Abstract: Identification of marker sequences related to immunity towards mastitis may be instrumental in improving resistance against this trait and as a result may reduce the costs related to the prevention and treatment of the disease. The ideal candidate genetic markers for immunity towards mastitis are the genes encoding bovine defensins which belong to the wide and varied group of peptide antibiotics. A lot of antimicrobial peptides identified in cattle have been classified as β-defensins. Defensins are particularly active against gram-positive bacteria and fungi but at higher concentrations they are also, capable of destroying gram-negative bacteria, mycobacteria, enveloped viruses and some protozoons. The aim of this study was to search for associations between the occurrence of clinical mastitis and Combined Defensin Genotypes (CDG) and to investigate the possibility of using defensin gene polymorphisms in marker-assisted selection for immunity towards mastitis in dairy cows. This study included such indicators as the number of clinical cases of mastitis acuta and chronica, number of affected udder quarters and duration of the condition in 1,025 cows (Polish Holstein-Friesian breed) kept on a farm located in the North-Western region of Poland. The cows were of different ages and in different lactations parities (from 1st to 6th). An analysis of associations between selected CDGs and susceptibility/immunity towards mastitis has showed statistically significant relations with regard to all the indicators under study and CDGs. Moreover, some genotypes have been found to have different effects on chronic and acute infections.
Katarzyna Wojdak-Maksymiec, Tomasz Strabel, Joanna Szyda and Kinga Mikolajczyk, 2012. Clinical Mastitis and Combined Defensin Polymorphism in Dairy Cattle. Journal of Animal and Veterinary Advances, 11: 2230-2237.