Pregnancy Indicator

Built in Pregnancy Indicator

One of the questions I get a lot is how to tell if a pig is pregnant. Well, first, is it female? You think I jest but I had a government official who was here once looking at our big boar Archimedes and said, “My what a big sow!” Yes, well… she was a little sheltered, perhaps – The Department of Agriculture officials need to get out more.

So, once you’ve made sure it is female, how do you tell if your pig is pregnant? Well the first thing I do is look at the pregnancy indicator built into the back end of every female pig.

No, this is not piggy porn. What you’re looking at in the photo above is the clitoral hood of a gilt, that is to say a female pig who has not yet had a litter. This gilt’s pregnancy indicator is pointing up. Thus she is pregnant.

In fact, in her case she is very pregnant and nearing the end of her gestation term which is about 114 days (three months, three weeks, three days or so). If you look under her belly you can see that her breasts, her udder and teats, are beginning to fill out and cone up. She will farrow, that is to say, deliver her littler of piglets this coming week out in our south pastures.

In a non-pregnant gilt or sow the tip of the hood would be pointing downward or straight out, the latter the tendency in older sows. This effect is the first thing we see when a pig becomes pregnant. Later there are other signs as she progresses through her gestation.

It is important to know the lady in question before evaluating her pregnancy status since you’ll want to know what she normally looks like. Gilts tend to have downward pointing clitoral hoods since they have not yet had a litter of piglets. As they have litters there is some stretching of the feminine tissues back there which will cause gradual changes and loosening such that by the time she has had eight or ten litters her hood may well be level when she is not pregnant. Not to worry and don’t mention it to her. She’s still beautiful, right? It’s just a sign of her great fecundity – appreciate her but take it into account when evaluating her pregnancy status.

FAQ: Walter when does the “visual” sign of pregnancy that you mention on the website show for a pregnant gilt?

It is going to depend on the gilt, her condition and how many embryos are implanting and thus how much she starts to grow in the uterus. I spot them as early as a few weeks. But, this requires knowing quite intimately the normal anatomy of the ladies since it is not an absolute but rather a change that you’re looking for.

It was an old farmer by the name of Archie who first alerted me to the “pointy thing” as he put it. He didn’t know why but had observed over his 30 years of pig raising that it told him a lady was in that piggy way as he put it. I add about another decade of observation to confirm his note.

Through reasoning and then dissection for confirmation what I have found is that the effect is caused by:

  1. Lady becomes pregnant – how is a discussion for another time if you are not familiar with these dynamics;
  2. Uterus begins to enlarge as the walls thicken and fills with fluid and a lot of developing but tiny fetuses;
  3. Uterus sags down in belly hanging from connective tissue and pulls downward on vagina;
  4. Vagina pulls down on external genitalia (e.g., vulva) pulling inward the entrance to the vagina just a little;
  5. Clitoral hood is beyond the fulcrum at the front point of the mons pubis so as the point of the clitoral hood is pulled upward – simple leverage; and finally
  6. Farmer Walter walks by and looks at her vulva and thinks to himself, “ah, good” giving her a scratch behind the ears.

Pregnancy confirmed.

As the lady nears her farrowing time her vulva will swell as the tissue prepares to pass piglets. This typically causes the clitoral hood to then point back down right before birthing. By this time her bag should be fully developed and she may well be producing milk.

Sows do change over time as they have litters and get stretched out and there are individual differences. This is more of a relative indicator than absolute. Know your pig parts.

There are all sorts of expensive high-tech gadgets you can buy which do ultra-sound and the like to detect pregnancy. In my experience with around a thousand pig pregnancies I have found this method to be a highly accurate at detecting pregnancy in pigs. Keep It Simple. I’ve never had one of my pig pregnancy indicators break down and they don’t require electricity. They’re also inexpensive – they come built in with each female pig. Sorry but male pigs do not have pregnancy indicators. If you’re not sure of the difference between males and females then please check this post and this post about essential differences. The first of that pair also shows an example of a non-pregnant gilt for comparison with the pregnant gilt’s photo at the top.

Update: Some subsequent thoughts based on decades of using this with hundreds of sows as well as talking with other people who it worked for or didn’t work for… The clitoralhood works very well for me but as a funny side thought I may have inadvertently selected for sows that show their pregnancy status this way since I’ve been using this method for decades – Selective pressure creating a little bit of unintended evolution here on our farm, perhaps. On the other hand, all sows I have bought in over the years have clearly shown this too – an argument against selective pressure causing this. Reading it is also a skill. Lastly, at the end of pregnancy as the sow approaches farrowing the tip points back down as the vulva loosens and swells. That could also cause confusion. Studying the vulvas of a lot of ladies – purely educational…

This method, unlike the ultra-expensive ultra-sound imaging machinery, does not tell you how many piglets are there but I would not suggest counting your piglets before they’re weaned. By then they’ll be easy to count and if you have a lot you can use this method.

