The aim of the study was to evaluate the effect of extruded rapeseed cake in diets of dairy cows on changes in milk fatty acid profile and iodine content in milk and on the thyroid gland status. An experiment was carried out on four lactating Holstein cows divided into 2 groups – experimental (R) fed a diet based on extruded rapeseed cake and control (S) fed a diet based on extruded full-fat soya. The experiment was divided into 4 periods of 42 days (21 days of preliminary period and 21 days of experimental period). Samples of milk and blood were taken three times a week during the experimental period. DMI was not affected by the treatment (<i>P</i> > 0.05). Milk yield and 4% FCM were lower in R compared to S (<i>P</i> < 0.05). Percentages of milk fat and protein were higher in R than in S (<i>P</i> < 0.05). The total content of SFA and UFA was not affected by the treatment (<i>P</i> > 0.05). However, the content of MUFA in R was higher (34.71 g/100 g) and the content of PUFA was lower (4.00 g/100 g) than in S (32.14 and 5.54 g/100 g, respectively (<i>P</i> < 0.05). The contents of C18:2 and C18:3 isomers and metabolites in R were lower than in S (<i>P</i> < 0.05). The content of <I>cis</I>-9, <I>trans</I>-11 CLA and <I>trans</I>-10, <I>cis</I>-12 CLA was lower in R (0.71 and 0.016 g/100 g) compared to S (0.97 and 0.022 g/100 g, respectively, <i>P</i> < 0.05). The index of atherogenicity and peroxidisability in R was lower than in S (<i>P</i> < 0.05). The index of desaturation was not affected by the treatment (<i>P</i> > 0.05). The mean daily intake of glucosinolates (Gls) in R was 50.14 mmol and resulted in a significant decrease in iodine concentration in milk in R (196.7 &mu;g/l) in comparison with S (367.0 &mu;g/l, <i>P</i> < 0.05) resulting in the lower daily iodine output in milk in R compared to S (4.4 and 9.2 mg/day, respectively, <i>P</i> < 0.05). Concentrations of T₃ and T₄ in blood plasma were not affected by the treatment (<i>P</i> > 0.05).

The aim of the study was to determine possible changes in isoflavones concentration in cheese made from either control or isoflavone-enriched milk during manufacturing and ripening. The experiment was carried out on four high-yielding lactating Holstein cows that were divided into two groups with similar mean milk yield. The control group of cows was fed a diet based on extruded rapeseed cake (C) while the experimental group of animals was fed a diet based on extruded full-fat soya (S). The experiment was carried out in the form of a cross-over design and was divided into 2 periods of 14 days (a 10-d preliminary period and a 4-d experimental period). Cows were fed individually twice daily ad libitum the diet based on maize silage, lucerne hay and supplemental mixture. In each period 20 kg of morning milk was collected from each group for cheese processing. After pasteurisation (65 °C, 30 min.) a total of 5 kg of milk from each sample in each period was weighed out to make cheese with a low-heated curd. Cheeses were salted in 20% solution of NaCl for 3.5 h and allowed to ripen for 90 days at 15 °C. During technological processing samples were taken to determine isoflavones content. Data concerning the nutrients intake, milk yield and concentration of isoflavones were analysed by means of multifactor analysis of variance using the GLM procedure of the Statgraphics 7.0 package. Average daily isoflavones intake in S (1284.7 mg/d) was higher than in C (2.9 mg/d, P < 0.001). Milk yield expressed in 4% FCM did not differ significantly between groups (P > 0.05). Concentration of daidzein, genistein and glycitein in pasteurised full fat milk was similar in both groups. Milk from S group had higher concentration of equol (26.7 µg/L) in comparison to C group (4.0 µg/L). After processing cheese in C contained 32.1 µg/kg daidzein and 5.6 µg/kg of equol while cheese in S contained 17.5 µg/kg of daidzein and 24.3 µg/kg of equol. During a 90-day ripening percentage decrease in isoflavones concentration was lower in S than in C. Concentration of daidzein was reduced by 47% in C and 37% in S. Concentration of genistein decreased by 51% in C and 31% in S, concentration of glycitein by 46% in C and 29% in S and concentration of equol by 50% in C and 38% in S.

the aim of the study was to describe the differences in composition, physical and technological properties of raw milk as affected by breed of cattle, season and type of feeding. the study was conducted from June 2005 to february 2007 on bulk milk samples (bms) collected from 8 commercial dairy herds consisting of Czech fleckvieh (Cf, 4 herds) and holstein (h, 4 herds) dairy cows. half of herds in each breed was grazing (g) during summer season while the other half was not (n). samples were collected regularly two times in winter (w) and two times in summer (s) period resulting in a total of 64 bulk milk samples (bms) examined. milk yield in Cf (5385.50 kg) was lower (p<0.05) than in h (7015.15 kg). milk fat in Cf was higher (p<0.05) than in h breed being 3.9 and 3.72 g/100 g, respectively. Cf cows had higher (p<0.05) content of crude protein, casein, true protein and non-protein nitrogen (npn) than h. Content of fat, crude protein, casein, true protein and whey protein was lower (p<0.05) in summer (s) than in winter (w). milk yield in grazing herds (g, 5197.50 kg) was lower (p<0.05) than in non-grazing herds (n, 7203.75 kg). Content of fat was higher (p<0.05) in g (3.89 g/100 g) than in n (3.73 g/100 g). Concentration of lactose, urea, crude protein, casein, true protein, whey protein was lower (p<0.05) in g than in n. in conclusion, the Czech fleckvieh breed had a lower milk yield but produced milk with higher concentration of the main milk components than the Czech population of the holstein breed. large seasonal variations were determined in concentrations of the main milk components. the most pronounced changes in milk composition were caused by the type of feeding with a clear decrease in milk yield and content of lactose and all studied protein fractions and higher content of fat in grazing herds compared to non-grazing herds. key words: cow genotype, Czech fleckvieh, holstein, bulk milk, pasture

The aim of the study was to evaluate the effect of extruded full-fat soybean in diets of dairy cows on nutrient intake, milk yield, content and daily production of milk components, fatty acid (FA) profile and indices of milk fat quality. Four lactating Holstein cows were divided into control group fed a diet containing extruded rapeseed cake (R) and the experimental group fed a diet in which a part of extruded rapeseed cake was substituted by extruded full-fat soybean (RS). Dry matter intake (DMI), milk yield and milk composition were recorded. Milk FA profile was determined with subsequent calculation of atherogenicity index (AI), peroxidisability index (PI), desaturation indeks (DI) and spreadability index (SI) characterising quality of milk fat. Cows fed diet containing RS had higher DMI (17.8 kg/d) than cows fed diet containing R (16.8 kg/d, P<0.05). Milk yield in RS (19.5 kg/d) was higher compared to R (17.6 kg/d, P<0.05). Content of protein and casein was lower in RS than in R while content of lactose and urea was higher in RS than in R (P<0.05). Experimental diet (RS) compared to control (R) had higher (P<0.05) content of unsaturated FA (31.64 % and 30.69 %, respectively). Content of polyunsaturated FA in RS (4.03 %) was significantly higher (P<0.05) than in R (3.66 %) mainly due to differences in C 18:2n6c, C 18:3n6 and C 18:3n3 FA (P<0.05). Proportion of short-, medium- and long-chain FA was similar in both groups (P>0.05). PI was higher (P<0.05) in RS than in R being 5.54 and 5.06, respectively.