Early Weaning and Part-Year Confinement of Cattle on Arid Rangelands of the Southwest

Abstract

This study compared part-year confinement 01 cows with yearlong placement on rangeland and weaning calves in late May with regular weaning in mid-October. Weaning rates tended to be higher with part-year confinement than with yearlong placement on rangeland (86% vs. 72%) and with early weaning in May than with regular weaning in October (86% vs. 72%). There were significant year effects in weaning weights with the lowest weights in drought years. The production per cow exposed tended to be higher with part-year confinement than with yearlong placement on rangeland (134 kg vs. 110 kg), and with regular weaning than with early weaning of calves (156 kg vs. 88 kg). Part-year confinement of cows and early weaning of calves are useful tools for the range manager in droughty years. Production of livestock accounts for about 75% of the total agricultural income in the arid and semiarid regions of the Southwest. Much of this production is on rangelands. Because of frequent droughts, livestock production is particularly perplexing. Every additional estrous cycle needed to get the beef cow rebred after parturition results in an economic loss. This loss is due to low weaning weights and eventually to cows left unbred at the end of the breeding season. Breeding performance is strongly affected by the cow’s nutrition. Nutritional levels, before and after calving, influence pregnancy rate for next year’s calf crop (Wiltbank et al. 1965). After parturition, the cow must provide milk for the growing calf as well as prepare for reproduction. This shift in feed requirements boosts dry matter and energy needs by about 40%