How do I know my horse is getting enough minerals and vitamins?

To stay on top of whether the mineral intake is enough, you need an analysis of the forage and of the other feeds you give. From there, work out the horse's requirements and check how much each feed provides. You can do this on the free programme at hastsverige.se (the Swedish equine information site Häst Sverige; UK readers can run the same calculation with a registered equine nutritionist or feed company). Test it back and forth until you reach a good balance.

The mineral that often proves tricky in Sweden is selenium, which has to be added to the ration because Swedish soils are very low in it. UK soils vary too, so check your own analysis rather than assuming. With vitamins, a horse may need a little A, D and E over the winter months. These are already added to many feeds, so read the ingredients list on what you already give before buying anything extra. The horse produces vitamins B, C and K itself, so there is no need to supplement those.