A comparison of the efficacy and pharmacokinetics of ivermectin after spring and autumn treatments against Cyathostominae in horses.

The research examines the effectiveness and absorption rates (pharmacokinetics) of the drug ivermectin in treating Cyathostominae infections in horses during spring and autumn seasons.

Study Background

• The study addresses the wider challenge of controlling parasitic infections in horses, particularly by Cyathostominae – a major cause of colic in horses.
• The drug ivermectin was used, which is a common deworming treatment in equines and well-known for its effective control of worms.

Research Methodology

• To test the drug’s efficacy and absorption rates, ivermectin was administered to warm-blooded mares aged 3-12 years, weighing between 450-550 kg.
• The treatment was given in both spring and autumn, with fecal samples taken before and after treatment at specified intervals to measure the reduction in parasitic eggs.
• In addition, blood samples were also collected during similar intervals to gauge the drug’s absorption and presence level in the blood of the horses.
• The concentrations of ivermectin in the blood samples were analyzed using high pressure liquid chromatography, a technique for separating and identifying components in a mixture.

Observations and Results

• The researchers noted a slower drug absorption rate during autumn (tmax: 21.89±11.43 hours) when compared to spring (tmax: 9.78±8.97 hours).
• Also, the maximum concentrations (Cmax, an important pharmacokinetic parameter indicating the peak serum concentration of a drug after administration) of ivermectin in the blood after administration varied between spring and autumn treatments.
• Within the first four hours after treatment, significantly higher concentrations of ivermectin were observed during the spring season compared to autumn.
• Notwithstanding the absorption rate differences, the treatment in both seasons successfully resulted in 100% elimination of parasitic eggs from horse feces, testifying to the effectiveness of ivermectin against Cyathostominae infections.

Significance of the Study

• This study provides valuable insights into the variations in pharmacokinetics of ivermectin in horses, depending on the season of administration.
• Such findings could influence and inform optimal deworming strategies in equines, potentially improving the overall health and performance of the horses.