NASCalf Weaning Age
NASCalf provides a detailed view of weaning and its effects on the calf, helping us understand not just when calves are weaned, but when they are truly ready to be weaned. Let’s take a closer look.
We’ll begin on the Performance tab, which you can access from the lower left corner of the screen. In the center of this page, you’ll see four speedometer-style gauges. These gauges summarize key weaning indicators and give us insight into how the feeding program aligns with calf development.
Weaning is driven by the liquid feeding program, shown here. Calves receive colostrum on day one, transition milk on days two and three, and milk replacer beginning on day four. Milk replacer solids are increased from about 680 grams per day up to one kilogram per day by day 49, and then gradually reduced as we approach weaning. Milk is completely removed on day 70.
The first gauge shows the actual weaning age, which is 71 days. This represents the first day the calf no longer has access to milk.
The second gauge shows the optimal weaning age, or the age at which the calf is biologically ready to be weaned. In this case, that age is 63 days. This point corresponds to when the calf reaches 15 kilograms of cumulative non-fiber carbohydrate, or NFC, intake. Research published in the Journal of Dairy Science suggests that this level of cumulative NFC intake indicates sufficient rumen development to support safe weaning. You can see this threshold marked both on the gauge and on the accompanying graph.
The third gauge shows the industry-recommended weaning age. These recommendations vary, but a common standard is for calves to consume one kilogram of starter per day for two consecutive days. If we select that standard from the Farm and Calf menu, we see that this target is met on day 51.
If we adjust the industry recommendation—say, to 1.5 kilograms of starter for three consecutive days—the target shifts to day 57. While this meets an industry guideline, it still occurs earlier than the biologically optimal weaning age of 63 days identified by the NFC intake threshold.
The final gauge shows the age at which calves double their birth body weight. We typically aim for this milestone to occur within the first 56 to 60 days. In this example, calves reach double their birth weight by day 60, which meets that target.
That concludes this demonstration of NASCalf’s weaning diagnostics. Be sure to explore the other videos available in the NASCalf knowledge base to learn more about the program’s capabilities. Thanks for watching.
