Horses and ponies sometimes suffer nosebleeds after very strenuous exercise - usually a race.
In these cases the blood is actually coming from the lungs, but nosebleeds can can also occur after a bang on the head or when a small blood vessel in the nasal lining starts bleeding or bursts - sometimes as a result of a horse rubbng his nose when irritated by flies or pollen.
The nosebleeds to watch out for however are the ones with no obvious cause - a nosebleed that occurs when the horse or pony is just standing quietly in the stable.
A nosebleed under these conditions can still be harmless but just occasionally it can signal something more serious.
The most common cause of nosebleeds in a horse is a simple knock on the head - this may result in large amounts of blood pouring from, usually, one nostril.
Nosebleeds caused by usually clear up by themselves, but it is always best to consult your vetif this happens.
A foreign body stuck in the horse's nose or throat can cause a mild nosebleed. This is usually accompanied by coughing.
Etmoid haematoma, which is a lump, similar to a giant blood blister, growing inside a horse's nose and sinus problems are possible causes.
The serious, but rare, condition to watch out for is guttural pouch mycosis -this can be deadly.
In Guttural pouch mycosis a fungus grows on the internal cartoid artery at the point where it crosses the floor of the guttural pouch. This condition usually requires surgery to stem the bleeding.
Sometimes tumours in the horse's respiratory tract or equine sinusitis can cause a trickle of blood to run from the horse or pony's nose.
Horses generally don't have spontaneous nosebleeds.
If your horse or pony is having unexplained nosebleeds it is best to have him examined by a vet.
Checking the guttural pouches will involve passing a fibre-optic endoscope up the nose and into the 2 pouches.
A thorough veterinary examination will also help to diagnose, or rule out, other causes of equine nosebleeds such as ethmoid haematoma.