Yearling laryngeal function in Thoroughbreds that underwent a laryngoplasty differs from controls

Area of Science:

• Equine veterinary medicine
• Animal surgery
• Respiratory diagnostics

Background:

• Yearling laryngeal function (YLF) assessments are crucial for sales, impacting equine economics.
• The relationship between YLF and subsequent need for prosthetic laryngoplasty (PL) is not well-established.

Purpose of the Study:

• To investigate the association between yearling laryngeal function grades and the risk of requiring prosthetic laryngoplasty.
• To test the hypothesis that YLF grade II.2 or higher increases the risk of PL.

Main Methods:

• A case-control study design was employed.
• 150 prosthetic laryngoplasty cases and 600 controls were analyzed using videoendoscopic examinations.
• Yearling laryngeal function was graded by blinded observers using the Havemeyer system, with risk calculated via logistic regression.

Main Results:

• Horses with YLF grade II.2 or higher had a significantly increased odds ratio (OR) of 4.61 for requiring PL compared to those with YLF below grade II.2.
• Higher YLF grades (III.1 and above) showed substantially elevated ORs for PL, indicating a strong correlation.
• Three-quarters of horses undergoing PL had a YLF of grade II.2 or lower, suggesting common post-sale laryngeal function deterioration.

Conclusions:

• Deterioration of laryngeal function after sale is a common issue in horses requiring PL.
• Yearling laryngeal function grading, particularly grade II.2 and above, is a significant predictor for the need for prosthetic laryngoplasty.