Cow size should not be overlooked when comparing calf weaning weights, according to University of Kentucky agricultural economist Kenny Burdine. While there is often debate about whether an “optimal” cow size exists, Burdine says profitability depends less on cow weight alone and more on how many pounds of calf a cow weans relative to the costs of maintaining her.
Burdine notes that market conditions play a key role in evaluating productivity. For example, a cow does not have to wean as large of a calf to be profitable in 2025 as she would have in 2022. The reality is that producers make culling decisions each year based on the best information available at the time, underscoring the importance of accurate records.
Individual animal records are critical in this process, Burdine says. Well-managed cow-calf operations track weaning weights for individual calves and match them back to their dams, allowing producers to measure productivity on a per cow basis. While it is difficult to calculate costs for each individual cow, most producers with solid financial records have a good sense of what it costs to maintain the average cow in their herd.
Larger cows generally wean heavier calves, but Burdine emphasizes they are also more expensive to maintain. Bigger cows consume more forage, feed, and minerals, and may also incur higher veterinary, transportation, and other related costs. If culling decisions are based solely on calf weaning weights, producers may unintentionally cull more smaller cows over time, gradually increasing average cow size and overall production costs.
Using a budget-based approach, Burdine adjusted costs for cows of varying sizes and accounted for higher cull values for larger cows. That analysis suggested a herd would need to wean approximately 50 additional pounds of calf for every 100-pound increase in mature cow weight to offset higher ownership costs.
A single optimal cow size likely doesn’t exist, But Burdine cautions that larger cows must consistently wean heavier calves to justify their higher costs. He concludes that calf weaning weights should be evaluated in relation to cow size to avoid misleading conclusions when making culling decisions.
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