What they are
Seromas are fluid-filled sacs that occur secondary to direct trauma, such as being kicked by another horse. They usually start out as haematomas (bruises) that become seromas over the course of a few days or weeks. These lesions can appear anywhere on your horse’s body but the most common locations are on his chest or upper hind legs. A seroma will feel like a fluid-filled lump, and it usually won’t concern your horse too much. However, if you find the lump in the early haematoma phase, the lump is likely to be harder, hot and painful to palpation.
Most seromas resolve on their own. However, in some persistent cases your vet may drain large seromas. This is a last resort as draining seromas can risk causing infection.