Question

Both of my mature mares (a Quarter Horse and a Chincoteague Pony) are very easy keepers and are holding their weight well on grass hay this winter in the Mid-Atlantic Region. They have access to a mineral block as well. I feed a few supplements for specific problems. Do I need a vitamin/mineral supplement? They both look fantastic. I don't test my hay, mainly because I pick up a new round bale every two weeks, and my supplier's source varies, though it’s always a timothy/orchardgrass mix.

Answer

Because you live in the Mid-Atlantic Region (eastern United States), there is a likelihood that your forage will be deficient in selenium and low in copper and zinc.

Whether you need a vitamin/mineral supplement will depend on what the horses are consuming in the other supplements. If you check the other supplements for those minerals, particularly the mineral block, and do not find them, then it may be good to either add a vitamin/mineral supplement or find a mineral block that is designed specifically for horses with those added minerals, particularly the selenium.

The mineral blocks or loose minerals designed for horses oftentimes are very high in mineral and low in salt (<25%), so it is helpful to offer white salt with it, either block or loose.

A one-on-one consultation with an equine nutritionist in your area will help you determine if your mares need an additional source of vitamins and minerals.