Common Diseases of Farm Animals

Disease is the general term for any deviation from the normal or healthy condition of the body. The morbid processes that result in either slight or marked modifications of the normal condition are recognized by the injurious changes in the structure or function of the organ, or group of body organs involved. The increase in the secretion of urine noticeable in horses in the late fall and winter is caused by the cool weather and the decrease in the perspiration. If, however, the increase in the quantity of urine secreted occurs independently of any normal cause and is accompanied by an unthrifty and weakened condition of the animal, it would then characterize disease. Tissues may undergo changes in order to adapt themselves to different environments, or as a means of protecting themselves against injuries. The coat of a horse becomes heavy and appears rough if the animal is exposed to severe cold. A rough, staring coat is very common in horses affected by disease. The outer layer of the skin becomes thickened when subject to pressure or friction from the harness. This change in structure is purely protective and normal.