Influence of type and breed of horse on serum osteocalcin concentration, and evaluation of the applicability of a bovine radioimmunoassay and a human immunoradiometric assay [corrected].

This study is focused on evaluating the applicability of a human osteocalcin immunoradiometric assay for use with horse serum, comparing it with a bovine radioimmunoassay, and observing the effect of horse type and breed on serum osteocalcin concentrations. The researchers found significant differences in osteocalcin concentrations between draft and warmblood types of horses, and the human immunoradiometric assay was found not to be valid for equine serum analysis.

Research Methods

• For this study, 100 healthy horses of either sex were selected. These horses were classified into two types: type I (draught) and type II (warmblood). Each type was further divided into two breed groups, each containing 25 horses.
• Blood samples were collected from these horses in the morning and serum was separated from the samples. Osteocalcin concentration in this serum was then measured using commercially available radioimmunoassay (from bovine) and immunoradiometric assay (from human) kits, following the manufacturer’s instructions.
• Each sample was evaluated twice to ensure consistency and reliability of results.

Findings

• The test results revealed that the human immunoradiometric assay did not detect equine osteocalcin, implying it is not valid for this type of analysis.
• The bovine radioimmunoassay results varied significantly between the two types of horses. Draught horses displayed lower osteocalcin concentrations than warmblood horses.
• There was no significant difference in osteocalcin levels when horse breeds within the same type were compared.
• Neither the sex of the horse nor its age demonstrated any significant influence on serum osteocalcin values.

Conclusions

• The researchers concluded that no crossreactivity exists between the equine and human amino- or carboxy-terminus of osteocalcin when using this specific human immunoradiometric assay kit.
• They also discovered a difference in blood osteocalcin concentration between the draught and warmblood types of horses.
• Therefore, when evaluating osteocalcin concentration in research or clinical situations involving horses, it is important to consider the type of horse, especially when expecting small variations in osteocalcin concentration.