The Effect of Diet on the Length of Third Stage Larvae Produced by Adult Haemonchus contortus Harbored by Lambs

Abstract

designated a control animal and the feces of these animals were examined frequently for helminth ova. They were consistently found to be free of ova except for a few Strongyloides sp. Twenty-seven to 30 days following the administration of the larvae, feces were collected from all of the lambs. The feces of each of the control lambs was crushed by hand, mixed with charcoal and placed, several millimeters thick, on two thicknesses of moistened filter paper in Petri dishes. The feces from each of the infected lambs were crushed and placed in saturated sodium chloride solution in large centrifuge tubes. With the aid of centrifugation the eggs were separated from the fecal material and were gathered from the surface of the solution. The eggs were then washed once with 0.9 percent sodium chloride solution and three times with tap water. Aliquots of the resulting samples were removed and the number of eggs counted. Approximately 8,000 fertilized eggs were placed on each control lamb's feces in the Petri dishes. The scheme for culturing was as follows: