Sire Breed Effects on Preweaning Traits of Crossbred and Purebred Calves from Angus or Hereford Dams

The objective of this research was to evaluate variation in calf performance from birth to weaning attributable to breed of sire (BRS), breed of dam (BRD), sex of calf, and all interactions. Records from 2,352 calves born at the Pinetree Research Unit of the Arkansas Experiment Station were utilized in the study. Physical environment and the available production resources make this location one of the more challenging environments for feeder calf production in the state. Some of these challenges include, but are not limited to, abundant rainfall, poorly drained soils, limited number of improved forage species, endo- and ectoparasites, fescue toxicities, and anaplasmosis. Calves resulted from mating Angus and Hereford dams to Angus, Hereford, Charolais, Santa Gertrudis, or Red Poll sires. Calf data collected were birth date, birth BW, preweaning ADG, weaning BW, weaning grade, and weaning body condition score (WBCS). Year, age of calf, BRD and BRS were significant (P < 0.01) for all traits studied. Sex of calf affected (P < 0.05) birth BW, ADG, weaning weight, and weaning grade, but not WBCS. The interaction of BRS x BRD affected (P < 0.01) all traits studied except preweaning ADG and WBCS. This interaction indicated that there were differences in calf performance between the 2 dam breeds depending on sire breed of calf. These data indicate breed differences exist for preweaning performance of calves produced in an eastern Arkansas production environment.