-During the periparturient period, some impairment of immune defences were observed. Reference values for the different non-specific immune parameters in cows are not generally available, thus limiting the application of these parameters in dairy practice. This paper reports the data on the measurements of different parameters in the blood, and explores the possible influence of the herd on the non-specific immune status of the cow. Five herds located in Northern Italy were selected and overall 39 heifers were enrolled in the trial. Blood samples were taken 14 and 7 days before the expected date of calving, then at 7, 14, 21, 28, 45, 60, and 75 days after calving. The parameters assessed were N-acetyl-β-glucosaminidase (NAGase), lysozyme, nitric oxide, superoxide dismutase, haptoglobin, respiratory burst, and serum protein profile. After calving, a significant decrease of respiratory burst and nitric oxide concentration were observed in comparison with the pre-calving values but not with the post-calving samplings. Total proteins, β-and γ-globulins showed a progressive and significant increase in concentration after calving, in comparison with pre-calving values. The results of the study confirmed 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 improved management and genetic selection. heifers / periparturient period / blood / non-specific immunity

-A practical protocol to study udder immune status in field conditions was planned with the aim to assess different non-specific immune parameters in 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. Milk samples were taken at 7, 14, 21, 28, 45, 60, and 75 days after calving. The parameters assessed were N-acetyl-β-glucosaminidase (NAGase), lysozyme, respiratory burst (RB), somatic cell counts (SCC) and serum protein profile. SCC and NAGase were higher in the first sampling after calving, while lysozyme showed large variations during the observation period without a definite trend. The levels of RB observed in the first two weeks after calving, even if lower, were not statistically different from the values observed in samples taken over the following weeks. This study confirmed that the levels of immune components in milk are different from what is observed at blood level in the same cow. A significant decrease in RB in milk polymorphonuclear leukocytes (PMN) post-calving was not observed; milk PMN from healthy cows showed low RB levels, 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. These data suggest that udder immune response could be influenced both by the cow immune status and by external factors such as pathogens and management. Therefore, the reduction in immune defences, particularly in heifers, is not unavoidable and methods to boost PMN activity should be explored.heifers / periparturient period / blood milk / non-specific immunity

To assess the impact of automatic milking systems (AMS) on the different aspects of milk production a research project
involving both commercial and experimental dairy farms with different AMS and different management was started. This
paper reports the results of a follow-up study on primiparous cows focused on assessing some markers to be used to
monitor udder and teat health. Heifers were included after calving and sampled for at least 12 months. Quarter milk samples
and teat measurements were taken to assess: intramammary infection (IMI) frequencies, somatic cell counts (SCC),
teat thickness changes, teat skin and apex conditions. The study included 28 cows in herd A and 27 in herd B for a total
number of 2344 samples. Overall, teat apex and skin conditions were maintained along the lactation. Teat skin conditions
tended to decrease because of the accumulated number of milkings while lactation proceeded, but at a largely
acceptable level in both herds. Teat apex conditions showed a decrease. Teat thickness changes displayed different patterns
in the two herds, probably because of the different type of AMS, but in both cases a trend to decrease in thickness
could be observed. The application of AMS in herd B, free from contagious pathogens, did not influence the frequency of
IMI and the SCC. In herd A, characterized by the presence of Staphylococcus aureus IMI, the frequency of IMI showed
a progressive increase, very likely as a consequence of the spread of infections during milking. Teat skin had no association
with the frequency of IMI. Teat thickness changes outside values considered as physiological proved to be associated
with decreased conditions in the teat apex score in herd A, but not in herd B. However, a decrease in teat apex score
proved to be associated with an increase in IMI frequency in both herds. The results of this field trial confirm that AMS
have no negative impact on IMI incidence, SCC and teat tissue conditions when the initial cow health status and overall
herd management are good. In the presence of contagious pathogens, and when cows have more than 300 days in milk
(DIM) the frequency of negative outcomes significantly increases and the proper control measures should be taken