Project overview: Assessment of intra-horse variability in Thoroughbred yearling laryngeal function

This project examines how upper respiratory tract endoscopy, or “scoping”, influences decision-making in Thoroughbred yearling sales.

Laryngeal grades assigned during pre-sale exams can affect buyer confidence, sale price and clearance rates. However, industry concerns remain about how consistent and reliable these assessments are.

Evidence shows that results can vary in the same horse when exams occur at different times or under different conditions. This uncertainty creates risks for buyers, vendors and veterinarians who rely on a single sales complex exam.

The study aims to measure how much laryngeal function varies within individual horses. Researchers will assess 100 yearlings using repeated, standardised endoscopic exams on farm and at the sales complex. They will also test how timing and the choice of nasal passage affect grading outcomes.

Results will provide the first clear evidence of intra-horse variability in this setting. The findings will help determine whether one exam reflects a horse’s typical laryngeal function. This work will support improved guidelines, increase grading consistency and strengthen confidence in pre-sale assessments.

It may also reduce costs and improve welfare by supporting practical alternatives to current sales-based examination practices.