At transportation of cattle, purchasing calves or moving them to other farms, a very contagious disease may occur - parainfluenza-3 of calves and cattle (Paragrippus bovum). This disease is also called “transport fever”, in English – parainfluenza-3. The disease is manifested by high fever, catarrhal symptoms of the nose and throat, lesions of the bronchi and lungs. In hyperacute cases, death is possible.
Historical reference
Symptoms of the disease in cattle were first recorded and described in the USA, by Scott and Farley (1932). Initially, there was a misconception about the causative agent of the disease - bacteria of the genus Pasteurella. In 1959, the causative agent was identified as a virus with an antigenic structure similar to human parainfluenza virus 3 (PI3). In the USSR, the disease was first registered in 1969.
Currently, the disease has not been overcome in the global industrial livestock industry; all countries have developed a set of quarantine measures and mandatory vaccination of animals against AI-3 cattle.
Causes of pathology
The etiology of the disease is associated with the introduction into the epithelium of the respiratory tract of cattle, especially calves, of a virus belonging to the paramyxovirus family. Its size is 150-250 nanometers, RNA is present in the structure. The danger of damage lies in the fact that the virus has the properties of gluing, decomposition and sedimentation of red blood cells (hemagglutination, hemolysis and hemadsorption). As a result of the virus entering the body, two types of antigens appear in the blood of animals: S and V.
The virus spreads through air currents when animals breathe, through nasal fluids and discharge from the reproductive organs of cows.
When livestock is transported in crowded conditions or kept in rooms with high air humidity from the carrier, the virus penetrates the respiratory epithelium of healthy animals and begins to actively multiply, causing symptoms of the disease.
Symptoms of parainfluenza-3
In adult animals the disease is mild. In calves, the following variants of the course of the disease are possible:
- acute (including hyperacute);
- subacute;
- chronic.
Depending on the variant and severity of the course, parainfluenza-3 can occur in the form of rhinitis, bronchitis, and bronchopneumonia.Each type of disease is characterized by a complex of features.
Acute
This type is divided into two stages - hyperacute and acute. In the first variant of the course, if calves up to 6 months of age become ill, coma and death are possible within the first 24 hours from the onset of the disease. In acute cases, in the first 2-3 days there is an increase in body temperature to 41-42 degrees, a dry cough, nasal and eye discharge increases. The animal refuses food, breathing becomes rapid and shallow (up to 84 respiratory movements per minute), heart rate increases to 120 beats per minute. Later, drooling and diarrhea develop. The animal quickly loses weight, and depression of nervous and cardiac activity is possible. The coat looks dull and disheveled.
Subacute
The subacute course of the disease PG-3 in cattle is characterized by the same symptoms as the acute one, but the body temperature does not rise to such high values, and the animal’s condition is not severely depressed. Full recovery occurs in 7-10 days.
Chronic
This variant of the course of the disease develops as an unfavorable complication and is expressed in the form of chronic bronchopneumonia. Animals become significantly emaciated, cough and rhinitis become protracted and difficult to treat. In the lungs of animals, wheezing and crepitus can be heard. Cattle with this stage of the disease usually must be slaughtered, since the animals are very weak, and sick pregnant cows infect their calves in utero. The question of the suitability of carcasses for sale is resolved during analysis for pathological changes.
Treatment methods
Treatment is effective in a complex of measures carried out in the acute and subacute stages.It includes general measures, administration of hyperimmune serum and antibiotic therapy.
General wrestling metas
Of great importance in the recovery of animals is the organization of normal conditions and maintenance regime - complete feed, frequent ventilation and disinfection of premises, replacement of bedding, stay of cows and calves in the open air, compliance with spatial requirements when keeping young cattle. When examining an animal, a veterinarian may prescribe restorative and symptomatic therapy, which includes:
- antiviral drug "Mixoferon";
- “Trivitamin” – to activate metabolic processes – intramuscularly, 5 ml of the drug per day;
- bronchodilators and expectorants - Theobromine, Theophylline, ammonium chloride, potassium iodide;
- when suppressing nervous and cardiac activity in cattle - solutions of caffeine, camphor, glucose;
- diuretics.
Sick animals are isolated in separate sections or boxes, after which the premises are completely disinfected, and contact animals are vaccinated. Farm quarantine is imposed for 14 days from the date of detection of the last case of the disease.
Hyperimmune serum
Prescribed as early as possible when the disease is detected. The serum contains antibodies to the AI-3 virus, while they have not yet been developed in the sick calves’ own bodies
Antibiotics
To prevent the addition of a bacterial infection and the development of pneumonia in animals, antibiotics are prescribed. Modern antibacterial drugs belong to the groups of cephalosporins and macrolides.Conducting a microflora sensitivity test can also show the effectiveness of sulfonamide drugs. For more severe cases of the disease, combined antibiotics are prescribed - “Oleandovetin”, “Tetraolean”.
Immunity
After birth, up to 2-4 months, calves can retain the immunity acquired from cow's milk. However, it does not guarantee protection against animal disease during transportation or temporary crowded housing.
To reliably protect young cattle from PG-3, a dry culture vaccine “Paravak” has been developed. In disadvantaged farms, it is more effective to use a complex vaccine against parainfluenza-3 and infectious bovine rhinotracheitis - “Bivak”. Calves, starting from 20 days of age, are subject to immunization. Vaccines are administered in two doses: the first time - into the nasal passages, the second, after 2 weeks - subcutaneously. Immunity is formed 2 weeks after the second administration and lasts 6 months.
Preventive actions
Prevention of parainfluenza-3 dictates to farms a special regime for keeping and receiving animals:
- if livestock is purchased abroad, it is kept in quarantine for at least 30 days;
- young animals are purchased only from reliable suppliers;
- livestock is kept according to a flow scheme - the entire barn is filled, then immediately emptied, followed by complete disinfection of the premises;
- strict adherence to cleaning and ventilation of premises with animals;
- The veterinary control service must inspect animals several times a day.
Responsibility for the spread of the disease lies with the managers of livestock enterprises. Every manager should remember this; only under their strict control and with immediate action is it possible to achieve a healthy livestock.
