Nutritional management of beef cows during the winter months has lasting impacts on reproductive performance of the cow, calf health and overall herd productivity in spring-calving herds. Recent research evaluating minimal and flexible supplementation strategies using distillers grain-based protein supplements for May-calving cows grazing native range compared three programs.
They were: a low daily rate (0.5 pound per cow per day), a standard rate (1 lb./cow/day) and a flexible strategy where cows were supplemented only during periods of environmental stress such as snow cover or cold rain. Supplementation began in January and ended about 30 days before calving.
Although cows receiving the lower supplementation rate were lighter at calving and tended to remain lighter at breeding, there were no differences among treatments in body condition score, pregnancy rate, calf birth weight, weaning weight or subsequent feedlot performance and carcass characteristics. These results indicate that flexible supplementation during stressful weather can maintain productivity while reducing feed costs—a valuable option when winter feed prices are high.
Maintaining adequate cow body condition during late gestation, however, remains critical for both cow and calf success. Loss of body condition late in pregnancy can reduce colostrum quality and immunoglobulin content, weakening calf immunity and increasing disease susceptibility.
Severe nutritional restriction in late gestation also decreases birth weight, especially in young cows, and can compromise the calf’s immune development. Additionally, nutrient restriction during pregnancy has been shown to result in calves with lower weaning weights, reduced post-weaning and finishing performance, lighter carcasses and less marbling—clear evidence that maternal nutrition influences lifetime growth and carcass quality.
This phenomenon, known as fetal programming, describes how poor nutrition, heat stress or other challenges during gestation can permanently affect offspring performance and reproduction. Maternal undernutrition can delay puberty and lower fertility in replacement heifers while reducing feedlot performance and carcass quality in steers.
Collectively, these studies underscore the importance of managing cow nutrition strategically through the winter. Flexible supplementation programs can reduce costs without sacrificing reproductive success, but cows must maintain moderate body condition to support calf health, feedlot efficiency and long-term productivity. Well-planned winter nutrition programs enhance economic efficiency, animal resilience and the sustainability of beef production systems in variable environments.
Take-home message
Flexible supplementation programs that target environmental stress periods can help reduce winter feed costs without compromising cow performance. However, maintaining adequate body condition through late gestation is essential to ensure optimal calf immunity, fertility, growth and carcass quality.
Investing in balanced winter nutrition not only supports this year’s calf crop—it builds long-term productivity, fertility and resilience across the cow herd. — Paul Beck, Oklahoma State University Extension beef cattle nutrition specialist
