Calf scours causes more financial losses to cow-calf producers than any other health problem in their herds. Calf scours is not a single disease; it is a clinical sign associated with several diseases characterized by diarrhea. Regardless of the cause, diarrhea prevents the absorption of fluids from the intestines; also, body fluids pass from the scouring calfs body into the intestines. A calf is approximately 70 percent water at birth. The scouring calf loses fluids and rapidly dehydrates. In addition, dehydration is associated with loss of essential body chemicals (electrolytes)-sodium and potassium-and the buildup of acid. The scouring calf becomes dehydrated and suffers from electrolyte loss and acidosis. Infectious agents cause the primary damage to the intestine, but death from scours usually results from dehydration, acidosis, and loss of electrolytes. The identification of infectious agents which cause scours, however, is essential for implementing effective preventive measures.
Causes of Calf Scours
The known causes of scours are grouped into two categories: (1) noninfectious causes, and (2) infectious causes. The noninfectious causes are often referred to as “predisposing” or “contributing” factors. Whatever they are called, there is a dramatic interaction between noninfectious causes and infection. Any effort to prevent infectious causes is usually fruitless unless serious control of contributing (non-infectious) factors is part of the overall program.
Noninfectious Causes of Calf Scours
Noninfectious causes are best defined as flaws in management which appear as nutritional shortcomings, inadequate environment, insufficient attention to the newborn calf, or a combination of these. The most commonly encountered noninfectious problems include:
(a) Inadequate nutrition of the pregnant dam, particularly during the last third of gestation. Both the quality and quantity of colostrum are adversly affected by shortchanging the pregnant dam in energy and protein. Deficiencies in vitamins A and E have been associated with greater incidence of calf scours.
(b) Inadequate environment for the newborn calf. Muddy lots, crowding, contaminated lots, calving heifers and cows together, wintering and calving in the same area, storms, heavy snow or rainfall, etc. are stressful to the newborn calf and may increase the chance for easy exposure to infectious agents. The wet and chilled newborn calf experiences a drainage of its body heat, may be severly stressed, and all too often lacks the vigor to nurse sufficient colostrum early in life.