I don't feed cod liver oil to horses, I use Veg oil, same calorific value, same effect but plant based, horses arn't known for their fishing ability, so it seems natural to me to use a veg based material whenever possible, speaking of being a hypocrit, I havn't tried my horse on soya milk, he probably wouldn't thank me for it. By the way he also loves a washing up bowl of tea, no sugar, milk of course!