Swine have a digestive system similar to humans and different from ruminants such as cattle and sheep, which can eat forages or grasses. Pigs are fed a diet that is primarily ground corn to supply heat and energy and soybean meal to provide protein. Vitamins and minerals are also added in their feed. Rations are closely tailored to optimize health and growth at each stage in their life. Many producers even modify the ration based on the pig’s gender.
The ration is normally changed to provide more energy and less protein as the pig grows. The goal is to optimize feed utilization for different stages of growth. Since nutritional needs are different for male and female grow-finish pigs, larger operations may even modify the ration, based on gender. Recent studies indicate that ration modifications that can reduce the amount of nitrogen and phosphorous excreted in the manure, while maintaining optimum pig growth and health. It takes nearly 1000 pounds of feed to raise a hog to market weight. This same pig drinks about one-and-a-half to two gallons of water a day over its six-month life.