Good Morning and welcome to Just answer. I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
My worries about this young bull in your area would be tick borne diseases as well as a Vitamin E/Selenium deficiency. It will not hurt to supplement him with Vitamin E/SElenium and treating for other tick borne diseases which will affect the younger immune suppressed bulls.
Lepto also has to be taken into consideration in your area so testing should be done to rule this out....
In bulls this young, I still worry about a hereditary condition that is causing this since now he is using up more nutrients because of his advanced age....this would include a heart condition which your vet will have to rule out as well.
Sincerely, XXXXX XXXXX