BOVINE LACTATION AND REPRODUCTION PHYSIOLOGY: A SURVEY ON SOME FUNDAMENTAL FEATURES IN AUTOCHTHONOUS DAIRY BREEDS REARED IN NORTHERN ITALY

In the last 40 years, the first goal pursued by dairy cattle community has been to increase individual production from a quantitative point of view, by high yielding dairy cows selection (BLAP). This mono-aptitude criterion has caused a decline in reproductive performances worldwide (eg increase in calving interval). The comparative physiological study of autochthonous cattle to value “Ancient Autochthonous Biodiversity” opens up interesting prospects for livestock to comply the FAO 2050 target, as these animals are guarantors of a good milk production, excellent and typical cheese making, peculiar characteristics of rusticity, frugality, longevity and resistance to multiple diseases. Therefore they appear to be good candidates for traditional food production. The study of autochthonous breeds lactation and reproduction physiology could be strategic to improve knowledge and develop a more rational dairy livestock in view of reduced availability of cereals and plant proteins for livestock in the next 40 years. From a productive point of view the most variable component was analyzed. The importance of fat composition of milk in human and animal nutrition has in the last years come rapidly to the fore. Several nutritionist Associations recommend the intake of higher levels of unsaturated fatty acids (PUFA and cis-MUFA) in milk despite of saturated fatty acid levels: increases in PUFA and cis-MUFA in milk fat can be reached by enhancing the activation of the enzyme Δ9-desaturase or by selecting subject with high desaturating ability. In this research, two endangered local bovine breeds of Northern Italy, Varzese and Cabannina, were considered for the PUFA and cis-MUFA content and compared with the PUFA and cis-MUFA levels in Friesian cows bred in the same conditions. The milk collections were performed from the 40th to the 180th day of lactation. Milk fat was analyzed by gas chromatography and desaturase indices for C14, C16 and C18 fatty acids were determined. Varzese and Cabannina milk fat contains significantly overall higher levels of some PUFA and cis-MUFA with respect to Friesian, and higher desaturase indices, mainly C16 desaturase and the total desaturase indices. The results rise the importance of the recovery and the reevaluation of local breeds, not only for the biodiversity per se, but also in order to bring out peculiar characteristics of niche milk. From a reproductive point of view serum hydroxyproline (HYPRO) trend was considered for the uterine involution monitoring. Postpartum period is a physiological process between birth and complete uterine involution, essential to bring the female genital apparatus back to favorable conditions for optimal embryonic development and implantation, resumption of ovarian cyclicity and future reproductive efficiency; the latter is a parameter that unequivocally determines the career of a cow in the herd. In this research, the same cows involved for milk analysis, were subjected to blood collection and hydroxyproline determination. Blood samples were performed the day of birth (day 0), 1,2, 3, 4, 5, 10, 15, 20, 25, 30. The two autochthonous breeds showed lower starting points and average concentrations than the Friesian cows. Only the Cabannina cows showed a peak in day 4 statistically higher than the value at day 0. All breeds showed at day 40 after birth a completely uterine involution and so it seems obvious that HYPRO patterns are characteristic of each breed. It remains to clarify the origin of HYPRO district that could not come solely from the uterine matrix, given the ubiquitous nature of collagen. These results can be considered as a starting point to try to clarify the mechanisms of uterine involution process, the intrinsic and extrinsic factors of the animals and any phenomena that would affect reproductive performance of cows.