by samantha_ashenhurst | March 16, 2023 3:54 pm
When it comes to feeding our pets, we know dogs are not wolves, and cats are not tigers. Domestic rabbits, on the other hand, have the same nutritional requirements as the wild European rabbit of which they are a subspecies, having been selectively bred over centuries.
Lop-eared rabbits resembling lambs, baby-faced dwarf rabbits, lumbering giant breeds, rabbits topped with ribbons and bows, rabbits walked in strollers, rabbits flopping down to sleep in little IKEA beds, rabbits decked out in harnesses and walked on leashes—they have all retained the ancestral gut designed for a spartan diet of grasses and roughage.
Today’s pet rabbit owners dote on their little friends and want to pamper them in every way to show their love. They will often ask if rabbits need probiotics, vitamin supplements, salt licks, or paste marketed to prevent trichobezoars. While these products may not be harmful in themselves, they should never be relied on to make up for deficiencies in the diet, much less to serve as remedies for medical conditions. Let us look at some basic principles of feeding rabbits.
Understanding rabbit nutrition requires a paradigm shift in the way we see their poop. We generally think of feces as something to be disposed of, not recycled—certainly not eaten. The term “waste” says it all. This is precisely why it is not applicable to rabbit feces: they are not refuse, but either highly nutritious food (cecotropes) or pelleted compost rich in beneficial bacteria (hard feces).
There is a prevalent belief young rabbits should not eat fresh vegetables or greens until they are at least three months of age, and pellets and hay are the only appropriate and safe diet following weaning and until the rabbits are older. The concern is young rabbits might get diarrhea, which can be life-threatening. Any new food has the potential to upset the gut, so it must be introduced slowly and gradually.
However, neither diarrhea, nor mucoid enteropathy in weanling rabbits, can be blamed on fresh plant matter itself. Likewise, there is no magical transformation which happens at three or six months that allows a young rabbit to start safely eating fresh greens and vegetables. Rabbits are born with a sterile gut that begins to form its microbiome at a very early age. Their food preferences are shaped by the mother’s diet.1
In nature, young rabbits start nibbling on whatever vegetation is available as soon as they leave the nest at about three weeks old. However, two studies have shown they start eating solid food even while still in the nest.2,3 Both studies found three to five days before giving birth, pregnant rabbits begin to deposit fecal pellets and hay in the nests they have prepared. They continue to leave a few more pellets during each visit to nurse the kits, until day 11 to 13 after birth. This was observed in both first-time and experienced mothers, meaning the behaviour is innate and not learned.
At two weeks after birth, the kits would begin to nibble on these pellets, as well as the hay the mother had put in the nest, and continued to do so until they left the nest at about three weeks of age, when almost all the pellets were found to have been eaten. Concurrently, plant material was found in the youngsters’ own feces.
In both studies, the mothers were not observed to feed cecotropes to their kits. The take-home message is anyone caring for kits with a nursing mother should not “clean” the nest to remove these pellets that are likely to be important, if not crucial, in establishing the gut’s microbiome in the kits. Likewise, pellets, rather than cecotropes, may be the optimal source of gut flora for both orphaned bottle-raised kits and adults suffering from dysbiosis.
Rabbits are often described as fermentation vats on legs. I think the work of the rabbit cecum deserves a more graceful description: preparing highly nutritious food in a portable kitchen and serving it piping hot. Rabbits begin to produce and ingest their cecotropes as early as three weeks of age.
Owners often notice their rabbits have gone off eating cecotropes, or are leaving some of them uneaten. If arthritis and other orthopedic or neurological causes are ruled out and the rabbit has no issues reaching down, it may simply not be hungry enough because it is sated with nutrients from “rich” and easily digestible foods, such as starchy vegetables, alfalfa-based pellets, cereals, or fruit.
Cecotrophy may not be as critical for maintaining gut flora as previously believed, and its primary value appears to be in providing nutrients. For rabbits ignoring cecotropes as redundant, it is recommended to decrease the amount of pellets and/or other nutrient-rich foods so the rabbit rediscovers its primal appetite for home cooking.
While rabbits in the wild grow up without eating any pellets, the plant matter available to them in a given location may not be nutritious enough for optimal growth, or provide all the necessary vitamins and minerals.
High-quality commercial pellets, in addition to hay, are important for young rabbits since they guarantee healthy growth, but in adult rabbits, they are not absolutely essential. If fed, they should not exceed one-quarter cup per one kilogram of body weight. They can serve as treats. For rabbits not fed pellets, a variety of hays or fresh grasses and greens is essential, since any one food source is likely to be deficient in nutrients and vitamins.
