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

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 differences were seen in the colostrum (T2), with significantly higher amounts of protective molecules (immunoglobulins and other immune-related proteins) in Rendena. b) “Milks” biodiversity i. Fatty acid profile, desaturase and atherogenic indices in milk of Holstein Friesian and Italian autochthonous cattle breeds In this study the characteristics of the fatty acid profile in local Italian bovine breeds (Cabannina, Varzese, and Valdostana) are compared with those of Friesian, , a conventional breed, during the first period of lactation. The local breeds show a general trend to have higher unsaturated fatty acid percentages, as well as lower desaturase indices (related to C14, C16 and C18) and atherogenic index, with respect to Friesian cows. ii. NMR-based metabolomics as a tool to characterize the milk biodiversity In the present study we investigated the variations of the metabolic profiles during lactation in milks obtained from Friesian and autochthonous breeds from Northern Italy by 1H-NMR metabolomics. Furthermore, the external factors influencing the milk composition were minimized: the cows were bred on the same farm, were fed with the same diet, and were matched by for the lactation interval and lactation stage. Our results showed a difference in milk composition between breeds and in relation to stage of lactation. iii. Milk microbiome characterization between healthy Holstein Friesian and Rendena cows The aim of this study was to compare the milk microbiota in 6 Holstein and 3 Rendena cows reared on the same farm under the same management conditions, with a special focus on the transition period. Four time points (dry-off, 1 day after calving, 7-10 days after calving and 30 days after calving) were considered. The taxonomic profiles of cosmopolitan and local breeds were dominated by Firmicutes, mostly represented by the Streptococcus genus, followed by Proteobacteria, Bacteriodetes, and Actinobacteria. In both Rendena and Holstein the most abundant species was represented by Str. thermophilus, a lactic acid bacterium widely used in the fermentation of dairy products. However, the microbial populations were profoundly different in the two breeds along all the time points: the Rendena milk samples showed lower biodiversity and more stable microbial ecosystem. c) Ethological biodiversity i. Cattle Personality biodiversity in autochthonous Italian breeds: a pilot survey This study assessed personality in five different cattle breeds (Bos taurus), two cosmopolitan (Holstein and Brown) and three Italian autochthonous, through a personality questionnaire completed by handlers (milkers). The objective was to determine whether this method could detect differences in personality, including breed, age and sex differences. Milkers’ assessments found breed and individual differences in the animals studied. Differences in personality traits resulted to be quite evident between individuals but consistent within each breed. With these results, we have shed some light on the physiological mechanism at the base of the interesting features showed by the autochthonous Italian cattle breeds. This can contribute to the re-evaluation of bovine local breeds and their products, in order to recover the continuously reducing numbers, and enhance the quality of derived products, with positive effects on farm economy and biodiversity.