Cattle necrobacillosis is an infectious animal disease caused by the anaerobic bacterium Fusobacterium necrophorum from the genus Fusarium. Its main unpleasant consequences are a significant decrease in milk yield and tribal losses. Although the death of livestock in this disease is rare, it can cause tremendous damage to households. And therefore, it is important for farmers and homeowners to know how its prevention and treatment are carried out correctly.
A bit of history
The causative agent of necrobacteriosis in cattle is, therefore, the bacterium Fusobacterium necrophorum. It has been described for quite some time - in 1882 by Leffler with calf diphtheria. Allocated this stick from the cornea of ââa ram affected by smallpox, in 1881 R. Koch. Subsequently, this virus was also detected by Schutz and Tartakovsky. The pure culture of Fusobacterium necrophorum was first obtained by Bang in 1890. Independently of it, in 1891 the microbiologist Schmorl did the same.
Cattle necrobacillosis: the causative agent of the disease
The microbe Fusobacterium necrophorum is polymorphic and has the form of sticks or thin long threads. The latter can form spherical or bulbous swellings. The bacterium Fusobacterium necrophorum is immobile, has no flagella and does not form spores or capsules. Moreover, it ferments glucose, levulose, galactose, sucrose, salicin and maltose. Ammonia does not produce this microbe. It does not restore nitrates to nitrates.
The causative agent of Fusobacterium necrophorum is relatively unstable. But, unfortunately, it can be stored for a long time in a variety of environmental objects. So, in animal feces, he lives up to 50 days, in urine and water - up to 15, and in milk - up to 35 days. The sun's rays on this microbe are destructive. Being not in the shade, the bacterium dies in half a day.
The sensitivity of Fusobacterium necrophorum to various disinfectants is high. Therefore, observing cleanliness in cowsheds, you can significantly reduce the risk of this disease in animals. Antiseptics such as kill the bacterium Fusobacterium necrophorum:
- caustic soda and potassium (0.5%);
- lysol (5%);
- creolin;
- phenol (2%);
- potassium permanganate (1: 1000).
Also, this microbe is extremely sensitive to tetracycline drugs.
Symptoms of the disease
Cattle necrobacillosis manifests itself mainly in purulent lesions. They occur in cattle most often:
- on the udder;
- lower limbs;
- the mucous membrane of the vagina and uterus.
Necrobacteriosis of cattle is also characterized by diphtheria inflammation of the mucous membranes of the larynx, oral cavity and internal organs. Such symptoms are usually observed in young animals.
How infection occurs
Necrobacteriosis develops in cattle most often when injured with damage to the skin. In wounds, as a result of violation of the integrity of the capillaries, an oxygen-free environment favorable for the life of this anaerobic bacillus is formed. In particular, this virus multiplies well in the blood with hematomas. As a result of the life of Fusobacterium necrophorum, a huge amount of toxic substances is formed. The latter block intracellular enzyme systems, which causes tissue necrosis. In this case, an unfavorable process such as blockage of capillaries by microbial cells also occurs.
Infection can occur not only through wounds, but also through the mucous membranes of the gastrointestinal tract, during pathological birth or during mating.
This virus spreads through the hematogenous pathway, that is, with a blood stream. As a result of this, secondary lesions occur in the tissues. In addition, due to the penetration of the virus into the blood, septicemia develops and metastases of necrotic foci in the heart, liver and lungs form. If the disease progresses to this stage, treatment is usually inconclusive. With the formation of metastasis, necrobacteriosis in cattle becomes malignant and the animal dies in most cases. Immunity in cows that have undergone this disease, unfortunately, is practically not produced.
When can an animal become infected?
Infection with cattle necrobacillosis often occurs:
- due to unsanitary conditions in the barn;
- due to non-compliance with the prescribed periodicity of prophylactic trimming of hooves;
- due to deficiencies in the equipment of the barn (in very shortened stalls, in the absence of litter in animals);
- as a result of chronic scar acidosis.
Sources of infection
The pathogen of necrobacteriosis is released into the environment with feces, saliva and urine of infected animals. Also, this virus is contained in purulent secretions.
The causative agent of necrobacteriosis most often gets to the farm with the repair of young animals acquired by the patient or manufacturers. Some time after infection of the first animal, the infection in the barn becomes stationary. If measures to treat cattle are not taken on time, pathological processes are aggravated due to the multiple transfer of bacteria from one individual to another.
The disease of necrobacteriosis of cattle in the barn is uneven, manifesting itself as small epizootic outbreaks (sequential infection of animals).
Clinical picture
The incubation period of necrobacteriosis lasts several days. The signs of this contagious disease depend on many factors. For example, such as the age of the animal, the form of manifestation of necrobacteriosis and especially its course. This disease can be both acute and chronic, as well as benign or malignant.
There are three main forms of necrobacteriosis:
- limbs (ungulate);
- mucous membranes and skin;
- internal organs.
The most common is hoofed necrobacteriosis in cattle. A photo of the characteristic lesions that appear with this disease is presented below on the page. Most often, cattle with this form of the disease suffer the hind limbs (or one of them). Such necrobacteriosis usually begins with reddening of the interdental fissure. At the next stage of the disease, bleeding purulent wounds, fistulas and abscesses appear. The animal experiences extremely unpleasant sensations and holds the affected limb in weight. During the examination, swelling of the joint of the hoofed phalanx is detected. With the further development of the disease, damage to the ligaments, bones and tendons is observed. If the process takes on a malignant nature, the overlying joints begin to hurt in the animal, right down to the hip.
The body temperature of an infected individual can rise to 42 g. Sometimes it also remains within the normal range. Only adult cows and bulls are ill with necrobacteriosis of the limbs. In calves, this form is extremely rare.
