The effect of sunflower oil on the fatty acid composition of the milk of Cows fed either a fat‐depressing diet or grass silage

Abstract

Two experiments have been carried out in which different forms of sunflower oil were added to the diet of Ayrshire heifers. In experiment 1, the animals were given a fat-depressing diet of dried, ground grass cubes and flaked maize. When either free sunflower oil or milled, unextracted sunflower seeds were added to this diet, the yield of milk fat and of all fatty acids up to 16: 1 was decreased and the yield of all 18-carbon fatty acids was slightly increased. When the sunflower oil was protected by encapsulation in formaldehyde-treated casein, the yield of milk fat was increased, that of the fatty acids up to 16: 1 was decreased and that of all the 18-carbon fatty acids, and in particular, of the polyunsaturated fatty acids was increased. In experiment 2, the animals were given a basal diet of grass silage and concentrates to which increasing amounts of protected sunflower oil were added. This tended to increase the yield of milk fat and to reduce that of the fatty acids up to 16: 1. The yield of all the 18-carbon fatty acids increased and, in particular, that of the polyunsaturated fatty acids increased progressively as more protected oil was added. It is concluded that it should be possible to produce a milk with any desired proportion of polyunsaturated fatty acids by adding a predetermined amount of protected oil to the diet of the cow.

Oilseed Lipid Supplements and Fatty Acid Composition of Cow Milk: A Meta-Analysis

“…Data for DMI, milk yield, milk fat content, and milk fat yield are given for their order of magnitude, but because of the wide variability between experiments, linked to the production levels of the cows or other experimental effects, they are not directly comparable between columns. In particular, 7 of the 8 values for protected sunflower seeds came from 2 publications (Bartsch et al, 1976;Clapperton, 1982) with very low production levels, and thus were not comparable with the mean of the unsupplemented diets.…”

“…Milk fat content was linearly decreased by all supplements given as oils and by rapeseed and sunflower as seeds. The strong increase observed with protected sunflower seed was based on 2 experiments (Bartsch et al, 1976;Clapperton, 1982).…”

Effect of inclusion of different forms of dietary fatty acid on the yield and composition of cow's milk

“…When soya oil, protected in a manner identical to that used in this work, was given to dairy cows there were large increases in the 18 :2 and 18 :3 contents of the milk fat (Clapperton, 1982). Thus, the method used in preparing the encapsulated fat offers considerable protection against ruminal activity without greatly depressing the digestibility of the fat.…”

“…Fat prills or molten free fat were mixed with the other concentrate ingredients in a farm mixer. Protected fat was prepared as previously described (Clapperton, 1982), except that two parts Na caseinate were mixed with seven parts fat, and the treatment with formaldehyde was carried out in a small cement mixer. The protected powder was added each day to a premix of the other ingredients.…”

“…The period mean was taken as the arithmetic mean of these two sets of values. Milks preserved as above were also used for determining fatty acid composition (Clapperton, 1982). During the last 3 d of each period, the milk from pairs of cows on identical diets was bulked over 24 or 48 h, to be used in manufacturing processes.…”