Weaning without setbacks: What research says about growth, welfare, and future performance | Dellait

Álvaro García

Weaning is one of the most important transitions in the life of a dairy calf. During this period, the calf must shift from a liquid diet to solid feed while simultaneously adapting to major physiological and behavioral changes. The challenge for producers is balancing calf performance, well-being, and labor efficiency without compromising future productivity.

Despite decades of research, weaning practices vary among dairy farms. Some producers wean calves at six weeks of age, while others wait until ten or twelve weeks. Some use gradual step-down programs, while others remove milk abruptly. Decisions are often based on tradition, labor constraints, or economics rather than biological readiness.

A 2024 systematic review by Welk and colleagues evaluated 44 studies examining the effects of weaning age, duration, and criteria, as well as alternative weaning strategies and their impact on growth, behavior, and health. The findings provide valuable insight into how weaning programs can influence both immediate calf performance and long-term herd profitability.

Earlier is not always better

Historically, early weaning was viewed as an effective way to reduce milk or milk replacer costs. The underlying assumption was straightforward: the sooner calves transitioned to starter feed, the lower the cost of raising them. However, research increasingly suggests that earlier is not necessarily better.

The review found that calves weaned at later ages achieved superior growth compared with calves weaned earlier. While earlier-weaned calves often consumed more starter feed sooner, later-weaned calves typically maintained higher average daily gain and achieved greater body weights. This finding highlights an important principle. The goal of a successful weaning program is not simply to maximize starter intake. Rather, it is to maintain growth while supporting rumen development and minimizing stress.

Milk remains a highly efficient source of nutrients for young calves. Removing it before calves are physiologically prepared can create growth setbacks that may be difficult to recover from. In contrast, calves weaned at older ages often transition more smoothly because they are better equipped to consume and utilize solid feeds.

The review suggests that weaning after eight weeks of age can support superior weight gain, particularly when calves receive adequate milk allowances during the preweaning period.

Why gradual weaning matters

The way milk is removed can be just as important as the age at which calves are weaned. Abrupt weaning remains common on some farms because it is simple and requires less management. However, the review found that longer weaning periods improve starter intake and support smoother transitions to solid feed.

Gradual weaning allows calves time to adjust their feeding behavior. As milk allowance decreases, calves naturally increase starter consumption to compensate for the reduction in liquid nutrients. This process promotes rumen development and helps maintain nutrient intake during the transition period. In contrast, abrupt weaning can create a sudden nutritional deficit. Calves may not consume sufficient starter immediately after milk removal, leading to temporary reductions in growth performance.

Interestingly, the review found that extending the weaning period did not consistently increase body weight compared with shorter weaning programs. However, it reduced the likelihood of abrupt nutritional disruptions and encouraged a smoother transition to solid feed. From a management standpoint, the objective should be to avoid forcing calves into a rapid dietary transition before they are ready.

Beyond age: Weaning by starter intake

One of the most practical findings from the review involves the use of starter intake as a weaning criterion. Traditionally, calves are weaned at a predetermined age. While convenient, this approach assumes that all calves develop at the same rate. Substantial variation exists among animals, meaning some calves are physiologically ready for weaning earlier than others, while some may require additional time before milk is removed. The review found that calves weaned according to starter intake consumed more starter feed and often achieved equal or superior growth compared with calves weaned strictly by age.

This result is not surprising. Starter intake is one of the best indicators of rumen development and readiness for weaning. A calf consistently consuming adequate amounts of starter has already begun the transition toward functioning as a ruminant and is less dependent on milk for nutrient intake. In contrast, a calf weaned solely because it reached a predetermined age may not yet have achieved sufficient rumen development, increasing the risk of reduced performance during the transition period.

Source: Adapted from Welk et al. (2024).

For this reason, progressive calf programs now combine age and starter intake criteria. Calves must reach a minimum age, but they must also demonstrate consistent starter consumption before milk is completely removed. This approach recognizes that successful weaning is determined by biological readiness rather than the calendar and helps ensure that calves maintain growth while adapting to a solid-feed diet.

Looking beyond growth

Growth is often the primary benchmark used to evaluate weaning programs, but it is not the only one. The review also evaluated behavioral indicators associated with calf welfare, including vocalizations, unrewarded visits to automated milk feeders, and other signs of hunger and frustration. Several studies reported that calves weaned at later ages exhibited fewer indicators of hunger than calves weaned earlier. Later-weaned calves often made fewer unrewarded visits to milk feeders and displayed fewer behaviors associated with nutritional frustration, suggesting that the transition away from milk may be less stressful when calves are weaned at a more advanced stage of development. These findings are important because behavior provides insight into how calves experience the weaning process.

Historically, weaning programs were evaluated primarily through performance measures such as weight gain and feed intake. Today, there is growing recognition that well-being outcomes deserve equal consideration. The authors noted that positive well-being indicators such as play behavior were measured infrequently despite their potential value and concluded that future research should place greater emphasis on understanding how calves experience different weaning strategies. A successful weaning program should therefore accomplish more than maintaining growth. It should also minimize hunger and stress while supporting positive behavioral outcomes.

The economic impact of getting weaning right

The consequences of weaning management extend well beyond the calf barn. Many producers focus on the immediate cost of milk or milk replacer when evaluating weaning programs, yet feed costs represent only a fraction of the lifetime value of a replacement heifer. Research has repeatedly demonstrated links between preweaning growth and future milk production. In a landmark analysis, greater average daily gain before weaning was associated with increased first-lactation milk yield, indicating that nutritional and management decisions made early in life can have lasting effects on future performance (Soberon and Van Amburgh 2013).

Viewed through this lens, weaning becomes more than a management event. It becomes part of a long-term investment strategy. Calves that experience significant growth setbacks during weaning may require additional time to reach breeding targets, potentially increasing age at first calving and rearing costs. In contrast, calves that maintain growth throughout the transition are more likely to reach developmental stages on schedule and enter the milking herd prepared to express their genetic potential. Calf and heifer programs should therefore be evaluated as investments rather than expenses because management decisions made during the first weeks of life influence future productivity, longevity, and profitability (Garcia 2025).

Although the review focused primarily on growth, behavior, and health, its findings support a broader conclusion. The most successful weaning programs are those that maintain growth, support welfare, encourage starter intake, and position calves for long-term success as productive members of the milking herd.

Conclusion

The best weaning program is not necessarily the earliest, the shortest, or the least expensive. Instead, successful weaning occurs when calves are physiologically prepared to transition from milk to solid feed without sacrificing growth or welfare.

Evidence from 44 studies suggests that later weaning ages, gradual milk reduction, and intake-based approaches provide the most favorable outcomes. More importantly, the effects of weaning extend beyond the calf barn. The transition from milk to solid feed influences growth, well-being, and potentially future productivity. Viewed as an investment rather than an expense, successful weaning helps raise healthy heifers, productive cows, and a more profitable dairy enterprise.

The full list of references used in this article is available upon request.

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