‘Wool Block’ and ‘Hairball’ are the same thing, and the terms may be used interchangeably, bunnies groom themselves and the hair stays in their gut. They are incapable of vomiting so the only avenue is for it to pass through. The primary cause is lack of GI mobility generally combined with a lack of fiber. Hay should be available at all times to a bunny, to maintain digestive health. There are a lot of opinions on treatments, but as far as I am aware there are not any hard scientific studies on best treatments. There are many folk remedies, they all focus on getting something into the bunny to help break-up and move the blockage. The following is a case study of bunny with extreme examples of a hairball and weight issues.
Common sense also dictates that keeping your pet rabbit, well brushed will decrease the amount of fur that is available for digestion
At this Writing Baxter is about 11 Years old, and has been in our family since July 2009. He is a brown and white Dutch. He spent his early years in a first grade school class room. He came to us when the teacher was no longer able to keep him in the class room. He was morbidly obese as seen in the pictures below, with a similarly rabbit of normal weight.
I must admit that at the time we did not realize the severity of his condition, we took him to a vet who was an exotic vet, but not as skilled in rabbits as we had thought. I won’t go into details, but the visit turned out to be less then helpful. Harmony on the left was our first bunny rescued from the local humane society WPHS a couple of months previously. Baxter and Harmony were bonded and living together in about 2 weeks (these photos are an early bonding session).
Over the next several months we became more active in the local bunny community, started volunteering at the shelter and interacting with the Pittsburgh House Rabbit Club, Baxter was losing weight and we were getting more educated about bunnies. Baxter and Harmony were sharing an endless supply of hay, Fresh greens twice a day and about two table spoons of pellets twice a day, plenty of water and a salt lick.
In about February 2010, Baxter had an “Episode” he stopped eating, seemed to be in some pain, and possibly having seizures. This was our first bunny medical emergency, we reached out to the bunny community and were put in touch with one of the founders of Rabbit Wranglers, we managed to get through the episode with a live bunny, and scheduled a visit with an exceptional rabbit vet.
The exam revealed a large mass in Baxter’s stomach, on x-ray he was found to have a huge hairball in his stomach (I have an x-ray but the scanner will not pick up the image). The hairball was about twice the size of his head. He had some irregular labs (CA 13.3 mg/dl; ALT 78U/L ; ALKP 46 U/L; CHOL 30 mg/dl) and the vet was worried about his kidneys. His molars needed to be trimmed. Several options were discussed for treating the hairball. We learned that a rabbit always has some hair in their stomach so the goal was not to completely eliminate it, just get it to a point that it did not interfere with GI mobility Sluggish Motility in the Gastrointestinal Tract, Susan Brown, DVM
We went home worried about the long term health of our bunny. It was obvious that months of “proper diet” had not controlled the hairball. We tried raw pineapple juice for a couple weeks, but did not notice a notable change in the hairball (it was very easy to feel just by touching his belly), nor did we notice an increase in linked poops (when passing hair bunny poop is often connected by the hair). Realizing the risk of prolonged consumption of high sugar foods we discontinued the pineapple. Digestibility in the Rabbit Diet, Marinell Harriman in consultation with Carolynn Harvey, DVM
There is some question if it is the increased moisture or the enzymes that impact the hairball, and as I have said previously there is not overwhelming scientific data for any solution. We began adding canned pumpkin to his diet (NOT Pumpkin pie filling). Pumpkin is a popular remedy for diet replacement in sick bunnies and those who have lost all their teeth due to massive dental issues.
Over the next couple of years, there have been multiple reoccurrences of the episode; presumably GI Stasis, but his presentation is slightly different then I have heard others described, and it has not reoccurred while in the presence of others more skilled. The possibility also exists that gas is part of the issue. For the first couple of years every episode was followed by a vet visit, a regime of Reglan (and occasional other GI drugs).
Our current emergency response to any suspected GI Stasis is to give gas drops right away (He will often lick berry flavored “Little Tummys Gas Drops” out of a spoon) force feed if necessary. If we don’t see positive results within an hour or two, we feed baby food, carrots, banana or squash are all good choices, again by force if necessary. So far he has always returned to his normal diet. Sometimes within 12 hours, but occasionally it has taken a couple weeks. Prolonged delay in return to normal, general involves a vet visit and Reglan. We discussed the possibility of surgical removal of the hairball but, our vet strongly discouraged this, he says that half of the bunnies do not survive stomach surgery.
Baxter continued to lose weight, it was probably six months before he could see his front paws around his dewlap. Even today his dewlap has not retracted, it is no longer full of fat, but is just baggy skin (See image of a normal sixed Baxter and two friends).
The increase in Pumpkin resulted in a decrease in hay consumption. We know of several bunnies that lived years with pumpkin as their only source of fiber so this does not cause us undue worry, one side effect in Baxter has been a decrease in the size of his poop, and a need for teeth trimming a couple times a year. At some point around a year after joining our family it became clear that Baxter was getting too skinny. We increased the pumpkin and added extra food pellets to his diet, the hairball was shrinking and by around 2 years it had shrunk to an acceptable size. But much like the skin of his dewlap that had not receded, it seems his stomach also did not rebound from the stretching. It is difficult to diagnosis but it seems that his stomach is no longer as effective at digesting food.
Baxter will occasionally binge on salt and water, licking the salt lick and then drinking water, repeating for several minutes. There is no doubt that it took years for the hairball to get to a reasonable size. In our estimation it was the salt and water, and/or the pumpkin that ultimately dissolved the hairball.
Currently Baxter is part of a bonded trio (Lyra is the white bunny) He shares regular meals and a “proper diet” with the girls, in addition twice a day he has two heaping table spoons of pumpkin, a teaspoon of rolled oats and two table spoon of pellets (this is easily doubling the normal diet for the other two). His weight is stable but remains a little under ideal.
Update 2 years later: Baxter continued to have digestive issue and bouts of stasis. As he got older his interest in food slacked, and it became more difficult to keep his weight up. At the age of 13 he passed, with issues related to age and digestive health.