PT - JOURNAL ARTICLE AU - Komprda, T. AU - Dvořák, R. AU - Fialová, M. AU - Šustová, K. AU - Pechová, A. TI - Fatty acid content in milk of dairy cows on a diet with high fat content derived from rapeseed DP - 2005 Jul 31 TA - Czech Journal of Animal Science PG - 311--319 VI - 50 IP - 7 AID - 10.17221/4172-CJAS IS - 12121819 AB - Two groups of dairy cows, Czech Red-pied × Ayrshire × Red Holstein crossbreds, received a diet with either production mixture with rapeseed, rapeseed cakes and rapeseed oil (Energol; E-group; final feed mixture with 62 g of crude fat per kg of dry matter, DM) or control production mixture (C-group; crude fat content in total feed mixture 37 g/kg DM). Milk samples were taken on the 14<sup>th</sup>, 30<sup>th</sup>, 60<sup>th</sup> and 90<sup>th</sup> day of lactation, and basic milk constituents and fatty acid content in milk fat were determined. E- and C-groups did not differ in either milk yield or yield of milk fat, milk protein and lactose (P &gt; 0.05). Lactose, calcium, milk protein and casein content increased linearly (P &lt; 0.05) with the increasing day of lactation both in E-milk and in C-milk. Casein content in E-milk was lower (P &lt; 0.05) than in C-milk but total lipid content did not differ (P &gt; 0.05) from that in C-milk. Dietary rapeseed decreased (P &lt; 0.05) palmitic acid content in milk by 20 percentage units and at the same time increased (P &lt; 0.05) oleic acid content by 10 percentage units in comparison with control milk; the ratio of total C16/total C18 fatty acids was consequently twice lower (P &lt; 0.01) in E-milk. As far as polyunsaturated fatty acids (PUFA) are concerned, the contents of linoleic acid (LA), α-linolenic acid (LNA) and eicosapentaenoic + docosahexaenoic acid were higher (P &lt; 0.05) in E-milk; however, the PUFAn-6/PUFAn-3 ratio was not different between E- and C-milk. It was concluded that 1 litre of E-milk could provide 20% of both LA and LNA daily requirement.