How different farming systems can affect nutraceutical and traceable components of cow milk?

The aim was to analyze different dairy farming systems to clarify if the management can influence the nutraceutical composition and traceable components of cow milk. All of the 29 farms studied were located in Northern Italy and they were members of a cheese factory which produced Grana Padano cheese P.D.O. Information about herd composition and milk production, feeding system and land utilization were obtained through personal interviews to the farmers. In each farm samples of bulk milk were collected for chemical and microbiological analyses. The farms had characteristics of high intensity: lactating cows was on average 78.4±46.6, stocking density 4.09±2.56 LU/ha, milk production (FPCM) 27.0±4.21 kg/d cow, milk fat 3.94±0.15% and milk protein 3.43±0.15%. Most of the farms included corn silage in the cow ration, forage intake was 59.5% and feed self-sufficiency was 63.6%. A cluster analysis was performed on farm characteristics (ha of land, number of cows, milk production level, dairy efficiency, feed self-sufficiency) and identified three different groups of farms. Cluster 2 included 11 farms characterized by low intensity level: few lactating cows (32.4), low stocking density (2.97 LU/ha), low corn silage intake (22.8% DMI) and high forage intake (64.1%). Milk microbial contamination (SPC, coliform count and clostridium spores count) was not statistically different among the groups while the lactic bacteria were higher in milk of cluster 2 compared to the others. Nutraceutical components (CLA, MUFA, omega 3 and omega 6 fatty acids) were similar among the clusters. Some non-volatile hydrocarbons present in the neutral lipid fraction of milk fat (phytane, phytene, phytyl C16, phytyl C18 unsaturated e phytyl C18 saturated) were significantly h! igher in the farms of Cluster 2 than in Cluster 1(10 farms) e 3 (7 farms). We supposed that these molecules were linked with the high forage content and low maize silage percentage of cows' rations in Cluster 2 farms. The results showed that the different level of intensity of farms involved had a low influence on nutraceutical composition of milk and that some non-volatile hydrocarbons in milk could be used as markers of forage composition of cow's diet.