Study on tolerance to increased D-Cyfenotrine Combo doses in the treatment of cattle of different age groups

The purpose of the research is to study the tolerance to increased doses of D-Cyphenothrin Combo (D-Cyphenothrin, pyriproxyfen and piperonyl butoxide) in the form of a solution for external use in the treatment of cattle of different age groups. Materials and methods . The VNIIP – FSC VIEV has developed a drug in solution formulation (concentrate) for external use based on three active ingredients: D-cyphenothrin, pyriproxyfen, and piperonyl butoxide, to treat cattle, horses, and sheep affected by ectoparasitic diseases. The study was conducted on clinically healthy bull calves and replacement young Holstein cattle of different sex in June and July 2025 in Moscow and on a farm in the Karachay-Cherkess Republic. The animals were treated with the product individually, using a single, medium-volume spray of a 0.005% aqueous emulsion at a dose of 12.5 mL per 1 kg of body weight (five times the therapeutic dose). The control animals were not treated. Before and 5 days after treatment, the animals were weighed, their body temperature was measured, and blood samples were taken to study certain morphological and biochemical parameters using common methods. Results and discussion. It was found that the study drug, if applied once to the animals' skin and fur at a fivefold increased dose during the experimental period, had no adverse effects on their general condition, physiological status, or behavior. No statistically significant changes were observed in morphological and biochemical blood parameters in the experimental cattle versus the control group.