Science / Medicine : Study Targets Cattle Pest

Researchers say they have found a way to eradicate a major livestock pest--the heel fly--that threatens cattle herds worldwide and causes annual losses of up to $680 million in the United States. Sterile male flies and insecticides were successfully used in a pilot project to stop the heel fly from reproducing, they said.

The joint project by the agriculture departments of the United States and Canada, which began in 1981, was carried out in ranches in Montana and the province of Alberta. The method may be used to eradicate cattle larvae elsewhere.

U.S. and southern Canadian livestock producers consider the heel fly to be a major problem. The pests lay eggs on the hairs of an animal’s legs or belly and the larvae bore into the animal’s hide, spending six to eight months traveling through it until they reach the upper back. They then cut breathing holes through the hide, molt and remain for one to three months inside cysts before emerging.