What is leukemia in cows, its symptoms and signs
Leukemia in cattle causes a special kind of virus. The activity of the pathogen leads to an excessive increase in the size of the cells of the blood. Cows leukemia is common.
Leukemia in cows
Today, the disease cannot be treated, and the only measure of control is a regular examination of livestock. Do vaccinated cows get leukemia? Maybe this is a problem of poor care? The answer to these questions can be obtained by carefully studying all the information regarding the disease and its causes.
Causes of Leukemia in Cows
Leukemia in cows is caused by a representative of oncornaviruses. This type of virus provokes malignant degeneration of healthy cells and tumor growth. The localization of the pathogen is white blood cells, more specifically, the lymphocyte fraction.
The main reason why blood cancer appears in domestic horned animals is the acquisition of new animals from questionable breeders, as well as neglect of preventive measures.
How is leukemia in cows transmitted? It happens:
- When contacting animals, through biological fluids (blood, milk, semen). From bulls to heifers, the virus is transmitted with sperm. Calves are infected from a sick mother in the womb or after birth through milk. Leukemia in cows is easily transmitted in herds where there is no seeding bull. During the hunting period, the cattle jumps on top of each other, as a result of which skin integuments can be violated, and this is the risk of infection. If one animal is infected with cattle leukemia virus, it is transmitted through the blood to the second.
- Through the bites of blood-sucking insects. The danger is represented by mosquitoes and other bloodsucking. It is impossible to cope with this problem, there is no panacea.
- Through stock for veterinary and zootechnical processing. Veterinary services very often use non-sterile instruments for mass examination of the herd, vaccination etc. The first signs and symptoms do not appear immediately, and this threatens the spread of the disease to other individuals in the herd.
The disease can occur in two forms: sporadic and enzootic. Enzootic leukemia is characterized by a long latent period of more than 3 months. The disease affects adult cattle. Young growth is prone to sporadic leukemia. This disease develops very rarely.
The development of leukemia virus in cows is not affected by climatic conditions, therefore infection of cows is common in different countries. A higher risk of getting the disease is observed in Africa, India, etc.
Stage leukemia in cows
Leukemia cattle affects cows, regardless of their suit and size. The disease develops in three stages:
- Hidden (incubation). It starts from the moment the virus enters the body of the animal. Outwardly, the disease does not occur. The stage can last a very long time if the immunity in pets is strong.
- Hematologic stage. It is characterized by a change in the blood composition of the animal. There is a rapid and constant increase in the concentration of white blood cells (bleeding). You can diagnose cattle leukemia by a blood test. The first symptoms also appear: disruption of the digestive tract.
- Tumor. There is an increase in hematopoietic tumors. The tumor stage can occur only 5 years after infection.
In the early stages of the causative agent of leukemia in adults, it can be found in milk, so it is important to regularly take it for research to the microbiological laboratory, and observe the rules for keeping animals. The disease is transmitted to healthy individuals very quickly. Timely identification will help to avoid significant cattle losses; treatment has not been developed for today.
Symptoms of leukemia in cows
Signs of animal leukemia in the early stages do not appear. Symptoms are noticeable at a late stage. A change in blood composition leads to serious disorders in the body.
To suspect that the cow is sick with leukemia, signs will help:
- Rapid panting.
- Digestion problems.
- Swelling of the chest, abdomen, udder.
- Lameness on hind legs.
- Strong swollen lymph nodes.
- The appearance of visible tumors in different parts of the body.
- Exophthalmos (eyebrows), a rare symptom.
Sick animals do not absorb proteins, fats, carbohydrates, vitamins and minerals from feeds poorly. This causes exhaustion, weakness. Also, the animal gives less milk. When signs of malaise appear, you need to isolate the animal, conduct an immediate veterinary examination to do blood tests. Cattle blood cancer is incurable. Abnormal white blood cells do not perform a protective function, so animals will be susceptible to various infectious diseases.
What can and cannot be done when a cattle disease is detected?
Diagnosis of livestock leukemia
The diagnosis of cattle leukemia is made only after a series of laboratory tests. The following tests will help determine the presence of the disease:
- Indirect serological tests - immunodiffusion reaction (RID), enzyme immunoassay.
- Direct detection of the virus in biological fluids is a polymerase chain reaction.
