Seasonal Pattern of Cortisol Fluctuation in Horsehair Samples from Three Different Body Areas: A Year Long Study.

The research article is about a study conducted to understand the pattern of seasonal changes in the cortisol concentration in horsehair, which is an indicator of chronic stress in horses.

Research Objective

• The primary aim of the research was to investigate the seasonal variations in the cortisol concentrations in horsehair (HCC) as an indicator of long-term or chronic stress in horses. The researchers intended to examine whether different seasons influence the cortisol levels in horses.

Methodology

• Hair samples were collected from twelve horses aged between 1.5 and 30 years. These samples were collected four times throughout a year, ensuring a fair representation of all seasons.
• The intervals between each hair collection, representing different seasons, ranged between 102 and 115 days.
• The samples were then analyzed using the ELISA (enzyme-linked immunosorbent assay) method, a standard test used to detect and measure antibodies or antigens in a sample.

Results

• The researchers confirmed seasonal dynamics in cortisol levels with the following pattern observed: August > November > January > April.
• The lowest mean cortisol concentrations were detected in the April samples (10.05 ng/ml) and the highest mean concentrations were observed in the August samples (18.63 ng/ml).
• The impact of the body area from where the hair samples were taken was also investigated. Samples were collected from the mane, tail, and carpal area of the right forelimb of the horses. However, it was found that the body area did not significantly affect the cortisol concentrations.

Limitations and Recommendations

• A slight difference was observed only for winter samples between the mane/leg and tail/leg, but this was not the case for mane/tail.
• No difference in HCC was associated with the variable of the horse’s age.
• The researchers cautioned that due to the small sample size and the multitude of diverse factors that might contribute to the seasonal patterns of HCC, the results of this study should be interpreted with caution.