Seasonal development of Cyathostominae larvae on pasture in a northern temperate region of the United Kingdom.

This research investigates the development of Cyathostominae larvae on natural pastures in Scotland, from April to December 2001. The study illustrates the role of temperature, rainfall, and time since faeces deposit in the larval development, with neither the number of eggs in the faeces nor their viability influencing the number of larvae retrieved.

Methodology of the Research

• The research engaged in tracking the development of Cyathostominae, a type of worm affecting horses, from the egg stage to the infectious larval third stage. This study was geographically located in the west central part of Scotland.
• Each week, duplicate samples weighing 1 kg each, obtained from naturally infected horse faeces, were laid on a cyathostomin-free pasture that was essentially an area of 78 cm².
• Weekly collections of grass samples from around the locations where the infected faeces were deposited were carried out over four weeks. The number of larvae found in these samples was then determined.

Findings

• Early results showed few larvae in the first week of development in the individual plots. However, the following weeks saw a rise in the larval numbers within the sample areas.
• The study found that climate conditions precipitated fluctuation in the rate of larval development. According to the statistical analysis, the number of infectious larvae found on the pasture was associated with the period since the faeces were deposited, as well as averages of temperature and rainfall occurring during the preceding week.
• An interesting interplay was observed between temperature and rainfall, which in combination posed a significant influence on the larvae growth rate.
• Contrary to expectations, the research model showed that there was no direct correlation between the number of larvae found on the pasture and either the number of eggs present or their viability in the initial faeces samples deposited on the plots.

Conclusion

• This research could contribute important understandings to the control and treatment strategies for cyathostominae infestation in horses, by revealing the interaction between climate factors and larval development rates.