Prediction of daily protein accretion rates of pigs from estimates of fat-free lean gain between 20 and 120 kilograms live weight.
The objective of this study was to evaluate a method for predicting daily protein accretion rates of various genotypes of pigs reared in different environmental conditions using easily obtained mean daily fat-free growth rates. Data were obtained for seven genotype-environment groups of gilts and nine groups of barrows. Daily empty body protein accretion rates were estimated at 1.0-kg intervals between 20 and 120 kg live weight. The estimates were fitted to a generalized exponential function, PA = A e(B x WT + C/WT + D x WT2), where WT is kilograms of live weight and A, B, C, and D are estimated parameters for each sex. Nonlinear least squares methods were used to estimate the intercept and regression coefficients expressing each parameter estimate (A, B, C, and D) as a linear function of the mean fat-free lean gain for each sex-genotype-environment group. The mean percentage absolute errors were 3.5% for gilts and 6.1% for barrows. The largest errors occurred between 110 and 120 kg live weight. From 20 to 110 kg, mean percentage errors averaged 2.7% for gilts vs 4.8% for barrows. These results offer encouraging evidence that a generalized equation can be used to predict daily protein accretion rates from mean fat-free lean growth data. Further research, with additional genotype-environment populations, is needed to increase accuracy of the generalized growth functions.
Schinckel
A P
AP
Department of Animal Sciences, Purdue University, West Lafayette, IN 47907-1151, USA.
Preckel
P V
PV
Einstein
M E
ME
D000822:Animal Husbandry / Q000191:economics; D000818:Animals; D001835:Body Weight / Q000235:genetics / Q000502:physiology; D004032:Diet / Q000191:economics / Q000662:veterinary*; D005260:Female; D005838:Genotype; D016018:Least-Squares Analysis; D016014:Linear Models; D008297:Male; D008954:Models, Biological; D011506:Proteins / Q000378:metabolism*; D013552:Swine / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D015430:Weight Gain / Q000502:physiology*
D011506:Proteins