Gestation length and racing performance in 115 Thoroughbred foals with incomplete tarsal ossification

Abstract

Incomplete ossification, especially Grades 1 and 2, is associated with a short gestation length. Foals with Grades 2 and 3 incomplete ossification were less likely to race and Grades 1, 2 and 3 earned around $30,000 less than their maternal siblings.

Clinical insights: Recent development in equine neonatology and foal medicine (2017–2019)

“…A total of 115 Thoroughbred foals were evaluated and compared to 594 maternal siblings. Not surprisingly, a significant correlation between incomplete ossification grade and gestational length was identified with the shortest gestational lengths associated with the most severe incomplete ossification . These findings support the widely accepted notion that skeletal immaturity is associated with premature birth.…”

“…Factors associated with failure to race that were retained in the multivariable model included prematurity/dysmaturity, noninfectious orthopaedic disease and female sex . It is not surprising that premature/dysmature foals were less likely to race because of the strong association with incomplete ossification of the cuboidal bones . In this study, of the 454 hospitalised foals, 394 foals were registered with the US Jockey Club which provided racing data to compare with 880 registered siblings that were never hospitalised.…”

“…Ossification of the cuboidal bones progresses rapidly during the last few weeks of gestation but fetal‐maternal diseases during gestation may result in some fetuses being born early and/or having incomplete ossification of the cuboidal bones. In a recent retrospective study over 17 years, foals less than 90 days of age that had tarsal radiographs were evaluated to determine if the degree of ossification of the cuboidal bones was associated with gestational length and if incomplete ossification impacted athletic performance . A total of 115 Thoroughbred foals were evaluated and compared to 594 maternal siblings.…”

Osteochondral fragments of the pastern joint at the origin of the collateral ligament of the distal sesamoid bone: performance after arthroscopic removal (2000–2015)

“…Histopathologic analysis of the fragments could have allowed insights into the pathophysiology of the underlying disease but was not performed. The control group used to assess the effect of fragments on performance in this study consisted of maternal siblings, representing a group of horses genetically similar to the treated horses . Although we cannot ascertain the absence of pastern fragmentation in the control population, these horses would have also undergone survey radiography according to the industry standard for thoroughbred yearlings.…”

“…The control group used to assess the effect of fragments on performance in this study consisted of maternal siblings, representing a group of horses genetically similar to the treated horses. [24][25][26] Although we cannot ascertain the absence of pastern fragmentation in the control population, these horses would have also undergone survey radiography according to the industry standard for thoroughbred yearlings. Including a control group of horses with osteochondral fragmentation of the PIP joint that did not undergo fragment removal and that were trained for racing was clinically impractical because owners aim for athletic performance.…”