Equol occurs naturally in cows’ milk. It is synthesised in the animal’s digestive tract from precursors (phytoestrogens) found in some forage plants (legumes). Equol is thought to have beneficial properties for human health: anticarcinogen, antioxidant, cholesterol-lowering and a thyroid regulator.
The aim of the trial, conducted in winter 2013-2014 as part of the GrassMilk project, was to increase the milk equol content by feeding silage rich in red clover in order to obtain milk of specific nutritional quality all year round.
Six dairy cows (average production: 24 litres) were evenly distributed according to a crossover experimental design. Two feeding systems were compared: one ration based on silage containing red clover and another based on grass silage. Three weeks of adaptation were followed by one week of collection. The cows were milked and fed twice a day and water was freely available.
The results show that the trial diets had no effect on production performance. On the other hand, the milk sampled (night and morning) was systematically and significantly (p < 0.001) richer in equol in the case of the red clover based ration, at 12,879 µg excreted per cow per day on average (i.e. 644.6 µg/l) as against 273 µg (i.e. 14.29 µg/l) in the case of the grass-based ration.