Pigs to Pork
MANAGEMENT
Energy for Swine
Vernon B. Mayrose and James R. Foster, Animal Sciences Department
AS-345 July, 1966
Carbohydrates and fats are the two main classes of nutrients fed to supply energy for swine. Just as an automobile needs fuel as a source of energy, swine also require energy for growth, maintenance and reproduction. Swine rations contain carbohydrates and fats to supply this energy in the form of calories.
CARBOHYDRATES
Carbohydrates make up the largest percentage of all nutrients in a swine ration.
This class of nutrients contains two fractions, fiber and nitrogen-free extract (NFE). The more important component for swine is NFE (sugars and starch) because it is easily digested by swine and yields more energy to the body.
Sugars are soluble in water and are the building blocks" for carbohydrates. The most common simple sugars are glucose, fructose and galactose. There are three important compound sugars which are formed by the union of two units of the simple sugars. Sucrose is made up of one unit of glucose and
one unit of fructose and is the same as cane sugar. Maltose is composed of two units of glucose, and lactose is made up of one unit of glucose and one unit of galactose. Lactose is the sugar present in milk.
Starch is composed of many units of glucose bound chemically to one another and is the chief carbohydrate in plants . Starch is a nutrient because it yields energy as it is digested and utilized in the body. Again, it is like gasoline in a car in that it is useful only as fuel. It does not repair worn-out parts.
Fiber is the second component of carbohydrates and this fraction includes the relatively insoluble carbohydrates such as cellulose and others that are less easily digested by swine. Fiber is broken down by enzymes produced by micro-organisms and not by enzymes secreted by the pig. These microorganisms are present in the stomach of ruminants such as cattle and sheep, but they are not present in the stomach of the pig. A pig's digestive tract includes a simple stomach of relatively small capacity in contrast to the compound stomach of cattle and sheep. For these reasons as the fiber content of swine rations is increased, feed efficiency is usually reduced.
Important factors in determining the maximum level of fiber for swine rations are the quality of the fibrous feed used and the stage of the life cycle of the animal being fed. For example, high quality alfalfa meal and high quality oats could be tolerated at