11 Fly Deterrent Tips for Effective Pasture Management
The Best Fly Repellent Strategies Keep Livestock and Poultry Healthy and Stress-Free

By Ken Scharabok – Flies can bother livestock to the point they become stressed and growth or overall health is affected. Fly deterrent strategies probably follow the 20/80 rule (20 percent of the effort produces 80 percent of the results). It will not be economically feasible to declare total war on flies, but some fairly simple practices can greatly reduce their numbers.
● Feed a balanced diet from correctly managed pasture fertilized with trace elements as necessary.
● Provide a free choice mineral and trace element supplement to pasture. Dried sea kelp is an excellent source of these. Face flies are particularly attracted to animals which are deficient in cobalt and zinc because both of these deficiencies cause excessive tears to run down their cheeks and leave a sticky mess to which flies go.
● Treat for worms and other parasites as required.
● Move them frequently so they are not forced to lie in their own manure (dirty animals attract flies and parasites) or made to graze where their own manure is breeding more flies.
● Train livestock to not gather under trees to avoid manure concentrations.
● If possible, move into paddocks in the prevailing wind. This will mean the animals are normally upwind from where flies may be breeding in manure left in recently vacated paddocks.
● If manure piles are required, treat them periodically by sprinkling on diatomaceous earth. The same can be done for silage pits or old haystacks as required.
● Earthworms and dung beetles should be encouraged so they consume or bury manure as quickly as possible.
● If a centralized watering point is provided, consider building a fly trap to catch flies each time the animals move through it. For plans for a walk-through trap go to http://extension.missouri.edu/p/G1195 . This type of trap has been found to work for most kinds of flies.
● If you use insect repellents on yourself, why not on your livestock? Use repellents or pesticides as required, including insecticide ear tags. However, these should be used to supplement good pasture management, not instead of it.
● Some animals just seem more susceptible to attracting flies than others. Cull out your fly baits.
Joel Salatin, a livestock producer in Virginia, reports excellent results for cattle using the following free choice mixture: Two parts stocker salt (for help in regulating heat), two parts dried kelp (for minerals and trace elements) and one part diatomaceous earth (to help control internal parasites). The diatomaceous earth use, in this case, is to will pass through the animals, also helping to regulate fly larva in dung pies. Healthy animals have far fewer problems with flies!
Mr. Salatin also uses a unique approach to reduce fly larvae which escape his diatomaceous earth fly deterrent treatment. He built a mobile chicken coop on a trailer frame. The bottom of the coop is wire mesh so droppings fall through on the ground. Chicken nesting boxes are built onto the side with a lift-up top offering access from the outside. He moves this mobile coop through his paddocks four days behind his cattle. The four-day lag is timed to optimize the hens’ eating emerging fly maggots in the cattle’s manure. The amount of insects the hens are able to glean from the manure and pasture has cut the feed consumption of the hens by 60 percent with no decrease in egg production. The hens are given whole shelled corn free-choice and have access to some meat scraps for supplemental protein. Now that’s an interesting answer to: “what to feed chickens.” Water is also provided. He has had no problems with predators (the hens are locked in the coop at night) and theorizes the chicken predators like to stake out the coop for several nights before bothering it and his frequent moves keep them off guard. It’s a win-win: An effective fly deterrent strategy while achieving a reduction in feed costs for his laying hens.
I think cracked corn would be a better feed than whole-shelled corn. Hammer mills are expensive. If you only need to process small quantities consider trying to find a used coffee grinder (the kind you see at supermarkets). They should grind corn as easily as they do coffee beans.
For more information on fly deterrent strategies and pest control for your livestock, read these great articles flystrike treatment and nasal bot fly larvae in goats.
Originally published in 2000 and regularly vetted for accuracy.
Fly Repellent for Horses (Recipe by Callie Fulmer)
This is a good fly repellent for horses, and the ingredients aren’t too hard to find:
1 oz. citronella oil
2 oz. Skin-So-Soft or Coat-So-Soft
1 cup cider vinegar
1 cup water
Mix in a 20 oz. spray bottle and spray on coat. You can also add a few tablespoons of garlic powder (not garlic salt) to their feed starting a month or so before fly season, or a 1/4 – 1/2 cup apple cider vinegar (depending on their size) to their feed. The vinegar has been reported to help prevent enteroliths in places where horse are prone to them (mostly in the West).
Originally published in 2001 and regularly vetted for accuracy.