Signs and who is the causative agent of colibacillosis in calves, treatment and prevention

Colibacillosis affects calves in the first few days after their birth - it is a serious disease of infectious etiology that requires immediate treatment. The causative agent of the pathology is Escherichia coli, which causes severe diarrhea, exhaustion, dehydration and general intoxication of the animal’s body. Without timely treatment, a calf can die within a few days, and in the case of a hyperacute form of the disease, within a few hours.

What is the disease

Colibacillosis has several other names - escherichiosis, colidiarrhea, colisepsis. Young animals are susceptible to the disease, starting from the first days of life. The most common route of infection is nutritional; less commonly, the animal can become ill in utero or aerogenically. Infection of calves occurs through contact with the pathogen:

• through infected objects;
• mother's colostrum and dishes from which the calf drinks milk;
• contaminated air;
• dirty hands of staff caring for animals and clothing containing bacteria on the surface;
• as a result of contact with rodents (mice, rats) - due to the instability of the body of newborn livestock to infections;
• in case of non-compliance with sanitary standards for keeping livestock in a stall;
• due to violation of the rules of feeding, caring for adult cows and young animals during weaning.

The disease is an intestinal lesion in which the animal suddenly develops diarrhea followed by dehydration. Pathology does not develop in young animals with strong immunity and complete intestinal microflora, which resists the penetration of E. coli into the mucous membrane.

When the balance of microflora is disturbed, the pathogen invades the intestinal tissue and actively multiplies. As a result of the growth of a colony of pathogenic microorganisms, an inflammatory process is triggered. Poisoning with endotoxins (waste products of the pathogen) and lack of phagocytosis are the main causes of the severe clinical picture of colibacillosis.

Infectious agents

White diarrhea, or colibacillosis, develops in a calf when infected with the causative agent of colibacillosis - the pathogenic Escherichia coli. Refers to gram-negative rods. It has rounded ends, reaches a size of 2*0.6 microns, and does not form spores or capsules.

Escherichia quietly reproduces in their usual nutrient medium - soil, manure, water, milk, surfaces of livestock buildings, and livestock care items. Favorable conditions for the existence of the causative agent of colibacillosis – temperature 37 ^OC, pH 7.2-7.4, in which the stick can maintain vital activity for up to two months.

Factors contributing to the occurrence of colibacillosis

Calves are at risk of contracting colibacillosis in the first 3-7 days after birth and in the post-weaning period. Outbreaks of pathology occur at any time of the year, but more often in the winter and spring periods.

Factors predisposing to the disease:

• reduced resistance of the newborn’s body to infectious diseases;
• lack of passive immunity in calves - ignoring feeding with colostrum containing antibodies to the causative agent of colibacillosis, which are produced in cows during routine vaccination with preparations containing serological variants of Escherichia coli;
• poorly developed barrier functions of the calf liver, high permeability of the intestinal walls;
• poor quality nutrition of pregnant cows;
• crowded livestock housing;
• violation of optimal temperature and humidity in the barn.

The risk of infection of young animals increases in stalls where compliance with sanitary and veterinary standards is ignored and mice and rats are bred.

What are the symptoms of the disease

There are three forms of colibacillosis:

1. Septic. After intestinal damage, the pathogen penetrates the circulatory and lymphatic systems and internal organs. If there are not enough natural immunoglobulins in the calf’s body, rapid inflammation of the entire body occurs.
2. Enteritic. It appears when infected viral forms enter the body. The accumulation of toxins leads to the formation of a large amount of fluid in the intestines and a sharp change in electrolyte balance.
3. Enterotoxemic. Mixed form of the disease.

The incubation period of the disease is 1-2 hours to 3 days, depending on the resistance of the calf’s body, nutritional conditions, housing and age. If diagnosis and treatment are not timely, livestock mortality can reach 60-70%.

