Humans have been drinking cow’s milk for centuries but we have become so disconnected from the source of our milk today. Some children do not even realize that milk comes from cows. A common misconception is that cows produce milk all the time. This is not the case and cows have to be pregnant and give birth to calves in order to produce milk in the same way as human mothers.
Hormones released in pregnancy stimulate milk production and release
In the second and third trimesters of pregnancy, various hormones like estrogen and progesterone stimulate the growth of the milk duct system in the udder of the cow. Oxytocin is another important hormone that stimulates milk “let down” or secretion of the milk.
When the calf suckles the udder of the cow or the cow is milked using a milking machine, this stimulates levels of the hormone called prolactin. The sucking of the calf or milking using a milking machine reduces the discomfort caused by a full udder. When farmers milk their cows, it sends a message to their bodies that they need to keep producing milk because the prolactin level keeps being stimulated.
Higher milk yield
Cows produce enough milk to feed their calves but this doesn’t satisfy the demand for milk and milk products that exist today. A modern dairy farm usually has hundreds and possibly even thousands of cows. Modern dairy farmers selectively breed cows and in some countries, they may give them growth hormones to produce much higher volumes of milk than they would normally produce.
Nutrition, breed, age, and Holstein dairy cow with its black and white spots is the most common dairy cow and it has been bred to produce large amounts of milk. The milk production per cow has more than doubled over the past 40 years.
The cycle continues
After giving birth, the milk production level rises and peaks at about 40 to 60 days afterward. It then steadily declines and stops at about ten months. The cows usually have about three months off before they calve again and the whole process continues. They are artificially inseminated so they can fall pregnant, give birth again, and continue to produce milk.
Artificial insemination usually happens for the first time when cows are about 25 months old and the cycle continues until they are about four to five years old. When their production slackens, they are no longer useful and they are killed and sold off as low-grade beef.
Could we get milk from a cow without needing it to be pregnant?
How would this work? A non-pregnant cow would be given hormone injections to replace what would happen during a natural pregnancy. The cow would then receive treatments every two weeks to maintain the hormone levels.
Research shows that cows given this treatment product have the same amount and quality of milk as cows that give birth to calves. At least this method would mean no unwanted calves but would it be really ethical to give cows’ artificial hormone treatment? For some, the fact that it would reduce the suffering of calves and prolong the life of the cow is enough justification.
Many critics of dairy farming are against farmers perpetually impregnating cows and believe that the industry perpetuates the suffering, exploitation, and death of dairy cows. Cows may be forced to spend their entire lives indoors due to a “zero pasture” environment at factory farms. The practice of removing calves from their mothers is inhumane and male calves are useless to the industry so they are shot or sent to veal crates.
The natural lifespan of cows can vary from 13 and even up to 20 years, whereas most dairy cows aren’t permitted to live more than four to six years. Cows may be slaughtered for a variety of reasons, including mastitis, infertility, lameness and failure to produce enough milk to justify feed costs.
Any stress, discomfort or disease can negatively affect milk production. It can therefore be in the interests of dairy farmers to try and address the negative issues. They could increase lying down, rumination, and eating. Cows need to lie down to ruminate well and good nutrition can improve milk production.