DAIRY COWS don’t get to spend much time with their mothers. Farmers separate dam from calf just after birth, and often house the calves in individual pens until they are weaned from milk, usually after about two months; they then go to live in large groups. Farmers like individual housing for young calves because they believe it cuts the risk of contracted illness. But it also limits the animals’ ability to interact socially, which makes it more stressful for them to wean.
Even calves need study buddies
Calves become cleverer if raised in pairs
By P.H.| SEATTLE
In laboratory animals—not to mention human infants left to fend for themselves in Eastern European orphanages—a lack of early socialization is also known to impede cognitive development. New research by Dan Weary and three colleagues at the University of British Columbia’s Animal Welfare Programme suggests that dairy cows also need early socialization if they are to achieve their full intellectual potential. The team’s findings may have profound implications for how dairy cows should best be raised.
Professor Weary likes cows (as does your farm-bred correspondent). And over the past few years, as he and his colleagues were studying how calves behave after they are weaned, one thing became clear: those raised alone in pens acted oddly when they were introduced into the large groups in which they would live. They took a long time to start eating normally, largely because they were unable to recognise the unfamiliar feeder. As a result, they lost weight. Calves raised in pairs had little trouble finding food.
The lonely calves also lacked social skills. At first they appeared fearful in their newly enlarged social circle, but then started nudging other calves and following them around—or as Professor Weary puts it, “acting just like the annoying kid in the playground”. In general they found it hard to deal with new or novel situations, appearing confused and fearful. In short, they seemed quite stupid in both cognitive and social terms. And cows are not stupid.
To test their theory that being raised alone was to blame, the team carried out two experiments. The first, when the calves were four weeks old, involved placing bottles of milk at the two ends of a Y-shaped “maze” with which the animals were familiar. One bottle, disguised by a white box, contained milk; the other, disguised by a black box, was empty—or vice versa. Initially, only the side of the maze that contained a full bottle was left open, and each calf was led to it. After that it had to make a choice. If it made the correct one, it got to drink some milk; if it failed, it was given a 20-second “time out,” and then given another chance. Training continued until each calf reached an 80% success rate during three consecutive sessions. The colour of box disguising the full bottle was then reversed, and the experiment repeated. (All calves eventually got to drink their daily milk ration during the sessions.)
The second experiment, at seven weeks, simply introduced a novel object—a red plastic bin—into the same space. The researchers then monitored how long each calf sniffed, licked, and pushed the bin over the course of five minutes. The test was repeated eight times for each animal, with the time between testing gradually increasing from ten minutes to 24 hours during that sequence.
In the initial phase of the first experiment, the researchers found little difference between calves that were reared alone or in pairs. But when the colours of the disguised milk containers were reversed, calves that were raised alone took an average of 19½ sessions to reach the 80% learning criterion; those that had been raised in pairs took 13. As for the red plastic bin, paired calves gradually lost interest in it over the eight sessions; individually raised calves showed no such insouciance—they appeared not to recognise the bin each time they subsequently encountered it.
Professor Weary notes that these findings appear to confirm that being raised individually creates a cognitive deficit in calves, perhaps the result of a lasting brain dysfunction (although the fear and anxiety caused by being left alone after post-birth separation from their dam may not help). He speculates that individual housing of calves may impair the development of neural structures—perhaps in the orbital prefrontal cortex, which might limit reversal learning, or in the medial prefrontal cortex, which might disrupt a calf’s response to changes in more abstract rules. He hopes to carry out further research into whether any damage is permanent or can be outgrown.
In the meantime, Professor Weary believes that more farmers should consider raising calves with a buddy. Paired raising doesn’t increase risks to the calf from a health perspective, and is cheap to implement, entailing little more than removing separators from today’s modular pens. He notes that modern farms, with their robotic milking equipment and automated feeders, are scary places for dairy cows. Helping them become less anxious and more able to cope with change can only be a good thing—for farmers, too, who would end up with animals that are more flexible and easier to manage.
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