[Association between BoLA antigens and bovine mastitis]

The association between BoLA class I antigens and mastitis was studied in Bohemian Pied breed (n = 17) and its crosses--Bohemian Pied x Red Pied Holstein (n = 161), Bohemian Pied x Red Pied Holstein x Ayrshire (37). The diagnostics of mastitis was followed in the course of two years and two diagnostic parameters were included: 1. a modified California Mastitis Test (CMT) was performed once a month; 2. a bacteriological infection was examined once quarterly using biochemical and serological methods. BoLA class I antigens were determined by specific antisera in the standard microlymphocytotoxicity test. During testing the majority of cows had at least one positive reaction of CMT test. The bacterial findings were detected in 31.63% of animals. The antigen A16 was found to be significantly associated with susceptibility to mastitis in both diagnostic tests. Animals A16 positive showed the highest CMT values and repeated bacterial infections (Fig. 1). The high values observed in A2 positive animals were not significant due to the very low frequency of this allele in the population under study. There was a slight increase of CMT values and the infection frequency in animals with higher parity number (Fig. 2). However, the order of lactations did not influence the relationship of BoLA A16 and mastitis. This association was not significantly affected by the breed. The increased bacterial infection observed in the Bohemian Pied breed is likely due to relatively high incidence of A16 allele rather than to breed differences (Fig. 3).