Efficacy of a Monensin-based medical product against intestinal coccidia in cattle

The purpose of the research is to evaluate therapeutic efficacy of various Monensin 20% administration regimens against natural eimeriosis in calves in the Vologda Region. Materials and methods. The study was conducted on 40 Black-and-White calves aged 2-3 months with confirmed eimeriosis in May-June 2025. The animals were randomized into two groups: Group 1 was given the drug at a dose of 125 mg/animal/day (for the active substance) with feed for 3 weeks; Group 2 was given the same dose for 4 weeks. The efficacy was assessed based on the dynamics of the clinical condition and parasitological parameters (infection prevalence and intensity) on days 0, 10, 20, 30, and 40 using the McMaster technique. Results and discussion. The 4-week Monensin 20% course was found to provide a significantly more pronounced and stable clinical and parasitological effect as compared to the 3-week course. The 4-week treatment group showed a 93.8% reduction in infection intensity by day 30 (P < 0.001) along with the completely eliminated pathogen in 20 % of the animals and a prolonged aftereffect after the drug withdrawal. The critical period for maximum efficacy was between days 20 and 30 of the therapy. The drug was well tolerated with no side effects and contributed to the restoration of production performance. Thus, the 4-week Monensin 20% treatment regimen was highly effective against eimeriosis in the calves and can be recommended for implementation in the veterinary control system at dairy units.