Forages can easily provide a horse with all necessary calories, protein, and most of the necessary macrominerals--in particular calcium and phosphorus. However, they often fall short in supplying necessary trace minerals, especially cooper and zinc. | Photo: iStock

Q: My horse is fed hay and gets turned out each day on poor-quality pasture. I know that I need to be feeding a balancer to ensure he is getting all the nutrition he needs, but I can only get to the barn three or four times a week, and my barn owners don’t give grain. Should I give it to him on the days I do go out? Is it doing anything, and is it okay for him to get it only sporadically, or am I doing more harm than good?

A: You’re quite right that, to ensure a diet is meeting all your horse’s nutritional requirements, he needs a balancer feed or supplement. Forages can easily provide a horse with all necessary calories, protein, and most of the necessary macrominerals—in particular calcium and phosphorus. However, they often fall short in supplying necessary trace minerals, especially copper and zinc. Dried forages and poor pasture also tend to offer inadequate amounts of vitamin E and omega fatty acids.

Forages might also have a poorly balanced mineral profile. I’ve tested a number of grass hays over the past couple of years here in California that turned out to have very low calcium to phosphorus ratios. For example 1.1:1 when an ideal ration is 1.5 to 2:1. Occasionally the calcium level is lower than phosphorus, which is something more typical of grain hays. This can lead to inadequate calcium consumption, hyperparathyroidism, and bone