Evaluation of an Alternative Method to Predict Sampling Errors Associated With Daily Protein Accretion and Amino Acid Requirements

Purdue University 1999 Swine Research Report. Currently, swine nutritionists formulate diets based upon estimates of protein accretion in controlled university or private research facilities. However, these dietary recommendations may not be correct because of farm-to-farm differences in environmental conditions, including health status, stocking density, quality and social factors. Methods have been developed to predict farm-specific protein accretion curves and daily lysine requirements. The technique has been used in numerous farms with different genetics. In most cases, 24 to 40 barrows and gilts have been weighed and ultrasonically measured every three weeks from 50 to 250 lb live weight. The precision of the protein accretion curves and lysine requirements can be evaluated by quantifying the sampling errors. Bootstrapping is a resampling procedure used to obtain the standard errors of the growth curves and predicted lysine requirements at each live weight or day of age. Bootstrapping procedures are not currently available on any commercially available statistical analysis packages. Data-specific programs must be written. The computer memory requirements for bootstrapping can be substantial. The objective of this research was to evaluate an empirical method to develop approximate standard errors associated with the growth and predicted lysine requirement curves.