Factors associated with long-term athletic outcome in Thoroughbred neonates admitted to an intensive care unit

Limited information exists on the long-term outcome of foals that survive following hospitalisation for disease as a neonate. Significant financial investment is required to raise foals to racing age, therefore improved understanding of factors that affect long-term outcome and future athletic performance is important.

To analyse racing performance in Thoroughbred foals hospitalised as neonates, compared with their maternal siblings and to determine factors associated with failure to race and racing performance.

Retrospective cohort study.

Medical records of Thoroughbred foals admitted to a neonatal intensive care unit between 1982 and 2008 were reviewed. Surviving foals of registered mares were included. Data including the foal's primary and concurrent diseases were extracted from the medical record. Racing records for foals and maternal siblings were evaluated. Multivariable logistic regression was used to identify disorders associated with failure to race and decreased racing performance.

Two-hundred and sixty-nine of 454 previously hospitalised foals (59%) raced. Sixty-eight percent (269/394) of registered foals raced, compared with 79% (697/880) of registered siblings. Foals with prematurity/dysmaturity (P = 0.002) and those with orthopaedic disease (P = 0.007) were significantly less likely to race than their siblings. Premature/dysmature foals also had significantly fewer starts and wins and lower earnings than siblings. Foals with orthopaedic disorders had a lower percentage of wins, relative to their siblings. There was no significant association between racing performance and other disease categories.

Small sample size in some disease categories and retrospective nature of study.

Foals hospitalised due to prematurity/dysmaturity or orthopaedic disorders were less likely to race than their maternal siblings and those that did race had decreased performance.