The livestock industry is extremely important to the economy of Oklahoma and includes not only commercial producers of meat or milk, but also purebred breeders and small producers with a few animals. The success of any type of livestock operation is closely related to the disease level of the animals.
Losses due to disease originate in many ways. Some are obvious, such as death, medication costs, and condemnations at the processing plant. Others are sometimes less obvious, such as poor growth, poor production, poor feed conversion, and downgrading.
Disease is an alteration of the body or body organs which interrupts or disturbs the body's function. Such disturbances often are recognised by detectable alterations of body functions.
Etiology is the study of disease causes. A disease often results from a combination of two or more causes - the indirect or predisposing factors which may lower the animal's resistance, and the direct or determining factors which produce the actual disease.
Predisposing causes of disease are referred to frequently as "stress" factors. Stress factors include chilling, poor ventilation, overcrowding, inadequate feeding and watering space, overmedication, etc. Times to be particularly aware of stress are at shipping and weaning.
Detectable signs of disease are known as symptoms. Visible changes in the size, color, shape or structure of an organ are known as lesions. Loss of body weight, decreased production, reduced feed consumption, droopiness and lameness are some symptoms. An enlarged liver, tumour on the intestine, or abscess in a lung are examples of lesions.
Many symptoms are general; they usually are seen in any diseased individual. Examples are droopiness, loss of appetite, labored breathing, nasal discharge and diarrhea.
Article made possible through the contribution of Oklahoma State University.