Change in hoof phosphorus content for bulls in a 112-day postweaning feedlot performance test

Abstract

Hoof samples for mineral analysis from four breed groups of bulls—Angus (n=20), Brangus (n=19), Hereford (n=31) and Simmental (n=53)—obtained during a 112-d postweaning feedlot performance test were used to study effects on the change in hoof phosphorus (P) concentrations. Hoof samples were obtained for mineral analysis from the right front foot of all bulls on d 1 and 112 of four tests conducted in three locations in Arkansas. Data were analyzed using least-squares analysis of variance. The model included terms for common element, an effect due to test, breed, farm of origin within breed, hoof pigment, initial age and residual error. Breed means were separated using repeated t-test. Residual correlations between P and other hoof minerals were obtained. Breed was the only significant source of variation on the change in hoof P. The model explained 45% of the variation (R 2). Breed means for the change in P showed both Angus and Brangus bulls significantly different ( P<.05) from Simmental bulls. Residual correlation for the change in P with the change in K was −.48 ( P<.001). Residual correlations for the change in P with the changes in Mg (−.28), Ca (−.27), Na (−.28), Mn (−.28) and Cu (.23) were significant at P<.05. Results from this study suggest there are breed effects on the change in the P concentration of hooves and that P changes are correlated to changes in other hoof minerals.