Management of drug-resistant cyathostominosis on a breeding farm in central North Carolina.

The study discusses the management of anthelmintic resistance in a breeding farm using targeted ivermectin treatment, considering the change in resistance patterns and efficacy over time. It also highlights the significant reduction of anthelmintic treatments in mare and foal groups.

Research Objective

• The study’s main goal was to manage small strongyle transmission in a horse herd showing resistance to both pyrantel pamoate and fenbendazole. This was to reduce the risk of individual horse diseases. The research aimed to track changes in resistance patterns over time and gauge ivermectin’s effectiveness throughout the study period.

Methods

• The researchers carried out a targeted ivermectin treatment on the farm’s mature horses with faecal worm egg counts (FWEC) exceeding 200 eggs/g, and for those less than two years old with FWEC bigger than 100 epg.

Results

• The 30-month long campaign resulted in acceptable cyathostome control as evidenced by the mare’s FWEC. Moreover, patent cyathostome infection control improved in sequential foal crops.
• The Egg reappearance time (ERT) post-ivermectin treatment was less than 8 weeks in mares and foals more frequently in the study’s second year than in the first year.
• Anthelmintic treatments decreased by 77.6% and 533% in mare and foal groups, respectively.

Conclusions

• The researchers concluded that targeted ivermectin treatment could be an economically viable solution to manage multiple drug-resistant cyathostominosis.
• They also emphasised the importance of closely monitoring the use of ivermectin for the potential development of resistance.