Ultrasonography of the suspensory ligament branches in yearling and 2-year-old Thoroughbred sales horses: Prevalence, progression of findings and associations with racing performance.
Authors: Peat Frances J, Kawcak Christopher E, McIlwraith C Wayne, Berk Jeffrey T, Keenan David P, Selberg Kurt T, Ojeda Alejandro
Journal: Equine veterinary journal
Summary
# Editorial Summary Peat and colleagues have established the first reference standards for suspensory ligament branch ultrasonography in sales Thoroughbreds by scanning 593 yearlings and 367 two-year-olds from major auction houses, tracking their racing careers through to four years of age. Grade ≥2 fibrillar changes were present in 8.9% of yearlings and 14.4% of two-year-olds, with approximately one-third of grade 2 yearling branches progressing to grade 3 lesions by two years of age; this progression carries clinical significance, as grade 3 fibrillar change substantially reduced the probability of racing and subsequent earnings. Beyond structural grading, specific ultrasound parameters showed predictive value: each 0.25 cm increase in branch width delayed racing onset by 49 days, whilst grade 2 hyperechoic foci correlated with £12,000–£23,000 lower total lifetime earnings and reduced earnings per start. Notably, grade 1 fibrillar pattern—the most common finding—associated with significantly higher earnings per start, suggesting these mild changes may reflect normal variation rather than pathology. For sales veterinarians and prospective purchasers, this work provides evidence-based criteria for risk stratification: whilst grade 1 changes and mild enlargement warrant careful monitoring, grade 2 hyperechoic foci and substantial branch enlargement at two-year-old sales constitute meaningful performance indicators that should influence purchasing decisions.
Read the full abstract on PubMed
Practical Takeaways
- •Use grade 1 fibrillar branch changes as a reference standard for normal young Thoroughbreds; these do not indicate poor prognosis and may correlate with superior racing performance
- •Grade 2 or higher fibrillar changes at 2-year-old sales warrant careful consideration as they carry meaningful risk to racing performance and earnings, with about one-third of grade 2 lesions worsening
- •Branch width measurement is a practical predictor—enlarged branches delay racing starts significantly; combine with hyperechoic foci assessment for presale evaluation
Key Findings
- •Grade ≥2 fibrillar branch changes present in 8.9% of yearlings and 14.4% of 2-year-olds at sales
- •Each 0.25 cm increase in branch width associated with 49-day delay in racing career start (P<0.001)
- •Grade 2 hyperechoic foci associated with significantly lower total earnings and earnings per start in racehorses
- •Approximately one-third of grade 2 yearling branch lesions progressed to grade 3 by 2 years of age
- •Grade 1 fibrillar changes associated with higher earnings per start and should be considered acceptable in sales horses