Necrobacteriosis in cattle

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The modern form of necrobacteriosis in cattle is a complex disease that is distinguished by its systemic nature. In other words, the pathogen does not make any difference where it is to parasitize. Often the disease affects large and medium-sized livestock farms, so the economic damage from it is enormous. Next, we will talk about where this attack came from and how to diagnose it in cows in time. In addition, you will learn about existing methods of treatment and advanced methods of prevention.

A bit of history

By itself, the disease necrobacteriosis people have known for several hundred years, but until the beginning of the XX century, veterinarians took it for a separate, somewhat similar, pathology. In cattle it was purulent phlegmon with hoofs, a number of diseases of the oral cavity, inflammation of the urogenital area and certain diseases of the uterus.

In addition to cows, necrobacteriosis affects almost all ungulates, but most of all it is dangerous for cattle and deer. Especially strongly the disease "mows" the young and breeding herds.

The wand was isolated in 1881 by the scientist R. Koch. After that, Leffler in 1884 compiled the first detailed description of the disease and made initial recommendations for its diagnosis and treatment.

This attack, for the most part, bypassed Russia. Mass outbreaks of the disease were recorded only in the seventies of the XX century. After the "Khrushchev thaw" tribal cows were brought to us, and with them came necrobacteriosis. Since then, our veterinarians are struggling with this pathology.

Causative agent

This type of bacteria is considered a strict gram-negative anaerob. Microorganisms are immobile, they do not form either spores or capsules. Visually visible in the form of sticks, in some cases, may take the form of cocci.

The stick is cultivated in meat-peptone broth and similar liquids. The microorganism has 4 types, but the most pathogenic are type "A" and serotype "AB". The wand is especially dangerous at the time of active reproduction, as it releases hard enzyme toxins. In different conditions it has different terms of life:

  • in water or urine remains active for about 2 weeks;
  • with ultraviolet radiation (in the sun) dies within 8 hours;
  • dies instantly in boiling water, and at a temperature of 60-70 degrees can live up to 15 minutes;
  • in milk remains a little over a month;
  • in manure up to 50 days;
  • with a positive temperature in the soil lives up to 2 months;
  • outdoors in a ventilated place can hold up to days;
  • solutions of traditional antiseptics - bleach, formalin and alcohol destroy the stick in 10-40 minutes.

Ways of infection

The causative agent of the disease in the external contact environment falls with absolutely all types and forms of excretion in cows. This may be saliva, feces, urine. A large number of microorganisms found in milk and vaginal exudate. Even sweat and fat secrets can become carriers of necrobacteriosis.

And not only sick cows are contagious. The wand is transmitted through recovered, as well as immunocompromised animals. In addition, all ungulates can be carriers - horses, sheep, pigs.

Cows and calves are infected through direct contact. Animals with a strong immune system have a chance to survive. In the primary risk group are weak cows, as well as animals with wounds.

Even a small scratch in the soft part of the hoof can be an open "road" for the disease. But the fastest pathology penetrates through ulcers and damage to the mouth, gastrointestinal tract and genitals.

Necrobacteriosis is more common in large livestock farms, where cows are kept and bred on an industrial scale. On private farms and small farms wand is rare.

Symptoms of the disease in young

If in an adult herd the disease affects no more than 20% of the livestock, then among calves the same figure is 80%. Plus, about half of the patients die. Therefore, if the wand has been sown, then it is especially necessary to look after the calves.

Incubation of the disease lasts up to 3 days, not more. After that, in young animals, the disease immediately becomes acute and begins to actively progress. If not treated, calves die within 4-6 days.

External signs of necrobacteriosis are similar to intestinal infection. Against the background of severe diarrhea, there is a general weakening, exhaustion and dehydration of the body. Appetite disappears, the temperature can "ride".

The disease in the calf may indicate the appearance of ulcers in the mouth, contamination of the feces of the tail root. Sometimes the skin on the head and nose may be affected. In a severe form, purulent exudate flows from the mouth. Calves die from either exhaustion or sepsis.

Symptoms of the disease in adult cows

In adult cows after an incubation period, the disease in 3-4 days turns into a chronic stage and is quite difficult to treat. To some extent, we are glad that here we are dealing only with the ungulate form of the disease. There will be no diarrhea, temperature and other manifestations of intestinal infection.

The first "bell" will be the limp of a cow, the backlog from the herd and the long keeping of the hoof in weight. First, the corolla and interdigital slit are affected. That is why this disease is often confused with corolla phlegmon and treated with streptocide or ichthyol ointment. Which in this case is not particularly helpful.

