As temperatures rise across Texas, the number of flies buzzing around livestock has also increased. While each rancher has his/her own way to ward off the pesky pests, some experts recommend another method—culling fly-attracting cattle.

Dr. Doug Colwell, a parasitologist with agriculture and Agri-Food Canada reports in Beef Magazine that some cattle have a natural resistance to flies and some are more attractive to flies.

He says 80 percent of the flies are on only 20 percent of animals.

“If you watch the cattle, those 20 percent of the cows are the ones every year with the most flies, and if you cull those cows, your fly problem should decrease,” Dr. Bob Judd, host of Texas Vet News on the Texas Farm Bureau (TFB) Radio Network, said. “This is not to say this is the only reason to cull a cow. A lot of other factors are involved, but it should at least be considered as part of the decision.”

Ranchers who keep good records of cows and the number of flies around them may refer back to records for help when making the decision to cull or keep a cow.

“This could make a difference. Since susceptibility to flies is heritable, her offspring will also be more susceptible to flies,” Judd said.

Multiple horn fly studies on cattle have been performed at the University of Arkansas-Fayetteville, and they have found there are also differences in breed susceptibility to flies.

“Chianina cattle are white with black skin. And if you compare the number of flies on Chianina to black cattle, the Chianina cattle, in general, have less flies,” Judd said. “This group of scientists actually developed a small herd of fly-resistant cattle of many different breeds, including Angus, Hereford, Chianina and Charolais. So it can be done.”

Cattle breeding focuses on many different areas when deciding which cattle to breed in your herd, and fly resistance is not a major one. But with the decrease in chemicals effective against flies, looking at breeding cattle less susceptible to flies should be considered, Judd said.

Hear more on Texas Vet News on the TFB Radio Network.