6 August 2013

3 minute read

In dairy cows, the intensity of metabolic activity, associated with the negative energy balance (NEBAL), is responsible for an increased production of reactive oxygen species (ROS).

This is then subsequently related to the development of the condition of oxidative stress, which may overwhelm the antioxidant potential of the bovine maternal organism.

This mades it prone to the development of many puerperal dysfunctions, as well as to an alteration of colostrum and milk quality, writes the team of A. Rizzo, E. Ceci, M. Pantaleo, M. Mutinati, M. Spedicato, G. Minoia and R. L. Sciorsci.

Material and Methods

Animals

In this study, all procedures were conducted in accordance with the institutional guidelines for animal care and use. A total of 110 pluriparous Italian Friesian and Brown dairy cows (4 to 7 years of age) during postpartum were selected. The animals were between the second and the fourth lactation, with an average milk production ranging from 8300 to 8500 kg per lactation.

Blood and milk samples

Just before evening milking, peripheral blood samples
were collected from the coccygeal vein in refrigerated serum
vacutainer tubes from each subject, at the following time
points:
T10: 10th day postpartum
T12: 12th day postpartum
T14: 14th day postpartum
T16: 16th day postpartum

Discussion

Ngative energy balance is easy to develop in the early postpartum of dairy cows, because of an alteration between energy intake and output, caused by a decrease in DMI and the increased energetic demands occurring at calving and at the beginning of lactation (Drackley et al., 2005). In such a stressful period, a rapid metabolic adaptation develops, during which the increased mitochondrial activity may lead to the overproduction of ROS (Albera and Kankofer, 2011).

This increase in ROS generation, if not properly counterbalanced by an ef?cient antioxidant defence, may be a cofactor in the determinism of many puerperal dysfunctions, as well as responsible for an alteration of colostrum and milk quality.

As a consequence, the maintenance of an equilibrium between ROS and antioxidants is crucial, above all in such a critical period of the dairy cow, as its abruption may also contribute to the outcome of many postpartum pathologies, which imply a prolongation of calving-?rst oestrus and calving-conception intervals and, consequently, economic losses (Kankofer, 2001; Rizzo et al., 2007 and 2009).

Conclusions

This study investigates ROS, lipoperoxide and vitamin concentrations in serum and milk of Friesian and Brown dairy cows, during NEBAL. The results show that even in presence of higher ROS concentrations the amount of antioxidant vitamins found in Brown cows with an elevated concentration of somatic cells (.400 000/ml) may have been able to counteract the oxidative damage, which is more likely to develop in these cows, compared with Friesian cows.

However, given their scavenging properties, the administration of vitamins A and E, should be recommended in all cows, in order to reinforce their endogenous antioxidant defences during NEBAL and to prevent or attenuate reproductive and productive failure postpartum.