Phosphorus in Swine. V. Interrelationships of Various Feedlot Performance, Serum Minerals, Structural Soundness and Bone Parameters in Barrows, Boars and Gilts

Abstract

Daily gain, daily feed intake, feed per unit of gain, serum Ca, serum P, serum Mg, structural soundness scores, foot pad scores, metacarpal breaking force and metacarpal ash values from five Ca P trials with barrows, gilts or boars were subjected by sex in each trial to multivariate analysis of variance. Correlation coefficients were obtained from the residual sums of squares and sum of products; thus, coefficients were corrected for treatment effects. Individual values were used for all comparisons except those involving daily feed and feed/gain, for which pen means were used. High positive correlations were observed between daily gain and daily feed; there was no relationship between daily gain and feed/gain, but daily feed was positively correlated with feed/gain. Serum Ca levels were not highly correlated with daily gain, daily feed or feed/gain. Although all coefficients were less than .5, serum P was positively (P less than .01 or less than .05) related to daily gain. Serum Ca and serum Mg concentrations were unrelated to serum P concentrations, but serum Ca was positively correlated with serum Mg. There was no relationship between daily gain and soundness or pad scores. Although there were some inconsistencies, a positive relationship was observed between daily gain and metacarpal dried weight, and between daily gain and breaking strength. There appeared to be little, if any, relationship between daily feed and feed/gain and bone parameters. Ca, P and Mg were not consistently related to metacarpal dried weight, breaking strength or ash. Dried weight was positively correlated to breaking strength in four trials and to ash in two trials. Breaking strength was correlated to ash in only one trial. These results offer no support for the belief that stronger, denser bones produce more structurally sound animals, because soundness and pad scores were not related to bone parameters.