Signs a Cow is in Heat

Late summer and early fall are when we AI our Jersey cows here on the farm. In order to ensure a successful breeding, it’s important to learn the signs a cow is in heat.

What is “heat”?

Heat, more technically called “estrus” or “estrous” is the time when an animal is at their peak fertility. An egg has been released and if they are bred, they will very likely get pregnant.

How often do cows go into heat?

This depends on the cow. The standard is 21 days for a Jersey cow but it really can vary anywhere from 19-24 days on average. This can of course be frustrating or a bit challenging when it comes time to plan and schedule for breeding, especially if you do AI.

How long is a cow in heat for?

The stressful part for me about a cow’s estrus cycle is how darn short the breeding window is. Typically you have between 12-24 hours to get that cow bred or you’ve missed your shot and have to wait about three more weeks before you can try again.

Signs a Cow is in Heat

There are three main ways I can tell that our cows are in heat. I’ll say right off the bat, not all cows will exhibit all or heck even ANY of these signs.


Juneberry, or matriarch cow, used to be a HUGE moo-er when she was in heat. Most of the time she was a pretty quiet cow, but in her younger years she’d stand and beller at the gate when she was ready. It’s usually pretty insistent and obnoxious as they yell as loud as they can, hoping to attract some far away bull for a visit.


A cow in heat will often try to mount other cows or other cows will try to mount her. Sometimes they even try to jump on you, which is never a fun surprise.


It’s weird to say this is one of my “favorite” indicators but for me it is one of the clearest. When I think a cow might be in heat or we are right around their heat window, I check their vulva twice a day for signs of discharge. Sometimes it’s a thick mucus hanging out. Sometimes it almost looks like they put lip gloss on their vulva.

If I’m a little unsure from outside, it’s easy enough to gently spread apart the folds of skin to look just an inch or so inside to confirm the presence of discharge. It should look almost like a clear, sticky stretchy, snot type consistency.

Their vulva will also be a little more swollen or red looking than usual.

If you are brand new to breeding cows, I recommend spending a month checking your cow twice a day and taking a good look a their back end. Even keep a notebook or take daily pictures so you can easily track the differences.

detecting heat in milk cows rough and tumble farmhouse

Other Signs a Cow is in Heat

  • Trying to Escape – Off to find a fella of course.
  • Being clingy – They’ll want to rub all up on you and be close to you.
  • Listless or plain stupid behavior- If your cow is normally pretty tame and suddenly they are acting wild and stupid, they might be coming into heat.

What should I do if my cow is in heat?

Ideally you will have been keeping track of your animal’s heat cycles for a few months so you can already be on the calendar of your AI technician. As soon as you detect an animal is in heat, best to introduce the bull or get the AI taken care of right away. Mark it on the calendar, then mark ahead to when she should come into heat again. Fingers crossed that day will pass and she won’t show any heat signs, which means she is pregnant!

jersey calf rough and tumble farmhouse

Can I make my cow come into heat?

Yep! By injecting your cows with a form of prostaglandin you can (through hormone interactions I haven’t taken the time to read much about) stimulate a heat to come. I would only use these types of product after consulting with your veterinarian about proper dosage and timing.

I’d also recommend allowing your cow at least a few cycles to naturally come into heats on her own. It usually takes several weeks or more after calving before they cycle will return to normal. This is a good thing! It helps protect the mamas and lets their bodies focus on sustaining their new calf and restoring their nutritional and energy reserves after having their baby.

Additionally, these products are typically not safe to be handled by women who are pregnant, trying to become pregnant, or breastfeeding.

How to Keep Track of Heat Cycles

I use the very basic method of a sharpie and our wall calendar. Around early summer, I’ll start paying attention to the cow’s behavior. I look for the signs I talked about above. If I see some of them, I’ll write that animal’s name on the calendar with a question mark. If is very obvious she is in heat, I’ll circle it or underline it.

Then I count ahead 19-24 days and will write the animal’s name again, this time usually in pencil with a question mark. When it gets close to those days I’ll do twice daily checks of the animal, looking for any signs.

I like to have a few certain cycles on the calendar by the time late summer rolls around and we start to make the AI attempts.

Want more homestead cow content? From homestead milk supplies to dehorning calves during fly season I’ve got you covered. Click here!

Watch and Learn

Here I show our three-year-old Jersey, Bea, the few days as we lead up to her heat cycle. She tends to have pretty quiet heats which can be frustrating. Here we will get up close and very personal with her hind end and see some other signs of estrus/heat.

Pin it for Later

how to tell if a cow is ready to be bred rough and tumble farmhouse

Similar Posts