How Do Dairy Cows Produce Milk: Various Cows Comparison And FACTs

Compared to other dairy animals, cows stand at an advantageous point. We say so because of the ease of milk the cow, their udder size, and the nutritional content of the milk.

The food the cows eat passes through all fours chambers of the stomach, where it breaks down and is fed by the microbes. In the final stage, the food passes into the small intestine, where the bloodstream absorbs nutrients and surplus water, which is subsequently circulated to the mammary gland in the udder, where the food transforms into milk.

Isn’t it an interesting process? So, in the below sections, we have focused on various facts related to cow’s ability of milk production.

By the end of the article, you will be able to understand in detail how dairy cows produce milk and what factors affect that ability.

Milk Cow'S Animal Product - Free photo on Pixabay
Image Credit: Milking a cow using machines by Ehrecke from Pixabay

Why do dairy cows constantly produce milk?

The demand for dairy cows is on a surge due to the increase in the demand for milk and dairy products across the globe. But have you ever wondered how or why dairy cows constantly produce milk?

Dairy cows constantly have to produce milk to bridge the gap between demand and supply of milk. In addition, however, a cow needs to produce a calf in order to lactate. As a result, most of the time, the cows are inseminated by trained technicians with bull semen so that they calve and, as a result, lactate almost constantly.

That being said, it is a different matter of fact if cows should produce milk constantly. In addition, the whole process of commercialization of the milking process has and is having some truly adverse impacts on the cows’ overall health status.

How do cows start producing milk?

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Image Credit: Cows in a ranch from Pxhere

As we stated above, a cow needs to produce a calf in order to produce milk or lactate. Now, let’s see what changes in its body prepare it to produce milk.

A cow’s body starts preparing itself to produce milk once it conceives. However, after calving, the period of peak milk production begins. During this time, the consumption of dry food would help a cow’s system transform the forage into milk. Also, the presence of its newly born calf would signal the cow’s body to lactate.

Scientifically speaking, a mammal body produces milk due to hormonal interplay. So, in cows, several hormones, including estrogen, progesterone, insulin, and others, work together to prepare the cow’s udder to lactate. And the hormones prolactin and oxytocin regulate milk production and milk release after birth.

How often do dairy cows produce milk?

It is a fact that around 80% of the world’s milk demand is fulfilled by cow milk. But this should not give the impression that cows can produce milk forever.

Cows would produce milk only after calving. Immediately after giving birth, a cow starts lactating, and the number of times it will calve will produce milk. That being said, in a commercial setup, a dairy cow gets the chance to milk 3- 4 years before they are culled. 

In other words, commercial dairy cows usually get to live for 5- 6 years. And after every 12- 13 months, a cow will be impregnated. Hence, in a lifetime, a dairy cow, in commercial settings, would milk for a lesser time as compared with the one that is mended in a non-commercial setup, where it can live for 15- 20 years.

At what age do dairy cows start producing milk?

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Image Credit: A calf drinking cow’s milk from Pxhere

We’ve already established that a cow’s calving and lactation are inextricably linked. As a result, it’s crucial to figure out when they calve in order to produce milk.

A dairy cow can start calving roughly at the age of 2 years, and immediately after calving, it will start producing milk. The cow would usually provide milk for ten months after giving birth before being given a two-month rest time before giving birth to the following calf.

However, this starting age of lactation may vary between dairy and beef cows, as the latter sometimes may calve at the age of 12 months due to precocious puberty. That being said, precocious puberty may cause birth complications. 

How do dairy cows produce so much milk?

With profit-making intentions, farmers nowadays use technologies and learn the ways to induce high milk production among their cows. High milk production would mean increased sales and high returns.

The milk production capacity of a modern dairy cow has increased almost 5- 7 times than what it used to do a century ago. This is because cows are ‘constantly fertilized’ throughout their lifetimes in order to produce milk. And hormones are injected into them in order to boost their milk production.

These processes, however, make milk a controversial product in contemporary society. Gone are the days when cows used to lactate naturally. These meek animals mostly spend their lives in indoor stalls or crowded feedlots in modern times. This, as a result, has attracted protests from animal welfare organizations and individuals. 

How long do dairy cows produce milk after giving birth?

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Image Credit: A cow getting milked from Pxhere

A cow’s capacity to reproduce and milk is its most valuable asset. And the latter is completely reliant on the former.

As stated above, a cow can have its first calf around the age of 2, and immediately after calving, it will start lactating. This period will continue for ten months. During this period, the milk production would intensify around the initial, around 40 to 60 days

In this context, one should remember that the above-stated fact is a general trend, and a cow’s milking capacity and duration would depend on certain external and internal factors, like:

  • The overall health status
  • Quality of dry food
  • External environment
  • Birthing easy or problems, etc. 

At what age does a dairy cow usually stop lactating?

Dairy cows are bred for producing milk. They are fed and fertilized with the sole purpose of producing milk. But can a cow produce milk throughout its lifetime?

In theories, cows can produce milk as long as they can calve, which is throughout their lives. And a cow can live up to its 15s and 20s provided it is offered a natural setup and is not treated as a milk-producing machine. Also, if a cow’s udder is rightly stimulated, it can produce milk even without calving.

However, it should be remembered that milk production without calving is not a very feasible thing to expect. We say so because such milk will be of poor quality. 

Can a dairy cow produce milk without getting pregnant?

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Image Credit: Cows in a milking parlor from Pxhere

The high global milk demand has pushed scientists to think about how to induce higher milk production among dairy cows. But is it possible to make cows lactate even when they are not pregnant?

A cow can produce milk even without getting pregnant. It doesn’t really matter how this may sound, but this is the reality. Administering progesterone and estrogen hormones that control the milk production system in mammals in dry and non-pregnant cows has resulted in lactation. This technique works best with exotic cow breeds.

However, hormone injected milk production may leave the stresses of hormones in the milk itself. This, in turn, might not be a very desirable thing to be consumed by humans. 

In other words, the forces milk production in cows comes with a cost of their as well a humans’ health.


This article was an endeavor to explore dairy cows’ milk production hows and whys. We are sure that you have understood a lot of this about the context by now. Cows are meant to produce milk, especially dairy ones, but it is essential to keep track of how they are pushed to lactate. This will be ethical and help ensure that milking is taking place sustainably.

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