Traditionally, swine nutritionists and veterinarians felt that sick pigs needed more nutrient-dense diets than healthy pigs, mainly because feed intake is reduced during a disease challenge, points out Marcia Carlson, University of Missouri swine nutritionist.

Certain enteric disease outbreaks respond to changes in diet makeup. Specifically, pigs infected with certain strains of E.coli respond to diets with less fish meal, less corn, more soy-protein concentrate, more processed oats and more animal plasma.

Healthy pigs require 0.15 to 0.30 percentage units greater dietary lysine concentrations and 2 grams to 5 grams higher daily lysine intakes than disease-challenged pigs at each 30-pound weight increment from 13 to 250 pounds. The nutritional program during a specific disease outbreak may vary based upon the disease, disease load and the environment of the operation, says Carlson.

Changing a feeding program during a disease challenge to meet the sick pigs' needs is not practical, says Carlson. But you should concentrate on vitamin E, selenium, vitamin A, vitamin C, B-complex vitamins, zinc, copper, iron, manganese and magnesium to meet the pig's requirements in order to enhance immunity.