Contents
Of all the invasive diseases, dictyocaulosis is the most common in cattle. Young calves are especially susceptible to infection in autumn. If timely measures are taken, mortality in the herd of cattle can be avoided, but curing dictyocaulosis is more difficult than other invasive diseases.
What is dictyocaulosis
Worms-parasites, which are called by the general word “worms”, are found not only in the gastrointestinal tract. Often coughing with a cold is caused by a completely different reason. It’s really hard to forgive. To do this, you need to cool down a lot. But even in this case, the development of pneumonia is more likely than “colds”.
Due to the season of infection, dictyocaulosis is often mistaken for a cold and not the cause, but the symptoms are treated. As a result, the disease develops and leads to the death of cattle, especially calves of the current year of birth.
The real cause of coughing in cattle is the worms that live in the lungs. These are nematodes: thread-like roundworms 3-15 cm long. They belong to the genus Dictyocaulus. There are several types of dictyocaulus. Although scientists have not yet agreed on the classification of these nematodes. In cattle, Dictyocaulus viviparus or bovine lungworm is the most common. The same species infects wild deer and elk with dictyocaulosis. Although there is a discrepancy here: some scientists consider the nematode that infects wild artiodactyls to be a different species. But it has been established that in any case these parasites can cross-infect cattle and deer.
Infection of cattle with pulmonary thread-like worms is called dictyocaulosis.
Animals are generally well adapted to life in the open. You won’t take them in the autumn rain.
Ways of infection with dictyocaulosis
Young cattle of the first and second year of life are most susceptible to nematodes. Animals become infected with dictyocaulosis in a pasture when grazing together with already sick individuals. Infection occurs when the nematode larvae are swallowed along with water or grass. Contributes to the spread of dictyocaulosis in cattle crowded content in the pasture of animals of different ages.
The spread of cattle dictyocaulosis on pastures is facilitated by:
- floods;
- rains;
- fungus from the genus Pilobolus.
In the southern regions, where summer drought is a common occurrence, cases of infection with dictyocaulosis of cattle during the period from July to August do not occur. In central Our Country, the “disease season” lasts from spring to autumn.
Life cycle of dictyocaulos
Parasites have a simple but very interesting life cycle, as they are spread by molds. Adult nematodes live in the branched passages of the bronchi. They also lay their eggs there. Since the worms, moving, irritate the bronchi, cattle cough reflexively. The laid eggs are coughed up into the mouth, and the animal swallows them.
In the gastrointestinal tract, the larva of the first stage (L1) emerges from the eggs. Further, the larvae, together with the host’s manure, enter the environment and develop in the faeces during the next two stages.
The mold fungus of the genus Pilobolus grows on manure. In the L3 stage, the larvae enter the interior of the fungi and remain there, in the sporangia (organs in which spores are produced), until the fungi mature. When the mature fungus throws out spores, the larvae fly with them. The radius of dispersion of larvae is 1,5 m.
Pilobolus spores pass through the intestines of cattle and in this way can spread over considerable distances.
In the wild, animals don’t eat grass near their own species’ feces, but in pastures, they have no choice. Therefore, along with the grass, the cattle also swallows the larvae of the L3 stage.
Parasites enter the gastrointestinal tract of cattle and pass through the intestinal wall, getting into the lymphatic system of cattle and through it they reach the mesenteric lymph nodes. At the nodes, the larvae develop to the L4 stage. Using the bloodstream and lymphatic system, L4 enter the lungs of the animal, where they complete their development, becoming adult nematodes.
Symptoms of dictyocaulosis in cattle
Signs of dictyocaulosis in cattle are often confused with a cold or bronchitis. As a result, dictyocaulosis in cattle passes into a severe stage and leads to death. Calves are especially affected by dictyocaulosis. The picture of the disease is not always clear, as it largely depends on the general condition of the animal. But usually there are:
- oppression;
- cough;
- elevated temperature;
- shortness of breath when inhaling;
- rapid breathing;
- frequent pulse;
- serous discharge from the nostrils;
- exhaustion;
- diarrhea;
- tactile frit.
The latter means that the vibration of the lungs during breathing in cattle can be “felt” through the ribs.
In advanced cases, dictyocaulosis is complicated by pneumonia, drags on for a long time and ultimately leads to the death of cattle. When dictyocaulosis passes to the terminal stage, the animal will not live long:
- bouts of severe painful coughing;
- constantly open mouth;
- a large amount of foam from the mouth;
- heavy breathing, wheezing.
Due to the lack of air in the lungs clogged with worms, the cow becomes suffocated: she falls on her side and lies motionless, not reacting to external stimuli. This stage of dictyocaulosis quickly ends with the death of the animal.
Diagnosis of dictyocaulosis in cattle
Lifetime diagnosis of “dictyocaulosis” is established taking into account epizootological data, the general clinical picture and the results of analyzes of cattle feces and sputum coughed up by animals. If nematode larvae are found in manure and lung secretions, there is no doubt that the cough is caused by dictyocaulosis pathogens.
Nematodes are different. Many of them live freely in the soil and feed on decaying organic matter. Such worms can also crawl to manure lying on the ground. But the presence of L1 stage larvae in manure from the rectum is a sure sign of dictyocaulosis in cattle.
Pathological and anatomical changes in dictyocaulosis in cattle
In a dead animal, a post-mortem examination reveals catarrhal or purulent-catarrhal pneumonia and a foamy mass in the bronchi. The latter is precisely the habitat of adult parasites.
