The disease that causes cows to cough strongly appeared in the last century and is called infectious bovine rhinotracheitis. This viral disease causes great economic damage to farm owners. His fame brought him the ability to manifest itself in various forms and affect not only the respiratory tract, but also other parts of the animal's body. Malaise is widespread throughout the world.
History of the disease
A cattle disease affecting the airways was observed in the United States as early as the middle of the 20th century. It has been described under various names: acute upper respiratory tract infection, acute tracheitis. As a result, the disease received the official name - infectious rhinotracheitis.
Gradually, the infection spread to different corners of the world, as there were reports from Canada, Australia, Africa, France. According to experts, the distribution was associated with industrial breeding of livestock.
In the 1940s, a similar disease was discovered in the USSR, called the infectious catarrh of the upper respiratory tract. In the late 60s, infectious rhinotracheitis virus cells were first found in the research laboratories of the USSR. A little later, the ailment was officially registered and his symptoms were identified.
Causes of disease
The causative agent of the disease is a herpetic virus that is contained in most mucous membranes of the body: the respiratory tract, genitals. It is inactivated when exposed to high temperatures. In the Russian climate, this takes about 10 days, and during this period the disease can lead to irreversible consequences. Acetone, chloroform and ethyl alcohol act the fastest and most efficiently on the cells of this type of herpes.
A DNA virus consists of a nucleotide, a capsid and a capsid membrane. It is exactly the same as the rest of the herpes viruses, it multiplies well on mucous membranes and is even able to form whole groups of harmful cells.
Previously it was believed that infectious vulvovaginitis does not depend on other diseases, but more recently it has been proven that the infectious rhinotracheitis virus is identical to the vaginitis virus, therefore now the disease is abbreviated as RTI-IPV.
Farm owners fear this disease due to the high mortality of animals, which leads to serious economic damage to farms.
Factors affecting infection
Among representatives of the animal world, representatives of cattle are mainly susceptible to infectious rhinotracheitis. A cow or a bull of any age can become infected, but the young are most susceptible to the disease up to a year. At infection of one calf the others get sick within two weeks.
Malaise spreads in various ways: sexual, airborne, with physical contact. The source of the disease are contaminated feed, equipment, water, staff.
Infections can be carried by representatives of the fauna who are not at risk of disease, for example, some birds and insects. Outbreaks of the disease most often occur in the off season and in winter. The first cases of infection occur approximately 1-2 months after the virus enters the farm. Malaise quickly spreads, covering all herds susceptible to it, and lasts several weeks.
Symptoms of illness
The incubation period of the disease varies from 2 to 40 days, the duration depends on the state of the immune system of the animal. The following symptoms are usually observed:
- the first sign is a sharp rise in the body temperature of the animal;
- power failure;
- hysterical cough;
- depressed mood;
- discharge of pus-like fluid from the nostrils;
- discharge from the eyes, drying near the eyelids with a dry crust;
- reduced milk yield;
- frequent drooling.
In case of complications of the disease, multiple compartments of pus from the nostrils are possible, difficulty in breathing, pneumonia can develop, the animal becomes very thin.
In the genital form of infectious rhinotracheitis, vesicles and nodules may appear on the external genitals. Later, films may form, with the discharge of which ulcers are observed. The animal can not stand still, constantly changing the position of the pelvis.
The course of the disease
There are such types of rhinotracheitis in cattle as acute, subacute, chronic.
The acute course of the disease is observed mainly in young animals. The first sign is the rise in temperature to 40 degrees and above. After that, it is possible to release purulent exudates from the nose, in which blood impurities may occur. The cow has a breathing disorder, she coughs often and tearfully. This is due to the accumulation of fluid in the nasal cavities and upper respiratory tract.
Subacute flow is characteristic for a much smaller part of the population. And the most favorable disease passes in cows bringing milk. The culmination of the pathology becomes fever, which lasts 1-2 days. At the same time, salivation and discharge from the nasal cavities practically cease. The animal recovers in a couple of weeks, while its milk production remains the same as before the disease.
