LAUSR

The aim of this study was to evaluate the behaviour of adenosine deaminase (ADA) activity, as well as its participation in the immunomodulation of pregnant cows. Thus, sixteen cows were divided into two groups (A and B): the group A was composed by cows not pregnant (n = 8), while the group B was composed by pregnant cows (n = 8). Serum levels of interleukin-10 (IL-10), IL-6, tumour necrosis factor alpha (TNF-α), reactive oxygen species (ROS) and C-reactive protein (CRP), as well as ADA and glutathione S-transferase (GST) activities, were measured on five sampling times (3, 5, 7 and 8 months of gestation, and soon after calving). Serum ADA activity was similar throughout the experiment in the cows belonging to the group A, but its activity increased during the experiment in cows from the group B, that is it was lower in the third and fifth months of pregnancy, and higher on months 7, 8 and after calving when compared to the group A. TNF-α and IL-6 serum levels were lower in pregnant cows compared to non-pregnant animals; however, they significantly increased after calving. Serum levels of IL-10 increased after 8 months of gestation, but it reduced after calving when compared to the group A, while CRP increased on month 8 of gestation and after calving compared to the group A. Pregnant cows showed lower serum ROS levels on months 3, 5 and 7 of gestation, and higher levels at the post-partum. Serum GST activity was higher on month 5 of gestation in pregnant cows, but it was lower on months 7, 8 and in the post-partum compared to the group A. Based on these evidence, we concluded that ADA activity and the others mediators or inflammatory modulators have important role in the maintenance of cow's gestation due to their immunomodulatory effects.