Weaning represents the single greatest stressor we impose on calves, says Joe Stookey, MSc, PhD, Western College of Veterinary Medicine, Saskatoon, Canada. For about three to five days they can be immunocompromised, have psychological stress and a setback in gain, he said at the 2nd International Symposium on Beef Cattle Welfare was held May 19-21 at Kansas State University.
Potential stressors associated with traditional weaning include:
- Managed weaning age is younger than the natural age at weaning
- Calves are in a new social environment
- There is an absence of adults
- There is a mixing of unfamiliar animals
- There is a formation of a new social hierarchy
- There is a physical separation of mother and calf
- There is a premature end of lactation
Stookey discussed several research projects involving different types of weaning. “Could the stress of weaning be reduced in the presence of adults?” he asked. “Calves are born in a matriarchal system were cows set the pace. Calves follow that. Cows are teachers, calves are pupils. Some people wean in fall, preg test, then put some cull cows in with weaned calves to calm them down.”
With that in mind, research has been done with “trainer cows” to see if they help the weaning process and help teach newly weaned calves how to eat at the feed bunk, etc. However, Stookey noted, they found no advantages and some disadvantages of using trainer cows. “Some cows would be dominant and not let calves up to the bunk. It sounds good but didn’t work. Calves also don’t know this cow and she doesn’t know them.” Stookey said a study looked at calves weaned in the presence of familiar adults didn’t help because a cow would not let a calf nurse her that wasn’t hers, and the calves won’t approach a cow that is not their mother. “A calf wants his own mother and a cow wants her own calf.”
They also studied cow and calf behavior at weaning. They observed cows and calves for two days, then weaned on Day 3. Cows are relatively quiet on a normal day, but after weaning, cows are calling to calves. “If vocalization equals fear and mishandling, what does it mean at weaning? Big stress,” noted Stookey. “Cows figure out soon that the calf is gone. It takes the calves a couple of days before they start calling.” In that same study, they found that eating time drops after weaning and walking increases.