Does a heart have five hearts?
This is a case of misunderstanding. The horse has a single heart but the frog structure in each hoof acts as a mechanical pump to assist in the return blood flow. This is a mechanical response to the hoof impacting the ground so the frog acts in assisting the circulatory flow and in shock absorption. In teaching youngsters it is just easier to say a horse has a heartlike action in each hoof than explain the concept of haemodynamic action in the hoof structures. It sounds like he was over stating the analogy. However the function of the 4 frogs is to overcome hydraulic resistance and increase circulatory flow in assistance to the heart’s pumping action. Horses that are not walked out or cooled down after a work out suffer from swelling in their legs. http://www.yourhorse.co.uk/Horse-Answers…
