Hay is a great prebiotic that supports healthy bacterial fermentation patterns in the caecum. These healthy bacteria have special enzymes enabling them to break down cellulose (fibers found in hay) and use it as an energy source. This is a very slow and stable process that requires a constant supply of new cellulose. This is why small herbivores should always have access to hay and water. In return the bacteria produce short chain volatile fatty acids (supports 1/3 of the basal energy needs of rabbits), B-vitamins, and other essential nutrients.
Long-stem fiber: As hay is chewed it is broken down into smaller particles. At the end of the small intestine (the cecocolic junction) they are sorted according to size. Long-stem fiber is actually the larger particles that are greater than 1.7mm in size. It primarily comes from lignified or woody portions of the stems that resist being broken down during chewing. These are directed to the large intestine while the small particles (smaller than 1.5mm) are directed into the caecum and fuel good bacterial fermentation.
The appetite and energy level of a small herbivores is dependent on the presence of the nutrients listed above. When all is going well small herbivores will be healthy, energetic and have a great appetite. However, they lose their appetite and ‘quit eating’ when their caecal fermentation patterns are disrupted (mild cases of this leads to ‘poopy butt’ and uneaten caecotrophs). For this reason when you are feeding small herbivores you must consider the effect the undigested portion of the food has on the caecal fermentation patterns and consequently your bunny’s overall health, behavior, and happiness.
For example, when excess starch (from grain) or undigested protein (typically from soy) enters the caecum both good and bad bacteria can consume it. However, because bad bacteria grow faster than the good bacteria it favors the rapid growth of bad bacteria. The fermentation of starch and protein changes the pH of the caecum further favoring the growth of bad bacteria.
The fermentation of too many simple fibers found in fresh fruits and veggies and even fresh greens can have the same effect. This negatively impacts the production of B-vitamins and fatty acids and causes rabbits to lose their appetite sending it into a downward spiral. Mushy poops or uneaten caecotrophes is a sign that your bunny may be suffering from this condition at a low level.
Sherwood Pet Health has always been an advocate of a hay-based diet for small herbivores (rabbits, guinea pigs, and chinchillas). To illustrate just how deep this basic principle runs through our entire nutritional program just compare our foods to other brands. While the first ingredient in other brands of food may be hay, they are actually grain and soy based pellets that likely contain less than 38% total hay. Sherwood adult rabbit, guinea pig, and chinchilla food formulas are grain & Soy-free and contain more than 85% hay.
Grasses include: Timothy, Orchard, Brome, Fescue, and others… All of these are nutritionally very similar to one another but offer some differences in textures and flavors. You are probably well aware of your small herbivores preferences. However, the main purpose for the variety is because different grasses are adapted to different growing conditions. They all provide a great source of fiber.
Legumes include: Clover, Alfalfa, Sainfoin, Trefoil and others. Legumes can form a symbiotic relationship with bacteria in the soil to fix nitrogen which the plant uses to make protein. Because of this legumes are naturally higher in protein than grasses. A mixture of clover (legume) and grasses are a nutritionally sound staple for small herbivores. Fortifying this base diet with extra minerals and other micronutrients found in a complete balanced food boosts their energy, health, and longevity.
Alfalfa and clover are very similar nutritionally for rabbits but alfalfa is commercially grown because it is a bigger plant with a higher yield. Sainfoin and trefoil are alternative legumes that are gaining popularity because of their secondary plant metabolites (molecules made by the plant that can have unique medicinal value). They have natural tannins (proanthocyanidins) that act as a natural anthelmintic (deworming) agent. In lower concentrations the tannins also favorably influence digestion and prevent bacteria from causing bloat or diarrhea.
Monoculture vs. Biodynamic Blend: Instead of feeding your rabbit a ‘monoculture’ of one type of grass hay it would be better to provide a blend of legumes and grasses (cut earlier in the spring ensures a higher percentage of grasses). This ‘biodynamic’ relationship between grasses and legumes enables the grasses to take advantage of the nitrogen the legumes are fixing… essentially providing free organic fertilizer. This relationship offers many un-spoken benefits that stabilizes and provides a robust long-term healthy stand of forage.
Most hay is pesticide and herbicide free but often to obtain a good yield it has to be fertilized.
Pesticides: Pesticides are very costly and are reserved for fruits, vegetables, and some grains. Most hay farmers do not use pesticides on their hay crop.
Herbicides: Herbicides are often used by farmers when they rotate their crop. They use it to ‘clean’ the field of any weeds so they can start a fresh crop. Once the new hay crop is established herbicides aren’t used again until the next rotation. Once established many hay fields, especially grass fields, are in production for many years, even decades and never see any herbicides again. If they weren’t using chemical fertilizers the fields could become ‘certified organic’.
Fertilizers: Farmers tend to provide a mix of organic and chemical fertilizers depending upon many factors. The organic fertilizer comes from composted animal manure. Although it sometimes costs more they prefer to use this because it provides the added benefits of organic matter that improves soil health. The compost is unbalanced because it is very rich in phosphorous but has limited amounts of nitrogen. For this reason farmers add chemical nitrogen to keep the nutrients balanced. Grasses are very ‘nitrogen hungry’. The nitrogen in chemical fertilizers is in the exact same form that plants naturally use. Organic nitrogen sources are very expensive and still need to be broken down by soil microorganisms (providing a natural time-released benefit) into the very same chemical form of nitrogen as the non-organic fertilizer that costs much less (but doesn’t have the added benefits of other trace nutrients and ‘time-released’ nitrogen). The biodynamic blend of grasses and legumes naturally provides grasses with the needed nitrogen without having to fertilize.
For a more complete explanation of dental health addressing some common myths see our dental health pamphlet.