Causes of Foal Mortality: a One-Year Snapshot

Neonatal losses are a significant problem for the equine industry. Of the 1,294 fetal, neonatal, and juvenile equine cases presented to the University of Kentucky Livestock Disease Diagnostic Center from September 2004 through August 2005, 259 cases of neonatal mortality were evaluated for this study. Cases included only those that resulted from a live birth and those that had a specific age of less than 180 days, with cases in which the animals' age was listed as "juvenile" being excluded.

Deaths Up to 30 Days

The majority of all neonatal deaths occurred by 30 days of age (174/259, 67%). Of these, the top five causes of death include septicemia (44/174, 25%), musculoskeletal issues other than rib fractures (29/174, 17%), pneumonia (25/174, 14%), gastrointestinal problems (19/174, 11%), and rib fractures (18/174, 10%). All deaths from rib fractures occurred in this age bracket. (Rib fractures can result from multiple factors, including dystocia and trauma.)

All Neonatal Deaths (Up to 180 Days)

Of the 259 cases, septicemia was the predominant killer, causing 21% of all deaths (54/259). Of these, Escherichia coli (17/54, 31.5%) was the primary single organism grown from cultures obtained from septic animals; however, mixed cultures (17/54, 31.5%) were equally significant.

Deaths from musculoskeletal problems accounted for 51 (20%) of 259 cases, with 33 cases attributed to fractures. Trauma, other than those resulting in fractures, accounted for an additional nine cases of mortality.

When gastrointestinal problems (42/259, 16%) were identified as the cause of death, ulcers (9/42, 21.5%) and colitis (8/42, 19%) were the top two diagnoses.

Of the 15% of cases attributed to pneumonia (40 of 259), cultures failed to yield growth in 40% (16 of 40) of the cases. This could be attributed to treatment with antibiotics or to a viral or fungal etiology. Rhodococcus equi was cultured from 13 of the 40 (33%) pneumonia cases.

While the majority of the musculoskeletal causes cannot be prevented, improvements in orthopedic therapy allow for better outcomes. Prevention may be the best option for reducing deaths due to infectious etiologies, as foals are uniquely susceptible to infectious diseases. Therefore, it becomes imperative that veterinarians continue to educate horse owners and farm managers about vaccination, hygiene, and early recognition of clinical signs. More inclusive studies are currently being investigated on foal mortality.

Contact: Dr. Tracy Sturgill, 859/257-4757,, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky.


Dr. Craig Carter, 859/253-0571,, University of Kentucky Livestock Disease Diagnostic Center, Lexington, Kentucky.

This is an excerpt from Equine Disease Quarterly, funded by underwriters at Lloyd's, London, brokers, and their Kentucky agents. More articles from Equine Disease Quarterly...

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