So effective. And so easy to use.

To achieve effective horn fly control with Altosid® IGR, just follow these simple instructions:


  • Begin feeding Altosid® IGR to your animals before horn flies appear in the early spring. Continue to feed Altosid® IGR during the summer months and then into fall. One general rule is to feed 30 days before the last frost and 30 days after the first frost in the fall.
  • If mixing Altosid® IGR with free-choice feeds, such as mineral supplements, put out a five- to seven-day supply and protect it from rain.
  • Use one feeder for every 15 to 20 animals.
  • Place the feeders near watering holes or loafing areas.
  • Check feed consumption for a few days. Increase or decrease the number of feeders, or move them if necessary, to allow for proper consumption.


When used as directed, Altosid® IGR alone usually provides excellent season-long control. If fly populations exceed acceptable levels due to migration from untreated neighboring herds, use an approved adulticide, such as Prolate/Lintox-HD™, to decrease the fly population.

  Mike John Testimonial