This is an extract from Boing Online's Feb newsletter:
Hay Science
Excerpt from Exotic Animal, Volume 5.4
By Dawn Hromanik, Oxbow Pet Products, Murdock, Nebraska
Feeding Physiology
Herbivores are physiologically designed to eat and digest plant material.
Free-ranging rabbits and guinea pigs are ground-dwelling prey animals that eat small meals frequently throughout the day.
They are hindgut fermenters that have a small stomach, complex cecum and relatively rapid rate of transit through the digestive tract. The microbial population in their digestive tract is designed to gain maximum digestibility from fibrous plant material. In captivity, it is the fibre content of hay that stimulates peristalsis and supports bacterial growth and gastrointestinal pH for proper digestion.
Hay Science
Hay is simply dried, preserved, fibrous plant material. Fibre has been referred to as an essential non-nutrient. A common term used to indicate the digestibility of hay is “acid detergent fibre” (ADF). ADF is a measurement of the cell wall mass of the plant minus the hemicellulose or the interior of the cell. Although stems contain the highest amount of ADF, or indigestible fibre, it is the physical courseness that provides the peristaltic stimulation commonly referred to as the scratch factor. Research has shown that the thickness of the intestinal wall, villi height, crypt depth and cecal VFA production varies in rabbits depending on the source of fibre.
Choosing Hay
The type of hay to feed depends on the maturity of both the animal and the hay.
All grass hays (oaten, orchard, timothy, brome and Johnson) are suitable for small mature herbivores, because they contain protein and calcium levels appropriate to adult maintenance diets in these species.
Legume hays (Lucerne/alfalfa, clover, vetch, peanut & pea) have relatively high protein and calcium contents, which make them beneficial for growing and lactating animals but unsuitable for older buns. Some legume hays also contain high levels of oxalic acid, which may lead to precipitation of calcium oxalate in the urine of some animals.
Maturity, harvesting methods, storage conditions, soil fertility and weather play a large part not only in the nutritional value of the hay but in the palatability to the animal and visual appeal to the owner. Hay should be green in colour and have a fresh aromatic scent to encourage consumption. It should not be overly dry, brown, damp, mouldy or dusty.
Tips for increasing hay consumption
• Introduce a variety of grass hays at an early age to increase acceptance
• Offer hay in generous amounts, at least half the body size in volume per day
• Offer hay in multiple locations and in a variety of containers to encourage play
• Use hay as bedding or place hay in preferred lounging areas (litter tray)
• Understand species-specific idiosyncrasies. Guinea pigs prefer to eat off the ground. Rabbits often eat more hay when it is placed in the litter box
• Do not remove hay unless it is soiled. Frequent changing of hay encourages the pet to be selective and eat only the leafy parts and ignore the stem
**changing a litter tray daily is advised. The hay on top may not look soiled, but underneath will be damp (also you can monitor whether your bunny is healthy by checking they are going to the toilet daily). Same for hutch bedding - check underneath & preferably change hay daily so your rabbit is not living in a health hazard (just think how horrible it would be if you had to live near your toilet and it wasn’t flushed for a week!!!!)
• Stimulate the senses and make foraging a tactile and enriching experience. For example, fill a wading pool with hay to allow burrowing
• Hide pelleted food or healthy treats in the hay to promote foraging behaviours
• Shred carrots into a pile of hay and make a “tossed hay salad”
• Lightly mist hay with flavoured water
• As a last resort, steam hay to increase the moisture content, make it tender and intensify the aroma and flavour
To steam hay: bring a pot of 1 inch of water to a boil. Place a handful of hay into a steaming basket, and steam for 10-15 seconds (unsweetened fruit juice can be added to the water for flavour)
In Australia, oaten hay is the best option for our bunnies. Oaten hay is a thicker and more fibrous crop. It should look a slightly green colour and smell fantastic!!
Don’t buy any hay that is very dry, dusty & brown. You’ll only end up with hay that never gets eaten. Most pet hays sold in pet shops are usually dry & old. It’s best to buy from a quality stockfeed store near you
Never buy damp or mouldy hay. The bacteria will cause stomach upsets & illness.
To find good quality stockfeed stores, check your yellow pages directory.
For really fussy eaters, you can now buy bags of Oxbow Timothy Hay from good rabbit vets (Melbourne Rabbit Clinic have a good supply!).
