[New trends in the control of enzootic bovine leukemia in Bulgaria]. / Novi nasoki v borbata s enzootichnata levkoza po govedata u nas.

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.

[Importance of saliva and colostrum in leukemia transmission in cattle]. / Znachenieto na sliunkata i kolastrata pri predavane na levkozata u govedata.

Studied was the occasional role played by the saliva of leukotic cows in the transmission of the infection to test lambs along with the role of colostrum as a factor neutralizing the leukosis virus in experimentally infected lambs. It was found that bovine leukosis could be transmitted by the saliva of affected animals. Colostrum that contained hightiter specific antibodies was found to be effective in neutralizing the leukosis virus in newborn calves provided no subsidiary infection took place.