Changes in fatty acid pattern, composition and technological parameters of milk in dairy cows fed heat-treated rapeseed cakes in the first stage of lactation
2001
Komprda, T. | Sustova, K. (Mendelova Zemedelska a Lesnicka Univ., Brno (Czech Republic)) | Dvorak, R. | Tieffova, P. | Poul, J.
Two groups of 8 dairy cows each (Czech Red-Pied x Ayrshire x Red Holstein) were fed basal diet and concentrate mixture with either heat-treated rapeseed cakes (HRC) or soybean meal (SBM) within the first hundred days of lactation. Milk constituents (solids, fat, solids-non-fat, crude protein, casein, whey protein, urea, lactose, calcium, citric acid), fatty acid pattern of milk fat, and technological traits (freezing point, acidity, heat stability, rennetability) were determined in milk samples taken on 21st, 2nd and 100th day of lactation. Solids-non-fat and lactose content was higher (P0.05) in HRC-milk as compared to SBM-milk. Content of saturated fatty acids was lower (P0.01) and content of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) higher (P0.01) in milk of dairy cows fed the diet with HRC. The ratio of total C16/C18 fatty acids was by 30 % lower (P0.01) in HRC-milk in comparison with SBM-milk. Content of myristic acid increased (P0.01) and content of stearic acid decreased (P0.05) in milk fat with increasing day of lactation irrespective of the feeding intervention. Content of linoleic acid, total PUFAn6 and PUFA/MUFA ratio increased (P0.05) with increasing day of lactation within the HRC group. It was concluded that inclusion of heat-treated rapeseed cakes in the diet for dairy cows instead of SBM did not influence negatively either composition or the technological quality of milk, and on the other hand improved its nutritive value from the viewpoint of more favourable fatty acid spectrum of milk fat.
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