For cows to produce milk, they must first give birth to a calf. Just like humans, the gestation period for calves lasts nine months. Cows then give birth to their calves. From that moment on, they produce milk, which is also known as lactating. The lactation period lasts around 300 days, or 10 months.
Cows lactate when they begin to produce colostrum. This milk is reserved for the calf, which receives specific antibodies from it that protect the calf from infections. After a week, the milk is sent to the plant. Milk production reaches its peak in eight weeks and then gradually decreases until dry off.
Cows are inseminated again while they are lactating. Finally, the 2 months before a cow gives birth to the calf is considered dry time, when she is not milked. And the cycle starts over. That way, cows can give birth to calves and lactate several times, but usually an average of four times. To ensure an effective production level, producers renew a quarter of their herd every year.
Cattle breeds are considered dairy breeds because they have the potential to produce good quality milk. These cows often descend from fathers and mothers who have specific qualities.
Artificial insemination is used a lot because it makes it possible to choose the semen from the bull that is most likely to father genetically strong and productive offspring. The semen is taken from specialized centres, such as the Centre d’insémination artificielle du Québec (CIAQ) located in Saint Hyacinthe, from bulls that are selected for their genetic potential.
Breeding and better feed management have made it possible to noticeably increase the milk production per cow. At the turn of the 1970s, there were close one million cows in Quebec. Today, the heard has approximately 350,000 cattle. The same amount of milk is made from three times fewer cows. Although the dairy herd has decreased substantially, the annual milk production has reached more than 3 billion litres, which is enough to fill the Olympic Stadium one and a half times!