Cattle paratuberculosis: symptoms and diagnosis, treatment instructions

Infectious diseases of cows can cause significant harm to animal husbandry, as they worsen the he alth of animals and can lead to death. Consider the causes and signs of paratuberculosis in cattle, methods for diagnosing the disease and preventive measures that need to be taken to reduce the likelihood of the spread of infection in your household.

What is paratuberculosis

Cattle paratuberculosis is a chronic infectious disease of ruminants. The causative agent is the bacteria Mycobacterium paratuberculosis, obligate parasites that are resistant to the negative effects of external factors and disinfectants.The disease proceeds mainly in a latent form, that is, without pronounced symptoms; in the clinical course, the disease can result in the death of the animal in 2-4 months.

Sources and routes of infection

Bacteria enter the body of cows with food, which becomes contaminated with fecal masses and secretions of sick animals, since in cows with paratuberculosis, the intestines are affected. Mycobacteria can end up on animal care equipment, pastures, water sources, forage, and buildings. Calves become infected through milk from sick mothers and may also be born already infected.

Isolation of parasites from the body of sick animals begins 3-5 months after infection. Paratuberculosis is dangerous in that many animals are asymptomatic, which is why they do not differ in appearance from he althy ones, but are carriers of bacteria.

Outbreaks of paratuberculosis can occur at any time of the year. A large number of diseases are recorded in regions where there are acidic, wet or saline soils, which is explained by the fact that plants grown on such soils are poor in calcium and phosphorus s alts.

The likelihood of developing paratuberculosis increases when cows are fed acidic feed, such as silage, with helminthic infestations, after hypothermia or overheating of animals. Cows can become ill during the acclimatization period or when kept in unusual conditions.

Symptoms of disease

The incubation period of paratuberculosis can last from several months to 1 year. Latently ill cows lag behind in growth, lose weight, and fatness is not restored. Those animals that are distinguished by a good resistance of the body and that are normally fed and well-maintained can recover on their own. A latent disease becomes clinical for various reasons that reduce the resistance of the cows.

Clinical signs of paratuberculosis appear mainly in young animals 3-5 years old, which have already had 1 or 2 calving.

Paratuberculosis can be determined by its first signs, such as a decrease in milk yield, the appearance of edema under the jaw and in the dewlap area, and progressive exhaustion. From time to time, diarrhea occurs in animals, over time it becomes persistent. Feces of a liquid consistency, have an unpleasant odor, lumps of mucus can be seen in them, rarely - blood and gas bubbles. Animals eat normally, do not lose their appetite, but due to dehydration, they begin to drink more water. There is no increase in temperature or pain.

The cow loses weight, muscle mass decreases, especially on the croup and hind legs. This reduces the economic value of the animal.

Disease diagnosis

Diagnosis - paratuberculosis - put on epizootic and clinical signs, according to the results of allergic tests and laboratory bacterioscopic studies for the presence of the pathogen. Additionally, another study is used - the complement fixation reaction.

When diagnosing, it is important to distinguish some other diseases - non-infectious colitis, the causes of which are irregular and improper feeding, coccidiosis, strongyloidiasis, tuberculosis, helminthic invasions.

Pathological changes in paratuberculosis affect the small intestine, its back. Characteristic symptoms - 5-10-fold thickening of the mucosa in the affected area. There is a narrowing of the intestinal lumen, clearly visible in the transverse section. On the longitudinal one, a clear longitudinal and transverse folding is visible; when stretched, the folds do not disappear. Lymph nodes on the mesentery and ileocecal valve are enlarged, elastic, moist on the cut, gray-yellow.

Some sick animals may have swelling of the serous membrane of the mesentery and intestines, enlarged lymph nodes, partial enlargement and partial atrophy of the intestinal villi.

Treatment of paratuberculosis in cattle

No specific treatment for paratuberculosis has been found, the treatment of the disease is considered ineffective, since there is no recovery. Sick animals are slaughtered, damaged organs are disposed of, meat can be eaten. According to the instructions, animals that have a positive reaction to tuberculin are separated from the general herd and raised separately. The young obtained from them can be grown for meat, but they are not suitable for breeding.

Prevention

In areas with paratuberculosis problems, cows are periodically examined. Animals with visible symptoms are handed over for slaughter. All the rest, who are already 1.5 years old, are diagnosed with the help of RSK. Those who have positive samples are also handed over for slaughter, with negative results they are left in the herd. These cows are then examined twice a year by the same method.

Calves up to 1.5 years old are raised separately from the rest of the herd. They feed milk from he althy animals or milk from those that have positive samples, but there are no clinical signs of paratuberculosis. Such milk is pre-pasteurized.

It is necessary to acquire new animals for completing the herd only from farms that are safe for this disease, because it is not always clear that a cow or a calf is sick. Animals should be fed and cared for in accordance with zoohygienic requirements. After harvesting, manure must be dried and burned or biothermally decontaminated in compost heaps.

To disinfect the premises where cows are kept, inventory and milking equipment. Hydrated lime, sodium hydroxide, formaldehyde solution, creolin, phenol can be used as disinfectants. Cowsheds are disinfected after examination of the livestock and after calving.A holding is considered free from paratuberculosis if it has been sanitized and no diseased animals have been identified within 3 years of the last case.

Cattle paratuberculosis is not treated, sick animals either die or are handed over for slaughter. In order to prevent the spread of the disease within the farm, it is necessary to conduct livestock inspections, do tests, make sure that cows can be raised separately from the general herd, if necessary.

Recommended