They come in various colors and sizes. Some weigh 50 pounds, others a pound or less. But how do we know which salt and/or mineral block to place before our animals? Should we offer all of them and let the horses choose? Can a horse actually get enough salt and minerals from a rock-hard block to meet his needs? Shouldn’t we simply buy feed that already contains the necessary ingredients for a balanced diet?

There are many questions about salt and mineral intake for horses. We have three of the top authorities in the business to help answer them. Harold Hintz, PhD, of Cornell University, is one of the world’s leading experts in the field of equine nutrition; Karen Davidson, PhD, is a nutritionist with Purina Mills; and the late M.E. Ensminger, PhD, authored more than 500 scientific articles, bulletins, and features–a number of them on equine nutrition–as well as authoring or co-authoring 21 books. In addition, we will draw on recommendations from the National Research Council’s (NRC) guidelines for proper equine nutrition.

The basic question is this: Can a horse get the proper amount of minerals from a hard block?Most of the 50-pound salt/mineral blocks on the market today contain 93-98% salt; the rest is a variety of other minerals. Some, like salt, are needed in abundance, while others, such as cobalt, are needed in only minute quantities.

It’s important to note that the mineral concentrations in the blocks are usually much higher than the NRC recommended concentrations in the total diet, because the block is expected to provide just a small part of the daily feed intake