[The genetic contribution of cows to the prevalence of mastitis in the following generation].

Investigations of mastitis prevalence were performed in 1227 dam-daughter pairs during 1985-1988. From the records of the last 10 years, the findings concerning mammary gland were obtained. Six herds of agricultural co-operatives in the Brno region were investigated.

[Similarity in the incidence of mastitis in the daughters of related bulls].

The overall prevalence of mastitis in the cow population, selected with respect to sire relatedness, was 12%. As positive for mastitis the cows with positive bacteriological findings in milk were considered. In order to objectify the evaluation by regarding the lactation number achieved, the index of morbidity In was introduced (In = number of positive findings/lactation achieved).

[Incidence of mastitis in cows of various breeds and their crosses-- estimation of the heredity of this disease].

In a large set of cows (24,165 head), consisting prevailingly of Bohemian Pied breed, Black Pied Lowland and Holstein breeds, and of their crosses, significant differences in the incidence of mastitis were proved. Mastitis was demonstrated by the bacteriological findings in milk. The lowest mean incidence was recorded in the cows of the acclimatized Bohemian Pied breed (8.