Colibacteriosis of calves: vaccine, pathoanatomical changes, home treatment

Colibacteriosis is one of the most common diseases of herbivorous mammals. Due to a number of features, which will be discussed further, the disease is difficult to control, and treatment in 40% of cases is ineffective, including from an economic point of view. Let's try to understand the problem and draw some conclusions for ourselves about how to save young cattle and adult cattle from the disease causing bacteria.

What kind of disease and what is dangerous

Colibacteriosis - A gastrointestinal tract disease that affects the stomach, intestines, spleen and lymph nodes. In acute forms, colibacteriosis is most often observed in the young of the first week of life and, in the absence of timely intervention, is always fatal.

The pathogen accumulates in the milk of sick or recently recovered females, urine and feces of sick animals. It is very easy to pass from cow to calf when feeding, physical contact of healthy calves with sick or litter from under sick animals.

The danger of the disease increases due to the high virulence and rapid course of the disease. The effect on the newborn calves and on pregnant females, which, if they are affected by the bacteria, is aborted in 100% of cases, regardless of the period, is especially pernicious.

Source and causative agent of infection

The causative agent of colibacillosis in animals and humans is pathogenic strains of the normal inhabitant of the intestinal microflora, Escherichia coli sticks.

These gram-negative bacteria multiply in an oxygen-free environment and produce shiga-toxin (STEC), which causes inflammation of the gastrointestinal tract, dysbacteriosis, Gasser's disease and some other pathological conditions. Sensitive to antibiotics of a number of aminoglycosides and fluoroquinolones.

E.coli, like all causative agents of gastroenteric diseases, is transmitted by the fecal-oral route. That is, it enters the body of an animal by consuming contaminated food or water. Sources can be:

• contaminated feed;
• non-compliance with sanitary standards in places of livestock;
• contamination of drinking water with sewage;
• late vaccination of breeding animals or its absence;
• E. coli animals;
• feces and urine of sick animals;
• female carrier milk or dirty udder;
• non-observance of sanitary standards and hygiene standards by service personnel.

Pathogenic serogroups affecting cattle: O8, O9, O15, O26, O41, O55, O78, O86, O101, O115, O117, O119.

It is worth noting that conditionally pathogenic strains can also cause colibacteriosis in calves, especially young ones that did not receive colostrum in the first days of life. Immunity in such calves is reduced, which in a known manner destabilizes the composition of the microflora.

Pathogenesis

Colibacteriosis is most often diagnosed in dairy calves 1-7 days old.

The first to fall ill are weak, predisposed animals: low acidity, low concentration of gamma globulins in the blood plasma, increased permeability of the intestinal epithelium - all these factors increase the risk of infection and complicate the fight against the disease.

Calves can suffer from three forms of colibacillosis, each of which, due to the specific pathogenesis, needs special treatment..

• Enteritis form. The most innocent of all three, characterized by dysbiosis, severe diarrhea and dehydration, but without signs of toxicosis. The strains that cause enteritis form: O1, 09, 025, 055, 086, 0117 - do not penetrate into the blood, and are localized in the small intestine and mesenteric nodes (lymphatic system of internal organs).

  Having no adhesive antigens, such that would allow the bacteria to spread throughout the body, the Escherichia penetrate and multiply in the intestinal mucosa, poisoning the body with endotoxin.

• Enterotoxemic form. Enterotoxemic strains do not penetrate the intestinal walls: when they enter the body, they are attached to the hairy epithelium with adhesive saw-antigens.

  The poisoning agent is a thermostable exotoxin, which affects the protein metabolism of the cell walls: it provokes hypersecretion of fluid and electrolyte accumulation in the intestine. Also, the toxin inhibits peristalsis of the small intestine, it complicates the excretion of harmful substances from the body and exacerbates the pathological processes.

• Septic form. The most dangerous form of colibacillosis, almost in 100% of cases, is fatal, it takes 2-3 days from the first symptoms to the death of the animal. Septogenic strains - O78, K80, O9, K30, O9, K101, O8, K25 - have capsular antigens, due to which they penetrate into the blood, lymph and tissues of other organs.

  The capsule reliably protects the bacteria from the action of blood immunoglobulins and most phagocytes, this should be taken into account when selecting antibiotics: you need to take those that would destroy the polysaccharide membrane of the Escherichia. These include cephalosporins, aminoglycosides and fluoroquinolones. The pathogenic agent is endotoxin, which is released after the partial destruction of Escherichia in the blood, its toxic effect is manifested in severe weakness and collapse of blood vessels.

Symptoms

Depending on the severity of the course, there are subacute, acute and ultra-acute forms of the disease.

