So Doc, what are his/her chances?

A question we are often asked is ‘…what is the prognosis for the foal?...’  Sometimes that’s easy to answer, most of the time it’s difficult.  There are some things that can help though.

There have been a lot of studies done at university level to try and shed light on this issue.  A lot of the time, the things found to be good indicators of survival when foals first arrived at the hospital were difficult to measure in the field, didn’t mean the same things in other locations, and sometimes weren’t repeatable between different years even in the same hospital.  This can make things really difficult when estimating a prognosis, especially before very much information can be gathered and laboratory results reported.  Often, we are using history to predict the future…we ask ourselves this: the last time I saw one of these, how did it go?  There’s nothing wrong with that, we base many of our decisions on the lessons learned at the School of Clinical Hard Knocks.  We are a product of our past.  The search for repeatable and consistent prognostic indicators we can all use wherever we are largely continues.

In a bit of good news, however, a recent study identifies a few things we can quickly find out that seemed to be useful, at least around here where some of the research was done:

Dembek, Katarzyna A., et al. "Development of a Likelihood of Survival Scoring System for Hospitalized Equine Neonates Using Generalized Boosted Regression Modeling." PloS one 9.10 (2014): e109212.

In this paper, the researchers looked back to look forward.  They had the benefit of what knowing what happened to the foals in the first part of the study, looked at how things were at admission, then made a model predicting survival based on those factors.  It is like looking at the answer page, going back to the question, and engineering an answer that fits.  Nothing wrong with that either.  The real test though was then using that model to predict what would happen on foals presented for treatment after the model was formulated, and seeing how well it worked.  So, that was like solving the problem first, then looking at the answer page to see how good you were.

Because I like to keep things simple, I was happy how this study turned out.  The following tables come from the paper.  Things we can easily assess – how warm the extremities are, gestational age at delivery, the presence of inflammation, and easily measured blood values (IgG, white blood cell count, and glucose) – turned out to be good predictors of how things were going to end up for the foal.  Each of these was assigned a number, and a score was calculated.

While you can’t take any of these in isolation, putting them together helped make better predictions about foal survival.

So, if you get a score of 4 or higher, you are above the magic 50-50 that we all get asked about.  The factor with the biggest weighting is cold extremities.  Think about it - if the legs and ears are cold, blood is not getting around, the foal is likely in shock and there is nothing good that is going to happen unless you intervene.

The authors caution that as with other studies dealing with the prognosis of foals admitted to hospitals, there will likely be differences in results using these very same parameters for different populations of foals, in different locations, with different people making the observations.  That is not to say that anybody is wrong, it just means there is a natural variation between situations that one study cannot overcome all by itself.  The most important thing is to not lose sight of the value of a good clinical examination of the newborn foal, and to make sure if there is any doubt a foal gets looked at in a timely manner.