Whether calves stay on the farm or arrive in a new group, the weeks around weaning are one of the most vulnerable points in a calf’s life. Calves at this stage are valuable, and their health and growth depend on decisions made long before they leave the cow.
A Strong Nursing Phase Supports a Strong Weaning Phase
Good weaning outcomes start with the cow. Calves born to healthy cows on a solid nutrition and vaccination program have a stronger immune system. High-quality colostrum at birth gives newborns their first protection. A well-planned vaccination program during the nursing phase builds on that base.
Vaccines help prevent viral diseases. These diseases are difficult to treat, and even when calves survive them, they often struggle with growth later. Antibiotics work against bacteria, not viruses. The goal is to keep the viral load in the herd low. When illness does occur, producers want it to be something antibiotics can treat.
Working with a veterinarian before weaning helps producers decide which booster vaccines to use and when to use them. This relationship also helps build a treatment plan before calves start showing signs of sickness.
Helping Calves Adjust When They Leave the Cow
At five months of age, most nursing calves eat a little more than 1% of their body weight in forage on a dry matter basis. After weaning, calves need to eat 2.3% to 3.0% of their body weight to keep growing.
The first goal after weaning is simple:
build feed intake fast and safely.
Familiar feed makes the transition easier. Calves used to grazing with the cow often prefer grass hay or a pasture-like diet. Calves that ate a silage-based ration with the cow usually adapt well to silage after weaning. Big diet changes can slow intake, increase stress, and weaken the immune system.
Rumen Development, Nutrition, and Clean Water
By 150 days of age, the rumen works well but is still small. Calves cannot eat enough poor-quality roughage to meet their needs. Low-quality fiber stays too long in the rumen and limits how much a calf can eat.
To stay healthy and growing, weaned calves need:
✔ Highly digestible, tasty feeds
These feeds help calves meet energy needs without putting pressure on the rumen.
✔ Adequate metabolizable protein
Calves need protein for both rumen microbes and body growth.
Distillers grains support muscle and skeletal growth better than feeds like alfalfa hay or soybean meal because of the type of protein they supply.
✔ A complete vitamin and mineral program
Trace minerals and vitamins, including Vitamin A, copper, and zinc, play a key role in immune function.
✔ Clean, easy-to-access water
Water intake drives feed intake. Calves that cannot find the waterer, cannot reach it, or avoid it because of poor smell or contamination will also stop eating.
Understanding Behaviour: Calves Hide Illness
Freshly weaned calves often hide signs of sickness. As prey animals, they try to look healthy when they sense a human watching. Sick calves may move into the middle of the group or act alert when someone walks through the pen.
To spot early illness, producers can:
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Move calves quietly and watch for slow or depressed calves
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Pay attention to which calves return to the bunk and eat
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Observe calves from a distance when they do not realize they are being watched
These practices help producers catch health problems early.
Building a Reliable Weaning Program
Weaning success comes from good nutrition, planned vaccination schedules, and daily observation. With today’s calf values, small improvements in feed, water, and health checks can make a big difference in performance and survival.
Producers who want help balancing rations or adjusting diets can reach out to beef nutrition specialists or extension educators.
