Keeping cattle requires significant effort from the farmer, especially if the farm has a large number of livestock. Detection of necrobacteriosis in animals is a disaster for the owner, since milk yield is significantly reduced, effort and resources are required to treat sick cows, preventive treatment of healthy herds and barns. Infection of breeding stock results in significant financial losses.
What is necrobacteriosis
Necrobacteriosis is an infectious disease characteristic of domestic and wild animals; birds are infected; humans can also be infected. The infection is especially dangerous for cattle and reindeer. The disease is caused by the strict anaerobic bacteria Fusobacterum necrophorum. Bacteria are polymorphic and can have the form of threads or rods. They produce several types of toxins with high pathogenicity. They quickly die under the influence of high temperature (within 1 minute at 100 ° C), oxygen, and sunlight. They are destroyed by bleach, potassium permanganate, formaldehyde, copper sulfate, and many other chemical compounds.
They remain in the soil for up to 1 month in summer and 2 months in winter. Water or urine contaminated with necrobacteriosis remains dangerous for 10-15 days. Sources of infection with necrobacteriosis are infected individuals that excrete bacteria in urine, feces, and putrefactive exudate. The infection is transmitted through contaminated pastures, drinking places, feeders and drinking bowls, and bedding.
Reasons for appearance
The main causes of outbreaks of necrobacteriosis are errors in animal husbandry. The infection can enter the body from the grass or soil on the pasture, when cows are received from other farms. The “gates” for it are:
- wounds, cuts and abrasions on the legs;
- damage to the genital tract;
- wounded hooves not trimmed in time;
- places of bites of flies and horseflies;
- helminthic infestations;
- overcrowding of livestock in a damp, cold barn;
- unbalanced malnutrition;
- long absence of walking.
The disease can be acute or chronic; in severe cases, if left untreated, malignant lesions occur.Often necrobacteriosis is complicated by the addition of a secondary infection, for example, bronchopneumonia or an abscess may develop.
Symptoms of pathology
At the initial stage of the disease, a purulent-necrotic lesion usually occurs on a finger or hoof. First, the skin becomes red and inflamed. The cow begins to limp and behaves restlessly. Most often, one of the animal's hind legs is affected. If left untreated, the infection rises higher, and ulcers cover the animal’s legs, udder and genital mucosa. If a cow licks the affected area, necrobacteriosis affects the lips and mucous membranes of the mouth. The following symptoms are noted:
- Weeping necrobacteriosis ulcers and wounds cause severe pain, and infected cows stop leaning on the injured leg.
- The tissue around the ulcer is dense and swollen, it constantly gets wet.
- The animals' temperature rises, sometimes above 42 °C.
- Appetite disappears, chewing gum is lost.
- Body weight and milk yield decrease.
- In advanced cases, ulcers degenerate into a malignant form or gangrene occurs. The animal dies.
If necrobacteriosis of the extremities is not treated in time, not only inflammation of the soft tissues occurs, joints and bones are affected, pus appears between the muscles, and the animal loses the ability to walk.
When the infection spreads to the oral cavity or genitals, it penetrates inside, necrotic foci form in the liver, spleen, and abscesses form.
Diagnostic measures
To establish an accurate diagnosis, microflora is taken from an ulcer or wound. The smear is examined under a microscope. A colony of bacteria is then grown and infected with the isolated material from laboratory mice or rabbits.In the presence of necrobacteriosis, after some time the experimental animals become covered with characteristic ulcers and die. Additionally, the presence of plague, vesicular stomatitis, foot-and-mouth disease and other diseases is excluded.
Treatment methods
Treatment of necrobacteriosis begins immediately after detection of the source of infection. The sick animal is isolated. The wound is cleaned surgically, necrotic tissue is removed completely, to the borders of healthy ones. Then the tissues are washed with one of the solutions: potassium permanganate, chlorhexidine, furacillin, formalin. Next, the wound is sprinkled with streptocide powder or treated with chloramphenicol or syntomycin.
If necrobacteriosis affects the oral mucosa or genital organs, antibiotics are prescribed, for example, tetracycline or chloramphenicol, bicillin and others, with a wide spectrum of action. Healthy animals are provided with general baths to prevent necrobacteriosis. The easiest way to make such a container for processing cattle is to dig a trench, fill the floor and walls with concrete and organize a strong gangway.
The best treatment option: divide such a bath into 2 parts, pour water into one, and a disinfectant solution into the other, for example, a 10% solution of formaldehyde or copper sulfate. The animals are first driven into a bath of water to wash their hooves, after which they are kept in a bath with an antiseptic for 10-15 minutes. The procedure is repeated 3-4 times with an interval of 5-7 days. The pasture can be used again after 1.5-2 months. If necrobacteriosis is detected on the farm, the barn is cleaned of manure, washed with a disinfectant solution, and the bedding is changed.
Restrictive measures from the farm are lifted no earlier than 4 months after the last animal infected with necrobacteriosis has recovered.
General preventive measures
Veterinary medicine has come a long way since the discovery of the disease. Today, to prevent cows from getting necrobacteriosis, animals are vaccinated. Adults and calves are vaccinated against necrobacteriosis from 3 months of age.
Veterinary service specialists examine and treat the hooves of all livestock. For preventive purposes, general baths with formaldehyde, copper sulfate or creosote are arranged. To prevent cows from contracting necrobacteriosis, the barn should be systematically cleaned, manure removed, and bedding replaced. The room should be warm and dry. It is necessary to protect animals from drafts. The floors are made level so that the animals do not get injured.
Animal nutrition must be balanced, including mineral supplements and vitamins. Cows are provided with salt, chalk, bone meal or special vitamin complexes. Walking areas are organized so that animals do not stagnate.
Since people working on farms can become infected with necrobacteriosis from animals, first aid kits are required on farms. After working with sick animals, hands must be disinfected. Sick employees must undergo treatment.
Is it allowed to eat meat and milk from infected cows?
If topical treatment is sufficient for the cow, the milk can be consumed after pasteurization.
Important: milk from animals undergoing a course of oral antibiotic treatment in large doses cannot be sold or processed.
Sick animals for which treatment is useless are sent to a sanitary slaughterhouse. The issue of selling meat is decided by a sanitary service doctor who examines the carcass after slaughter. Usually the area of the carcass affected by necrobiosis is removed, the rest of the meat is allowed for sale or processing.
