Pig Courtship

Boar Foaming at the Mouth

On the left is a gilt who’s being checked out by a young boar on the right. A lady smells very special when she is in that special time of the month, e.g., ovulating, in heat, estrus, etc. This tends to make guys go ga-ga and foam at the mouth. At least, that’s what happens with pigs.

  1. Female enters estrus about every 21 days.
  2. Female’s vulva pinks and swells.
  3. Female releases heat pheromones.
  4. Boar detects female heat and foams at the mouth releasing pheromones.
  5. Boar nuzzles females belly and vulva.
  6. Female enters standing heat and allows boar to mount.
  7. They mate.
  8. They mate again ideally about 12 hours later to maximize the number of piglets.
  9. About three months, three weeks and three days later she farrows a fine litter of piglets.
  10. Nursing lasts about four to eight weeks. More than that tends to stress the sow and result in her becoming peakid and out of condition.
  11. Piglets wean
  12. About 3 to 7 days later the sow comes into heat and is ready to mate again.
  13. Rinse & repeat…

Note that ringing the nose of the boars, a practice done by some to keep the pigs from rooting, can lead to the boars tearing the delicate tissues of the vulva when he nuzzles his lady. We don’t ring our pigs, in part for this reason.

There is another reason boars will foam like this: competition with another boar. If boars were raised together they don’t tend to fight but if a new boar enters the picture you’ll see foaming and fighting. In smaller boars they don’t have tusks so the fighting consists almost exclusively of shoulder pushing, charges and spinning round and round. Bigger boars have significant tusks which can be razor sharp. A big boar battle can be dangerous. Don’t get between them!

We run our boars with our sows. Generally the boars leave the sows alone, not bothering them sexually unless the sows are near or in heat. This may work because we have large herds of 10 to 40 sows plus the multiple boars. If you just had a single boar with one or two sows he might pester them more. The thing to definitely avoid is a ratio of too many boars to sows. I would suggest not having more than one boar per six sows when running them together. On the upper limit I’ve heard it recommended that a ratio of one boar to 15 sows is about ideal.

I like running multiple boars in a herd because then they act as backup for each other. If a boar gets a cold it can lose fertility for several weeks. Having a backup boar means your less likely to miss matings. This of course means that you need boars that get along together. Typically this is done by having a younger shadow boar raised from a young age with the dominant boar.

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About Walter Jeffries

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15 Responses to Pig Courtship

  1. pablo says:

    Those boars sound like teenage boys. Or at least the smack talk of teenage boys.

  2. Jim Curley says:

    I have heard some breeders removing tusks periodically. Do you? And if so, how?


  3. Jim, we don’t cut teeth or remove tusks. You can see some tusks from our pigs here.

  4. Evelyn says:

    Nursing only lasts 4-8 weeks? I thought I saw some writing saying that commercial growers wean at 10 weeks & were thinking of letting them go to 15? Maybe it was 10 days? It seems as if you often let the sows self wean? I know I've been reading of you moving sows out to wean the piglets, but that the sows had pretty much already done it.
    If you don't move the sows… will they let the piglets nurse for an unlimited time? My farm partner is worried that, if we don't move the piglets (that we'll have in the spring) they won't wean & might harm the sows teats.
    If you only had 2 sows & planned only 1 liter each per year, would you move the sows out? If they did nurse the piglets longer, they'd still have the rest of the year to recover. Or would you let the sows wean when they wanted? That's how we do the rest of the stock. I try to let Nature determine how things should work, w/ as little interference as possible. How do piglets in the wild get weaned? Do they harm the teats on the wild sows? I know that many of our pigs could make it in the wild; they are not so overly domesticated that they couldn't.

    My dog used to foam at the mouth when my bitch went into heat. He wouldn't even drink unless I kept them separate for hours.

  5. Evelyn,

    The big producers, aka factory farms or Confinement Feeding, wean at 10 days. There is discussion in the pork industry magazines about increasing that to 15 or 21 days.

    Piglets often won’t self-wean and a sow mobbed by a dozen hungry 50 pound pigs is not good. It is best for her if we separate her from them so she can recover. Otherwise she becomes peakid and loses condition. This can even injure her teats as you noted or worse.

    In nature pigs have fewer offspring and most of the die very young being eaten by predators so there is less stress on the sow.



  6. Jim Curley says:

    We are breeding a young boar (8.5 months) to a young gilt (also 8.5 months) for the first time. (Both are about the same size-boar may be a hair taller).

    Gilt is in standing heat and lets the boar mount. Boar doesn’t seem to be able to get high enough to enter.

    Is there anything I should do to help? (I am there the whole time.)

    We have only tried once as heat seemed to start today or yesterday.

    Thanks for any advice.


  7. Jim,

    If they’re both the same size then he should have no trouble reaching. I’ve seen much smaller boars succeed at mating larger sows.

    But, if he can’t reach for some reason, try getting the boar to stand up hill of the gilt or perhaps having him stand on a platform of pallets or something. He does need good footing. Outdoors on dirt is ideal.



