Comparison of blood and milk non-specific immune parameters in heifers after calving

A practical protocol to study udder immune status in field conditions was planned to assess different non-specific immune parameters in blood and milk samples from dairy heifers during the periparturient period. Five herds Located in Northern Italy were selected and overall 39 heifers were enrolled in the trial. The parameters assessed were SCC, N-acetyl-beta-glucosaminidase (NAGase), Lysozyme, nitric oxide, superoxide dismutase, haptoglobin, respiratory burst, and serum proteins profile. After calving, a significant decrease in blood PMN respiratory burst (RB) and in serum nitric oxide concentration was observed in comparison with the pre-calving values but not with the post-calving samplings. Total proteins, beta- and y-globulins showed a progressive and significant increase in concentration after calving, in comparison with pre-calving values. In milk, we did not observe a significant decrease in RB, post-calving; milk PMN from healthy cows showed Low RB [eve[, while the values from infected quarters were significantly higher. Significant differences between healthy and infected animals were also observed for milk NAG, lactoglobulin and albumin. The results of the study confirm that a decrease of immune functions can be observed in commercial dairy herds in the first four weeks after calving. The amplitude of this phenomenon is not common to all animals and all herds, suggesting the possibility to reduce the impairment by improving management and genetic selection.