Assessment of lipid peroxidation in dairy cows with subclinical and clinical mastitis

摘要

Mastitis is still one of the major causes of economic losses in dairy sector. The routine application of bacteriologic examination of milk samples is often insufficient and for this reason, alternative parameters are used to identify trends in the development of the udder health. Therefore, the objectives of this study were to determine the relationship of oxidative product levels, using malondialdehyde (MDA) as a marker on occurrence of mastitis and its causing pathogens. Dairy herd of 223 Slovak spotted cattle were tested for etiology and occurrence of mastitis based on assessment of clinical signs, abnormal udder secretions, Californian Mastitis Test (CMT) with subsequent collecting of milk samples for bacteriological examination. From 892 quarter milk samples were selected for MDA detection 51 subclinical (SM) and 26 clinical mastitis (CM) quarters with positive CMT score and positive bacteriological examination of Staphylococcus spp. and Streptococcus spp. as well 40 healthy quarters. Results showed that among the current pathogens of the mammary gland belong CNS, S. aureus, S. sanguinis, S. uberis and E. coli, which were the most frequently isolated from SM and CM. The highest MDA level was observed from clinical cases of mastitis however, increased MDA levels were detectable from subclinical cases. Bacterial isolates from subclinical quarter milk samples are different levels of MDA. In this study, we found that quarter milk samples infected with S. uberis were higher compared to other pathogens. In conclusion, differences in both severity of mastitis and mastitic pathogens were associated with differences of oxidative products in infected udders.