Efficacy of moxidectin and an ivermectin-praziquantel combination against ascarids, strongyles, and tapeworms in Thoroughbred yearlings in field tests on a farm in Central Kentucky in 2016.

The research study is an investigation into the efficiency of moxidectin (MOX) and a ivermectin-praziquantel (IVM-PRAZ) combination in treating ascarids, strongyles, and tapeworms in Thoroughbred yearling horses, with field tests conducted on a farm in Central Kentucky in 2016.

Study Background

• The study was carried out on a farm in Central Kentucky, where 143 Thoroughbred yearlings were subjected to the field tests. The tests aimed to evaluate the performance of two drugs, MOX and an IVM-PRAZ combination, in eradicating ascarids, strongyles, and tapeworms.

Methodology

• The study was initiated on March 1st, 2016 and concluded on August 23rd, 2016.
• Fecal samples were collected from the yearlings every two weeks to determine the Egg Per Gram (EPG) count of ascarid and strongyle eggs and to identify the presence of tapeworm eggs.
• MOX was administered to 88 yearlings on March 1st, while 55 yearlings were treated two weeks later.
• All the yearlings remaining on the farm (n=87) received the IVM-PRAZ combination on June 15th, 2016.

Findings

• A low number of ascarids were found in horses treated with MOX, indicating that the drug had minimal effect on this type of parasite. The researchers suggest that the low prevalence of ascarids prior to treatment could be attributed to age-related immunity in the horses.
• Both MOX and the IVM-PRAZ combination had similar efficacy rates against strongyles. It was observed that strongyle EPG values were reduced over 90% two weeks post-treatment, started rising again at four weeks, and returned almost back to pre-treatment levels at six weeks post-treatment.
• IVM-PRAZ demonstrated 96% efficacy against tapeworms two weeks post-treatment, and this level of effectiveness was maintained throughout the ten-week post-treatment examination period.

Conclusion

• The study provides valuable insights into the effectiveness of MOX and an IVM-PRAZ combination against ascarids, strongyles, and tapeworms in horses. While MOX showed considerable effectiveness against strongyles, it was less effective against ascarids. The IVM-PRAZ combination maintained a high level of effectiveness against strongyles and tapeworms during the study period.