How to keep bugs off your cattle this Spring

By Staff
Justin Rodgers / 4-H youth agent
April 7, 2002
Spring has arrived once again, the weather is warm and most of the calves are on the ground.
The grass is beginning to grow and external parasites are beginning to peak. However with proper preventive and treatment methods, producers can control many common parasites in cattle. Common external parasites include horn flies, lice and grubs.
Horn flies reproduce in fresh cattle manure from early spring to late fall and usually peak in late spring and late summer. Horn flies suck blood, irritate and annoy cattle, which reduce weight gains and cause weight loss.
Treatment is economically justified when horn fly populations reach 250 flies per head. To control them throughout the season, use self-treatment insecticides or routinely apply spray, pour-on, spot-on, dust chemicals or insecticide ear tags.
Biting lice and blood-sucking lice are transmitted between cattle by contact. This is usually more of a problem in the fall and winter months when cattle bunch up because of the cold weather, but does occur periodically in the summer.
These lice cause a condition called lousy, an itching skin disease with possible anemia. Some of the signs of lice are dry, scaly skin, hair loss and itching exhibited by biting, rubbing and scratching.
Chemicals can be used effectively, however they do not harm the lice eggs. Use spray, dust, pour-on, spot-on, injection or self-treatment methods in fall and winter for control. Injection will not work for biting lice.
Cattle grubs are larvae of heel flies, which lay eggs on hairs of the lower legs of cattle in late winter and spring. The grubs appear in the backs of cattle in winter. Damage by the grubs can cause weight losses and reduce weight gains and milk production.
To control these grubs, administer systemic organophosphate insecticides, avermectins or milbemycin to cattle no later than 3 months before grubs appear in the back.
Use pour-on, spot-on, spray or injection methods to kill migrating grubs before they reach esophagus. If cattle are not treated in the summer, the systemic organophosphate insecticides and averectins used in the fall and winter for control of lice, horn flies, and worms may cause reactions in the esophagus if many grubs are present.
Fly control should be started early before population buildup. Use back rubbers, dust bags, ear tags, spray-ons, pour-ons or sacks soaked with a mixture of oil and insecticides.
For more information, contact your local county MSU Extension service. In Lauderdale County, the number is 482-9764.