A comparative study of normal equine populations and those with grass sickness (dysautonomia) in eastern Scotland.

This research article conducts a comparison of horse populations in Eastern Scotland, investigating patterns of a condition called grass sickness. It finds that younger, healthier horses grazing in the spring or summer are more susceptible, and that factors like changing grazing locations and experiencing stress can increase the risk.

Research Methodology

• The researchers conducted a retrospective survey of premises in Eastern Scotland where at least two cases of grass sickness had been reported between 1970 and 1987.
• For comparison purposes, they also surveyed 49 other horse establishments, where no grass sickness had been documented, from 1986 to 1988.

Findings of the Study

• The study found that younger horses, particularly those in healthy physical condition grazing full time during spring or early summer, were more susceptible to grass sickness.
• Moving horses to new grazing areas increased the risk of grass sickness, suggesting a possible link between unfamiliar grazing territories and the disease.
• Stressful situations were also identified as a potential contributing factor, which indicates that the horses’ emotional well-being may influence their susceptibility to the disease.

Role of the Establishment

• The researchers examined the role of the type of horse establishment in the prevalence of grass sickness.
• The type of establishment was found to influence the animals’ physical condition during the summer, but it did not significantly influence the prevalence of grass sickness.
• Riding schools and livery establishments with records of the disease typically kept more horses than unaffected premises of the same type. This finding might suggest that overcrowding or more competitive environments could contribute to the spread of the disease.

Food and Grass Sickness

• The researchers examined if there were any links between supplementary feeding or the stage of pasture growth and the prevalence of grass sickness.
• They found no clear relationship, indicating that these factors may not be significant contributors to the disease.

Overall Conclusion

• The researchers conclude that, while grass sickness is associated with grazing, other multiple factors may influence the onset and expression of the disease.
• This suggests that preventing or treating grass sickness may require interventions addressing several different factors – not just changes in grazing practices.