Abstract: Mammary infections are one of the most serious problems in dairy cow farming. The factors that reduce the incidence of mastitis may include prolactin-one of the most multifunctional hormones in the body. Prolactinís biological activity consists of various roles in reproduction, lactation and a number of homeostatic biological functions including immune functions. In view of this fact, it is reasonable to investigate in pursuit of any associations between PRL polymorphism and somatic cell count (susceptibility/resistance to mastitis). The study included a herd of 720 Holstein-Friesian cows, Red-and-White variety. The frequencies of prolactin alleles and genotypes (recognized by endonuclease RsaI) were determined. The statistical analysis also included a search for associations between prolactin polymorphism and SCC in milk. Parity, barn, date of study, stage of lactation, Holstein-Friesian gene share and cow were also included as sources of variability. Two prolactin alleles: A and B were found in the studied population of dairy cows, Statistically significant association was found between SCC and PRL genotype. It was also confirmed that statistically significant associations existed between SCC and the barns, date of study, parity, lactation stage and cow. The highest SCC (transformed to a logarithmic scale) was recorded in the milk of BB cows while the lowest one-in AA cows. The differences were confirmed statistically.
Katarzyna Wojdak-Maksymiec , Marek Kmic and Joanna Strzalaka , 2008. Prolactin Gene Polymorphism and Somatic Cell Count in Dairy Cattle. Journal of Animal and Veterinary Advances, 7: 35-40.