How to Tell When a Goat Is in Heat

Some goats show obvious signs of heat. Others display only subtle signs. How to tell when a goat is in heat is important when you need to determine the right time to bring the doe to a buck.

Heat Cycles

Throughout the breeding season a doe periodically comes into heat, or estrus. A heat cycle, or estrous cycle, is the time between the start of one estrus and the start of the next.

The estrous cycle of each doe is pretty consistent, and can range from 17 to 25 days. A typical cycle is 19 days. My Nubians average 21 days. If you keep track of when each doe shows the strongest signs of heat, you can determine the length of her specific heat cycle.

Estrus lasts for 2 to 3 days, starting gradually, reaching a peak, and then tapering off. During the peak of estrus the doe comes into standing heat. That’s when she is receptive to a buck’s attention and can become pregnant. Before and after standing heat, when a buck comes up behind a doe she’s likely to either move away or turn to face him.

The Alpine, or Swiss, dairy goats are seasonal breeders, as are Angora goats. They typically cycle from mid summer until around the end of the year. Seasonal breeders include Alpines, LaManchas, Oberhaslis, Saanens, and Toggenburgs.

Nubians, like other desert or equatorial goats, are aseasonal breeders, meaning they can come into heat at any time of year. Other aseasonal breeds include Boer goats, Fainting goats, Kikos, Kinder goats, Nigerian Dwarves, Pygmies, and Spanish goats.

Signs of Heat

I can’t speak for the other aseasonal breeds, but my Nubians show the strongest signs of heat during late summer and early fall. Over time, however, I’ve had my goats kid during every month of the year.

I like to breed my does to kid when it’s not so cold the kids could freeze, or not so warm they’ll be susceptible to coccidiosis. With Nubians, I can put a doe in with a buck at any time of year and most likely end up getting kids at the optimum time.

Some does experience what’s known as silent heat. But most does show at least some signs, which may be so subtle they’re easy to overlook. And not all does exhibit all the potential signs. If you watch for the following signs of heat, and note which does display which signs, you’ll have a better future chance of determining exactly when a specific goat is in heat.

1. Change in milk volume.

One of the first signs of heat in a doe I’m milking is a sudden drop in milk volume. In my mind I go through the possible causes. The most common one is that she didn’t graze for the usual amount of time because it rained. If it hadn’t rained recently, I come to the conclusion the doe is in heat.

2. Disinterest in eating.

Along with a drop in milk production, a doe in heat becomes less interested in eating. I feed my does while I’m milking, and they’re always eager to eat. So if one fails to eat, I again start looking for a potential cause: She doesn’t like the feed. The feed dish needs cleaning. She’s not feeling well. Whether or not I clean the dish and change the feed, within a day or two the doe’s appetite returns. She wasn’t ill, she was in heat.

3. The doe gets balky.

Another sign related to milking is when a doe that is usually eager to jump on the milkstand, instead backs away when I open the stall gate. That kind of behavior may occur when I start milking a doe for the first time. But once a doe catches on to the routine, balking at milking time can be another sign of heat.

4. The doe has a new personality.

When a doe is not being milked, or is dry, additional signs can indicate she’s in heat. For instance, a normally submissive doe may become aggressive toward herd mates. Or a normally aggressive doe may let others push her around without resisting. Such personality changes are attributed to raging hormones.

5. A doe gets bucky.

Raging hormones also cause a doe in heat to mount other does in the herd. Or other does may mount the one that’s in heat, which can complicate making a determination as to which one is in heat. Watch for the doe that lifts her tail when others move up behind her to sniff. The does are noticing the unusual odor of the one in heat and do what a buck would do — move closer to get a better whiff. Don’t worry, doe odor is not something most humans can detect.

6. The doe wags her tail.

Besides lifting her tail when other goats move up behind her, when a goat is in heat she may constantly wag her tail. This behavior is called flagging. A doe that’s flagging may let you handle her tail, while at other times she doesn’t like you to touch it. The purpose of flagging is to spread around her estrous odor in the hopes a buck will take notice. A doe that’s flagging is not necessarily in standing heat, but may soon be.

7. The doe’s tail gets sticky.

When a goat is in heat, the area under her tail may become red, swollen, and wet with a gel-like vaginal discharge. The best way to detect vaginal discharge is to notice if the hair at the sides of the tail appears damp or clumps together. At this point, the doe likely has passed standing heat, so mark your calendar and watch for her next cycle.

8. The doe pees a lot.

Bucks love the odor of doe pee, especially from a doe that’s in heat. Her urine contains chemical substances (pheromones) that tell a buck she’s ready for breeding. When she’s with a buck, he’ll stick his nose in the urine stream, then raise his head and curl his upper lip (flehmen) to take in the odor. Whether or not a buck is present, a doe in heat pees more often than usual.

9. The doe gets talkative.

Most goat breeds don’t bleat a lot or otherwise make much noise, but a doe of any breed may noticeably “talk” more than usual when in heat. Nubians are already noisier than most other breeds. A Nubian doe in heat may let out bloody screams like she’s being murdered. If no buck is around, the doe may also make the same moaning and blubbering sounds as a buck does when in rut.

10. The doe gets schmoozy.

A doe in heat will try to get as close to any nearby buck as possible. When they are on opposite sides of a fence, the doe will moon over the buck like an infatuated teenager. If no buck is close by, she will moon over a buck rag, which is a piece of cloth that’s been rubbed against the forehead of a mature buck. When I’ve been trimming hooves at the buck barn before visiting the doe barn, the doe most interested in sniffing me all over is the likeliest one to be in heat.

11. The buck acts goofy.

A buck that’s nearby when a doe comes into heat will act the complete fool. He will wag his tongue, slap a front hoof against the ground, and pee all over his own face (on our farm we call it “buck cologne”). A buck that can’t actually see the doe will go into his goofy routine when he smells the doe’s odor on you. If you happen not to notice that one of your does is in heat, the buck will tell you.

12. The doe stands for mating.

So you get the signs right, and timely put the doe in with a buck. If she’s not in standing heat, she will move away when he tries to mount her. A doe in standing heat will remain stock still while the buck mounts her. Or she may urgently push her body against his. The act of mating itself takes mere seconds. You can tell a trial run from the real thing by the way the buck arches and throws his head back during ejaculation.

To make sure a doe truly has been bred, I leave her in with the buck through a second heat cycle. Even when a doe settles (successfully has been bred), she may show signs of coming back into heat on her next cycle. In the event she did not settle during the first cycle with the buck, she most likely will the second time around. When the buck loses interest in breeding the doe, you can expect her to kid within 5 months.