Antibiotic Use In Horses

There are many times when antibiotics are needed to save a horses life.

In this blog I wanted to remind you all of times when antibiotics can TAKE a horses LIFE.

The horses hind gut is a complex mix of microbiota which includes Bacteria, Protozoa, Fungi and Yeasts. Many things can disturb the very importance balance of these organisms. The most common causes are fast changes in feed, which can include grass as well as hard feed, infection with bad bacteria such as salmonella, but most importantly our antibiotic usage.


Every time a horse is administered antibiotics, it will upset the delicate balance of microorganisms in the hind gut. This usually happens at a very low level and the hind gut can still function correctly. If the antibiotics kill enough of the ‘good bacteria’, it changes the way the microorganisms ferment food, and converts the hind gut into a state of promoting ‘bad bacteria’. As a result, there is release of damaging substances and eventually we see sever ulceration of the hind gut walls. This ulceration causes pain, the horses feel unwell, and often present with diarrhoea.  As this ulceration worsens, bacteria can move across into the blood stream and cause septicaemia which has a very high mortality rate.


I wanted to remind you all of this today, because I commonly am requested for antibiotics for small local skin infections, or as a preventative for injection when a horse sustains an injury.

Often these antibiotics are warranted. However, EVERY SINGLE time we use antibiotics in our horses we must balance the risk of giving them versus the very real but thankfully rare, life threatening risk of using them.

Let’s not forget topical antibiotics, washing with antiseptics, and early recognition of problems being the key to reducing the need for using them.

I hope you found this a useful reminder.