A healthy horse, free of worms and on a healthy diet will have a rich glossy coat, so long as it doesn't have a skin infection eg ringworm.
There are several serotypes of this bacteria that can infect a horses gut. Salmonella typhimurium appears to cause more severe symptoms than others.
Respiratory diseases are classified by their location (Upper - above the throat, or Lower - wind-pipe (trachea) and chest cavity (thorax) including the lungs - Respiratory Tract) or their causes.
Most horse owners have at some time or another had to deal with injuries of their horse, often as a result of accidents while the horse is grazing.
OCD is usually seen in young, rapidly growing horses (weanling through to 2yo), but can be occasionally seen in older horses.