Metals, Heavy Metals and Nutrients like Selenium accumulate in the hair of horses when exposed to forage that is for instance high Selenium. Concentrations of Selenium in forage correlate strongly with Selenium concentration in the mane and tail hair of the horse. Additionally, horse hair analysis is used successfully to assess exposure to toxic metals.
Previous studies have demonstrated that there is a continual growth in the permanent hair of equine mane and tail. These studies indicate a relatively constant rate of growth of manes and tails over periods of time up to 12 months. Tail and mane (medial) grew at 0.792 and 0.746 mm/day, respectively. To simplify data visualisation of the results above, we have estimated population average values of trace elements and toxic metals in horse hair based on the research literature.
In addition, studies have found gender differences in hair trace element content in mane hair in horses. These studies (Valeriy V. Kalashnikov et al, 2019) recommend that gender-specific values of hair trace element content should be used for interpretation of hair analysis results in horses. If needed, you can see gender specific horse hair references ranges for a more detailed analysis of metal/nutrient levels more relevant to your horse in the literature articles provided below.
"Analysis in Horse Hair as a Means of Evaluating Selenium Toxicoses and Long-Term Exposures", T. Zane Davis,et al. 2014
AND "The content of essential and toxic elements in the hair of the mane of the trotter horses depending on their speed", Valeriy Kalashnikov et al, 2018
AND Assessment of Gender Effects and Reference Values of Mane Hair Trace Element Content in English Thoroughbred Horses (North Caucasus, Russia) Using ICP-DRC-MS, 2019, Valeriy V. Kalashnikov et al. All articles are available for loan here (they belong to Toxtest) or online via standard research channels or Google Scholar.