[Mastitis in dairy cows in large-scale farming operations from the genetic aspect].

Genetic predisposition to mastitis was studied in 893 dairy cows of the Black Pied Lowland breed, daughters of 19 breeding bulls used in stocks with large-scale production technology and with loose housing, over the years 1980 to 1983. Every cow with positive bacteriological diagnosis or with a clinical manifestation of the disease was considered as suffering from mastitis. High resistance to mastitis was determined in the progeny of AO-4, EM-01, NC-17, NB-10, NEB-15, NUN-3, Nx-33 bulls, while opposite results were recorded in the progeny of NAR-45, NAR-47, NER-01, NOM-19 and REN-100 bulls. Higher milk efficiency, by 9 to 408 litres of milk was observed in positive dairy cows in the years of study. The coefficient of heritability (h2) is 0.3032. It can be concluded that the systematic control of cows from the aspect of suitability for large-scale production technology and resistance to mastitis, and evaluation of bulls according to predisposition of their daughters to this disease, is very favourable in view of the prophylaxy of bovine mastitis.