While little consensus exists in the best way to wean calves from milk, many studies have generally agreed that later weaning is superior to early weaning. That was the conclusion of a literary review conducted by researchers at Aarhus University in Denmark.
As the group described in a recent Journal of Dairy Science article, “There was a consensus for positive effects (or at least no negative effects) on overall growth of calves weaned at later ages, over longer durations, based on starter intake, or weaned using step-down or meal-based milk removal approaches.”
In 2014, the average age of calves at weaning in the United States was 9 weeks according to the National Animal Health Monitoring System. This was comparable to other countries like the United Kingdom (8 weeks) and Canada (8 weeks).
Most of the 44 studies that the research group disseminated investigated weaning age (22 experiments) while weaning duration (13 studies), weaning criteria (nine studies), and other methods were also evaluated. As they indicated in the paper, weaning age is not the best measure for weaning preparedness. However, that data point is correlated with growth, behavioral, and health outcomes.
Interestingly, the review showed that later weaning was also correlated with lower total starter intake. Most studies also found that elongating the weaning process with a method such as step-down weaning, however, was associated with improved starter intakes.
There’s still something to learn
Although the reviewed literature represents a wide swath of research, effort, and time, the Danish scientists concluded that some aspects of weaning are still both unknown and very important.
For Allison Welk, Heather Neave, and Margit Bak Jensen, who conducted the review, behavioral effects of weaning demand additional research. “Weaning at later ages can reduce signs of hunger (based on unrewarded visits to the milk feeder), but it is unclear if weaning over longer durations or weaning by starter intake reduces or prolongs hunger,” they explained.
Additionally, few studies in the review had adequate scale to measure health results of different styles or times of weaning. Given that health is such an important part of what farms do, this is a critical gap. That being said, researchers do agree on a few best practices for weaning.
“A successful weaning program must minimize signs of hunger while promoting high growth and feed intakes,” the scientists concluded.