The walls of the blood vessels in the lungs are hyperemic. The affected lobes are dense, enlarged, dark red. Mucous swollen. Noticeable areas of atelectasis, that is, the “collapse” of the alveoli, when the walls stick together.
The heart is enlarged. The wall of the heart muscle is thickened. But a variant of delation is also possible, that is, an increase in the chamber of the heart without thickening the wall. Changes in the heart muscle are due to the fact that when the lungs were clogged with worms, the animal did not receive enough oxygen. To compensate for the lack of air, the heart was forced to drive large volumes of blood.
Since the larvae from the gastrointestinal tract and the mesentery “made their way” into the lungs, they also damaged the intestinal walls. Because of this, pinpoint hemorrhages can also be seen there: the exit points of the larvae at the time of the “journey” to their permanent place of residence.
Treatment of dictyocaulosis in cattle
The main treatment for dictyocaulosis is the timely deworming of cattle with special drugs that affect nematodes. But there are a lot of drugs for dictyocaulosis. Some have been in use for over 20 years. There are also more modern ones.
Worms are not complex enough to keep their DNA intact despite exposure to various substances. Therefore, like insects, they mutate and adapt to various drugs.
Old drugs:
- Nilworm (tetramisole). For cattle 10 mg/kg with feed or as a 1% aqueous solution. Set twice with an interval of 24 hours.
- Fenbendazole (panakur, sibkur, fenkur). Dose for cattle 10 mg/kg with feed. Once.
- Febantel (rintal). For cattle 7,5 mg/kg once orally.
- Albendazole. 3,8 mg/kg orally.
- Mebendazole. 15 mg/kg with feed.
- Oxfendazole (systemex). 4,5 mg/kg orally.
All dosages are indicated for the active substance.
Over time, newer drugs for dictyocaulosis have appeared, which have already become familiar. Some of them are complex, that is, they contain more than one active ingredient:
- Levamectin: ivermectin and levamisole. 0,4-0,6 ml / 10 kg. Used for dictyocaulosis of heifers;
- Ritril. Used to treat young cattle. Dose 0,8 ml / 10 kg, intramuscularly.
- Prasiver, the active ingredient is ivermectin. 0,2 mg/kg.
- Monesin. Adult cattle 0,7 ml/10 kg orally, once.
- Ivomek. For young cattle 0,2 mg/kg.
- Eprimect 1%.
The latter drug is not yet licensed, but the recovery of cattle from dictyocaulosis after its use was 100%. The drug is produced in Belarus. The complete release of cattle from nematodes occurs already on the fifth day after the use of new generation drugs. Today, in the treatment of dictyocaulosis, aversectin anthelmintics are already recommended.
Treatment of calves the old fashioned way
They drive nematodes from the lungs of cattle and with the help of “miraculous” iodine. This method is used in relation to calves, which are easier to fill up than an adult.
Preparation of the solution:
- crystalline iodine 1 g;
- potassium iodide 1,5 g;
- distilled water 1 l.
Iodine and potassium are diluted in water in glassware. The calf is tucked up and placed in a dorsal-lateral position at an angle of 25-30°. The dose per lung is 0,6 ml/kg. For therapeutic purposes, the solution is injected with a syringe into the trachea, first into one lung, and a day later into the other. For preventive purposes – in both lungs at the same time.
Preventive measures
Given that it is very difficult to remove nematodes from the lungs, and besides, dead worms begin to decompose there, prevention is more cost-effective. To prevent infection with dictyocaulosis, isolated keeping of calves is practiced:
- stand;
- stall-camp;
- stall-walking;
- pasture in areas free from grazing since autumn last year.
Calves are divided into age groups so that older and possibly infected individuals do not pass the nematodes to the young.
On pastures, young cattle are regularly examined for dictyocaulosis (manure analysis). Surveys begin one and a half months after the start of grazing and are repeated every 2 weeks until the end of the grazing season.
If infested individuals were found, the entire herd is dewormed and transferred to a stall. Calves of the second year of life undergo preventive deworming in March-April. Cubs born in the current year are wormed in June-July. If necessary, that is, if dictyocaulus were found on the pasture, additional deworming is carried out in November before being put into stall keeping.
Also, back in the days of the USSR, phenothiazine was fed to pasture cattle in fractional portions, along with feed additives: salt and minerals. In areas unfavorable for dictyocaulosis, as a preventive measure, cattle are dewormed monthly. But such a practice is undesirable, since all anthelmintics are poisons and poison the animal being prevented in large quantities.
There is another measure, not adopted in Our Country, but helping to reduce the number of worms in the pasture: regular cleaning of manure. Since the larvae are spread along with the spores of fungi growing on cow feces, timely cleaning will reduce their number. And along with the mold, the number of scattered larvae will also decrease.
In other words, in the West, manure is removed from pastures not because there is “nothing else to do,” but because of harsh economic considerations. Manure removal is cheaper, faster and easier than treating cattle for dictyocaulosis.
Conclusion
Dictyocaulosis in cattle can cause a lot of trouble for the owners if they write off the cough and mucus from the nose for a cold. When a cow suddenly shows similar signs, you must first remember how long ago the animal received an anthelmintic. And follow an important rule: when changing the regime of keeping, always deworm your livestock.