Efficacy of complex solid dispersion of Fenbendazole and Niclosamide against gastrointestinal strongylatosis and dictyocaulosis in young cattle

The purpose of the research is to study the anthelmintic efficacy of a complex solid dispersion based on Fenbendazole and Niclosamide against gastrointestinal strongylatosis and dictyocaulosis in young cattle.Materials and methods. A complex solid dispersion was obtained by combined mechanochemical processing of FBZ, NZM, and polyvinylpyrrolidone (PVP) substances (2 : 20 : 78) in an LE-101 roller mill using previously developed technique. Anthelmintic activity was studied on 50 heifers naturally infected with gastrointestinal strongylates and on 22 heifers naturally infected with dictyocaulosis. The animals with strongylatosis were divided into 5 groups. A single dose of the complex solid dispersion was administered orally to the heifers of the 1st, 2nd, and 3rd experimental groups at doses of 2.0; 3.0, and 4.0 mg/kg, respectively, according to FBZ. Animals of the 4th experimental group received a mechanical mixture of FBZ, NZM, and PVP in the same ratio at a dose of 3.0 mg/kg according to FBZ. The 5th group received no treatment and served as controls. The animals naturally infected with dictyocaulosis were divided into three groups of 7–8 animals each. The 1st group of heifers received a solid dispersion orally at a dose of 3.0 mg/kg of FBZ. A mechanical mixture of FBZ, NZM, and PVP was administered to the animals of 2nd group at the same dose. The 3rd group served as controls and was not treated. The efficacy of the drugs was evaluated according to the results of coproscopic studies by the flotation method and the Berman method before and 13 days after drugs administration according to the "control test".Results and discussion. The solid dispersion of FBZ, NZM with PVP showed 100, 96.8, and 70.9% efficacy, against gastrointestinal strongylatosis at doses of 4.0, 3.0, and 2.0 mg/kg according to FBZ respectively, versus 42.0% activity of the basic mixture. The solid dispersion demonstrated 97.0% effect against dictyocaulosis at a dose of 3.0 mg/kg according to FBZ, and the mechanical mixture exhibited 43.9% activity at the same dose.