[Interbreed and interspecies variation in the occurrence of subclinical mastitis in cows and buffaloes].

Studied were for subclinical mastitis 3252 cows of the Bulgarian Brown breed, 1409 cows of the Bulgarian Simmenthal breed, 1082 cows of the Bulgarian Red cattle, 341 cows of the Iskar cattle, 1086 cows of the Black and White breed, and 418 buffalo-cows. Established were mathematically dependable variations with regard to the individual sensitivity to subclinical mastitis of the main cattle breeds reared in this country. Highest was the percent of subclinical mastitis in the cows of the Bulgarian Simmenthal breed - 28.22. Bulgarian Brown cows and the cows of the Bulgarian Red breed were equally affected with subclinical mastitis - 25.24 and 25.23 per cent, respectively. In the Iskar and Black and White cattle the values were 12.60 and 12.70 per cent, respectively, i.e., the per cent of subclinical mastitis was more than twice lower as compared with the first three breeds. Buffalo-cows showed high absolute and relative resistance both with regard to subclinical and to clinical mastitis.