Rabbit Nutrition 101
If you have a rabbit, or are thinking of getting a rabbit as a pet, you may be puzzled by what to feed him. If you go to the pet store you will see shelves full of hays, pelleted food of all types and colors, grains, dried fruits, and snacks with exotic-sounding names like Drops, Nibblers, Rings, Fiesta, Sticks and Lofty’s. Bugs Bunny eats carrots, so you might think all rabbits should eat those. And the rabbit in Monty Python’s Holy Grail had carnivorous tendencies and a real thirst for blood. But Bugs is a cartoon and the Monty Python rabbit is a spoof, so we know they are not nutritional experts. The truth is that rabbits will eat almost anything put in front of them. How do we choose a proper diet for these small friends?
To understand rabbit nutrition we must first understand how a rabbit digestive system works. Rabbits have continuously-growing teeth suited for grinding food into small bits. Then there is a thin-walled stomach that serves mostly as a temporary storage site for food, but not much digestion occurs in the stomach. After the stomach comes a relatively short small intestine. The small intestine carries food to a very large cecum (first part of the large intestine) where most of the digestion of nutrients occurs. The cecum is suited for digesting diets high in plant fiber. Various bacteria, yeasts, and protozoa in the cecum “ferment” the plant material into a mixture containing amino acids, volatile fatty acids, vitamins and enzymes. This mixture is formed into cecotropes which are passed through the remainder of the colon and eaten directly from the anus by the rabbit. The cecotropes are full of valuable nutrients which are then absorbed from the intestines. Waste products consisting of undigestible fiber and other substances are also passed in great quantities. How the rabbit knows which type of material is coming out and whether it should be eaten or left on the ground is a subject for another time, but it is a beautiful variation on digestion that mother nature has devised.
As you can see, the rabbit digestive system is designed to use very high fiber food. Too much carbohydrate, protein or fat in the food will alter the balance of microbes in the intestinal tract, change how the intestines function, and change the taste or consistency of the cecotropes so that the rabbit may not eat them as he should. Not enough fiber in the diet can cause gastrointestinal slowing (called stasis), and robs the animal of vital nutrients.
What foods are sufficiently high in plant fiber for the rabbit? Grasses are the main thing that rabbits should eat – Timothy Grass, Bermuda Grass, Orchard Grass, and Oat Grass are all good types of grass hay to feed. Grass hay should comprise about 90% of the diet. Dark leafy vegetables should make up the remaining 10% of the diet – Kale, Mustard/Collard/Turnip greens and Romaine fall in this category. Vegetables like carrots and zucchini are deficient in fiber and contain too much carbohydrate so should NOT be a regular part of rabbit diets. Similarly, fruits and grains contain too much sugar and carbohydrate. Snacks made of papaya, milk products, seeds and dried fruit are marketing gimmicks and there is no good reason to give these items to your rabbit.
Pellets made of timothy hay can be used as an occasional treat only, and should not be fed routinely. Pellets were originally designed for rabbit production (i.e. raising rabbits for food) where maximum rapid growth is desired and long life is not important. Also, pellets are crunched by the teeth and not ground as food should be, so dental problems can occur if mostly pellets are fed. Too much pelleted food also leads to obesity.
Ultimately, feeding your rabbit is simple. Feed grass hay free-choice, and provide a small amount of dark leafy greens. Remember, greens should comprise only 10% of the diet, so a small cup of greens a day is plenty. With this diet your adorable little rabbit will remain fit and active throughout its life.