Leukemia in cows: symptoms, diagnosis, prevention

Leukemia in cows is a chronic infectious disease. It is caused by the RNA-containing virus of the Retroviridae family. In the development of the disease, veterinarians distinguish three stages: incubation, hematologic and tumor.

Infection

It should be noted that leukemia in cows is a highly contagious phenomenon. The virus can easily be transmitted from an infected animal to a healthy one at all stages of the disease. In this case, infection can occur enterally and parenterally, with the penetration of lymphocytes into the body. The disease is transmitted through blood, milk, saliva and any other materials that include lymphoid cells of infected cattle.

Etiology

As noted above, leukemia in cows is caused by an RNA-containing oncogenic cattle virus (its morphology is similar to that of leukemia in animals of any other species). According to experts, the virus is not resistant to disinfectants, but it is inactivated in milk when it is heated and sour.

Symptomatics

How to diagnose leukemia in cows? It is not easy to do this: the incubation period of the disease can last from two months to several years. To date, several stages of the disease are distinguished: preleukemia, initial, expanded and terminal. The first of these can be identified through serological and virological studies. Hematological signs are not observed. The only factors that can be fixed at the initial stage of leukemia are changes in blood composition. The number of leukocytes is growing, their percentage is increasing. The next stage can be recognized by some clinical signs: the cow begins to give significantly less milk, weakens, there are malfunctions in the heart, lymph nodes increase (as a rule, internal "suffer" more often than superficial ones). Signs of leukemia in cows at the terminal stage are characterized by a general depletion of the hematopoietic organs and blockade of the immune system. In most cases, after this comes the death of the animal.

Diagnostics

How to diagnose leukemia in cows? Symptoms are quite obvious, however, in most cases, several tests are required - virological, histological, serological, etc. All this is necessary in order to exclude the presence of tuberculosis, actinomycosis, mastitis, hepatitis and sporadic leukemia in young individuals.

Prevention

Unfortunately, effective methods of treatment for today do not exist. However, owners of cattle can follow preventive measures. They are based on timely diagnosis and prevention of drift of the pathogen. If there is even the slightest suspicion that the animal is infected, its milk can be used for food only after pasteurization (and it should be boiled for at least five minutes). In this case, meat and internal organs should also be thoroughly boiled. If an infected specimen is found in the holding, it will regain the status of a safe one only two years after the last sick cow is sent to slaughter.