Protection from insects

Summer time is insect time and in order to keep your horse healthy it is vital that you protect him from these pests, especially from the biting variety.
Insects bother horses everywhere: in the barn, during work-out, and out on the pasture. The most commonly encountered insect pests associated with horses are horse flys, keds, botflies, midges and black flies. The most dangerous ones are those that inflict bites. They feed on the horse’s blood and can transfer diseases in the process.

To protect horses from insect pests can take a whole combination of measures. The barn should be kept clean and hygienic to help keep insects away. Pastures should be on dry land as insects prefer wetlands as their habitat. In some cases it might be wise to take horses inside during certain times of the day. Insects are most active at dawn and dusk. Fly masks and blankets can offer external protection.

However, if you don’t want to leave your horse „dressed“ out on the field or during work-out, you can offer relief by using insect protection in the form of either insecticides or repellents. Insecticides are substances used to control insect populations by killing the adults, larvae or eggs in their different stages of development. They mostly work as nerve gas agents, but often kill off beneficial insects as well as the pests.
Most of the insecticides commonly sold in tack shops contain the Pyrethroid Cypermethrin and Permethrin, which are contact insecticides. They block the voltage- dependent sodium channels and receptors of insect nerve membranes, thus working very fast and efficiently against all insects. Pyrethroids are used in large quantities in conventional farming which often leads to Pyrethroid resistance. A resistance is caused by a blockage of the mode of action. For this to occur, the insect has to come into contact with the agent, i.e. absorb the active substance through the skin, lungs or stomach.

The insecticidal substance then takes effect inside the body.
Organisms which by way of a genetic variation are not killed by the insecticide, go on to create new populations. Resistance against Pyrethroids is developed mostly in species which produce more enzymes capable of breaking-down molecules. Pyrethroidic resistance can also be inherited. There are some species which show altered sodium channels in their nerve cells. Another characteristic of insecticides is that they can be absorbed by the skin in very small quantities and stored in the adipose tissue.

Alternatives to insecticides are repellents. The Latin verb repellere means to stave off or to dispel. Repellents are substances, mixtures of substances or formulations which by being applied to the skin, clothes or other materials keep insects away. Insects are attracted to the horses by their chemoreceptors. These chemoreceptors sit on sensors which are the smallest unit in the insect sensory system. Chemoreceptors react to smells (sweat), carbondioxid (breath) or heat (body temperature). Insect repellents intercept the chemoreceptors which the insects use to navigate and to communicate with each other, thus preventing the pest from landing on the target organism, the horse.