Strategic control of gastrointestinal nematodes in equines in an extensive livestock production system in a tropical region.

The research focuses on the strategic control of gastrointestinal nematodes in horses, studied within a tropical region in Brazil. The goal is to reduce the parasite population without putting the horses’ health at risk or contributing to parasite resistance. The study suggests a strategic control protocol involving two treatments per year effectively reduced the parasite count without affecting the horses’ health.

Research Objectives and Methodology

• This study aims to explore the efficient control of gastrointestinal nematodes in horses that can reduce the parasite population in the host and environment without harming the animal health or creating resistant parasites.
• The study was carried out in Anastácio, a municipality of the state of Mato Grosso do Sul in Brazil, over a span of two years from April 2021 to March 2023.
• Two groups were involved in the study — a control group and a treated group. The horses in the treated group received oral ivermectin as treatment in May and September, each year of the experiment.
• Every 28 days, the researchers collected feces, weighed the animals, calculated body condition scores, counted eggs per gram (EPG) in feces, and performed larval counts in the pastures.
• DNA from the eggs was analyzed using real-time polymerase chain reaction (PCR) to identify species of the parasite, particularly Strongylus vulgaris.

Key Findings

• The treatment considerably reduced the EPG count, demonstrating a decrease in parasite load.
• There was no significant impact on the weight or body condition score of the animals, showing that the health and vitality of the animals were not affected negatively by the treatment.
• Among the parasites identified, the most prevalent was the taxon Cyathostominae.
• The study found that the treatment acted as a protective factor against S. Vulgaris, therefore indicating its efficiency against this particular parasite.
• There was a significant difference observed in the dry season between the control and treated groups in terms of larvae present in the pastures, which suggests that the treatment was successful in reducing environmental parasite loads.

Conclusion

• In conclusion, applying strategic control with two treatments per year managed to reduce the egg count, number of larvae in the pasture, and the presence of S. vulgaris.
• This was achieved without influencing important health indicators of the horses, such as their weight and body condition score.
• This study’s findings imply that, at least in a tropical context, it is possible to manage and control equine gastrointestinal nematodes strategically without posing a risk to the health of the animals or contributing to the development of resistant parasites.