With necrobacteriosis of the mucous membranes and skin, lesions are most often noted in the trunk, usually in the back of it. In young animals, purulent necrosis of the mucous membranes of the mouth, gums, trachea, tongue, nose, larynx, gastrointestinal tract, etc. can also be observed.
Necrobacteriosis of internal organs in cattle manifests itself most often as an abscess of the liver. In this case, characteristic clinical signs are usually not observed. But the animals themselves, infected with this form of necrobacillosis, feel extremely unwell - they eat poorly, lose weight quickly, significantly reduce productivity, moan when trying to get up. With necrobacteriosis of internal organs, among other things, cows can significantly increase body temperature.
Diagnostics
In addition to symptomatic signs, necrobacillosis of cattle (the photo of the pathogen is presented below) can be determined by laboratory tests. Such a check must be carried out necessarily. The fact is that the clinical picture of this disease may be similar to other common cattle infections. This may be, for example, foot and mouth disease, vesicular stomatitis, viral diarrhea, plague or dermatophilia. Also, when diagnosing necrobacteriosis, arthritis of various etiologies, erosion, ulcer of hooves, and dermatitis should be excluded.
How exactly is a disease such as cattle necrobacillosis determined? Diagnosis of it is usually performed by a selected piece of tissue affected by necrosis, taken at the border with a healthy site. In the laboratory, this material is placed in a special environment (most often Kitt-Tarozzi with 10% blood serum) and incubated for two days at a temperature of 37 ° C. To determine the concomitant microflora, additional studies are carried out on MPB and MPA. The final diagnosis is made to animals if a pathogen is detected in the smears.
Cattle Necrobacteriosis: Antibiotic Treatment
Take action if you detect signs of this disease should be immediate. Otherwise, pathological changes can become irreversible. The treatment of necrobacteriosis in the complex. At the same time, large farms use group methods, and in small ones - individual ones. When treating dairy cows, only drugs that do not pass into milk are used.
When a cattle diagnosis of necrobacillosis is established in cattle, the following recreational activities are performed:
- Make a thorough chemical treatment of the affected areas with tissue removal.
- Wounds are washed with hydrogen peroxide, furatsilina solution, etc.
- Apply liquid and powder antiseptic drugs.
Anaerobic bacteria, including Fusobacterium necrophorum, always form a barrier between the vascular bed and the affected tissues. And this, in turn, greatly complicates the penetration of drugs. Therefore, antibiotics in the treatment of necrobacteriosis are used in high doses. In addition to tetracyclines, the most effective types of drugs of all used for this disease include:
- chloramphenicol;
- ampicillin;
- erythromycin;
- penicillin;
- telazine.
Also, for the treatment of a disease such as necrobacillosis of cattle in cows, modern broad-spectrum antibacterial drugs can be used. For topical use, aerosol antibiotics based on the above drugs are also suitable. They are used mainly for the treatment of hooves after dry cleaning.
Farm restrictions in outbreaks of necrobacteriosis
If this disease is detected in animals on a farm, the following measures are taken:
- infected animals are isolated from the herd;
- the hooves of healthy bulls and cows are treated in foot disinfectant baths;
- treat sick animals according to the method described above.
If treatment, due to neglect of necrobacteriosis, is impractical, cows and bulls are handed over to a sanitary slaughterhouse.
What you need to know
Unfortunately, cattle necrobacillosis is a contagious disease, including for humans. Cases of infection of farm personnel with this infection are rare, but you should not take into account the existing danger. In order to exclude the possibility of infection of people working on the farm, with an outbreak of necrobacillosis of livestock should:
- without fail to observe the rules of personal hygiene when working with sick animals (wear protective clothing and gloves, take a shower after work);
- all wounds on the skin must be treated in time with effective antiseptic agents.
In the room for farm personnel, a first-aid kit must be present, equipped with all the necessary medicines according to the standards.
Prevention of necrobacillosis
A number of measures taken in advance help prevent an outbreak of a dangerous disease such as necrobacillosis of cattle. The vaccine for the prevention of this disease can be used multivalent, emulsified VIEV or Nekovak. In farms located near farms that are unsuccessful for necrobacteriosis, among other things, the following measures should be taken:
- Farm personnel should carry out activities aimed at the general strengthening of the animal organism. To do this, balancing the feeding of animals is primarily performed. In the diet of cows, bulls and calves, it is mandatory to introduce various vitamin and mineral supplements. In addition, carefully monitor the quality of feed.
- They carry out activities aimed at improving the conditions of animals on the farm. Manure in the stalls must be cleaned carefully and on time. Also, if there is a suspicion of a possible infection with necrobacteriosis, all rooms should be inspected for possible injuries.
- They clean and drain pastures and walking areas.
In addition, it should be periodically carried out on a farm during an outbreak of a disease such as necrobacillosis of cattle, disinfection. In order to minimize the potential risks of loss of livestock, timely prevention and treatment of endometritis and mastitis should also be performed. The fact is that these diseases can greatly complicate the course of necrobacteriosis.
What to do with meat and milk
Necrobacteriosis in cattle causes significant harm to farms primarily due to a decrease in the productivity of sick animals. In the local pathological process, only the affected areas of the carcass of a cow or a bull are sent for disposal. If the disease was septic, all products of slaughter are burned. If the animal has several internal organs, but its carcass has a sufficient degree of fatness, the decision about the possibility of using meat for food or for sale is made after a thorough microbiological study in the laboratory.
The skins of animals suffering from necrobacillosis are dried in isolated rooms, disinfected according to the instructions and sold. Milk of sick cows can be eaten only after pasteurization, carried out in accordance with all the rules. From healthy animals, even from a dysfunctional farm, it is allowed to sell it freely.