Without proper treatment, infiltration begins and necrotic lesions increase. Later, the disease flows into abscesses, fistulas are formed. Further, the disease goes inside and can lead to serious damage to the nearby joint. If an infection gets into the lymphatic and circulatory systems of a cow, everything can end in a rather pitiable way, there have been cases of pneumonia and even gangrene.

Pathological manifestations

The lesion is most noticeable in the soft tissues of the hoof. At the same time, nearby organs become inflamed and swollen. The nidus itself is often filled with pus; multiple necrotic tissue lesions are seen.

Putrid lesions can occur on joints, ligaments and bones throughout the body. At autopsy, traces of the disease are clearly visible on the knee and hip joints. Muscle tissue near the affected areas partially dies. In cows, the spleen and liver can be affected. Some tissues in these organs bear traces of necrosis.

In young animals, severe exhaustion and complex damage to vital organs is observed. In this case, traces of the disease on the limbs appear very rarely. In addition to the liver and spleen, the calves have necrotic changes in the lungs and heart.

Laboratory diagnosis

Due to the fact that the external symptoms of necrobacteriosis in cows are similar to a number of various diseases, the final diagnosis can only be made on the basis of differential complex studies.

Laboratory tests go in 3 stages. At the initial stage, smears and scrapings are taken from the affected tissues and mucous membranes. Going full range of tests, urine, feces, samples from the genitals. Saliva is surely taken, and in cows a sample of milk is added to all this.

At the second stage, from all obtained samples, it is necessary to isolate and identify the causative agent of the disease. The third stage involves research on rabbits and white laboratory mice.

Laboratory animals inject infected fluid taken from the source of the disease. Such a study can last up to 5 days. If the diagnosis is positive, then noticeable necrosis forms at the injection site and the animal dies. At autopsy, colonies of rods are clearly visible.

Treatment

At the first suspicion of the pathology of the cows, if possible, should be isolated from the main herd. Since the disease usually affects a large number of animals at the same time, the treatment of necrobacteriosis must begin with general disinfection.

For this purpose, runways with disinfecting baths are equipped. To drive the cows through the baths should be no less than once a week. It is important that the cow’s hooves are in the liquid for at least 2-3 minutes.

During this time, small wounds are actively washed and disinfected. Plus, most of the contagious microflora is destroyed. Common solutions: blue vitriol, zinc sulfate, formalin. Proportions standard 5-10%.

Individual external treatment of cows is done in the same way as with corolla cellulitis. That is, wounds are anesthetized, washed with peroxide, and a bandage is applied with streptocide. But in parallel with this, cows are pierced with a reinforced course of antibiotics, without them the disease cannot be cured. Tetracycline, Nitox 200, Bitsilin-5 and the like give good results.

Disease prevention in disadvantaged farms

If necrobacteriosis is detected, the economy is transferred to quarantine mode. It is strictly forbidden to bring in new cows or take away any cattle from the herd. All changes in the maintenance and movement of animals within the farm should be monitored by a veterinarian.

Cows that have a disease are separated and prescribed a course of treatment. The rest is a vaccine against necrobacteriosis. Both sick and healthy cattle, without fail, once a week are driven through disinfecting corridors with baths.

Slaughter of cows is allowed, but for this there are separate sanitary slaughter. Plus you need to get a special permit from the veterinary service. As a rule, carcasses are either burned or processed into flour. Milk can be used, but it must be pasteurized.

According to the rules, quarantine can be removed only 4 months after the recovery or slaughter of the last sick animal. Necrobacteriosis is dangerous for people, therefore all manipulations with wounds are carried out only in gloves.

General disease prevention

If the economy is healthy, then the vaccine against necrobacteriosis is not used in the general complex of preventive measures. The fact is that the artificial formation of immunity in this disease does not bring tangible results. Therefore, vaccination is advisable only in case of a clear threat of infection.

Common preventive measures include:

  • completing a herd of exceptionally healthy cows from proven farms;
  • new cows must be kept on a monthly quarantine;
  • before introducing new animals into the herd, they need to be driven through the disinfecting corridor;
  • hooves are processed 2 times a year;
  • cows should receive the full vitamin complex;
  • once in 3 months disinfection of all premises.

Necrobacteriosis is a very insidious disease and it cannot be underestimated.

You have found out a lot of interesting things about him, share this information with your friends and, perhaps, your likes will help to identify or prevent cases of infection with such a dangerous disease.

If you already had experience in dealing with the described disease, tell us about it in a comment.

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