Tham khảo tài liệu 'food production approaches, challenges and tasks part 11', khoa học tự nhiên, công nghệ sinh học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Milk Biodiversity Future Perspectives of Milk and Dairy Products from Autochthonous Dairy Cows Reared in Northern Italy 179 be appreciated with the increase of free fatty acids mainly short chain ones Randolph and Erwin 1974 several fatty acids are endowed of a good antibiotic power that can be expressed via inhibition of enzyme fatty acid synthesis nutrient uptake cell lysis metabolites leakage disruption of electron transport chain interference with oxidative phosphorylation and lipid peroxidation Desbois and Smith 2010 Clément et al. 2007 . Furthermore by enhancing the activity of stearoyl CoA desaturase SCD the nutritional value of milk would be ameliorated but the simple up-regulation of its activity seems to be limited as reported in a comprehensive milk lipid synthesis model Shorten et al. 2004 . In the present research the local breeds considered show either higher levels in cis-MUFAs or in desaturase indices features that are likely to be linked to genetics as evidenced by Schennink et al. 2008 by a complex interaction in gene allele expressions and that could be used to improve the nutritional value of milk. About reproduction physiology the results obtained indicate that the reproductive physiology of Varzese and Cabannina is characterized by an early resumption of ovarian activity and by an early fecundation opportunity in fact the onset of first estrus can be observed 20 days after birth and the opportunity to impregnate can occur in the following cycle . approximately 40 from birth. That would allow farmers to achieve the goal of a calf year as the primary indicator of welfare reproductive efficiency and good mammary function. According to unpublished data obtained during trials it could be said that autochthonous breeds have peculiar features to solve current problems of the scenario of high yielding dairy cows. As previously said in the current system of cattle breeding cows have dramatically increased energy and financial voracity diet based on