The chronic course, in most cases, is the result of complications after the illness. Ailments last for several months, but the symptoms are usually mild.
Forms of pathology
Among the main forms of infectious rhinotracheitis are: respiratory, genital, atypical.
The main feature of the respiratory form is a profuse nasal flow. Complications in this case may be diarrhea, corneal clouding, lactation reduction. For pregnant animals, infection threatens abortion.
In genital syndrome animals refuse to feed. They have swelling mucous membranes of the external genital organs, reduced productivity. In cows, this leads to vulvovaginitis with developing ulcers, and in bulls, inflammation of the mucous membrane of the prepuce (foreskin).
The atypical form is distinguished by the fact that, in addition to the general symptoms of diseased animals, emphysema develops under the skin and extends to the abdomen and hips. There may be intestinal lesions resulting in diarrhea. This form also includes cases of RTIs where the manifestations of the disease consist only in the development of conjunctivitis.
Treatment of infection
Like any disease of cattle, this disease requires complex therapy. The best drugs for the treatment and prevention of rhinotracheitis are serum. For example, polyvalent against RTI, infectious diarrhea and adenovirus or serum of convalescents, containing blood with antibodies produced against the disease at a concentration of not less than 1:32.
These drugs are administered at several points on the body of the animal under the skin at a dosage of 2 milliliters per kilogram of live weight (not more than 200 milliliters). It is also recommended that hyperimmune serum be instilled into the nasal cavities or sprayed indoors at a dosage of 1-4 milliliters per square meter of space.
In the treatment of genital syndrome, antibiotics are prescribed in the form of solutions and ointments, in particular, ichthyol and synthomycin ointments are used. During infectious rhinotracheitis it is forbidden to use bulls for insemination.
In order to prevent further complications of the disease, antibiotics are used that act on the harmful microflora of the animal's upper respiratory tract, for example, oriprim or norsulfazole. Additionally, the premises are disinfected with chlorosipidar or hydrogen peroxide using an aerosol, without isolating animals.
The extent to which the therapy will be effective depends largely on the mode of maintenance and the properly balanced diet of animals.
Survived animals acquire temporary immunity. Moreover, after the respiratory form, the cows are much longer resistant to infection than, for example, after the genital one.
For artificial immunization, both activated and inactivated vaccine are used. Calves are vaccinated when they reach the age of 10 days, twice, with a break of two weeks (the first time the vaccine is injected into the nasal cavities, the second time - subcutaneously). Immunity to the disease in vaccinated individuals is produced within a week and lasts for about a year.
Intranasal vaccine is always more effective than subcutaneous or intramuscular. Due to the appearance of local antibodies directly in the affected areas, the production of immunity against infectious rhinotracheitis is accelerated.
The best vaccines are considered "Bivak", "Tetravak" and "Combovak", differing in the number of antibodies to different diseases. For example, "Tetravak" also protects against viral diarrhea, and rotocoronavirus infection.
As with other diseases, the basis of the prevention of infectious rhinotracheitis is a complex of sanitary and hygienic measures. Drafts, dirt, high levels of pathogens can weaken the condition of the animal. All these factors contribute to the emergence and more severe course of the disease. An important role is played by sanitation.
Particular attention should be paid to checking for various diseases of animals brought into the farm, in the case of disease of cows apply quarantine measures. This also applies to bull-seers. It is also necessary to allocate in a timely manner the animals most susceptible to infection and to group them with stronger ones. This is done to minimize the risk of contamination of the entire population.
It is not recommended to import and export household items without prior disinfection. Milk from sick cows should be pasteurized.
Sick animals need isolation and therapy, and individuals who are not infected should be vaccinated with an active vaccine. Animal rooms should be systematically disinfected. The farm must create a normal microclimate.
Restrictive measures are removed from the farms one month after the last sick animal recovers or is slaughtered.
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