• The subacute course is most often characteristic of the enteritis form. Symptoms appear on the 6-10th day of the calf's life: diarrhea, general weakness, conjunctivitis. Perhaps the development of arthritis of the hock and knee joints, which in the early stages manifest as pain on palpation and instability in the legs, may appear limping.A frequent complication of the subacute form is the defeat of the upper respiratory tract, a symptom in the form of mucous discharge from the nose and frequent shallow breathing appears at 2-3 weeks of the life of the calf.

• The acute course is observed at the age of 3-7 days. The disease begins to manifest itself with diarrhea, which is accompanied by loss of appetite and general depression of the animal. The day after the first symptoms appear, the color and consistency of the feces changes: it becomes yellowish-gray, with air bubbles (foaming feces), in the masses there are clots of undigested colostrum, mucus, bloody inclusions are possible. The temperature rises to 41 °. On palpation the abdomen is hard and painful, excessively swollen or, conversely, tightened. Due to severe dehydration caused by persistent diarrhea, the eyes lose luster and sink, as a complication, conjunctivitis can develop. The mucous membranes look anemic, there is an unpleasant smell from the mouth.

  With timely, properly selected treatment, the prognosis is most often favorable, but recovery will be followed by a long period of rehabilitation - the calf will lag far behind in its growth and development from its peers.

• The over-acute course is observed at the age of 1-3 days and almost always ends in death.

  Diarrhea in such cases is rare, but sick animals are too weak to stand up or suck the udder, the temperature is raised to 41-42 °. Wool ruffled, the pulse is weak and frequent. From the nostrils and mouth, a white foamy substance can be released, superficial and frequent breathing. The septic form of the disease is accompanied by an ultra-acute course, as a rule, the calf dies in the first 2-3 days of life from exhaustion and blood poisoning (sepsis).

Diagnostics

Initially, colibacteriosis is diagnosed empirically: if the calf is constantly bored, the appetite is gone, the depression is observed, this should already cause suspicion of colianteritis.

The first thing to do to diagnose the disease: determine the strain of the bacteria and pick up antibiotics. For this purpose, an analysis of feces or a swab from the rectum is taken. In the case of lethal outcomes, tissue samples are taken from the intestines, spleen and liver of a deceased animal.

Pre-colianteritis can be diagnosed at necropsy - the organs of the patient calf undergo characteristic pathological changes:

• the gallbladder is enlarged and full of bile;
• the liver is enlarged, with fatty inclusions;
• intestinal swollen, full of white mucous, fetid masses with blood inclusions;
• lymph nodes are enlarged;
• hemorrhages in the area of ​​an epicardium or lungs are possible.

Treatment

The treatment consists of antibiotic therapy, taking immunostimulants and drugs that restore the microflora. In addition, against the background of the main treatment may prescribe drugs that stop diarrhea in the calf,to avoid fluid loss.

These antibiotics are used successfully:

• tetracycline: "Biovit", "Vitatetrin", "Orimitsin", "Solvovietin";
• aminoglycoside series: "Gentamicin", "Normandomixin", "Polymyxin".

High escherichia have resistance to penicillins and cephalosporins.

Often, therapy is supplemented with sulfanilamide drugs - antimicrobial agents: Norsulfazol, Sulfazin, Sulfadimezin, Etazol, Sulfapyridazin, Sulfadimethoxin.

From probiotics, Olin, Emprobio, Lactobifadol or Bio Plus 2B are used to restore microflora.

After diagnosis, treatment usually continues at home. First of all, the sick animal must be isolated from the rest. Then, to stop diarrhea and restore water and acid balance, calves are given Calvolit or another similar drug prescribed by a veterinarian. Next, antibiotic therapy begins with parallel administration of probiotics to colonize the intestine with lactic acid bacteria and restore normal microflora.

Prevention

The best prevention of the disease will be compliance with the schedule of vaccination of adult livestock and compliance with sanitary standards in places of livestock.

To increase the resilience of the young, you need to monitor the quality of the feed (colostrum) and its timely receipt. For the purpose of prophylaxis, in the first days of life, in combination with colostrum, probiotics can be given, such as "Kolibakterin" and "Bifidumbakterin".

This will increase the body's resistance and reduce the permeability of the intestinal walls for pathogens.

If a sick animal is identified, it should be immediately isolated due to the high virulence of the bacteria. It must be ensured that farm personnel are provided with two sets of uniforms: for the care of healthy and sick animals.

Gastrointestinal diseases in cattle should be taken very seriously.Despite scientific progress, 8-12.5% ​​of young cattle perish from colibacillosis annually, mainly due to non-observance of sanitary and hygienic standards on farms and agriculture.

In addition to economic damage, this situation significantly reduces the quality of livestock and animal products.

The second in the ranking is untimely and poor-quality treatment, which often does not eliminate, but only stops the problem, and after a while it pops up again, in the next livestock.