Work on characterization of the effect of collibacillosis on calves' performances

Abstract

Collibacillosis is one of the most common diseases of farm animals caused by pathogenic stains of E.coli bacteria. The occurrences of this disease are as Septicemic and enteric forms. The form is caused by strains that are able to invade the extra intestinal tissue, resist the bactericidal effect of complement, survive and multiply in body fluids, escape phagocytosis and induce damage by the release of cytotoxins. Later the strains of E.coli have colonize and proliferate the ability in the upper part of the small intestines and produces enter toxins, which causes an increase in net secretion of fluid and electrolytes from the systemic circulation. The enteric Collibacillosis is one of the most common causes of diarrhea in very young calves (in the first week life) and causes high mortality in this age group. Demonstration of enterotoxigenic strains can be done by cultural isolation of the relevant strains, assay of toxins, and histopathological, serological, and molecular techniques. When therapy is to be established, physical examination should be done to determine the current disease and level of dehydration. Although antibiotics are frequently used in the treatment of Collibacillosis, fluid and electrolyte therapy is the major part of treatment to prevent dehydration and electrolyte imbalance. Measures to control the disease includes avoiding group housing, weather, stress and poor hygiene; supplementing nutrition to the pregnant dam; early colostrum feeding to the calves; vaccination of pregnant dams in endemic areas; and effective management of outbreak when it occurs.