IS THE DAIRY INDUSTRY READY TO RETHINK HOW WE FEED CALVES?
For decades dairy calf nutrition programs have been built around compromise: to provide enough milk to support calf growth, while restricting milk intake to stimulate early starter feed consumption and rumen development, ultimately for an earlier weaning. This approach has made the calf rearing process relatively predictable and economical, but is it the right answer? Are we missing out on the true biological potential of modern dairy calves?
In a recently published JDS Invited Review, Dr. Ghaffari and Dr. Hammon critically analyzed decades of research to understand what happens when we elevate whole milk or milk replacer (MR) consumption well beyond the standard 8-10% of calf body weight or approximately 4-5 quarts/day (Drackley et al., 2026 DOI: 10.3168/jds.2025-28038), to feeding rates of 8-12 L/day or ad libitum feeding approaches. (Ghaffari and Hammon, 2026, DOI: 10.3168/jds.2026-28404). This review takes a comprehensive look at the effects of these intensified systems on growth biology, behavior and welfare, rumen development and starter intake concerns, health, economics, and long-term performance. It provides an important framework for reconsidering what we have traditionally viewed as the “right” answer, and I encourage you all to dive deeper into their work.
If calves are biologically capable of consuming more milk than traditional feeding programs provide, perhaps our perspective should shift. Rather than focusing on limiting milk allowance to encourage earlier starter consumption and weaning, we should consider potential gains and losses of providing greater milk allowances. Historically, restricted milk programs were often used to reduce reliance on liquid feed and promote starter intake, but modern feeding strategies are increasingly evolving to support higher milk intakes and later weaning ages to better align nutrient supply and growth potential. Yet an important question still remains: Are we feeding enough milk to maximize on calves’ biological potential?
Research by De Paula Vieira, 2008, (DOI:10.1016/j.applanim.2007.03.006) and Jasper & Weary, 2002, (DOI: 10.3168/jds.S0022-0302(02)74391-9) has shown that calves on restricted milk allowances consistently display indications of chronic hunger through behaviors like increased vocalizations, longer standing times, and frequent unrewarded visits to automated feeders. In Jasper & Weary’s study, calves offered milk ad libitum consumed 89% more milk than restricted calves and gained 63% more weight during the pre-weaning period, resulting in a 10.5 kg body weight advantage by 35 days of age. Although both groups exhibited similar rates of gain during the weaning and post-weaning period, the ad libitum fed calves maintained a greater body weight through the end of the study, demonstrating that increased milk intake supported enhanced early growth without negatively impacting later performance and adaptation to solid feeds.
While increased average daily gain (ADG) is often viewed favorably, the biological significance of that gain extends well beyond body weight alone. A pound of gain can be varying proportions of lean tissue, fat deposition, organ development and skeletal growth. What makes up that gain matters and current research is painting a clearer picture of requirements in maintaining equilateral calf growth, not just fat deposition.
In their review, Ghaffari and Hammon draw on the work of Van Amburgh (DOI: 10.3168/jds.2018-15270), emphasizing that the goal of early life nutrition practices should be formulating diets to support the developmental trajectory that optimizes body size and composition, as well as future milk yield, rather than simply focusing on maximizing ADG. This consideration becomes particularly important as we consider feeding more milk in the preweaning period.
Elevated feeding programs have been shown to improve feed efficiency of preweaned calves, (Ghaffari & Hammon, 2026: Xiao et al., 2025 DOI: 10.3128/jds.2025-26555), largely because nutrients from milk or MR are more digestible than those from solid feed. As these calves consume and utilize more nutrients to support accelerated growth, diets need to be formulated accordingly. Increasing energy supply alone is not sufficient; protein and energy must be balanced and continuously adjusted based on body size and targeted ADG to support organ, skeletal and lean tissue development.
So, what does this look like in the calf?
When milk allowances increase, starter intake generally decreases. Although, it is important to note research has found minimal differences in starter consumption within the first three weeks of life when comparing conventional and elevated systems. (Ghaffari & Hammon, 2026) because overall intake of starter is low and in either feeding scenario solid feed intake is supported mostly through the milk or milk replacer. Nonetheless, the functional development of the rumen still relies on solid feed fermentation to transition to microbial protein synthesis and avoid the post weaning slump we dread. This is where the balance of the diet becomes critical. As Ghaffari and Hammon (2026) describe, total intake levels need to be considered alongside macronutrient composition to maintain an appropriate protein-to-energy ratio, while recognizing that the calf’s capacity for protein accretion changes over time and is not unlimited.
This is not a question of whether milk or starter feed is more important. Instead, the goal is to develop a nutrition program that supplies sufficient milk allowances to support a calf’s biological potential while simultaneously encouraging adequate starter intake prior to weaning. Achieving this balance requires attention not only to starter quality but also the calf’s ability to consume it in meaningful amounts to support development of the rumen.
Equally important to this is the weaning strategy we implement. If we still expect calves to wean primarily based on age, milk solids should gradually be decreased as we approach that age target. This encourages starter consumption and helps ensure that nutrient intake remains adequate, minimizing post weaning slumps and drops in average daily gain. Ultimately, weaning should be viewed as a transition, rather than a date on the calendar, especially when implementing an elevated feeding program.
The value of elevated calf nutrition programs potentially extends beyond the preweaning period. In a recently published study by Hemmert et al. (2026; DOI: 10.3168/jds.2025-27925), calves were fed 12 L/d (12.7 quarts/d) of MR during first 15 ± 1.9 days of life and then transitioned to group housing with ad libitum milk access until weaning. They were then retrospectively grouped into a moderate (MOD) or maximum (MAX) average daily gain (ADG) groups based on growth achieved during the first two months of age. Calves in the MAX group consumed, on average 1.1 L/d (1.16 quarts/d) more than MOD calves and remained heavier throughout the rearing period, from weaning through approximately 25 months of age at first calving. In addition, MAX heifers reached a 400 kg (881.8 lb) insemination threshold 42 days earlier and produced 1269 kg (2793 lb) more milk over a 305 day first lactation than MOD heifers. (Hemmert et al., 2026). If early life nutrition influences subsequent growth, reproductive performance, and milk production to this extent, then the economic evaluation of a feeding program should not stop when the calf is weaned.
When looking at economics, the payoff is extremely farm specific. Feeding more milk immediately comes with more measurable costs like supplies, additional labor, in certain cases specialized feeding equipment (i.e. Computerized feeding systems), greater and more careful management requirements, possibly longer weaning periods, etc.
On the other hand, there are potential returns in greater preweaning growth, improved feed efficiency in some systems, earlier insemination, increased first lactation milk and component production, and improvements of longevity and decreased culling rates.
The important question is not whether feeding more milk costs more. It does. The question is whether the additional upfront investment generates enough value to justify those costs on your farm.
The growing body of research on elevated and ad libitum milk feeding suggests that traditional calf feeding programs may not fully support the biological potential of these calves. However, simply increasing milk allowance is not the answer. It requires greater attention to starter intake, weaning management, and farm level economics that varies for each producer. Rather than abandoning traditional practices altogether, we should reconsider whether our current rearing programs are designed around the biological potential of the calf, or simply around the convenience and economics of the system.
— Abbygail Allen