Note that this does not work the same way in humans due to structural and postural difference between sows and women. Fortunately in pig society it is considered perfectly polite to investigate someone’s butt. However, I would very much suggest suggest that you don’t go walking down the street looking at ladies of non-swine species like this as you might get in trouble.

See In a Piggy Way for another picture of a pregnant gilt a little further along.

Please Note:

I do not do pregnancy diagnostics over email so please don’t send photos of your vulva. The pregnancy diagnostic is really something where you need to know the lady in question before being able to consider if her private piggy parts indicate pregnant or open. As explained, this changes with age. It also varies with breed. It can also give a false indication if she just ate a lot and is feeling rather full – never caller her fat, just fine. The best thing to do is watch for change in your gilt or sow and get to know her normal indicator positions. Then observe the change after mating.

Outdoors: 63°F/58°F Stormy, 11″ Rain, high winds, no damage, ponds full
Tiny Cottage: 69°F/67°F

Daily Spark: Be prepared. It’s a way of life. The alternative is extinction. Either way evolution wins.

About Walter Jeffries

Tinker, Tailor...
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261 Responses to Pregnancy Indicator

  1. Arlene Koniecki says:

    We are first time pig owners, and I am trying to find out best product for bedding, especially my (hopefully) pregnant sows. I have seen oat straw and oat hulls advertised, would they be good? Also I have leftover clean hay, mostly alfalfa. Would that be ok to use or would it be too scratchy? The piggies have made themselves at home in the horse barn, and have pulverized the horse apples into dust. They like to mound it up and lay in it, but I worry it isn’t healthy for them. Should I scoop it all out to the garden and replace it with ? The floor is concrete, should I put down rubber pads for warmth? We live in Wisconsin, so it will be frozen by the time they farrow. Thank you, Arlene

    • Best can have several meanings. I like hay because the pigs bed in it and eat it too. But don’t try to add hay to a sow’s nest. Let her do it herself. You don’t have the great weight and sharp pointy feet needed to properly pack the bedding nor the strong jaws for chopping the hay. If you must add bedding to a sow’s nest then use dry wood shavings.

      On the concrete I would do a deep bedding pack of wood chips then hay.

  2. George Eiland says:

    Hi I just read your article from 2011 about pregnancy indicator on a sow…what a great article.
    I have a very old boar (12-14) years old that I keep as a pet…about 2 years ago a little feral piglet came up and moved in with two old sows that have since passed on. When the sows died I put the young feral in with my old boar thinking that she would keep him company which she has. However in a shocking turn of events after their being together for well over a year I saw and took a photo of Red mounting Betsy…this was October 15th of last month. Much of the surprise came from Red who has had multiple health problems all summer which I expected would lead to his passing but there he was going for it…who says old guys can’t have fun 😎.
    Since reading your article I went and checked under the “hood” and her equipment is pointing straight down.
    We are “old” folks and really not able to manage baby pigs anymore so I will continue to check her and pray thing keep pointing down.
    Again thanks for that article.

    Sent from my iPad

  3. Kyei omega says:

    I gave the boar to the sow during the it heat and I checked them mating on 22 November 2019 but I just saw the sow in heat 4 February 2020.Please,I will like to know if the sow is pregnant or not

  4. Breanna says:

    Great article. Question as to piglet movement. I have a 2.5 yr old Hereford gilt who has been bred. I am not sure when this happened so just patiently watching her at this point. Lady parts pointing upward, swollen belly, nesting for over a month, restlessness, swollen vulva, and today something new. I was able to feel the babies kicking and visually see lots of movement. For a gilt how close would you say they are to farrowing if you can see/feel movement? Also have you found your momma pigs to eat the day of farrowing or have no appetite? Sure this is an all pigs are different kind of thing but curious as to your experiences. Thank you for your time 🐽

    • Interesting that she has been nesting for so long. That is a good strong nesting instinct. Vulva swelling is her getting ready so you should be close. I often see a lot of movement in the last few weeks. That is fun to see and feel. I am guessing she is definitely within the last two weeks and may be days away. Does she have privacy – no other pigs? Calm situation?

      • Breanna says:

        She has shown many signs that she will be an excellent mother. When I purchased my boar as a piglet she was so good with him and welcomed him into her pen immediately. Yes she does I moved her to a smaller pen and away from our boar about 2 weeks ago. The pen she is in now is about 40X50 and their are goats she can watch but they cannot bother her. She has grown exceptionally restless the past 3-4 days. Normally she is terrified of the electric wire but has managed to go under/over it multiple times in the past few days. Due to her size the only way to get her back is snacks and even that doesn’t work at times. It is definitely not her normal and I’m hoping she has them soon. I have read so many articles where the momma doesn’t eat the day of farrowing. Do they seems ravenous in the days before? Thank you so much for responding!!! 🐽

        • he’s seeking privacy to build a nest. Making a set of walls out of plywood that leave a corner behind them may give her what she wants. Keeping noise down in her area may help too. It is common to fast before farrowing but not universal.

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