Megacolon Syndrome

What is Megacolon Syndrome?

Megacolon is an inherited genetic condition that is believed to affect the nerves in a rabbit’s intestinal tract and causes dysfunction, leading to unresponsive and intermittent diarrhea and weight loss. It often gets progressively worse as the rabbit ages. The condition can lead to a slowing of food through the digestive system and may need to be regulated with motility medication(s) and diet manipulation. Rabbits with megacolon typically have droppings that are irregular shapes and sizes, regardless of their diet, and sometimes can be very wet or have mucus present.

Which Rabbits Typically Have Megacolon?

Spotted rabbits who are mostly white but have fewer spots, rabbits who have only color around their eyes, and rabbits with irregular markings on their nose/ears have more of a predisposition to megacolon. Rarely, a white bunny with pink eyes can be affected. If a bunny has this coat pattern and irregular size/shape droppings, visit a rabbit-savvy veterinarian to get a fecal test to rule out coccidia. You should also inquire about the possibility of megacolon and what treatment they may recommend, such as motility medications. There is no definitive test for the syndrome.

Examples of Megacolon Rabbits

In the photo above, Waffles has a touch of color surrounding her eyes that predisposes her to megacolon syndrome. In the photo to right, Dippin’ Dots (on the left) is spotted, however she has more coloration and pattern on her body and does now show signs of megacolon. Burrito (on the right), who does have megacolon, has the classic markings of megacolon with fewer spots, only color around her eyes, and irregular markings on her ears.

How is Megacolon Treated?

For rabbits with megacolon, it’s critical to notice any signs of discomfort, lack of appetite, and a decrease or change in droppings, as these are indications the condition could be worsening, and veterinary help should be sought immediately. Rabbits with megacolon require more regular preventive vet visits than other rabbits as their condition should be checked by a veterinarian to see if any medications need to be added, changed, or adjusted, or dietary changes are needed. HRS recommends a rabbit see a rabbit-savvy veterinarian once a year, and twice a year or more for senior rabbits (6 years+). Rabbits with megacolon may also require vet visits twice a year or more.

Dietary Considerations for Megacolon Rabbits

Rabbits with megacolon may not absorb the nutrients from their food well. Without treatment, rabbits can lose weight and muscle, especially along their back. Rabbits with megacolon need pellets in their diet for the extra nutrition and calories, and they may need larger servings than other rabbits. Extruded, alfalfa-based pellets may be easier for them to digest. Young rabbit pellets may also be needed.

Rabbits with megacolon may do well with most greens, to help give them extra moisture and fiber. Some rabbits are more sensitive to certain vegetables, so it’s important to observe your rabbit when you introduce new greens. Herbs such as peppermint and cilantro, both of which can help with digestion, may help rabbits with megacolon as well.

HRS recommends not feeding fruit to rabbits with megacolon—in general, fruit should be rarely fed to rabbits due to its high sugar content. Treats should only be fed in limited quantities as well, and hay-based treats are best.

Like with any rabbit, rabbits with megacolon need to get plenty of exercise time outside of their enclosure, to keep them happy and healthy. Encouraging hay eating is also very important, as is offering a variety of types of hay