Rectal Prolapse in Pigs

These Geese and Duck are not Pigs
Just look at the pretty picture. Don’t read any further unless you have a strong stomach. Are you still reading? Well… You were warned…

On Raising a Pig For Meat Jeff asked about rectal prolapse a.k.a. anal prolapse a.k.a. prolapse a.k.a. pigs who turn inside out:
Hey Walter, I just had to send 2nd of 5 landrace gilts (born April 2010) to the butcher with a prolapsed rectum. I am trying to follow how you raise them as much as possible , outside with a portable shelter with lots of hay in the shelter. I feed them hay and whey. We are going through a cold snap with temps or minus 30 Celcius or so. Ive read that the cold can cause prolapse.

They seem to prefer sleeping outside even in this cold temperatures bedded deep down in the feed hay. They come out of it all steaming and look quite comfortable. but so far 40% of my gilts have had prolapsed rectums! Am I doing anything wrong? All the gilts were sisters. I am (optimistically maybe) attributing it to bad genes, so should I cull all offspring of the remaining gilts and my Berkshire boar?

What are your thoughs on breeds? Do you think would be less of a problem with heritage breeds? As soon as I can I will be switching over to purebred Berkshires but am concerned that I will pay top dollar for those gilts and have same problem. When you got your herd going did you have this problem?

It isn’t that you’re doing anything wrong – you just got bad luck of the draw. There are some things you can do to help as I’ll describe below.

My observation is that prolapse is strongly genetic. When the the genes are aligned the pig is more sensitive to prolapse because their internal connective tissues are weaker. Then stresses such as diarrhea, constipation, coughing and squashing can all trigger the prolapse. The good news is you can breed away from it and it is manageable. If only some of your pigs have it then some of your pigs may not have it and with a few generations of hard selection you may be able to move away from it with the genetics you have or with new genetics.

The best solution for the individual pig is slaughter. To get them to the point of slaughter isolate the pig from others as they’ll bite at the protruding bloody rectal tissue and can turn the victim inside out. You can try inserting the prolapse back in if it is small and then using a tennis ball or such and taping the pig to push it back. I’ve heard of people doing that. You can also trim the tissue using a tube in the anus and constriction ring around the tissue. I have heard of this working. The anus muscles themselves may even do this naturally – I have seen this happen several times. Lubricating the tissue (vegetable oil) can help according to some reports I have read. The key is isolating the pig from others to allow it to heal and reduce stress. The worst prolapses I’ve seen were about 6′ of intestine in large sows. They were not pregnant, not particularly cold, not constipated, not crowded and other than genetics I don’t have anything I can link it to. They were related to each other (mother-daughter-sister). In any case, cull the animal to slaughter as soon as possible. Very bad prolapses won’t survive long.

To prevent prolapse make sure the pigs have plenty of water, avoid sudden diet changes, give them lots of dry hay, wind protection and avoid crowding. If you have a lot of pigs, try breaking groups up into smaller collections like they would naturally sleep in the warm months. Sorting by size can also be key in the winter for susceptible pigs – Smaller pigs crowded between bigger pigs are more likely to have the problem than same size pigs. Growers are the most susceptible to this problem.

On the genetics, my observation is that it is recessive. This means both of your parent animals probably carry the trait since it is being expressed. This is a trait that only exhibits itself under the stress so one can have an animal that has it but if not stressed won’t show it. This means if you have a breeding pair that have produced offspring of which some showed the problem you might have some that do not carry the genes for prolapse. Using very simplified genetic modeling:

x	P	N
P	PP	PN
N	NP	NN

Mating of two Prolapse Carriers

P=Gene for prolapse
N=Gene for not prolapse (normal)

25% PP will prolapse in the presence of the stress

50% PN/NP carriers of the prolapse gene

25% NN desired non-prolapse breeders

Your parent pigs are probably both PN carriers.

Your next generation is probably a mix of the PP, PN and NN. What you want to do is select the NN’s to be your future breeders. To do this you stress this generation as has unfortunately happened and cull all the ones that show the prolapse. The ones that don’t prolapse you breed. If they produce PP offspring who prolapse then you cull those breeders with the goal of eventually ending up with NN breeders who don’t carry the prolapse genes.

It may be more complex than a simple gene pair though. Definitely do not breed prolapsed animals. Cull back the line of prolapses to remove it from your gene pool.

We had this with one boar we brought in and bred away from it. What that showed was that one of our sows carried the gene too. I identified the carriers and culled hard. At this point we rarely have prolapses but I continue to be vigilant.

In addition to anal prolapse there is vaginal prolapse which can be triggered by difficult deliveries, rough mating and other factors. This is also a genetic predisposition issue. We have fortunately not had the vaginal version. I have read that in dairy cows and some sheep it is a major problem.

As to the issue of which breeds are most susceptible, my wife Holly was recently told by the gentleman at the slaughterhouse that he sees a lot of prolapses come through all year round. This is interesting as we have only seen the prolapse in the fall. One difference might be that in the warm weather our pigs are spread out whereas the confinement pigs are always crowded. Most of the animals he was seeing are the commercial hog crosses. That isn’t a scientific opinion, just his observation from unloading pigs for many years but certainly worth something. I would expect that heritage breeds who have been raised outdoors to have less of an issue because they are more robust animals but poorly done inbreeding could accent the issue. The lack of crowding may also help a lot.

When you buy new genetics ask about prolapse. Also asked how they were housed in the winter. If they were kept indoors in a heated space then it doesn’t tell you if they’re going to prolapse in when they huddle in the winter which is what it sounds like you’re getting. If they spent the winter outdoors and aren’t prolapsing then you have a strong indication that they aren’t carrying the weak tissue genes that lead to the prolapsing tendency.

Googling about I find that there is evidence of genetics behind prolapse in humans, swine[1, 2, 3], horses, cattle, sheep, goats, guinea pigs and cats. Here is one description of a surgical fix for the adventurous souls.

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