[Comparative behaviour studies in horses infested with flying insects treated with insecticide or repellent substances].

This research investigates the impact of flying insects on the behavior of grazing horses, particularly in relation to the use of insecticides and repellents. Two substances, ‘Well-care emulsion’ and ‘Bremsen-Frei-Plus’, were trialed and their effectiveness compared to horses that weren’t treated. The study found both substances had a positive impact on modifying the horses’ behavior when infested.

Research Design

• The study was conducted over three periods, each lasting seven days, between June and August 2008.
• There were two groups being treated using ‘Well-care emulsion’ and ‘Bremsen-Frei-Plus’ respectively, along with one control group that received no treatment. The groups alternated to ensure fair comparison.
• Several climate parameters were taken into account during the study. These could include factors like temperature, humidity, wind, and rainfall which are known to influence Fly activity.
• The number of insects per animal was estimated at certain times. Additionally, at set intervals, insects were trapped using Malaise traps and identified to species level.

Findings

• The research found that the most relevant species affecting horses were of the Diptera genus, specifically Culex pipiens and Musca autumnalis, making up 9% of the trapped insects.
• There was, surprisingly, no correlation between the number of Tabanidae (a family of biting flies) trapped and the number actually observed around the horses. The reasons for this are not given.
• It also revealed varying behavior changes in horses as the number of infesting insects increased. Horses tend to swish their tails, shake their heads, stamp, twitch, snap at their bodies, and move more frequently. These are reactions to the discomfort caused by the insects. Importantly, the horses’ feeding activity reduced while their locomotion activity increased.

Impact of Insecticide and Repellent substances

• Both the insecticides and repellents had a positive effect for approximately 50 hours following application, with no significant difference noted between them.
• However, horses treated with Permethrin, a component of ‘Well-care emulsion’, exhibited reduced frequencies of head shaking and tail swishing. This could suggest that Permethrin is more effective at repelling or reducing insects around the head and tail area of horses.

Based on these findings, the study suggests that both ‘Well-care emulsion’ and ‘Bremsen-Frei-Plus’ are effective at reducing horse discomfort from flying insects. They can help modify behavior in horses caused by insect infestation, improving their comfort and feeding habits, but the effects only last for about 50 hours after application.