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.
Fenceline weaning is another strategy that holds better promise for reduced stress. Stookey says a 1985 study in horses using fenceline weaning with foals on one side and the mares on the other showed less nickering and walking. It was also demonstrated in domestic elk herds in 1997. “Cattle studies show fenceline weaning reduces calling. Traditionally weaned calves called 50% more than fenceline-weaned calves. Calves were calmer than if they were completely separated. It also reduced walking and increased lying time. Fenceline weaning is superior to pasture-separated and or feedlot weaning.”
“Two-stage weaning” was also studied to determine if at weaning the calf was missing the milk or missing its mother. Plastic clips were placed in the calves’ noses that allowed them to eat grass, but not nurse, and calves were left with their mothers. Stookey says calves stayed closer to the cows for the first few days (within 10 meters of their dam), and there was an increase in grooming.
The second step was to then separate cows and calves. When separated, there no real response either. “They don’t complain when milk turns off or when mom disappears,” Stookey says. “They are already weaned. They spent four days getting weaned before separation.”
There’s a limit to how long you should leave the nose-clips in. If you leave them in too long, they depress performance compared to control calves. After about 14 days you get more “cheaters” that figure out how to flip the tags around and nurse. Stookey suggests that 3-7 days of the nose clips will get you the results you need.
If you were to rank the weaning systems, Stookey says the worst on calf stress is abrupt separation, fenceline weaning is better, and two-stage weaning is the best.