How Can A Dairy Cow Milk If She Is Not Pregnant?

Jersey cow in sunflowers

Doesn’t a cow have to be pregnant to also be milking? What is the real scoop here?

A dairy cow will start milking after the birth of her calf. At this time she is no longer pregnant, but is milking, which will last for three months. Then she will breed back and for the remainder of her lactation, which is another 7 months, she will be pregnant and milking, at the same time. Next, the cow will have a dry period, where she is in the last two months of pregnancy, but not milking, which lasts until the birth of her calf when the cycle starts again.

The milk production cycle for a dairy cow can look confusing at first, but it’s really the same thing that happens for most any animal that feeds her baby milk.

This is our family cow, Aleene, with her new calf.

Cows produce milk after having a calf

Cows start to produce milk after giving birth to a calf. This is the case with all cattle, whether they are dairy animals or being managed as beef cattle.

A mom needs the milk to feed her baby once it is born, but not before! This is why the cow does not start milking and then the calf is born, it’s the other way around. There’s no reason to have milk available if there is no baby to drink it.

The pregnancy produces hormonal changes in the cow that help her body prepare to take care of her calf by providing initial immunity for the calf in the colostrum which transitions into milk to help the calf grow.

The reason pregnancy is the first step is to start the hormonal changes that will result in milk production.

The biologically required steps for the cow to produce milk are:

  1. pregnancy
  2. birth
  3. milking

These steps must be done in the order listed. Milk production is a biological system, so you have to go by the biological rules for the system.

If you think about the steps, you’ll notice that the cow is actually not pregnant when milking starts!

She just had her baby, so the gestation (pregnancy) part of her reproductive cycle is over for this year and she is now in the lactation or milking part of the cycle.

If you want an easy to understand overview of the hormonal changes in a cow that influence milk production, read Is it True That Cows Can Only Produce Milk If The Have Been Pregnant?

author's husband milking cow by hand
This is my husband milking our cow. She went into the machinery shed for some reason, so he just milked her there. We just have one cow and milk her by hand, so as long as she is happy to stand still, we milk her there!

Cows will continue to milk once bred back

Milking while pregnant is possible and happens normally in the life of a dairy cow.

She will have her calf and milk for 10 months or so.

Then she will have some time off of milking, called a “dry period” where she is no longer milking, she is just resting and relaxing to get her body ready for the new baby and the start of the next milking cycle.

While she’s milking, she will be bred back at 3 months of lactation, so she’s milking and pregnant at the same time for 7 months of her milking period per year.

This overlap period, where the cow is milking and pregnant is normal and is the same for both dairy and beef cows.

This basic schedule is also roughly the same schedule for a beef cow, with the exception being that the calf is the only one getting the milk.

Milk Production Cycle is an article I wrote to explain what is called the lactation curve (amount of milk the cow produces and when that amount goes up then down is called the curve).

The most milk is produced 6-8 weeks after calving

The most milk produced by the cow is made around 6-8 weeks after calving. This is the time when the calf needs the most milk to keep growing well, but is not able to feed itself well enough off of the things it can eat.

After the 6-8 week mark, production tends to naturally fall. The better fed the cow is, to meet her nutritional demands, the longer she will keep milking at her best levels.

Most farmers do their best to keep milk production high per cow, to give her the best chance at having a productive lactation.

How long will the cow continue milking?

A cow will generally follow the milk production cycle every year for 5-10 years, depending upon how well she is managed.

Some cows are not on a yearly cycle, they are milking well and will keep milking for longer than the normal 10 months, so they are bred back at a later time in lactation.

This keeps the cow producing more milk, since she does not also have to support a pregnancy. As long as the cow can eat well, she will be able to also milk well.

Once the cow breeds back, she will start to naturally taper off the amount of milk she is producing. This makes sense.

With the new pregnancy established, she needs to keep herself in good shape and have plenty of energy for the growing baby. As her body feels it is appropriate she’ll reduce the amount of milk now to keep her baby growing well.

The amount she milks will depend upon her breed and how she is fed. If you are interested in learning more about breeds of cattle that will work well for a family cow, read Best Family Cow Breeds.

How are the dairy cows bred back?

Bred back is the term folks use for when the cow is bred for another pregnancy. At this time she is milking, as well. Cows are bred back at three months so they have a calf at the same time each year.

Most dairy cattle are bred by artificial insemination, called A.I. for short. It is a very common practice in dairy herds and also done in smaller beef herds.

Wondering About A.I. In Cattle? goes over the basics of A.I. for anyone with a small herd, even a herd of one, that is considering using A.I. this year.

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