Materials and methods. The studies were performed in the Bukhty peasant farm enterprise in November 2021 on the Kizlyarsky District winter pastures in the Republic of Dagestan. Three groups of sheep were formed, of which two groups (second and third) had a confirmed clinical diagnosis of psoroptic mange (P. ovis) and one group (first) was free from scab mites. Sheep from the first and second groups were treated with Delcid at a dose of 10 ml of the drug per animal. After 10 days, sheep from the second group were treated with the drug repeatedly at the same dose. Sheep from the first and second groups were treated with the drug applied on dry and intact skin of the back along the spine using the drop method. The third control (infected) group of animals was not treated. All experimental groups of sheep were kept in a common flock. The Delcid persistent activity and thera-peutic efficacy were evaluated by clinical examination and microscopy of the skin for P. ovis mites before the experiment started and at 1, 3, 7, 10, 14, 21, 25 and 30 days after treatment in the first group and at 1, 3, 7, 11, 13, 17, 20, 24, 31, 35 and 40 days in the second and third groups of sheep.

Results and discussion. It was found that Delcid 7.5 showed persistent activity in sheep against psoroptic mange pathogens for 21 days after a single treatment at a dose of 10 ml per animal. Delcid acaricidal effect after double treatment against P. ovis was 31 days.