Subacute stage

Signs of the subacute stage:

• prolonged diarrhea;
• content of mucus and blood in stool;
• dehydration;
• retraction of the sides and eyelids.

More often, the subacute stage occurs in the enteritic form.

Acute stage

In the acute stage of colibacillosis, signs of the septic form most often appear. At the onset of the disease, the calf's temperature rises by 0.5-1 ^OC, then the indicators decrease. The following are the most pronounced symptoms:

• weakness;
• increased heart rate and breathing;
• wave-like contractions of the body;
• diarrhea.

As a result of the release of a large amount of bacterial waste products and the destruction of part of the pathogen colonies, septic shock occurs. It manifests itself as vascular collapse.

Hyperacute stage

In the hyperacute stage, an enterotoxemic form of colibacillosis is observed.All of the listed symptoms are present, including seizures and the onset of severe coma. Therapy in most cases is pointless; the animal dies after 2-3 days.

How is the disease diagnosed?

Often young calves suffer from salmonellosis, vibrio and viral diarrhea, diplococcal infections, therefore differential diagnosis of colibacillosis is important. In addition to the clinical picture, the results of laboratory tests are evaluated. The feces of several infected animals are examined, in which the pathogen is sown. In the presence of fallen heads Cattle examine the heart, head, liver, lymph nodes of corpses.

How to cure colibacillosis in cattle

The therapy uses an integrated approach - a combination of antibacterial drugs, immunoglobulins, detoxification of the body, and diet.

It is important to restore water-salt metabolism, remove toxins, and replenish the supply of carbohydrates and proteins in the animal’s body.

Elimination of contagion

Treatment begins with isolating the sick animal. This is necessary to prevent disease in the entire livestock. The calf is put on a diet with the complete exclusion of milk. It is important to disinfect the room in which the causative agent of colibacillosis has multiplied.

Removing intoxication

To eliminate the symptoms of intoxication, the animal is soldered with alkaline solutions to remove decay products of the pathogen from the body. Droppers with saline solution, Trisol solution, and glucose are used. The use of bacteriophages, hyperimmune Escherichia serum, antitoxic serum against colibacillosis and salmonellosis, and gamma globulins will allow you to avoid a fatal outcome.

Rehabilitation therapy

It is mandatory to prescribe antibiotics, which are selected depending on the sensitivity of the pathogen:

• "Sulfazol";
• "Sulfadimethoxine";
• "Enroxil";
• "Gentamicin";
• "Furazolidone";
• "Levomycetin";
• "Tetracycline";
• "Flumequin."

Antibiotics are given three times a day with water or colostrum, changing drugs to avoid the development of pathogen resistance to them. Combine antibacterial and antihistamine drugs.

Symptomatic and general restoratives

Symptomatic therapy has the following goals:

• restore water-salt metabolism;
• normalize the acid-base balance;
• neutralize the effects of toxins;
• compensate for the deficiency of vitamins and minerals.

Intramuscular injections of vitamin preparations, rehydration therapy with Regidron solution, Orsol and Ringer-Locke drips are useful.

Prevention

To prevent colibacillosis from developing in a newborn calf, it is necessary to take timely preventive measures, including:

• scheduled vaccination with inactivated drugs - 4 weeks before the cow mates (2 vaccinations with an interval of 14 days);
• timely vaccination of newborn livestock;
• observance of hygiene during childbirth, drinking milk;
• compliance with sanitary and hygienic standards by personnel caring for livestock;
• keeping equipment used in caring and feeding animals clean;
• regular disinfection measures in the stall.

Preventive measures are not troublesome and expensive, but help to minimize the labor-intensive and not always successful treatment of colibacillosis in young animals.

Escherichia is sensitive to a solution of bleach at 3% concentration, 20% freshly slaked lime, and a solution of hot sodium hydroxide at 4% concentration.This must be taken into account when preventing colibacillosis in calves in the form of regular disinfection of premises. Infected livestock require immediate treatment to avoid serious complications and death.