hay science

Except 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 capitivity, it is the fibre
content of hay that stimulates peristalsis and supports bacterial grown 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
preciptitation 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 trays)

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

Change soiled hay daily to ensure fresh, dry hay is available to your bunny

Stimulate the senses and make doraging 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 unsweetened fruit juice

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 near you, check your yellow pages directory.

For really fussy eaters, you can now buy bags of Oxbow Timothy Hay from good rabbit vets.