Understanding Event Lines
Event lines are lines that form on the outer hoof wall that represent an event in a horse's life that caused an inflammatory response. Event lines can be caused by numerous factors such as medications, vaccinations, a change in diet such as hay, wormer, stress and so on. Barney’s hoof on the left shows catastrophic event lines caused by uncontrolled Laminitis, Cushings and EMS whilst being turned out onto grass. This specific photo shows the newer growth at the top of the hoof and the ridges of the event lines further down, marking a particular period in his life that caused this ongoing inflammation. These event lines/ridges are considered extreme and are just one of the many tell tale signs of Laminitis in the Acute or Chronic stage.
Some event lines show inflammatory events that have occurred but on a smaller scale. It’s important to remember that although event lines don’t always occur on a compromised horse like Barney, they still represent a ‘trigger’ that caused inflammation. More specifically, a singular event line can be read like a story – how far down the hoof is the marker, aka when did this event happen and what caused it? In an uncompromised horse and hoof, a singular event line doesn’t always necessarily mean any issues will arise from whatever caused the line but it is important to take notice and reflect on why this happened.
When we get reoccurring event lines as seen in the images below, we then know that something is off with our management or the horse’s diet that is consistently causing inflammation known as Laminitis. Typically an event line is a more readily observable symptom of sub-clinical Laminitis but do become more prominent in the later stages too, as seen on the left hoof.
When working with or owning compromised horses, often or not they will continue to be overly sensitive to certain ‘triggers’ such as changes in hay, even after removing the initial trigger/s and addressing the Laminitis which again can be seen by less prominent event lines. We typically expect horses like this to need a couple of years in recovery to see a change in this.