So, Do Cows Have To Be Pregnant To Produce Milk?

Milk comes from cows, but does a cow need to be pregnant in order to produce milk in the first place?

It seems like an obvious question, but when you think about it, most people just assume that milk comes out of female cows pretty much all the time. That’s what they are there for, after all!

Milking Shorthorns cows in the field
Milking Shorthorns cows in the field

But surely the answer isn’t that obvious considering all the work that goes into forming and maintaining a dairy herd. So, do cows have to be pregnant to produce milk?

No, a cow must not currently be pregnant in order to produce milk but she must become pregnant and then calve first for milk production to begin. She will produce milk for many months after the birth of her calf.

It’s an answer that really makes sense. Lactation in most mammals begins shortly before or immediately after the birth of young, and cows are no different.

Naturally, we have exploited this tendency and also selectively bred domestic cattle breeds for maximum milk production and for longer periods after the birth of their calves.

It’s an interesting topic, but more importantly, it’s also one you must understand from front to back if you have dairy cows. Keep reading and I’ll tell you a lot more…

Do Cows Have to be Pregnant to Produce Milk? How Do Cows Produce Milk When not Pregnant?

Cows Will Continue to Produce Milk After Calving

To be perfectly clear, a cow will produce milk for quite a long time after her calf is born.

Generally, milk production will be steady and continuous for at least 10 months after the calf is born, although maximum output happens immediately after birth and continues only for the first month or two, slowly tapering off after that.

Cows Won’t Produce Milk Continuously, However

Cows do not produce milk forever after they have their first calf. That is a common misconception.

As mentioned above, 10 months is the typical cutoff for a cow that has given birth, and though she might still produce dribbles of milk after that it is nowhere near commercially viable.

In order to restart milk production, the cow must be made pregnant again to give birth to another calf, after which her milk production will resume as normal.

It should also be noted that cows are typically given a few months off, called a dry period, after the cessation of milk production.

This allows the cow to rest and her body to recharge to prepare for the following pregnancy and the later resumption of milk production about 9 months after she is inseminated when the next calf arrives.

Are Cows Made to Produce Milk for Their Entire Lives?

For dairy cows, yes, generally. Or at least, they are made to produce milk for the entirety of their useful lives.

A cow will produce milk for every calf that she births assuming she is healthy and normal.

A good cow might give birth to 10 or more calves in her lifetime, and will produce milk for each and every one of them.

However, in the United States, most dairy cows only go through three lactation cycles, because their production typically diminishes enough after the third one that they’re no longer commercially competitive, and so after this they will be sent to slaughter.

What Determines How Much Milk a Cow Produces?

The actual, net production of milk is determined by many factors. The diet, age and overall health of the cow are important as you would expect, but also the individual genetics of the cow and environmental factors also play a part.

It isn’t just marketing spin to say that happier cows make more and better milk: cows that enjoy their lives, have lower stress, and get more exercise produce more milk across all domains.

Is also worth considering that domestic breeds invariably produce way more milk than wild cows and other bovines: this is because they have been selectively bred for maximum and sustained production.

In fact, pretty much every domestic cow breed produces considerably more milk than any calf could hope to drink!

That’s lucky for us, because we get to collect and use the surplus for ourselves!

How Do Cows Produce Milk When Not Pregnant?

A cow that has given birth, and is thus no longer pregnant, will naturally produce milk for her baby due to the interaction of hormones in her body.

These hormones ramp up and begin interaction during pregnancy, and peak immediately before and after pregnancy to stimulate milk production.

The hormones progesterone, oxytocin and oestrogen are primarily responsible.

Do Cows Need to Be Milked?

Yes! Cows must be milked every single day when they are in milk, no exceptions. Failing to milk a cow can result in devastating health consequences and slow production overall.

On the health front, mastitis and other potential infections are outcomes that can be fatal. Even without these complications, a cow’s other will swell to the point of agony and make her miserable.

An overfull udder is also extremely vulnerable to physical damage and inflammation.

This physical pressure in turn will basically cause a physical “dry out” of milk production that can make getting the cow back in milk, the restarting of milking, difficult or impossible.

What Happens to a Cow that is No Longer Producing Milk?

When a cow can no longer produce milk, whether she is pregnant or not, one of two things will happen.

The first outcome on some farms is that the cow will simply be retired and allowed to live out her days peacefully roaming around the farm.

But unfortunately, because it costs so much money to take care of cows, and because of the rearing of commercial dairy cows is a business and an incredibly expensive one, any cow that stops producing milk is immediately sent for slaughter or culled.

Slaughtering will allow the cow to be repurposed for the production of meat or other meat products, recouping some of her investment and creating more profit.

But if the cow stopped producing milk because of some defect or disease, it is likely she will be simply destroyed to prevent unintended consequences of using her meat.

What Might Stop a Cow from Producing Milk?

There are a variety of causes as to why a cow might stop producing milk at any given time in her life.

Old age is one of the most common, and often alongside that as a consequence infertility. If she doesn’t have any “buns in the oven,” she won’t be making any more milk.

Various infections and diseases can likewise lead to a cow’s milk supply drying up entirely or slowing to a trickle.

Mastitis (mammary gland infection) uterine infections, milk fever, cysts on the udder for other organs and more can all completely compromise a cow’s lactation.

A remarkably poor diet is another cause of a lack of milk production, as cows need tons of protein to produce that protein rich milk itself.

Other dietary havoc can likewise cause problems, specifically a sudden change in diet, overfeeding or underfeeding, or natural or man-made toxins present in any food source.

Also, simple stress can cause a lack of production or even a total cessation: heat stress and physical injury are both routinely to blame for drying out a cow.

Do Commercial Calves Get to Have Some of their Mother’s Milk or Not?

Only sometimes. Depending on the farm and their objectives, Calves may be allowed to suckle on their mother’s milk for a few days to a week after birth in order to grow strong, and particularly to get that probiotic-rich colostrum that they desperately need.

After that, the calf is usually separated from its mother in high-volume and high-efficiency operations.

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