Some rabbits can be greedy for pellets, often leading to tragic cases of choking. Foraging mats placed in different areas are useful for slowing rabbits down and mimicking rooting and grazing in the wild.
Two factors are essential in maintaining healthy teeth in rabbits: abrasiveness of the food’s surface and sufficient time spent grinding it. Grass, fresh or dried, meets both of these requirement—its surface is raspy and its fibre is long and tough (literally “chewy”). A study found rabbits fed hay on top of pellets had stronger mandibular bone due to remodelling than rabbits fed pellets alone.4 Further, rabbits do not need hard food: indeed, there is nothing in their natural diet requiring cracking or shattering.
Why does grass cut your fingers and cling to your clothes? Under the microscope, the edge of a blade of grass looks like a fine-tooth saw. The surface of grass is covered in silica phytoliths (microscopic “stones”), which give it the effect of fine sandpaper.
Leafy greens, while providing important vitamins and minerals, simply do not cut it by themselves when it comes to dental health. For foraged grass and other plants to be safe, the rabbit must be vaccinated against rabbit haemorrhagic disease virus (RHDV), even if it lives indoors. The harvested grass must be away from roads, not frequented by dogs, and free of pesticides and herbicides.
Other plants with the sandpaper effect rabbits can have are cleavers (Galium aparine) and meadow horsetail (Equisetum pratense).
A note of caution: never feed clippings cut by an electric or gas lawnmower. This grass has been flash-cooked, leading to fast fermentation that will harm a rabbit.
Rabbits, wild or domestic, are selective grazers that go for tender, nutritious items first. In nature, such food is very limited compared to coarse long-stem fibre, which is poor in nutrients. A rabbit requires a high amount of such food, so wild rabbits are guaranteed to spend enough time grazing and grinding.
House rabbits often eat meals of pellets and/or greens and vegetables. They satiate themselves quickly and have no incentive to move around for their food, or to chew up sufficient amounts of hay. To mimic the discovery of a new patch of grass, offer daily hay in installments so each helping looks and smells fresh, and catches the rabbit’s interest.
Fresh, clean water should be available at all times. Bowls are better than inverted bottles at keeping the water from growing bacteria. Some rabbits drink less than others; others do not drink at all, but, instead, rely on moisture in their food.
For rabbits drinking excessive amounts of water, the first question the owner should ask themselves, after making an appointment with their veterinarian, is whether their rabbit is hungry. Was its hay or other food source(s) changed recently? Is it eating enough? If not, does its appetite change if it is offered its previous food, or a variety of new foods? In the absence of medical issues, rabbits that drink too much water are doing so to blunt their hunger.
As much as I love cats and dogs, the painful truth is rabbits are the only ecologically friendly of the three most popular pet species. Their owners can build on this by playing an active role in environmental protection and advocacy. They can empower themselves by learning practical botany, getting to know their local flora in order to forage and make some of their own hay and dry other plants for winter, and advocating for preservation of parkland and against the use of pesticides and herbicides.
Veronica Gventsadze, MA, PhD, DVM, worked as a conference interpreter and a university professor of the humanities before gathering the courage to turn her love of science and animals into a profession. Upon graduating from Ontario Veterinary College (OVC) in 2008, she settled in British Columbia, where she works in small animal private practice. Besides advocacy for rabbits, Dr. Gventsadze writes fiction incorporating lessons learned from animals. She can be reached through her website, veronica-gventsadze.com/contact.
1 Altbäcker V., Hudson R., Bilkó Á. 1995. Rabbit mothers’ diet influences pups’ later food choice. Ethology 99: 107-116. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1439-0310.1995.tb01092.x
2 Hudson R., Bilkó Á., Altbäcker V. 1996a. Nursing, weaning and the development of independent feeding in the rabbit (Oryctolagus cuniculus). Z. Säugetierkd. Mammalian Biology. 61: 39-48. https://www.researchgate.net/publication/279901038_Nursing_weaning_and_the_development_of_independent_feeding_in_the_rabbit_Oryctolagus_cuniculus
3 Barrios-Montiel R., Arteaga L., Bautista A., Hudson R. What’s in a nest? Contribution of mother’s feces and of nest hay to pup growth and survival in the European rabbit Oryctolagus cuniculus. Presentation given at the 6th World Lagomorph Conference July 4-8 2022. Proceedings to be published.
4 Ravosa M. Mechanobiology and adaptive plasticity in the Lagomorph skull and feeding apparatus. Presentation given at the 6th World Lagomorph Conference July 4-8 2022. Proceedings to be published.
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