How to treat nodular dermatitis in cows
Nodular dermatitis is a dangerous and contagious viral disease of cattle. Productive thoroughbred individuals suffer from it most of all, therefore the disease can cause serious economic damage to agriculture. So far, the disease mainly prevails in the Asian lands, where it came from the African continent, but its outbreaks in Russia and some European countries are already noted. Therefore, any farm should be ready to deal with the disease.
What is this disease
Nodular dermatitis is an infectious-viral disease accompanied by fever, swelling of the subcutaneous connective tissue and organs. It affects the skin, lymphatic system, mucous membranes, eyes and is manifested by tubercles on the skin and tissues. In infected individuals, the quality of milk deteriorates and its milk yield decreases, they are depleted and become sterile.
The causative agent of the disease is very similar to the causative agent of smallpox. There are several strains of the virus: Ethiopian, Turkish, Guinean. Large breeds of cattle virus of large breeds and zebu (a subspecies of a wild bull living in India) are most vulnerable to attack.
How cattle infection occurs
The virus enters the external environment from the exfoliated upper layer of the skin of a sick animal, from the opened purulent tubercles, mucous membrane. Often, the pathogen is found in urine and seminal fluid. Even if the disease proceeds in a latent form or the animal has already recovered, it remains a carrier.
Did you know? Cows are able to learn from the mistakes of others. For example, if one individual from the herd gets an electric shock when in contact with the fence and her relatives saw this, then almost the whole herd will avoid contact with the fence.
Infections help spread blood-sucking insects, as well as birds (herons). The disease can also be transmitted through a farmer who came in contact with a sick individual, and then came to healthy food through care items. If the disease affects the herd for the first time, it can kill 5–50% of its population, in rare cases 75–100%.
Form and symptoms
The incubation period of the disease takes 3-30 days, but most often 7-10 days. After this, the disease almost immediately manifests itself in one of three forms, since the prodromal period (between the incubation period and the disease as such) in the disease is almost absent.
At the initial stage, along with a jump in body temperature up to 40 ° C, the following symptoms are observed:
- appetite worsens;
- severe lacrimation and mucous discharge from the nose;
- milk turns pink, thickens and is difficult to milk;
- lymph nodes are enlarged;
- 48 hours after the onset of the first symptoms, the skin is seeded with tight nodules of 0.5-7 cm in a circle, 0.5 cm high;
- a few hours after the appearance of the tubercles, their edges exfoliate, a dent forms in the center, the skin dies;
- after 7–20 days, the tubercle can be cut off, or it will disappear, and the wound will gradually overgrow;
- with complications, ulcers may appear.
Did you know? Cows are able to distinguish between sweetness, acid, bitterness and salinity due to the fact that 25,000 taste buds are located in their oral cavity.
This form is noted only in newborn calves. Her symptoms:
- there are no noticeable changes in the skin;
- diarrhea with appearing and disappearing symptoms.
Nodular dermatitis in an asymptomatic form does not manifest itself in any way, but a sick animal is a carrier of infection. His body also produces virus-neutralizing antibodies.
The first outbreaks of the virus in Russia and Europe were recorded in 2015–2016 and were of a single nature.In addition, the ailment proceeded in an acute form, therefore, by its pronounced symptoms, it was easy to suspect and recognize it.
On the African continent, an atypical form is quite common, which greatly complicates the diagnosis of the disease. In addition, the clinical picture of nodular dermatitis in many ways resembles some other diseases - smallpox, foot and mouth disease.Therefore, so far, the main way to detect an ailment remains an analysis of its clinical picture, along with some laboratory studies. In their course, an analysis of the skin, mucous membrane, blood of fallen or suspicious animals is performed, which makes it possible to detect traces of the virus or its antigen.
Important! If the disease proceeded in a particularly severe form, the diagnosis is made on the basis of pathological studies.
In 10% of cases, the course of the disease is fatal. The bodies of fallen animals look exhausted; if the calf is dead, he has signs of dehydration and anemia. The mucous membranes, the skin and the adjacent layer of tissue undergo changes most of all, they are much less likely to suffer from muscle ailment. The affected areas are covered with tubercles, erosion, ulcers.
There are areas with dead tissue. If an incision is made in the tubercle, then its section in structure will resemble cottage cheese. Fiber under the skin is permeated with exudate, nearby tissues are swollen. Lymph nodes are poured, covered with tubercles, can be purulent. The vessels are filled with blood and have a thickened wall.In mature individuals, the lungs look like with croupous pneumonia, emphysema or edema, there may be adhesions in the pleura. If the bronchi are opened, tubercles can be seen on their mucous membranes, and pus in the alveoli. In the body of calves, the gastrointestinal tract first of all suffers - its mucous membrane is inflamed, covered with erosion, ulcers. Lymph nodes are enlarged.
What to treat
So far, there is no medicine that can cope with the causative agent of the ailment, so all treatment is aimed at combating the symptoms:
- disinfection of a room where there are sick individuals with the help of ethyl, chloroform, alkaline solutions, quartzization;
- disinfection of opened nodules with antiseptics;
- taking sulfonamides, antibiotics as a prevention of secondary infection;
- injections of nitox, tetracycline, oleandomycin to prevent pneumonia;
- intraperitoneal injection of novocaine to young animals against enteritis;
Important! An animal can be considered recovered if it has lost nodules, swelling has subsided, the affected areas have bald, cracked skin has disappeared and a new one has appeared in its place.
- if the virus killed about 90% of the livestock on the farm, group treatment is used (disinfecting shower, spraying drugs).
Is it possible to eat meat and drink milk
When the cattle population recovers, quarantine is removed from the farm and the corresponding control studies are carried out, livestock meat will be suitable for human consumption, since the virus mainly affects the skin integument and adjacent tissue layer. In addition, the virus of nodular dermatitis is not dangerous to humans.
Milk is also usable after lifting all prohibitions. But you can drink it only after sterilization at 132 ° C for 1/4 minute, or boiling.
Prevention and vaccination schedule
Due to the fact that the virus is spread by insects, it is extremely difficult to prevent its appearance. In addition, the development of immunity takes a long time and it lasts only a year. But to minimize the likelihood of the disease, you can use the vaccine sheeppox.
Vaccination is carried out according to this scheme:
- three-month-old calves are given the first vaccination with an interval of 14 days;
- each subsequent vaccine is given every year;
- if the disease has manifested, then the entire population is vaccinated immediately, regardless of when the vaccination was before.
- Do not breed damp in cowsheds;
- isolate the room from insects as much as possible;
- treat livestock and stalls with repellents;
- Do not import animals from disadvantaged regions and without documents;
- allow veterinarians to inspect the farm;
- conduct a regular inspection of the livestock;
- if a sick animal is found, isolate it from the rest.
As soon as there are suspicions that your herd was attacked by the dermatitis virus, you should immediately contact veterinarians and follow the instructions of the sanitary and epidemiological services. We must be prepared for the fact that we have to kill sick animals, since the disease has not yet been studied much in our countries.
Although nodular dermatitis has existed for about 90 years, this disease has not been studied much in European lands. It is quite difficult to deal with and it brings significant economic losses to the household. Therefore, it is better to try to prevent its appearance in all possible ways.