Energy needs: equine animals
Horses, donkeys, and mules are non-ruminant animals. They do not store food and later chew it, as oxen do. In addition to their molars, they have a set of upper and lower front teeth suitable for grinding roughages. (Bovines have no upper front teeth: they pull the grass loose, swallow it, and later bring it up and chew it with their rear molars.) With equines, digestion begins in the mouth, continues in the stomach, and is completed by various intestinal organs.
Equine animals must be fed with respect to their particular digestive functions and abilities. Where an ox can be fed its entire ration at the end of the day, a working horse, because of its smaller stomach and faster rate of metabolism, should be given its feed in small quantities. This facilitates complete, regular digestion of nutrients and ensures that the animal will be comfortable when working. A common plan is to feed the grain (concentrate) ration in three equal parts, morning, noon, and night; the roughage ration 1/2-3/4 at night, the remainder being given in the morning and at noon.
Body weight being equal, horses have somewhat higher maintenance energy needs than oxen because they are naturally more active. Their activity is related to their more nervous disposition and higher rate of metabolism (rate of using digested nutrients to build and repair body tissue and to produce heat and work). But horses can store more energy in their muscles than oxen and this explains their ability to produce greater bursts of power and work at a faster rate.
Research in both tropical and temperate climates shows that equine animals need about twice their maintenance requirements when doing medium-to-hard work. The following guidelines are suggested by CEEMAT for equines:
Idle horses: 2.5 U.F. per day (Assume 250-kg horse.)
Working horse: 5.0 U.F. per day (Assume 4-5 furs. pulling cultivator, medium soil.)
Idle donkey: 1.5 U.F. per day (Assume 100-kg donkey.)
Light work donkey: 2.5 U.F. per day (Assume 3 hrs., cultivator, light soil.)
Continuous work donkey: 4.0 U.F. per day (Assume 5 hrs., cultivator, light-medium soil.)
Unfortunately, very little data is available on the value of feeds as they apply to equine animals in the tropics. Thus it is necessary to use the tables adapted for bovines when formulating diets. Experience indicates that the values are generally applicable with the exception of straws. Bacteria in the ruminant's stomach enables it to digest straw and low-grade roughages effectively. Equines can derive very little energy from coarse fiber, so care must be taken to supply them with better hays and fodders.