PHYSIOLOGICAL APPROACH TO THE STUDY OF AUTOCHTHONOUS CATTLE BREEDS OF NORTHERN ITALY

Abstract

This PhD project is focused on the physiological characterization of some autochthonous bovine breeds of Northern Italy, using many biological parameters in order to make a comparison with the cosmopolitan breeds. Despite the lower milk production, these breeds present other interesting and peculiar features, such as rusticity, frugality, good food conversion, high product quality (milk and meat), good fertility and good resistance and resilience against the diseases. We applied a multidisciplinary approach to study the physiological bases of the interesting traits present in the local breeds, studying three main issues: the metabolism of the transition period, the milk composition and technological properties and the ethological traits. a) Biodiversity of the transition period i) Study of the milk ketone bodies assessment in Modenese breed and Holstein with a characterization of physiological, reproductive and productive performances. The objective of this study was to characterize some productive, reproductive and metabolic parameters (ketone bodies) in the Italian autochthonous cattle breed Modenese, comparing them with those of Holstein and their crossbred (F1=Modenese x Holstein; F2=Modenese x F1) breed in the same farm, in order to understand if there is a different metabolic picture that can influence the reproductive performances. Milk samples have been collected at different times of lactation (20, 40, and 90 days in milk (DIM)) and analyzed by gas chromatography-mass spectrometry to obtain the the concentration of ketone bodies. In all time points, the Modenese breed showed a significant (p<0,05) lower concentration of ketone bodies. The F1, F2 and Modenese showed also better reproductive performances when compared to Holstein, with a significant lower (p<0,05) length of days open period. ii) Comparative evaluation of the transition period: Italian autochthonous breed vs. Holstein We evaluated the metabolic indicators, milk protein profiles and the milk microbiota in 6 Holstein Friesian and 4 Rendena cows reared on the same farm and under the same management conditions. Quarter milk samples and blood were collected from all cows at dry-off (T1), 1 day after calving (T2), 7-10 days after calving (T3) and 30 days after calving (T4). Blood samples were used for the analysis of plasma metabolites such as: glucose, total cholesterol, urea, inorganic phosphorus, total protein, albumin, total bilirubin, aspartate aminotransferase (GOT), γ-glutamyltransferase (GGT), creatinine, NEFA, β-OH-butyric acid (BHBA), thiol groups (SHp) and ferric reducing antioxidant power (FRAP). Quarter milk samples were subjected to bacteriological culture, protein profiles and characterization of the milk microbiota. Holstein cows showed a more severe fat mobilization, lower muscle mobilizationand systemic inflammatory response at T2 and T3 in comparison with Rendena cows. Significant differences were seen in the general composition of the milk microbiota of the two breeds. Concerning the milk protein abundance profile, pronounced…