Marker of innate immune response during periparturient period in dairy cows

The study has the aim to assess the level of several marker of immunity and inflammation during drying-off and after calving. This will allow to define cow (udder) health status after calving, to identify sensitive markers to predict health status of the udder and to define markers to identify animals at risk at drying-off or after calving. 15 cows from 3 herds and, overall, 150 blood samples and 360 milk samples were taken from cows from 14 d before drying-off up to 30 d after drying-off. Bacteriological analysis, flow cytometry, CK expression by Real-PCR, SCC were applied to the samples. Results showed large differences in blood PMN, Iymphocyte, apoptosis and necrosis pattern among herds, during the follow-up periodo Such differences were present, but in a lesser extent for CD4, CD8 and their ratio. ILi, 112 and ILB cytokine pattern showed, as expected, large variations both at drying-off and around calving. When milk was considered, as expected, the results showed to be largely different from blood ones. Indeed, the proportion of CD4 and CD8 in milk was the opposite to the one observed in blood and thus their ratio. This latter one dropped significantly after calving, when compared to the value observed prior to drying-off. This change was related mainly to the increase in CD8 proportion. On the opposite milk cells apoptosis and necrosis showed to increase after calving. Interestingly, among the herds, the one with the lowest levels in SCC «100.000 cells/ml) and the best hygiene management showed the largest increase in blood CD4/CD8 ratio after calving and the largest drop in milk; a lower increase in apoptosis and necrosis; the highest proportion in blood Iymphocytes and the lowest in PMN. These preliminary data confirm that herd could have a significant effect on cow innate immune status and, therefore, management procedures avoiding the decrease in innate immune defenses can be identified.