Elevation of Conjugated cis-9, trans-11-Octadecadienoic Acid in Bovine Milk Because of Dietary Supplementation

Abstract

Cows on pasture were fed full fat soybeans (toasted, flaked, and pelleted) or ground full fat rapeseeds to investigate effects on cis-9, trans-11-octadecadienoic acid in milk. Three herds of 16 cows each that were on pasture were fed 3.1 kg/d of unmolassed beet pulp (control), 3.0 kg/d of rapeseed concentrate, or 3.1 kg/d of a soybean supplement. The concentration of cis-9, trans-11-octadecadienoic acid in the milk of cows fed the rapeseed and soybean supplements was significantly higher than in the milk of cows fed the control diet during the feeding trial. Over the trial, the cis-9, trans-11-octadecadienoic acid concentration in the milk of individual cows varied from 6.8 to 25.7 mg/g of fat in the control herd, from 10.6 to 33.5 mg/g of fat in the herd fed the rapeseed concentrate, and from 8.8 to 30.5 mg/g of fat in the herd fed the soybean supplement. The concentration of cis-9, cis-12-octadecadienoic acid, the substrate for cis-9, trans-11-octadecadienoic acid synthesis in the rumen, was 4.9 g/100 g of fatty acid methyl esters in the milk fat of cows fed the soybean supplement, 2.5 g/100 g of fatty acid methyl esters in the milk fat of cows fed the rapeseed concentrate, and 2.3 g/100 g of fatty acid methyl esters in the milk fat of the control cows. Milk yield and milk constituent yields were not affected by supplementation of either full fat soybeans or rapeseeds compared with controls, but milk protein concentration was significantly reduced by both oilseed supplements.

The effects of supplementation with sunflower and soybean oils on the fatty acid profile of milk fat from grazing dairy cows

“…Unlike what happens with diets composed of conserved forage and variable proportions of concentrates, there is less information in the literature concerning the effect of oils or vegetable seed supplementation of diets on the concentrations of CLA and TVA in the milk fat of grazing dairy cows. Stanton et al [18] and Lawless et al [9] reported significant increases in the concentrations of CLA and TVA in the milk fat of grazing cows directly related to the amount of FFS and FFR supplemented, which were supported by the results of the present study. Partially replacing maize grain by CaFA in the concentrate supplemented to grazing dairy cows, increased the CLA content in milk fat by 58% [20] and by 173% [16].…”

“…The concentration of oleic acid and its different cis/trans isomers (including trans-10 C 18:1 ) significantly (P < 0.05) increased in the milk fat of cows supplemented with VO as a likely consequence of the rumen biohydrogenation process of linoleic and linolenic FA present in the diet and due to the desaturation of stearic acid in the mammary gland [4]. These results are globally supported by data reviewed by Schroeder et al [17] and by the works of Murphy et al [11], Lawless et al [9], Vidaurreta et al [20] and Schroeder et al [16], leaving cows feeding on pasture. All these authors used oleaginous seeds treated or not, or calcium salts of fatty acids (CaFA), which provide a reduced degree of protection of long chain unsaturated fatty acids to the biohydrogenation in the rumen.…”

“…Kelly et al [10] reported that oils rich in linoleic acid (sunflower) were more efficient than oleic or linolenic sources in increasing the CLA content of milk fat. In contrast, Lawless et al [9] found that FFR (oleic acid) were more efficient than FFS (linoleic acid).…”

“…Despite the fact that the oils used in this study were good sources of linoleic acid, its increase in milk fat of supplemented cows, though statistically significant (P < 0.05), was low, suggesting a modest transfer efficiency of this fatty acid from vegetable oils to milk fat and a high rate of rumen biohydrogenation. Using fullfat rapeseeds (FFS), full-fat soybeans (FFR) or CaFA which provide some protection from rumen biohydrogenation, other authors observed a two fold increase in linoleic acid concentration in milk fat of grazed cows (4.9 g·100 g -1 FA) [9,11,16]. Unlike what happens with diets composed of conserved forage and variable proportions of concentrates, there is less information in the literature concerning the effect of oils or vegetable seed supplementation of diets on the concentrations of CLA and TVA in the milk fat of grazing dairy cows.…”

Feeding Polyunsaturated Supplements to Grazing Dairy Cows Improve the Healthy Value of Milk Fatty Acids

“…Milk yield and milk fat content tended to increase when oilseeds rather than vegetable oils were fed to not grazing dairy cows [26] but such positive effects were not detected when lipid treatments were compared to control rations without oils seeds [25] [26] [27]. In our experiment, milk yield tended to be higher (13%) in sunflower oil treatments ( Table 7) a result that differed from [26].…”