The 66 heifers used were good to choice grade Herefords purchased near Fort Davis, Texas, and assigned to treatments on a random weight basis.
They were rotated among pastures to minimize pasture differences during the first winter and summer. Di-calcium phosphate was fed to standardize phosphorus intake among groups during the first winter and each was fed 15,000 I.U. of Vitamin A daily. Salt was available to all lots throughout the test. They were fed three times weekly during the winter.