Once the cows knew the drill, the researchers switched it up so that only the black bottle contained milk. After just a few trials, calves that had been raised with others figured out that they should now go for the full black bottle instead of the empty white one, the researchers report today in the journal PLOS ONE.
Calves raised alone, on the other hand, were still making many mistakes after eight or nine chances to learn that the reward had moved.
In another experiment, calves that had been raised with a pen-mate quickly got used to the introduction of a plastic red bin into the maze, while isolated calves never stopped sniffing, licking and pushing the strange object around.
Without a companion to make their living environments more complex, the findings suggest that calves have a much harder time getting used to change.
Modern dairy farms tend to be complex places, Weary said, full of robotic milkers and computerized feeders. Housing calves in pairs -- instead of alone or in larger groups -- could be a simple way to make cows more adaptable to evolving methods without increasing the risk of illness.
The new study reinforces evidence that calves raised alone may be more likely to act abnormally and have trouble coping, said Catherine Douglas, a cattle behaviorist at Newcastle University in the United Kingdom.
Those kinds of stresses could potentially lead to other negative consequences for cows and farmers, she said, making the animals harder to manage. In her work, she has also found that stressed cows kick more and are slower to let down milk.
Other recent studies have found that calves raised together are quicker to approach food and are more socially adaptable, added Marcia Endres, who studies animal behavior and welfare at the University of Minnesota, Twin Cities.
But adopting new farming practices is not as simple as reorganizing housing pens.
“It’s like having your kids go to daycare,” Endres said. “If they’re home, they’re not exposed to other kids and they don’t get sick. But when they go to daycare, they bring home all sorts of diseases."
"You have to be aware that when you put animals together when they’re young, they might get sick more,” she said. “It takes a little different kind of management. There are always different sides of the story.”