When to breed your cow


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Content: Farmers who get the most milk from their cows make sure that each cow has a calf at least once every two years. Farmers must be able to recognize when cows are in heat so they can be bred at the proper time. This is simple if the farmer keeps more than one cow, but not nearly as simple for the owner of just one cow that isn’t close to other cattle. There are certain signs to look for, and two specific ways of knowing when she is in heat. After breeding your cow, it’s important to be sure she is in calf. You must know how to tell if she is. If she’s not in calf, you must breed her again.


Cows, calves, milk, and a bull

Today, let’s think about the one or more cows or water buffaloes that you keep, to produce milk for you and your family and perhaps to sell.

You know that before a cow will produce milk, she must give birth to a calf. After the calf is born, milk begins to form in the cow’s udder and it must then be taken from her regularly two or three times a day. Usually she’ll produce enough milk for her calf and some for you as well. But, as you know, unless all the milk she produces is taken from her every single day, she’ll stop producing milk. Or as we say, she’ll dry up. After that, she won’t produce milk again until she gives birth to another calf.

Before a cow can have another calf, she must mate with a bull, or she must be bred by artificial insemination. After a successful breeding, it will then be another nine or 10 months before the calf is born. To continue getting as much milk as you can from your cow, you must arrange to have her bred sometime after she gives birth to each calf. You’ll know from experience how soon you should think about breeding her to produce her next calf, but it should be at least within 16 months after giving birth to her last one.

Let’s think now, for a few minutes, about choosing the actual day to breed your cow, doing it the natural way: that is, by naturally mating her with a bull. (If you are using artificial insemination, the person who does that for you can advise you about any special techniques.)

A cow in heat

You can’t just breed your cow any time. Your cow has to be ready or, as we say, she has to be “in heat.” If she’s not in heat, she won’t stand still and let a bull breed her. Of course, if you don’t keep a bull, you have to arrange to take your cow to a neighbour who keeps one, or have that neighbour bring the bull to visit your cow; and this has to happen on the day your cow is in heat. What you have to know, then, is exactly when your cow comes into heat and is ready for the bull.

If you keep more than one cow, you’ll know when any of them are in heat by the way they act toward each other. If one’s in heat, another cow will try to get her front legs up on the other’s back like a bull does, and the cow that’s in heat will just stand there and let her do it.

But what if you keep only one cow? How will you know when she’s in heat? It’s important that you do know this, so she can be bred and have another calf as soon as possible after her last one. By doing this, you’ll be able to get the most possible milk from her and she’ll be a healthier, more contented cow if she has a calf as often as she can.

There are several other ways to tell when your cow is in heat. You may already know some of them, but let’s talk about them now.

Counting the days

To begin with, it’s a good idea to mark on a calendar the date that your cow gives birth to her calf. Or, if you have a farm record book, write it down in your book. If your cow is healthy, it’s likely that she’ll come into heat between one and seven months after her calf was born, and then again 21 days after that—a little longer if she’s a water buffalo. She’ll continue to come into heat every 21 days or more, depending on which kind of animal she is. Don’t breed her the first time she comes into heat, but it’s a good idea to do it the second time.

It may be that you have a heifer that hasn’t had a calf yet; or you may have bought a cow and you don’t know about any dates for her. In any case, whether you have a heifer or a cow, you must know how to tell when she is in heat and ready to be bred.

Some good advice

Zheng Hong Pei is a professor of animal science at the Sichuan Agricultural University in China. He has had many years of experience with all kinds of cattle, including dairy and beef cattle, river water buffalo, and swamp water buffalo or carabao. He has told us all the different ways he uses to tell when a cow is in heat.

To begin with, he says that if you’re a good farmer and treat your animal well, it should be tame and not afraid of you when you’re near it, or when you touch and pat it. In fact, he says, you should spend a little time with it each day. If you do this, you’ll get to know what your cow is like on a normal day. When she comes into heat, however, she’ll act differently and you’ll be able to notice that.

