Survey of retinal haemorrhages in neonatal thoroughbred foals.

This research study examined retinal hemorrhages in newborn thoroughbred horses, finding that 16% of the studied population had such hemorrhages. Other factors, such as sex and the type of hemorrhage, were also analyzed.

Methodology

• The researchers carefully examined the complete fundus (the interior surface of the eye opposite the lens) of 167 newborn thoroughbred foals.
• Importantly, the study noted the effect of savviness in differentiating hemorrhages from other lesions and the selection bias involved in choosing these foals from a largely normal population.

Findings

• Results showed that 27 out of 167 neonatal foals (16%) had retinal hemorrhages.
• The hemorrhages were more common in bilateral cases and the frequency was significantly higher in female foals.
• The incidence of hemorrhages ranged from one to twenty per animal.
• 36% of eyes with retinal hemorrhages had the small punctate type (small, pinpoint hemorrhages).
• A larger 56% had the splash-like form (larger, irregularly shaped hemorrhages).
• There was no change observed from one type of hemorrhage to another, and the patterns of resolution were similar
• All but two of the retinal hemorrhages occurred in the tapetal fundus, and they resolved within 10 days.

Implications

• The study did not find any short-term or long-term ocular or neurological effects resulting from the retinal hemorrhages.
• No correlation between these hemorrhages and incidents of abnormal foal behavior was observed, implying that the hemorrhages do not significantly impact foal behavior or health in the longer term.