You are what you eat, according to the famous proverb. A team from the Faculty of Agricultural and Environmental Sciences of McGill University's Macdonald Campus is putting this wisdom into practice by studying the effects of cows’ diets on the nutritional quality of their milk. The researchers’ goal: to help Quebec farmers make milk healthier—and Quebec’s dairy industry more competitive.
“We wanted to see to how changes in the feed given to dairy cows were reflected in their milk, especially the fatty acids in their milk,” explains Kevin Wade, Chair of the Department of Animal Science and Director of the Dairy Information Systems Group. “We were looking for a way to meet the needs of today's consumers, who, for health reasons, want low fat foods with a larger proportion of unsaturated fats.”
Today’s researchers draw on a long tradition of McGill contributions to Quebec’s dairy industry. Back in the 1960s, John Moxley, now a Professor Emeritus of Animal Science, began helping dairy farmers collect data to improve their milk production. His Dairy Herd Analysis Service revolutionized Quebec’s dairy industry and was the direct precursor to the Valacta Dairy Production Center of Expertise, which continues to be one of the main drivers of the dairy industry’s productivity and profitability.
With the support of various partners, such as Novalait Inc., the current McGill researchers mined Valacta’s invaluable database, which compiles information about the feed given to most dairy herds in Quebec. They then analyzed milk samples from 33 Quebec farms to establish nutritional profiles, specifically the chemical composition of the milk’s lipids and proteins.
At first glance, the connection between the composition of a cow’s milk and what she eats may seem straightforward. But ruminants, such as cows, use bacteria in digestion that considerably modify the protein ingested. Teasing out the connections between the cows’ feed and their milk, then, becomes a surprisingly complex task.
Preliminary results show intriguing possibilities. For example, the concentration of omega-3 fatty acids in milk seems higher when cows are fed using the TMR (total mixed rations) system rather than fed grains and forages separately. Changing feeding methods could boost milk’s levels of omega-3 fatty acids and conjugated linoleic acids (CLA); these types of fat that can be beneficial to human health. The same strategy could help reduce trans fats, a source of less healthful fat, in milk.
This research could lead to the creation of an even better grocery essential at a reasonable cost. “It's only a beginning – a pilot study - but at least we now have some ideas about where we're going,” says Wade.