Radiographic abnormalities of the thoracolumbar spinous processes do not differ between yearling and trained Thoroughbred horses without perceived back pain.

The research investigated whether young, untrained horses and older, trained thoroughbred horses without apparent back pain differed in terms of any observed spinal abnormalities. It was found that there were no significant differences in the severity of such abnormalities between both groups, suggesting these physical differences likely develop naturally instead of being caused by any form of training.

Overview of Methodology

• The research team carried out a prospective comparative study involving 102 thoroughbred horses, specifically untrained yearlings (47 of them) and trained horses (55).
• All the horses underwent a digital radiographic study of their thoracolumbar vertebral column, spanning T7-L3. The researchers were keen to observe the interspinous spaces (ISSs), which were graded based on criteria such as narrowing, increased opacity, radiolucency, and modeling of the cranial and caudal margins of two adjacent dorsal spinous processes (DSPs).
• The grading system generated an individual anatomical space score for each ISS and a collective score for each horse, facilitating comparisons.
• The findings underwent statistical analysis to draw conclusions.

Key Findings

• Almost a third of the ISSs examined unveiled signs of narrowing and impingement. More than half of the yearlings exhibited increased opacity, radiolucencies, and modeling in the dorsal spinous processes (DSPs).
• The median total score for individual horses did not vary significantly between yearlings and trained horses, hinting at quite similar frequency and severity of radiographic abnormalities across both age groups.
• The same trend was observed when comparing the median total score for each anatomical space in yearlings and trained horses.
• No substantial differences arose between both groups when considering the number of radiographic abnormalities, scores, and the total score.

Interpretation and Implications

• This study provides insights into the incidence and nature of DSP radiographic abnormalities in Thoroughbred horses.
• The lack of significant difference in the occurrence of such abnormalities between yearlings and older horses points towards a developmental, rather than acquired etiology. This means the abnormalities are likely not induced by training or any external influence, but rather develop naturally as part of the horses’ skeleton growth dynamics.