On a day that your cow is in heat, you’ll first notice that she looks around more than usual and seems to be upset. If you clap your hands behind or beside her, she’ll turn her head more quickly than she would normally. She’ll moo or bawl more often and louder than usual, and, if there are other animals nearby, she’ll pay more attention to them. You’ll also notice that she’ll eat less than she usually does.

If you go around behind her and push hard with your hands on top of her back, she’ll become stiff and stand very still. These are all signs that your cow is in heat.

Two specific signs of heat

Another thing. Professor Zheng says that you should look just inside your cow’s vagina every day. If you pull it open a little with your fingers, you’ll see that it’s normally a pale flesh colour. As she comes into heat, however, you’ll see that the colour becomes a much darker red. Also, as she comes closer to her heat period, you’ll find mucus in her vagina. It will be watery at first, but gets thicker as your cow comes closer to the time she should be bred. When the mucus in her vagina gets really thick, a practical test will show the best time to breed her. Here’s the test. Insert the thumb and first finger of one hand just inside the cow’s vagina so you get some mucus on them. Take your thumb and finger out and spread them apart 10 centimetres (4 inches). When you do this and the mucus sticks to both finger and thumb, it should form an unbroken string of mucus between them. Next, close them together so they’re only 5 centimetres (2 inches) apart. The mucus string will then take the shape of the lower half of a circle. If it stays that way and no drop of liquid falls from it, it means that your cow is fully in heat and ready to be bred by a bull, so breed her right away.

Important checks after breeding

After your cow has been mated with the bull, if all goes well, a new calf will start growing in your cow’s womb. Sometimes this doesn’t happen, however. And how can you tell whether or not it happened? If a new calf hasn’t started to grow in your cow’s womb, she’ll come into heat again three weeks or so after she’s been bred. It’s most important to know whether or not she does come into heat again. To know this for sure, it’s best to start watching carefully for all the signs after 18 or 19 days. If she doesn’t come into heat by the 25th day, you can be fairly sure that a calf has started growing in her womb, or, as we say, she is “in calf.” If she does come into heat again though, breed her again, but, as before, be sure to watch carefully for signs of another heat period. If you can’t get her in calf after being bred two or three times this way, you should probably give up trying. After a few months when she dries up, you might still use her as a work animal, or she could be slaughtered for meat. If you have any questions, however, you could check with a veterinarian if there’s one in your area.


One final thought. Many farmers who have a cow that’s not a work animal and not regularly producing milk and a calf, consider that they’re wasting their time looking after her. They also feel that they’re wasting good feed or pasture that would be better used by another animal that could be productive. You might want to think about this if your cow becomes unproductive.


1. The types of bovine animals discussed in this item are females of local breeds of cattle kept mainly for producing milk, and females of river water buffalo or carabao, and swamp (bog) or Chinese water buffalo. As the physiology of these bovine animals is different, we have omitted detailed recommendations about the interval between the date that a cow gives birth to a calf and time for breeding her again for her next calf. Other factors to be considered can be climatic conditions such as the date of the beginning of the rainy season in relation to the date of calving, the availability of feed, feeding patterns, and the health and thriftiness of the individual cow. Some figures that may be helpful are:

2. References are made in this item to topics that are more fully covered in other DCFRN items. Information from them could well be presented with this item:

Getting more milk from your dairy cow – Package 15, Item 3 or Package 2, Item 8

Two basic needs of cattle – Package 8, Item 9/C

Keeping farm animals healthy and productive – Package 10, Item 1

Care of a newborn calf and its mother – Package 10, Item 2

Good farm records: a key to higher profits (Part 1 – Getting started) – Package 11, Item 1

Good farm records: a key to higher profits (Part 2 – A diary) Package 11, Item 2

Linda Bolinao, model farmer in the Philippines (B. A useful set of farm records) – Package 19 (this package), Item 6

Information sources

Useful information in this item was obtained from Zheng Hong Pei, Professor of Animal Science; Zeng Wen Xian, Lecturer, Department of Animal Science, Sichuan Agricultural University; Ya An, People’s Republic of China, during an interview by George Atkins, DCFRN’s Founding Director.