Heifers aren’t usually analyzed for feed efficiency on forage, but a study at Oklahoma State University (OSU) shows high forage efficiency early in life could foreshadow long-term production potential.
David Lalman and Bailey Tomsom explained the research findings in a recent issue of the Cow-Calf Corner newsletter. The extension beef cattle specialist and graduate research assistant suggest the results from the study could help producers select replacement heifers that become more forage-efficient cows.
While there has been substantial research to assess genetic variation in feed efficiency of growing heifers consuming concentrate-based, mixed diets after weaning, there is less data to draw conclusions about the feed efficiency of weaned heifers consuming forage.
“This is important because approximately 74% of the total feed required to produce beef comes from forage,” the authors write. “Indeed, the ruminant animal’s primary advantage over nonruminant species is its ability to convert forage into a high-quality human food source.”
Additionally, market analysts expect to see greater beef heifer retention over the next few years. Considering current beef prices and opportunities for herd expansion, the extension specialists suggest now is a good time to identify and implement strategies that improve the efficiency of forage utilization by replacement heifers.
Variable gain on hay
Every year, OSU researchers evaluate weaned heifers, lactating cows, and dry cows in the university’s forage intake facility. For each trial period, animals spend roughly 90 days in the facility, where they are fed bermudagrass hay and provided mineral, with free-choice access to both. The hay typically has 12% to 14% crude protein (CP) and 57% to 60% total digestible nutrients (TDN).
“High-quality bermudagrass hay is selected so the protein requirements of growing heifers and lactating cows are met without the need for protein supplementation,” the specialists write. “Hay is fed unprocessed, allowing us to evaluate intake and performance under conditions similar to many real-world forage systems.”
Results routinely vary within each group. For example, in 2024, the average daily forage intake of weaned heifers ranged from 9 to 19 pounds, whereas average daily gain ranged from slightly negative to 1.6 pounds per day.
“Notably, heifers with unacceptable weight gain have been observed in every contemporary group,” the specialists report. “At the same time, many heifers exhibited moderate forage intake coupled with acceptable — or even exceptional — weight gain.” They hypothesize that these animals ultimately become more forage-efficient cows, which they define as animals that are highly productive without consuming excessive amounts of forage.
No grain correlation
There is no pattern to heifers’ ability to gain weight on forage, and researchers have concluded that these results are independent of animal performance on energy-dense diets. “Across seven independent studies, no statistically significant positive correlations have been detected between gain on concentrate-based diets and gain on forage-based diets,” the specialists write. “Additional research is clearly needed, including larger experiments with sufficient data to estimate genetic correlations.”
With that said, they suggest that farmers can replicate the experiment on-farm to evaluate the forage efficiency of their own animals. “Producers only need a reliable scale and a 70- to 100-day period during which heifers are grazing moderate quality forage or consuming hay with little or no supplementation,” they write.
“In practice, some producers may already be selecting for forage performance, perhaps unintentionally," the specialists add. “For example, low-input heifer development programs, short breeding seasons, and only retaining heifers that conceive early may naturally favor females that perform and reproduce efficiently on forage-based systems.”
