Readability and histological biocompatibility of microchip transponders in horses.

This research article investigates the readability of microchips in horses by different scanners, and also evaluates the effects of these microchips on horse tissue. The findings reveal that microchip readability varies by scanner type and location on the horse, and that the chips’ presence causes some histological changes, but they generally remain a reliable and safe method for horse identification.

Microchip Readability and Factors Affecting It

• The research examined the readability of microchips in a study that involved 428 horses and employed three different scanners for the microchips.
• The study found significant differences in the identification of microchips among the different scanners. Scanner C had the highest microchip identification rate at 100% on the side of the neck containing the microchip, while Scanners A and B had lower identification rates of 93.5% and 89.7%, respectively.
• The location of the microchip also played a role in its readability. From the contralateral (opposite) side of the horse’s neck, the scanners had lower identification rates; Scanner C still had the highest readability rate at 89.5% while Scanners A and B could only identify 21.5% and 26.9% of the microchips, respectively.
• The research also found that the age of the horse significantly impacts the readability of the chips, while the breed of the horse does not.

Impact of Microchips on Tissue

• The study also extensively examined the effects of microchips on horse tissues, based on necropsy findings from 16 animals.
• The researchers found that the microchips were surrounded by fibrous capsules of varying thickness in most of the animals (15 out of 16).
• Microchips were located in different locations within the tissues – subcutaneous fat, inter- or peri-muscular connective tissue, or musculature.
• Additionally, the study noticed some degrees of lymphohistiocytic inflammation within the fibrous capsules surrounding the transponders. This inflammation ranged from severe to mild.
• The study pointed out that in some instances, granulation tissue with attendant granulomatous inflammation, and granulomatous myositis were observed around the microchip.

Conclusions

• Despite the histological changes observed in horse tissues, the study concludes that microchip transponders are a highly reliable and biocompatible method for identifying horses.
• Given how mandatory horse identification is within the European Union, with few exemptions, this study’s findings uphold the effectiveness of microchip transponders for this critical task.