Colibacteriosis of calves: signs and who is the causative agent, treatment and prevention

Colibacillosis affects calves in the first few days after their birth - this 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 in a few days, and with a hyperacute form of the disease, in a few hours.

What is the disease

Colibacillosis has several more 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 alimentary, less often an animal can get sick in utero or aerogenically. Infection of calves occurs through contact with the pathogen:

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

The disease is a lesion of the intestines, in which the animal suddenly starts diarrhea, followed by dehydration. Pathology does not develop in young animals with strong immunity and a full-fledged intestinal microflora, which resists the penetration of the mucous Escherichia coli.

When the balance of microflora is disturbed, the causative agent of the disease is introduced into the intestinal tissues 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 the lack of phagocytosis are the main causes of the severe clinical picture of colibacillosis.

The causative agent from the intestinal mucosa penetrates the lymphatic and circulatory systems, provoking a septic process. Against the background of intoxication and tissue decay, the nervous system of the animal is affected, which, without timely treatment, manifests itself as a severe coma.

Infectious agents

White diarrhea, or colibacillosis, develops in a calf when infected with the causative agent of colibacillosis - pathogenic Escherichia coli. Refers to gram-negative rods. It has rounded ends, reaches a size of 20.6 microns, does not form spores and capsules.

Esherichia quietly reproduce in their usual nutrient medium - this is soil, manure, water, milk, surfaces of livestock buildings, livestock care items. Favorable conditions for the existence of the causative agent of colibacillosis - temperature 37 ^{оС, pH 7.2-7.4, in which the bacillus can survive up to two months.}

Factors contributing to the occurrence of colibacillosis

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

Predisposing factors:

• reduced resistance of the newborn 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 Escherichia coli serological variants;
• poorly developed calf liver barrier function, high intestinal wall permeability;
• poor nutrition of pregnant cows;
• crowded stall keeping of cattle;
• violation of the optimal indicators of 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, 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 into the circulatory and lymphatic systems, internal organs. If there are not enough natural immunoglobulins in the body of the calf, rapid inflammation of the whole body sets in.
2. Enteritic. It manifests itself when invading 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 the electrolyte balance.
3. Enterotoxemic. Mixed form of the disease.

The incubation period of the disease - 1-2 hours to 3 days, depends on the resistance of the calf's body, nutritional conditions, maintenance and age. With untimely diagnosis and therapy, the mortality rate of the livestock can reach 60-70%.

Subacute stage

Signs of the subacute stage:

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

More often the subacute stage proceeds in the enteric form.

Acute stage

In the acute stage of colibacillosis, signs of a septic form are most often manifested. At the beginning of the disease, the calf's temperature rises by 0.5-1 ^{оС, then the indicators decrease. Further, pronounced symptoms are added:}

• weakness;
• increased heart rate and breathing;
• wavy body contractions;
• diarrhea.

As a result of the release of a large amount of waste products of bacteria and the destruction of part of the colonies of the pathogen, septic shock occurs. It is manifested by vascular collapse.

Superacute stage

In the hyperacute stage, an enterotoxemic form of colibacillosis is observed. All of the above symptoms are present, up to convulsions and the onset of a severe coma. Therapy in most cases is meaningless, the animal dies after 2-3 days.

How the disease is diagnosed

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

How to cure colibacillosis in cattle

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

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

Elimination of contagion

Treatment begins with the isolation of the sick animal. This is necessary to prevent the disease of 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.

Removal of 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 are used with saline solution, Trisol solution, glucose. The use of bacteriophages, hyperimmune Escherichia serum, antitoxic serum against colibacillosis and salmonellosis, gamma globulins will allow avoiding a lethal outcome.

Rehabilitation Therapy

Be sure to prescribe antibiotics, which are selected depending on the sensitivity of the pathogen:

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

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

Symptomatic and restorative remedies

Symptomatic therapy aims:

• restore water-s alt metabolism;
• bring back to normal acid-base balance;
• neutralize the effects of toxins;
• compensate for vitamin and mineral deficiencies.

Useful are intramuscular injections of vitamin preparations, rehydration therapy with the Regidron solution, Orsol, Ringer-Locke droppers.

Prevention

In order for a newborn calf not to develop colibacillosis, it is necessary to take care of preventive measures in time, including:

• routine vaccination with inactivated drugs - 4 weeks before mating of the cow (2 vaccinations with an interval of 14 days);
• timely vaccination of newborn cattle;
• observance of hygiene of childbirth, drinking milk;
• compliance with hygiene standards by staff caring for livestock;
• cleanliness of equipment used in the care and feeding of animals;
• regular disinfection of the stall.

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

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

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