ENERGY FOR THE HORSE
The chemist recognizes the importance of feed energy and measures it in an instrument known as the bomb calorimeter , in which the feed is placed , then burned with the aid of oxygen .
Briefly stated , the procedure is this : An electric wire is attached to the material being tested , so that it can be ignited by remote control ; 2,000 grams of water are poured around the bomb ; 25 to 30 atmospheres of oxygen are added to the bomb ; the material is ignited ; the heat given off from the burned material warms the water ; and the thermometer registers the change in temperature of the water . For example , if one gram of feed is burned and the temperature of the water is raised one degree centrigrade , 2,000 calories are given off . Hence , the material contains 2,000 calories per gram . A kilocalorie ( kcal ) is equivalent to 1,000 calories .
THE HORSEMAN MEASURES ENERGY IN PERFORMANCE
The horseman recognizes the importance of feed energy and measures it in terms of work — in speed and endurance . Additionally , feed energy is essential for normal reproduction , and for growth of young stock .
The energy needs of horses vary with the individuality and size of animals , and the kind , amount and severity of work performed . In racing , horses may use up to 100 times the energy utilized at rest .
It is common knowledge that a ration must contain proteins , fats , and carbohydrates . Although each of these has specific functions in maintaining a normal body , they can all be used to provide energy for maintenance , for work , or for fattening . From the standpoint of supplying the normal energy needs of horses , however , the carbohydrates are by far the most important , more of them being consumed than any other compound , whereas the fats are next in importance for energy purposes . Carbohydrates are usually more abundant and cheaper , and they are very easily digested , absorbed , and transformed into body fat . Also , carbohydrate feeds may be more easily stored in warm weather and for longer periods of time . Feeds high in fat content are likely to become rancid , and rancid feeds is unpalatable , if not actually injurious in some instances . Also , fats are utilized very poorly by horses .
Generally , increased energy for horses is met by increasing the grain and decreasing the roughage .
A lack of energy may cause slow and stunted growth in foals , and loss of weight , poor conditions , and excessive fatigue in mature horses .
CARBOHYDRATES
The carbohydrates are organic compounds composed of carbon , hydrogen , and oxygen . This includes the sugars , starch , cellulose , gums , and related substances . They are formed in the plant by photosynthesis as follows :
6CO2 + 6H20- } -energy from sun = C6H1206 ( glucose ) + 602
On the average , the carbohydrates comprise about three-fourths of all the dry matter in plants , the chief three-fourths of all the dry matter in plants , the chief source of horse feed . They form the woody frame work of plants as well as the chief reserve food stored in seeds , roots , and tubers . When consumed by horses , carbohydrates are used as a source of heat and energy , and any excess of them is stored in the body as fat , or , in part , secreted .
From a feeding standpoint , the carbohydrates consist of nitrogen-free extract ( N . F . E .) and fiber . The nitrogenfree extract includes the more soluble , and , therefore , the more digestible , carbohydrates — such as the starches , sugars , hemicelluloses , and the more soluble part of the celluloses and pentosans . Also N . F . E . contains some lignin . The fiber is that woody portion of plants ( or feeds ) which is not dissolved out by weak acids and alkalies . Fiber , therefore , is less easily digested . It includes cellulose , hemicellulose , and lignin .
The ability of horses to utilize roughages — to digest the fiber therein — depends chiefly on bacterial action . It is a true symbiotic type of relationship , carried out chiefly by anaerobic bacteria , mostly in the cecum and colon of the horse . This bacterial digestion breaks down the cellulose and pentosans of feeds into usable organic acids ( chiefly acetic , propionic and butryic acids ).
The fiber of growing pasture grass , fresh or dried , is more digestible than the fiber of most hay . Likewise , the fiber of early cut hay is more digestible than that of hay cut in the late-bloom or seed stages . The difference is due to both chemical and physical structure , especially to the presence of certain encrusting substances ( notably lignin ) which are deposited in the cell wall with age . This is understandable when it is recognized that lignin is the principal constituent of wood ; for no one would think of feeding wood to horses .
Young equines and working ( or running ) horses must have rations in which a large part of the carbohydrate content of the ration is low in fiber , and in the form of nitrogen-free extract .
34 VOICE of the Tennessee Walking Horse