older mare with running nose

Question
My daughter was give a mare that is 16-years old to use for 4-H.  She is a registered American Saddle Horse.  She is having discharge from the nose, yellow goopy looking.  She is up to date on shots per prior owner. Wondering if we should give another series of rhino vaccine.  She is also underweight.  Ribs stick out, so we wormed her too and have purchased senior grain for her.  

Answer
Hello Della
It would be an execellent idea to get her checked by a vet. This can be any kind of infection. Keep her in a warm place for now, and keep wiping her nose. I find Macintosh feed works very well to fatten up some horses. Seniors feed is good also. Good idea.
I hope everything goes well
Thank you