[Studies of the etiology of infectious abortion in cows in Ruse District].
A total of 28,159 blood serum samples have been examined for brucellosis, 87--for leptospirosis, 84--for toxoplasmosis, 554--for the presence of rickettsii and neoreckettsii, and 193--for total protein content, albumin, and protein fractions, taken from cows in the course of the years on 40 dairy farms in the district of Rousse. Bacteriologically were examined 349 aborted fetuses, 178 samples of estral secretion, 57 placentae, and 1002 samples of washings and seminal fluid from bulls for vibriosis. Bacteriologic investigations were also carried out on 383 fetuses for salmonellosis, listeriosis, and colibacteriosis, and virologic studies of 398 placentae and parenchymal organs of fetuses. Twenty-eight fetuses were studied parasitologically for toxoplasmosis, and 118 blood smears were examined for hemosporidiosis. It was established that most important in the etiology of the infectious abortions in cows in the district of Rousse were Vibrio organisms. They were found in 36.9 per cent of the studied bovine fetuses and in 24.4 per cent of all materials examined bacteriologically. Only 4 cases were noted of neorickettsii from fetuses and placentae. Serologically, there were 23.6 per cent cases positive for neorickettsiosis, and 12.6 per cent--for Q fever; 56.4 per cent of the investigated sera proved positive for leptospirosis. In 0.8 per cent of the examined fetuses there was Escherichia coli. Abortions in cows were also due to anaplasmosis and francaillelosis; 14.2 per cent of the investigated respective sera were positive for toxoplasmosis. On the days of abortions the amount of total protein was 7.13 mg%, that of albumins--36%, and of globulins--64%. It is considered imperative to elucidate the cause of abortions of infectious nature in cows in connection with the establishing of cattle-breeding complexes.