[Age-related changes in the intervertebral disks of the cervical vertebrae of the horse].

The research investigates how age influences changes in the intervertebral disks of horses’ cervical vertebrae. The study reveals that with age, horses experience degenerative lesions such as connective tissue fiber deterioration, leading to either partial or full disk separation, commonly seen as yellow discoloration.

Study Methodology and Findings

The researchers studied the cervical vertebral column (the neck area of the spinal cord) of 103 horses of varied ages, spanning from a 42-week-old fetus to a 23-year-old adult. Through this study, they found:

• There was no pulpy (gel-like) nucleus in the cervical intervertebral disks of the horse, countering what previous bodies of literature suggest. Instead, the disks were found to consist only of fibrocartilaginous (fibrous and cartilaginous) tissue.
• As the horses aged, they found an increasing number of age-related degenerative changes. These changes included the degradation or break down of the connective tissue fibers, resulting in either a partial or complete loss of connectivity between the disks.
• In more severe cases, the disks that had separated or broken down were observed to have a yellow discoloration. This was found to be more common in older horses.

Grade and Incidence of Lesions

Age and location in the cervical vertebral column influenced the grade and incidence of the lesions. Findings showed:

• The incidence and grade of these lesions increased with the age of the horse.
• The progression of degenerative lesions moved from the cranial (closer to the head) to the caudal (closer to the tail) regions of the cervical vertebral column.
• It is noteworthy that despite the high degree of degenerative separation exhibited in some cases, no clinical symptoms had been reported, indicating horses could suffer from such conditions without showing any apparent signs of discomfort or pain.