Colic, part 2 - food to feed

There is a link between colic and the quality of the food a horse is given. Since colic is a serious condition for any horse I have taken the help of Sara Beckman with this posting on feed.

The horse is a roughage eater and the nutrients in the feed is made available to the horse in the fermenting process that occurs in the colon. The forage is largely grass and it comes in three forms: fresh (pasture), dried (hay) and acid conserved (silage)

Grass can be contaminated by soil due to heavy rain. Newly mown grass placed in a pile without aeration will soon take heat and harmful bacteria and mould is growing rapidly.

Hay is preserved by drying. The water content is about 16% (dry substans, 84%). When there is no free water micro-organisms can not grow. If the hay is brought in, or pressed into bales before it is completely dry the hay is quickly pestered with bacteria and mould. The same happens if the hay gets wet from leaks in the roof, if damp stable air passes through it or from moisture during the storage directly on concrete floor without an air gap (eg, on pallets) below.

Silage is preserved by a combination of acidification, compare sauerkraut or boston cucumber, and airtight storage. As the lactic acid-producing bacteria grow and provide an acidic, oxygen-free environment where unwanted - in which, for the horse harmful, microorganisms can not grow. Silage is a generic term for ensilage, 65-75% water (dry substance 35-25%), and haylage is drier 45-60% water (dry substance 55-40%). Haylage is most commonly used for feeding horses. Hygiene requirements are however equally regardless silageform.

If the grass is too dry when the bale is pressed, the beneficial bacteria has difficult to grow and preserve the gras. If the field is harvested during blooming the stalks are tough and it's hard to pack the bale and it remains a lot of air in the bale - that benefits the harmful organisms' growth. When the bale is opened or if there are holes in the plastic air will come in and the bacterias can begin to grow. If you see a lot of the coarse straw in bloom in the bale - feed it more quickly to "get ahead" of the mould.

A good silage should smell slightly sour - as sauerkraut. If it has a sweet-sour or sharp smell to it, or if it is warmer than the outside temperature that indicates a mishap in the fermenting process and harmful organisms thrive.

In harvesting a farmer can affect the quality a lot! By drying the hay in the barn it is preserved better. The ensiling process can be accelerated and the process ensured by: baling hay with the right moisture content, if necessary, cut the raw material, acidification of the grass if it is dry or coarse, rolling the bales tightly, wrapping with many layers of plastic to seal the bale.

Generally speaking seven adult horses is needed to eat from a haylage bale after it has been opened to be able to eat faster than the feed is destroyed by air. In northern Sweden you can have fewer horses per bale during winter time, if it's minus degrees (below freezing) when opened.

In forage with visible mould, or smells "dusty" or have gained heat there are usually very high levels of unwanted organisms. Feed it quickly or discard. Which is most expensive? To discard the bale or to call the veterinarian because of colic?

Problems with colic may occur if forage contains readily soluble protein and low fiber content - it gives the wrong balance and a disturbed fermentation in the colon. That quality occur with forage that is harvested during periods of heavy rain or when you take an extra harvest in late autumn. The feed can be recognized by a high content of green leaves and almost no grass stalks. To feed should not pass too quickly through the intestines and cause bloating, it must be combined with an extra feed of straw daily as fiber supplement.

If the gut flora is disturbed and extra gas is produced and if bowel movements are not stimulated enough by fibers then the transportation of gas is impeded and that can lead to colic. This can be caused by either to much starch in the diet from oats or fabric feed mix or too little roughage in the diet.

A horse should eat at least 1.2 kg hay or 1.5 to 1.7 kg haylage (depends on water content) per 100 kg horse on a daily basis. Most ponies/horses ridden 1-2 hours per day feeds well only on roughage + minerals + salt in the summer. (Studies at the University of Agricultural Sciences in Sweden has shown that even trotter in full competition can be fed only roughage and reach full performance level).