Nasal discharge

[Secret Smiley]

In the last week is i have noticed that Sek has now a milky, not thick discharge from both nostrils, what may be the cause of this?

He is 24/7 at pasture and fed twice a day. rugged and ridden regularly through the week.

It is mid-winter here and he shows no other symptom of illness (no coughing) and is as lively and as full of himself as ever.

Should i be worried? Also what are the possible causes of this runny nose that ONLY occurs whist he is RIDDEN?

Advice greatly appriciated

[Mehitabel]

it's perfectly common for noses (horses and human) to run during exercise, and shouldn't be anything to worry about.
as a rule, if the discharge is clear or white it's not normally a problem, if there are no other symptoms. green or yellow discharge means a cold or other infection - again, just like people.

[ros]

We had the same - milky white discharge, only during exercise, earlier this year. Merlin had it just once in a while, but his stable companion, who was rather less fit at the time, had it more regularly. It seems to have disappeared now that they're both quite a bit fitter. The vet didn't have any bright ideas and as it wasn't accompanied by any more sinister symptoms we didn't really worry about it too much.