[Complement fixation test act in the diagnosis of mucosal disease-virus diarrhea in cattle]. / Reaktsiia za svurzvane na komplementa pri diagnostikata na mukoznata bolest-virusna diariia, pri govedata.

Experiments were made to obtain a highly active antigen for the complement-fixation test, using purification and concentration with methyl alcohol in a cell culture suspension of the causative agent of mucous disease-virus diarrhea. It was established that the CF test was sufficiently rapid and specific in the diagnosis of the disease in cattle. It proved instrumental in detecting complement-fixing antibodies in diseased and survived cattle, in calves with a latent infection and in cows with abortions.

[Combined prevention of viral infections in cattle]. / Kompleksna profilaktika sreshtu niakoi virusni infektsii po govedata.

On the basis of clinical observations and serological investigations a mixed type of virus infection of MD-VD parainfluenza-3 and adenovirus I was established. A complex prophylaxy against the virus infections proved in 2,800 heads of cattle was carried out, also on 1,400 heads of growing animals at the age between 6 and 18 months, as well as on 2,777 calves at the age of 6 months. The results of the immunoprophylactic actions showed the leading role of MD-VD in a virus infection. Owing to the steps taken the respiratory syndrome in the calves and in the cows was suspended. The falling away of calves was reduced from 15.4% to 3.2%, and the average daily growth was increased from 220 to 470 grams.

[Serological studies of the dissemination of neutralizing antibodies against the mucosal disease-viral diarrhea virus in cattle]. / Serologichni prouchvaniia za razprostranenie na neutralizirashti antitela sreshtu virusa na mukoznata bolest-virusna diariia; pri govedata.

During a serological study of 56 samples from cows, taken from prosperous farms, were proved in 37.5% neutralizing antibodies against the MD-VD, whereas the study of 89 samples from cows, taken from failing farms, the neutralizing antibodies against the same virus were 50.3%. Out of the 145 serum samples from calves, originating from prosperous farms 30.5% proved positive for neutralizing antibodies against the MD virus. Out of the 151 samples from calves, originating from failing farms, 65.7% proved positive. The data show the high degree of dissemination of the virus of that disease both on prosperous and on failing farms.

[Production and study of the immunogenic properties of a bivalent inactivated vaccine against mucosal disease (bovine viral diarrhea and infectious rhinotracheitis)]. / Poluchavane i prouchvane imunogennite kachestva na bivalentna inaktivirana vaksina protiv mukozna bolest (virusna diariia i zarazen rinotrakheit po govedata).

Bivalent inactivated vaccine against mucous disease (MD) and infectious rhinotracheitis (IR) in cattle was produced from cell cultural MD and IR virus suspensions. The vaccine was concentrated on aluminium hydroxide, inactivated by ethanol and is without residual virus. Saponine in final 1:1500 dilution is added as supplementary adjuvant. Immunogeneity of the vaccine was tested on 10-month-old calves, which had shown full resistance against experimental infection with virulent strains of both viruses. Testing on calves for harmlessness by use of a five-fold higher vaccine dose indicated complete tolerance of the vaccine. The prophylactic effect of the vaccine applied in practical work to directly threatened with immediate MD and IR infection cows, including pregnant ones, consisted in reduced number of cases of abortion, of inborn malformations, in lower neonatal calf death-rate, etc. No disturbances were observed following two-fold vaccination of the animals, a fact proving its harmlessness. The positive results of the studied vaccine allow its further application in the combined prophylaxis of MD and IR in calf fattening and breeding complexes.

[Trial of a hyperimmune serum against para-influenza 3, bovine adenovirus 1, infectious rhinotracheitis and mucosal disease]. / Izpitvane na khiperimunen serum protiv parainfluentsa-3, govezhdi adenovirus 1, zarazen rinotrakheit i mukozna bolest.

A four-valent serum was obtained by parallel hyperimmunization of cattle with live viral suspensions of parainfluenza-3, bovine adenovirus I, the virus of infectious rhinotracheitis and the mucous disease virus. The serum's neutralizing titres are between 1:1280 and 1:2560. The lasting exploitation of serum producing cattle indicates that no competition exists between the four antigens used in the process of hyperimmunization. Experimental testing of the serum on calves and its application in practical work proved its prophylactic and medicative effect. These results confirm the thesis that the use of passive immunoprophylaxis is needed in respiratory diseases of calves under conditions existing in intensive cattle-breeding.