Diagnosis using RID and ELISA allows you to identify antibodies to VLCRS in the biological fluid. The pathogen settles in the animal’s body for life, integrating its genome into the blood cell. The immune system begins to produce specific antibodies a few days after infection. They are constantly present in the blood of a sick individual.
Diagnosis of PCR reveals cattle leukemia pathogen in the blood of RNA. This most sensitive and accurate method has not yet been widely adopted due to the high cost of reagents and equipment. The result of PCR does not depend on the age of the animal, unlike RID tests, therefore, using this method of analysis, you can identify a sick calf. RID is used only for adults. In the early stages, it is difficult to detect infection using immunological tests. The body has not yet developed response molecules. PCR can detect infection from the first days. To quickly identify infected animals and improve the herd, it is advisable to use a set of studies of RID, ELISA and PCR.
Is cattle leukemia virus dangerous for humans
Cattle leukemia is a serious and incurable disease. The appearance in the herd of one sick individual can lead to a fall in the total number of livestock. Is the disease dangerous for people and is leukemia dangerous for young cows? This is the most common question asked by doctors. People are not susceptible to existing VLSC strains. Until today, cases of human infection with livestock leukemia have not been identified in medical practice, but still doctors still cannot accurately determine whether animal leukemia is dangerous for humans, all very individually.
The viruses are very flexible, they quickly mutate, adapting to drugs and environmental conditions, so there is no guarantee that tomorrow there will not be a new strain of VLCK, which will be dangerous for people.
From a sick cow, goats and sheep can become infected with leukemia. The infection is transmitted through milk.
Can I drink milk or eat meat from a sick cow
Cow leukemia is not dangerous for humans. But you should refrain from consuming milk and meat: an infected specimen produces dangerous products. During the development of cancer, harmful substances, toxins accumulate in the animal’s body. You can get sick not with leukemia, but get an ailment from harmful toxins. The causative agent dies during heat treatment, and it is impossible to get rid of toxins, therefore it is better not to eat meat and drink milk from cows with leukemia, do not give it to children.
If the disease was detected in the first stage, the animal is slaughtered on a common basis.
Sick cows with a hematological stage of infection are killed in a sanitary slaughterhouse. The meat undergoes a mandatory examination, the veterinarian gives recommendations on its further use. The meat can be allowed to eat in the form of sausage or stew. Unsuitable raw materials are disposed of.
Cows Leukemia Prevention
Leukemia in cows is not treated even in the most developed countries. Infected individuals are given for slaughter. However, cattle disease can be prevented. Measures to prevent the fight against leukemia were developed for large and small farms back in 1999.
To prevent cattle leukemia infection, you must follow these rules:
- You can only buy and import into your household young animals from healthy bulls and cows. In their family tree there should not be patients with leukemia.
- The first 2 months of new animals are kept in rooms isolated from the main herd. During this time, the veterinarian must inspect the animals twice and take the blood for PCR. If negative test results are obtained, livestock are introduced to the general herd. If sick animals are found among young animals, they are transferred for fattening. The rest are checked twice by the method of RID and ELISA, introduced into the general herd, if the tests both times gave a negative result.
- From RID-positive animals, a separate herd should be formed and kept isolated from others. Such animals go for fattening. Calves of the last calving from RID-positive cows must be checked by PCR. If the answer is yes, the animals go to fattening. Older offspring are used depending on the recommendations of the veterinarian.
- In large farms, hardware milking, veterinary processing, etc. you need to start with healthy cows.
- It is important to number the calves with liquid nitrogen, decontaminate them thermally or chemically, so as not to infect through the instruments.
- Preventive measures should cover all livestock.
- Blood for analysis from seeding bulls is taken 4 times a year.
- Pregnant cows are examined two months before and two months after calving.
It is also important to ensure sanitary conditions for animals. It is necessary to process milking machines, all veterinary equipment. In premises for calving cows in large farms, special sanitary conditions must be created. Free mating should not be allowed in a herd of cattle. If there is no seeding bull, sperm for artificial insemination of cows should be bought only from trusted people and taken for research to the microbiological laboratory.
Cows leukemia is a serious illness. Pets are infected by contact with patients through veterinary equipment. Sick individuals and calves go to slaughter, treatment is not performed. Leukemia of cows is dangerous for sheep and goats, a person is not susceptible to the virus. Milk from infected individuals cannot be consumed; it is rarely possible to eat meat, but only after veterinary examination. Regular prophylactic testing of livestock blood will help maintain a healthy population.