Oklahoma State University animal scientists evaluated weaning dates of 158 Angus fall-calving cows over a 4 year period. Cows were allowed to nurse their calves for about 210 days (April Weaning) or 300 days (July-Wean). All cows calved in September or October and were weaned in mid-April (April-Wean) or mid-July (July-Wean). April-weaned young cows had greater re-breeding percentages (98.4% versus 89.3%) than July-weaned young cows. Young cows were defined as the two and three year old cows.
However, there was no advantage in the re-breeding performance of April-weaned mature cows compared to July-weaned mature cows (90.2% versus 96.7%). Mature cows were defined as cows that were 4 years of age and older. April-weaned cows were heavier and fleshier at calving than July-weaned cows.
Calves weaned in July were 90 days older and 204 pounds heavier (642 lb versus 438 lb) when weaned than were the April-weaned calves. The April-weaned calves were allowed to graze native pasture after weaning and weighed 607 pounds in mid July. Source: Hudson and co-workers. Journal of Anim. Sci. 2010 vol. 88:1577.
With the lack of forage, high priced supplements, and concern about summer pasture prospects, April weaning of fall-calving cows may be worth a close look in 2013. Young and/or thin cows should benefit most from the early-weaning date. A couple of extra months without a nursing calf should give thin cows a better chance to “bounce back” in body condition before calving next fall. Selling calves at a younger age and lighter weight should be offset by a higher rebreeding performance in the cow herd during next winter’s breeding season.