  8. Jim Curley says:

    Thanks for the tips. I contacted our extension agent and the breeder we bought both the gilt and boar from. Both suggest I “hand-assist” the boar till he can find the right place to enter.

    I tried once, but he obviously doesn’t like me near him when mounting-and I was probably a bit skittish to “hand-assist” this time.

    Looks like I’ll have to wait 21 days for next opportunity.


  9. dan says:

    Hi Walter, I’ve been serching your archives for an age or size for breeding. This seems to be the closest blog on the subject, 8.5 months. I was hoping to try at 6 or 7 months. Do you think this is to early, or evan possable. I don’t have alot of land, and I fear the smell of a large sow over the hot summer will anger the neighbors. where as a crop of piglets in the yard and a sow in the freezer would probably be welcomed by all. Not nearly the smell and cute little piglets to watch. THanks

  10. Dan,

    I aim to breed a gilt around six months if possible to have her first litter around a year. It is more size and condition that matter than age. I have had gilts accidentally breed and take as young as 4 months – we named one of them Lolita. They did fine and had big litters.

    Males also can breed around six months although they hit their peak fertility at more like 10 months from what I’ve read.

    A sow should not be creating a stink in the summer, or any other time of the year in particular. If you live in suburbia people may smell with their eyes creating that problem but otherwise I would not expect a herd on pasture to make a problem for you and your neighbors.



  11. Georgia says:

    im doing some homework about Pigs Courtship and since im only in year 9 i cant really put that pigs drull over female pigs the they mate and a bout 12 hours later they mate again? —-••—–

  12. Snowballs says:

    I’m considering buying a female potbelly from a gal near me that raises pigs. I Googled about pigs conceiving and whatnot and came back here again to your very informative and entertaining site. Google likes you! LOL How many hits do you get now, just curious? Anyways, this piggy gal. She is a year old now? She has been bred several times by this gal’s boar, things looked like they took, then at the next cycle, she went into heat again. She is currently in heat today on 12/29/12, as the gal mentioned and sent me pics of the sow mounting the boar. The boar seems uninterested, today. She is selling off the sow at a pretty good price, and these people seem honest. I’m just curious, if there is any way for the average yahoo like me to tell if it’s the boar or the sow? I have a little boar that is too short to get the job done, probably, but who knows? He’s 6 months old potbelly, and I thought maybe they could get together and if babies don’t happen, then I have meat for my freezer.

    • Unfortunately it is near impossible to tell if it is the female or the boar without having multiple other animals to test mate.

      Question #1: Has this ‘sow’ had piglets before? Probably not since she is only a year old. This means she is a gilt rather than a sow (see the FAQ) which means she is an unproven female. The probability is that it is the female who is infertile since the female reproductive system is far more complex than the male system and thus has more places for failure. But, we don’t know.

      Question #2: Has this boar ever sired piglets before? If he has sired before then the probability is that he is firing on all cylinders and not duds to mix metaphors. However, if he were like your boar of only six months old he almost certainly has not sired piglets and thus may be firing blanks. Quite frankly, at six months of age I don’t expect him to be productive. Males hit their stride around ten months.

      My suggestion if you want a pregnant gilt to farrow in the spring is to leave the gilt with the current owner for several more months until she is definitely showing pregnancy. When she starts to bag is the time to take her to her new home. Then use your boar the next round. It is worth paying the woman a little extra to have this happen. It means that in the future you’ll have more genetic diversity in your herd.

      If someone had never had pigs before I would not suggest starting with a pregnant pig. Instead, raise a pig or two over the summer for meat and then after one has done that for a year or few they’ll be far more experienced. Then is the time to consider getting a pregnant gilt or sow and trying your hand at farrowing piglets. Farrowing is a whole ‘nuther ball of wax than raising pigs.

  13. Bridgett says:

    Hey you mentioned a Gilt doesn’t become fertile until about 8 months……is that just farm hogs or is that mini’s? I am just not raising mini’s I have Pot Bellies and will have some Juliana’s in a couple months. I was suppose to have got a couple sows, a boar, and a couple gilts. I ended up with all 5 gilts 4 of which I sold, and kept one. She’s been exposed to a boar and is only 5 months. I do not want her pregnant, but bc of this situation I am in with only having one pen and needing help building another, and my friend bringing me these pigs before I had something built she’s been exposed. I also have a sow who I don’t mind if she’s pregnant but it’s been a month since her and the boar have shared a pen and he still sniffs around her but I am not sure she’s pregnant. He’s short with a long body (I call him a weenie pig lol he reminds me of a dauschund) and she’s taller and bigger. He has produced nice litters but I think the females he mated with were more of his size. Could you please e-mail me and feel free if you like and have time to check out my facebook page at BnN’s Little Oinkers.

    • Our gilts from our breeds on our diet do not typically get pregnant until their eighth month. Occasionally I see a Lolita who gets pregnant as early as six months. I have heard that the small breeds like Pot Bellied Pigs are fertile earlier. If your gilt is pregnant you’ll know for sure in a few months – the ultimate test is does she farrow. Best of luck!

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