New research is urging dairy producers to rethink calf nutrition strategies, warning that cutting feed costs during early life can significantly undermine long-term performance and profitability.

Speaking at a nutritional masterclass hosted by Mole Valley Feed Solutions, Professor James Drackley at the University of Illinois highlighted the importance of mimicking natural feeding systems to maximise calf growth.

Calves left on the cow grow three times faster than those taken off and fed standard milk replacer – and producers can mimic that with more targeted feeding protocols, he explained. Under natural conditions, calves benefit from frequent feeding of high-protein milk, consuming up to 1–1.5kg of milk solids daily, compared to 0.5kg typically supplied through milk replacer. Weaning is gradual, taking place between six and 10 months, rather than the abrupt transition often seen at four to eight weeks.

The impact of these differences is significant. Trials show calves left on cows grew at 1.04kg/day in the first 14 days, compared to just 0.36kg/day for those separated early and fed milk replacer. “We overlook this period of high growth and shouldn’t be missing out on what mother nature designed,” said Prof Drackley. “It’s the most cost-effective time to increase body weights.”

While leaving calves on cows is not practical for all systems, optimising milk replacer feeding can deliver substantial gains. Increasing both the protein content and feeding rate of milk replacer improves feed efficiency and growth. For instance, feeding a 26% crude protein powder at 10% of bodyweight/day achieved growth rates of 0.55kg/day, rising to 0.81kg/day when intake increased to 18% of bodyweight.

“In the first two weeks you want to maximise milk dry matter intakes – it accounts for 52% of the variability in liveweight gains,” said Prof Drackley. Higher protein intake supports lean growth: Body protein deposition increases in direct proportion to the protein fed.

The relationship between milk and starter feed is also critical. Trials demonstrated that calves fed higher protein milk replacer (22%) responded better to increased protein in starter pellets (from 18% to 22%), improving growth and skeletal development. Calves receiving higher milk solids showed better resilience to disease, improved vaccine response, and produced an additional 435kg of milk in their first lactation.

However, Prof Drackley cautioned against premature weaning when feeding higher milk volumes. “Delay weaning by two weeks and step down the milk gradually to maintain growth rates – otherwise there will be too big a weaning check.”

Supporting these findings, a study by Mole Valley Farmers, Volac and the University of Reading found that calves fed higher protein starter diets achieved post-weaning growth rates of 0.78kg/day, compared to 0.71kg/day on lower protein diets. The research has informed the development of Ambition Calf 23% protein feed, which is designed to be fed from day one to 12-16 weeks of age. The unique combination of starch, digestible fibre and protein type helps to reduce any post-weaning check and drive overall performance.

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