Why is adding hay to a rabbit's diet important?

Question

These questions mention feeding rabbits hay:

• What are healthy treats for a house rabbit?
• How can I help my adult rabbit gain weight?

Why is adding hay to a rabbit's diet important? I am particularly curious about potential health concerns throughout the life of the bunny that may be affected by feeding or withholding hay.

Answer 1

Rabbits need to be feed hay and grass daily. It needs to be the basis of a healthy diet.

It is important for:

Dental health

• The teeth are worn down by eating grass and hay.

Digestion

• Rabbits have two processes of digesting. The fibre is vital to stimulate the rabbit's highly specialized digestive system.

• Hay and grass, this coarse type of roughage is digested in the cecum (a part of the rabbit's large intestine) that partially digest the hay, which is then expelled as a specialized pellet called a cecotrope. This partially digested hay, or cecotrope is then ingested by the rabbit, where further nutrients can be absorbed.

• Without this source of fibre, rabbits are prone to diarrhea and motility disorders, because the peristalsis (movement) of the gut is not stimulated enough, so it causes digested food to rot. A diet high in sugar will also promote the growth of bacteria in a sluggish bowel. This in turn can interfere with absorption of nutrients.

• A sluggish bowel, can also lead to loss of appetite and thirst, resulting in dehydration and weight loss. This decreases the production of cecotropes, lowers the rabbit's well being, as it's nutritional needs are not being met.

Hairballs aka wool block

• Maintaining healthy motility of a rabbit's gut is also necessary for the rabbit to pass hairballs. With a sluggish bowel, hairballs can remain in the rabbit's stomach, where, hastened by the increasing dehydration of the rabbit, the hairball hardens, creating the rabbit to feel bloated and full, further decreasing appetite, thirst, increasing dehydration, weight loss and this destructive cycle continues.

• The best remedy to relieve a rabbit's unpassable hairballs is to offer the rabbit a diet only of fresh green hay with plenty of fresh water on hand. It takes three days for a rabbit to create more fecal matter. This is the best treatment for hairballs in rabbits and it is rare that a rabbit will require surgery, if offered a diet like this.

The following picture gives a great visual idea of how much hay is needed in a rabbit's diet.

image subject to copyright and courtesy of San Diego House Rabbit Society sandieograbbits.org

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References:

University of California
Agriculture and Natural Resources

San Diego House Rabbit Society

PDSA
People's Dispensary for Sick Animals

AAHA
American Animal Hospital Association

Susan Brown, DVM
Midwest Bird and Exotic-Animal Hospital in Westchester, Ill.

Answer 2

Hay is important for a lot of reasons. Some of which are

• Reduces the size of their ever-growing teeth
• Provides enough fibre needed for their digestive tract

• Hay keeps the gut moving Hay is made up of long fibres that help the muscles of the bunny's gut stay strong. A rabbit's complex digestive system means they need to constantly snack on hay throughout the day to keep things moving inside, and help prevent blockages (eg. from fur or things they've eaten - rabbits seem to have little concept of what they can and cannot digest!) Blockages can often be fatal. If a rabbit doesn't eat enough hay then this can slow down the rabbit's intestinal functions and cause serious problems eg. GI Stasis (see below).

• Chewing hay grinds their ever-growing teeth down to a safe level Rabbits' teeth continually grow, including all of their back ones (did you know rabbits have 28 teeth?!) If these aren't kept in check by wearing them down on hay and grass, they can grow out of control and cause painful abcesses, and even grow into the eyes from within. It's a fast process - rabbit teeth grow about 12cm a year! Eye problems are often linked to the teeth. Other foods (even hard pellets) do not wear the teeth down like the side-to-side jaw action used when eating hay.

• Keeps bunnies busy rearranging it and searching for the best tasting pieces

• Teaches rabbits good litter tray habits Source : Why is hay so important for rabbits?

Answer 3

User34 has a very good answer! Here is one other thing I would like to add: Hay is vital because rabbit's can't vomit. This is where I read up on it: http://smallpetselect.com/blog/timothy-hay-rabbits-cant-vomit