Macroscopic and Histological Morphology of the Equine Digital Cushion and Its Association with Subcutaneous Fat Thickness.

The research article evaluates how a horse’s Body Condition Score (BCS) and subcutaneous fat thickness affect the composition of their digital cushion—a specially designed tissue within the hoof. It was found that differences in subcutaneous fat patterns cause changes in the relative areas of adipose tissue, fibroelastic tissue, and collagen fibers in the digital cushion.

Sample and Methodology

• The researchers studied sixty Criollo mixed breed horses (21 males and 39 females) that were sent for slaughter. These horses underwent a Body Condition Score (BCS) analysis, a visual antemortem evaluation. The subcutaneous fat thickness was estimated using ultrasound evaluation.
• Postmortem, a macroscopic analysis was done on a thoracic and a pelvic limb of each horse, assessing the weight, volume, and density of the hooves and digital cushions. Furthermore, measurements of the internal structures of the hoof were carried out.
• Finally, histological analyses were conducted to measure the areas of adipose tissue (body fat), fibroelastic tissue (flexible, elastic tissue), and collagen fibers (structural proteins providing strength and firmness) within the digital cushion.

Key Findings

• The results revealed no macroscopic differences in the digital cushion between the thoracic and pelvic limbs or between male and female horses. Similarly, the histological characteristics between limbs and genders were found to be alike.
• Contrary to prior expectations, the study found no correlations between the weight, volume, and density of the digital cushion and the Body Condition Score.
• Interestingly, a positive correlation was found between the area of adipose tissue and a negative correlation with fibroelastic tissue surface area and collagen fibers. That is, the amount of subcutaneous fat directly affected the relative proportions of different types of tissue within the digital cushion.

Conclusion

• Therefore, the study concluded that the adipose tissue, fibroelastic tissue, and collagen fibers of the equine digital cushion change in size in relation to the horse’s subcutaneous fat patterns. This suggests that the fat coverage on a horse may have a substantial impact on the tissues constituting the digital cushion.