results were obtained in predicting weight of boneless cuts (ham, loin, and shoulder), weight of lean cuts (bone-in ham, loin, and shoulder), and weight of fat-standardized carcass lean. Less accuracy was obtained in predicting ratios of all estimates on a live basis. Independent variables analyzed for the live models were live weight, sex, and ultrasonic fat depth and muscle depth at the 10th rib. Independent variables for the carcass models were the same as on the live animal; the estimators for boneless cuts (ham, loin, and shoulder) were most precise. Equations were tested against an independent set of experimental pigs (n = 23). Equations for predicting weight of boneless cuts, weight of ham and loin, and percentage of fat-standardized lean using both live and carcass measurements were most accurate, with R2 values between .78 and .87 and RSD values between 1.30 and 1.92 kg. The results of this study reinforce the potential of assessing carcass composition and value by using a single longitudinal B-mode scan on both live pigs and carcass; live weight, sex of pig, and fat depth at the 10th rib were the greatest contributors to variation.

Two trials were conducted with mature cows to develop prediction equations for estimating carcass composition from live animal measurements. Trial 1 involved 82 animals that were used to develop these equations. Subjective criteria (frame and condition scores) also were utilized along with live weight in development of prediction equations. Equations using subjective independent variables predicting energy and carcass tissue weights apparently were slightly more variable in precision (R2 = .69 to .91) than those developed with objective variables (R2 = .74 to .90). Equations predicting percent compositions from subjective variables had lower coefficients of determination (R2 = .49 to .76) than those developed with objective variables (R2 = .63 to .83). Forty-one animals similar to those used in Trial 1 served as a test group in Trial 2. Measured carcass composition was regressed on composition predicted by equations developed in Trial 1. These equations generally had slopes and intercepts with confidence intervals that included 0 and 1, respectively, indicating that most of the prediction equations were unbiased. This work indicates that carcass composition can be predicted from both objective and subjective measurements, with some accuracy and precision.