FLYSTRIKE IN SHEEP

July and August are the months of the year when flies are at their worst in our barns, barnyards and pastures. Several SEKSPA members have reported large fly infestations and maggots in open wounds on the skin of their sheep. Flystrike in sheep is a serious problem where flies lay eggs on open wounds or soiled wool. When the eggs hatch, the maggots dig deep into the sheep’s wool and under the skin. If untreated, the larvae will develop and flies will continue to deposit eggs on new areas and the problem can spread to other sheep in the flock. Flystrike can be lethal for sheep due to ammonia poisoning. 

We asked the sheep experts at the University of Kentucky for their advice and Endre Fink and Dr. Don Ely sent these recommendations for controlling flies and maggots:

“Sheep can get nicks/cuts of the skin under normal production situations, especially if they are short-wooled (recently sheared).  They often can get small cuts in the shearing process, which usually go unattended.  If the shearing is in late spring when flies are out, the shearing nicks/cuts may attract flies which lay eggs on the cuts/nicks.  These eggs can develop into maggots.  The maggots eat the flesh of the sheep to the extent that the sheep may even die if not treated.

To control flies, pour Martin’s Fly-Ban Synergized Pour-On along the entire backline of the sheep.  It’s effect lasts quite a long time, but will leave a dark stain down the backline.  This Pour-On should be available at local farm supply stores.  If not, order online from sheep supply stores.

If maggots get onto sheep, shear wool or hair from around the area and spray with Catron IV Spray (made by Bayer).  Treatment may have to be more than once.  The best way to prevent maggot infestation is to see the sheep everyday and look for excessive fly attacks.  If this occurs, use the Pour-On.  If sheep are trying to scratch, stomping their feet, and/or biting themselves, they may already have maggots.  Then, shear around the area, spray Catron, and use the Pour-On down the backline.  Observe closely and daily.”Endre Fink, M.S. and Don Ely, Ph.D.

Endre Fink, M.S. and Don Ely, Ph.D.
Department of Animal and Food Sciences 
College of Agriculture, Food and Environment 
University of Kentucky
Lexington, Kentucky