By Jack Vander Byl

Reading the title, you’re probably thinking about the severe cold weather we Canadians get in January and February, and how cold it must be for cows to be outside. Not so. On a cold, clear, sunny day in January at 30°C below 0, our beef cows are happily lying on the snow chewing their cuds. Their protection from the cold comes with their birth. Calves born in the late fall arrive with a thick hair coat and ready for winter. The rest of the cattle in the herd also grow a thick hair coat for the winter. In the spring, the cattle start rubbing against whatever they can find to slough off this winter coat: fences, trees, buildings, etc. Then they are ready for summer.

Calves that are born in the springtime, however, come with a very slight haircoat to help them cope with the severe heat of plus 30°C summer days. And how do cattle cope with those very hot summer days? They do their grazing early in the morning and in the evening, spending the rest of the day lying in the shade of any big old tree they can find and chewing their cuds. Yes, everything a cow eats, she regurgitates and chews it 70 more times to break it into smaller particles that get passed on down to her other 3 stomachs.

On cold, clear winter days cattle cope very well as long as there is no wind. But if you add some strong wind, cold rain or a severe snowstorm to the cold, the cows eat quickly and head to shelter to chew their cuds. In our case – we’re in eastern Ontario – we have a lean-to on the south side of the main barn so the cows can get out of the wind and snow. A windbreak will also do nicely. If they don’t have a building they can shelter in, they will head to the bush, preferably a cedar bush which gives excellent protection from the wind. If nothing is available, the cattle will form a circle with the calves in the centre to protect them and cows around the outside packed in close together so only their behinds are exposed to the wind, taking turns being on the outside of the ring.

When I joined a veterinary practice in 1975, the dairy cattle in eastern Ontario were all housed in barns of 30 to 70 milk cows. The barns were all packed tight with cattle and not very well ventilated. Cows give off a lot of heat and the barns became too hot for the cows. As a result, we treated a lot of pneumonia in our dairy cows. The farmers were happy because the barns were very comfortable to work in, but the cows are very comfortable at 0°C.

During the summer, the cows had gone to pasture every day during the summer but spent most of the day lying under the trees to get shade. If they were left on pasture too late in the fall, they started to grow a winter hair coat and then the farmers had a big job to clip all the hair off so they wouldn’t overheat in the warm barns.

Gradually, things changed. Ventilation in the barns improved, and milk production improved as the cows were kept in a cooler environment. So now, all new barns have open sides with a curtain that can be pulled up in the worst of winter; the barns are generally just above freezing – good for the cows but not so good for the farmers and veterinarians who have to work with them. During the summer, these barns have massive fans that move air through the barns very rapidly and cool off the cows. Dairy cows do not go outside anymore.

So, even though the Canadian climate may be harsh, cattle will adapt, as long as they have water to drink and enough food to eat.

Jack Vander Byl is a retired large animal veterinarian who now enjoys helping out at his son’s beef cattle farm in Eastern Ontario.