A U.S. Department of Agriculture Agricultural Research Service study shows that, in rangelands of the western United States, calving in late winter instead of spring maximizes calf weight gain by supplying high-quality forage when it’s most needed, the USDA reported March 22.
Changing climate conditions affect the costs and benefits of calving at different times. One of the factors ranchers can adjust to improve beef production is selecting the right calving time, the report said. Utilizing rangelands to lower costs has a high value.
“The long-term data allowed us to estimate the relationship between calving date and calf weight averaged over many years,” Matthew Rinella, USDA research rangeland management specialist, said. “The average relationship helps producers determine the best calving date over the long term. This must be considered because the calving date of a herd is difficult to adjust once set.”
The study was carried out by scientists at the ARS Livestock and Range Research Laboratory, the release said. It consisted of an analysis of more than 80 years of data from more than 39,000 calves to obtain an accurate reading of the effect of calving date on calf weight gain.
Calves born in late winter were about 13 percent heavier than calves born in early May, after 180 days. The research study said calves born in March can better utilize the high-quality forage available in summer because they are older and larger, according to the release. Forage quality has declined in early November when May's calves reached 180 days of age.
