The mineral analysis of hair samples is being promoted to evaluate dietary intake in horses and support the feeding of mineral supplements.

This experiment, conducted at the Institute of Animal Nutrition in Germany, compared results from three commercial laboratories to evaluate the reliability of hair analysis and determine the relationship between mineral intake and mineral content of mane hair.

Four healthy horses with a consistent diet, exercise regimen and housing situation were fed a mineral supplement over a 2-month period. At the end of the trial, the ration was analyzed to measure mineral intake, and hair samples from the same four horses were submitted to three different laboratories.

Despite the standardized experimental conditions, the results and reference ranges varied considerably between the laboratories. Some laboratories identified deficiencies of minerals for which other laboratories reported normal values. These disparities included results for minerals commonly considered important to evaluate in a ration such as copper, zinc and iodine. 

The authors concluded the analysis of hair samples is not reliable for evaluating mineral intake in horses, and traditional methods such as the analysis of feedstuffs and rations are more effective approaches to ensure adequate mineral intake in horses.

— Wahl L et al. JEVS 2022:104145