U of G researchers use pedometers to determine cattle fertility
University of Guelph researchers have fitted cows with heavy-duty pedometers – not unlike the ones fitness enthusiasts use to track how many steps they’ve taken – to bank on the long-accepted idea that cows are more active when in heat.
Population medicine professor Stephen LeBlanc, researcher Melanie Quist and graduate student Rob Walsh are keeping close track of the activity levels of a herd of cows outside Guelph to determine whether the process of detecting cows in heat can be automated, leading to higher efficiency and lower breeding costs.
“Finding cows in heat is a challenge,” said LeBlanc. “We usually look for other signs, such as mounting, but this can be easy to miss – hence the interest in automating heat detection.”
The premise is simple: with a pedometer designed by a firm in Israel fastened to its ankle, each cow enters the milking parlour three times a day at eight-hour intervals. At each visit, a computer tracking the cow’s activity is automatically updated (via transponder) with its pedometer reading.
Because the number of steps a cow may take in an eight-hour period is highly variable – from under 100 to several hundred – a baseline is constructed for each cow using its own data over a 10-day period. A computer program is then used to identify which cows are at their peak activity level, information that is compiled into a report for the farm manager.
Pedometry data yield stunningly clean charts – graphs of steps against time that look like flat lines with a steep spike of activity when the cow is in heat – that can be used to inform farmers about the best time for breeding, said LeBlanc. But there is little information about which part of the peak activity presents the greatest potential for successful breeding. “We don’t know yet when the optimum time for insemination is,” he said.
To determine the peak insemination time, the researchers are using farm records to compare pedometry data with information about when cows were bred and whether the breeding resulted in pregnancy. “I’ll be looking specifically for when the cow was bred and whether she was at the beginning, middle or end of her increase in activity,” said Quist.
Using pedometry to predict when cows should be bred makes use of evolutionary cues that have been part of cattle behaviour for centuries, she added. “It’s the estrogen that makes them act the way they do when they’re in heat. When they were breeding naturally on the plains, their increased activity was probably the result of them looking for a mate or increasing their chances for social contact.”
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