Milk composition and fatty acid profile of residual and available milk from ewes fed with diets supplemented with different vegetable oils

Milk in the udder can be split into two fractions: available, obtained after conventional milking and residual, which can only be removed after oxytocin injection or suckling by the offspring. In order to compare the chemical composition, mainly the fatty acid (FA) profile, of available and residual ovine milk, thirty-two ewes, divided into four treatments and fed with diets supplemented with 3% of palm, olive, soybean and linseed oil, were milked before and after intravenous oxytocin injection. Residual milk represents almost 12% of total milk, and its fat percentage was higher than that for available milk (11.7 vs 8.8%). Although FA composition was modified by the diets, only a slight decrease in 16:0 content was observed in residual milk with respect to available milk in the four diets assayed. Therefore, despite large differences in fat content, the FA profiles for available and residual ewe milk do not differ.