What Is Cattle Grub?

Cattle grub occurs worldwide and is actually the larvae of a fly. The flies, known as the heel fly or warble fly, can be a nuisance to grazing cattle and lay their eggs in the skin of cattle. These eggs hatch into larvae that infest the hide of cattle, frequently along the back, and are deemed cattle grubs. Damage to the hide causes financial loss and irritation can cause cattle to lose weight. Cattle grub is a treatable parasite.

  1. Life Cycle

    • Flies lay eggs along the legs, back and lower abdomen of cattle. Eggs are laid either in rows or in a one per hair pattern. Eggs are small and yellow and adhere firmly to cattle hair coats. Eggs hatch into small white larva with spines that eventually turn black. Larva develop into a hardened black pupa, then to adult flies.

    Issues with Cattle Grub

    • Flies cause extreme annoyance as cattle try to escape - even walking into water. They distract the animal causing decreased time spent feeding and ruminating and potential weight loss. Infestation with cattle grub larva that migrate through the skin damage hides and decrease potential leather values. Cattle are uncomfortable and susceptible to secondary bacterial infection through open wounds caused by grubs.

    Chemical Treatment

    • Insecticides can be used to control cattle grubs. Applied directly to skin or hair coat, taken orally, or on plastic strips hung around cattle legs or necks, insecticides manage flies and larvae. Treatment for larva must be given systemically while the larva are noted to be migrating in the tissue.

    Non Chemical Treatment

    • Flies are typically worse in hot months and are inactive during the day. Cattle can be kept stabled during the day and grazed at night during the most intensive times of fly activity to avoid egg laying and contamination.