Combination of pelleting and monensin does not affect antioxidant properties and fatty acids in milk of grazing dairy cows supplemented with a concentrate containing soybean seeds.

This study was performed with the main objective of evaluating the effect of the combination of pelleting and monensin on fatty acids (FA) composition, the concentration of total polyphenols and flavonoids, and the oxidative stability of milk in cows fed a concentrate containing soybean seeds. Eight Holstein multiparous cows were distributed in a replicated Latin square design. The four supplement treatments consisted of the combination of two factors (pelleting and monensin) and one concentrate as follows: (1) unpelleted concentrate with no monensin (CO); (2) pelleted concentrate with no monensin (PE); (3) unpelleted concentrate with 96 mg of monensin/kg of dry matter, DM (MO); and (4) pelleted concentrate with 96 mg of monensin/kg of DM (PM). There was no interaction between pelleting and monensin for milk production and concentration of milk protein, lactose, total polyphenols, flavonoids, conjugated dienes (CD), and reducing power. Fat and total solids concentration in milk were decreased when cows were fed pelleted (PE and PM) concentrates. Feeding cows with PE and PM concentrates increased the CD concentration in milk. Regarding milk FA concentration, there was no difference among treatments for total saturated, monounsaturated, and polyunsaturated FA. The most prominent result was that pelleting increased the milk concentration of omega-3 FA. Altogether, the present study suggests that the pelleting process can improve the milk fat quality by increasing the omega-3 FA, while the combination of pelleting and monensin in the diet of grazing dairy cows fed soybean-based concentrate adds no further improvements to FA profiles and oxidative stability of milk.

Effect of supplementation with Yerba Mate (Ilex paraguariensis) and vitamin E on milk lipoperoxidation in cows receiving diets containing ground soybean seeds.

This research communication addresses the hypothesis that the association of dietary vitamin E and Yerba Mate could help to prevent or decrease oxidation of milk enriched in unsaturated fatty acids (UFA). Four multiparous lactating Holstein cows were used in a 4 × 4 Latin square. Treatments were: (1) control diet with no Yerba Mate or vitamin E; (2) diet containing 375 IU/kg vitamin E; (3) diet containing 30 g/kg Yerba Mate; and (4) diet containing 375 IU/kg vitamin E and 30 g/kg Yerba Mate. To increase unsaturated fatty acids in milk, cows were fed 172 g/kg soybean seeds (on a dry matter basis). There was no interaction between vitamin E and Yerba Mate supplementation for milk antioxidant-related (polyphenols, reducing power, conjugated dienes, and TBARS) analyses. Milk reducing power was increased when cows were supplemented with Yerba Mate. Our results suggest that the association of dietary vitamin E and Yerba Mate does not help to prevent or decrease oxidation of milk in UFA.

Production, Composition, Fatty Acids Profile and Stability of Milk and Blood Composition of Dairy Cows Fed High Polyunsaturated Fatty Acids Diets and Sticky Coffee Hull

Four lactating Holstein cows were assigned to a 4 × 4 Latin square design to determine the effects of feeding sticky coffee hull (SCH) as a source of antioxidants on dairy cows fed with high PUFA diets. The treatments (on DM basis) were control diet, diet with 30 g/kg of soybean oil, diet with 30 g/kg of soybean oil and 100 g/kg of SCH, and diet with 30 g/kg of soybean oil and 150 g/kg of SCH. Inclusion of 150 g/kg of SCH decreased the crude protein digestibility. Lower values of NDF digestibility were also observed when cows were fed with 100 g/kg and 150g/kg of SCH. The digestibility of NDT was lower in the control and 150 g/kg of SCH diets. Milk production and composition did not differ among the treatments. Inclusion of SCH increased the total polyphenols and flavonoids in the milk and reducing power as well. Soybean oil and SCH supplementation increased the LDL and total cholesterol concentration in the plasma. Milk fatty acid profile was barely altered by the treatments. In conclusion, the results confirmed that SCH added up to 15% in the diet did not alter milk production, improved its stability, and incorporated antioxidants substances in the milk, improving its quality for human health.