Weaning causes stress, reduces immunity, leading to illness

Calves suffering separation anxiety are susceptible to disease, so producers should avoid transporting, commingling and diet changes

MANHATTAN, Kan. — There is no more stressful event in a calf’s life than being weaned and taken from its mother.

There is physical proof that their systems are in upheaval after weaning, which can lead to sickness, researchers said at the International Symposium on Beef Welfare held last month in Manhattan, Kansas.

“Stress has a negative impact on animals, especially in terms of their immune response,” said Bernadette Earley, who works with Teagasc Animal and Grassland Re-search and Innovation in Ireland.

Her work has found altered physiological and immunological responses, in which the blood plasma and metabolic profiles were different when compared to those that had not been weaned. Immune cells were reduced, and calves were more susceptible to disease, particularly bovine respiratory disease.

Earley also found reduced response to vaccines. The calves do recover, returning to normal seven days after weaning.

“From day two to day seven, post weaning, is at the time when calves immune system is severely challenged,” she said.

Cows also undergo stress at weaning, but there isn’t much information about that group .

Irish studies also found behavioural changes among the calves and their dams.

“We find following weaning, activity immediately increased with all calves spending less time lying and more time standing,” she said.

Similar changes in behaviour are also apparent in Canadian studies, said Joe Stookey of the University of Saskatchewan.

“The animal itself is a very good indicator and tells us how stressful certain events can be,” he said.

Weaning causes visible changes in behaviour and overt signs of distress that last for three to five days. The calves are even more distressed than they are after dehorning and castration.

A recent western Canadian study showed more than half of producers wean calves and ship them the same day.

Besides the separation, the young animals also struggle with the negative effects from transportation, commingling, change of diet, change of home and dusty or muddy feedlot conditions.

Multiple studies have found that abruptly weaned calves become sick easier. The calves are at less risk if producers wait a week after weaning before transporting.

As well, many of those calves were not vaccinated.

An American study found that 64 percent of producers are not vaccinating for respiratory diseases on the farm, even though BRD is a common problem in feedlot cattle. Antibiotic use would be reduced if they were vaccinated before leaving the farm.

“It is just being responsible as beef producers to do this,” Stookey said.

“I find it incredible we are not vaccinating on the farm when we know they are going to get sick.”

Research projects have tested alternatives to help young animals cope with separation.

Cows and calves are relatively quiet before weaning but start bawling once it occurs. They also spend less time eating because they are pacing, calling and trying to reunite.

Some animals walked up to 24 kilometres in a day. They did not eat and lost weight, which put more stress on their systems.

It was often thought that calves sent to the feedlot do not eat right away because they do not know where the feed is, but they are actually stressed from weaning and spend more time walking.

Fence line weaning studies from the 1990s found that keeping pairs next to each other reduced vocalization by one-third, but it was not a perfect system.

A graduate student project from 10 years ago questioned whether weaning stress had more to do with calves missing the milk or missing their mothers.

The use of nose tags, which prevented calves from nursing while allowing them to stay with the mothers, determined that turning off the milk didn’t cause distress, but separation from the mother was agitating.

A recent study said the tags could be left in for up to 21 days, but Stookey said that is too long.

“The longer you leave those tags in, the sloppier those tags become and calves will learn how to manipulate them and nurse,” he said.

Producers who want to try a two stage weaning system should vaccinate calves at that time because the vaccines need two weeks to activate.

The Western Canada cow-calf survey from 2014 found the following:

  • Seventy percent of producers used traditional abrupt weaning.
  • Twenty-two percent used fence line separation.
  • Six percent tried two stage weaning.
  • Three percent used natural weaning.

About the author


Stories from our other publications