Evaluation of the effects of topical permethrin insecticide on bull semen quality

Abstract

A number of different chemicals, including synthetic pyrethroids are used to treat and prevent ectoparasitic infestations in cattle. Permethrin is a type I pyrethroid insecticide that is commonly used to treat cattle for lice and flies via topical application. Concerns have recently been raised as to the effects of pyrethroid insecticides, including permethrin, on male fertility and semen quality. However, no controlled studies have been conducted to evaluate the effects of type I pyrethroids on beef bull semen quality. To this end, 15 purebred beef bulls were assigned to either a permethrin treatment group (PER; n=8) or control group (CON; n=7). Bulls in the PER group were treated with Permethrin 1% (Control Solutions Inc., Pasadena, TX) at 150% label dose on d 0 and d 14. Sperm motility and morphology were analyzed via light microscopy on d 0, 7, 14, 21, 35, 49, 63, and 84. Dermal application of a permethrin insecticide did not affect the proportion of normal sperm cells even at 150% label dose. Thus, it was concluded that permethrin parasiticide labeled for livestock use did not increase the risk of producing morphologically abnormal sperm cells.