[New trends in the control of enzootic bovine leukemia in Bulgaria].

Experimental and literature data as well as personal observations with herds infected with enzootic bovine leukosis have revealed some new aspects that could be made use of in the control of the disease. The more important ones are stated: newborn calves of cows with positive leukosis response can be given untreated colostrum which has been shown to neutralize the virus; in individual regions and Agro-Industrial Complexes where sporadic cases of leukosis have been recorded isolation premises for positively reacting animals could be designed; cows in the last two months of pregnancy do not always give reliable results with the immunodiffusion test, so such animals should not be investigated at that time with this method.