To figure out how much your mare needs, you first have to know what she's getting at baseline. If you don't, it's pure guess work, and the price you may pay is the health and soundness of the foal. For this example, we'll use a 500 kg (1,100 lb.) mare whose maintenance/nonpregnant/nonlactating diet is meeting NRC-suggested minimums. These are the amounts listed under "maintenance" in the table below.
The reason some of these nutrients don't take a bigger jump with lactation is because the mare must eat considerably more of the base diet to hold her weight when lactating. In reality, most mares really don't/won't eat 70% more food when they are lactating so this has to be taken into consideration. For example, if the mare is eating 5 pounds of grain and 15 pounds of hay in her nonpregnant state, she would have to eat 8.5 pounds of grain and 25.5 pounds of hay when lactating. If she won't clean up that much, you'll have to increase her supplements accordingly. If she'll only clean up half that much, you'll need to make up 50% of that difference with supplements. Mares that are easy keepers and can't be fed as much will also come up short.
Warning: The examples and recommendations used in this article refer to an 1,100-pound mare, whose base diet (both hay and grain) when not pregnant was known to be balanced and to meet the minimum NRC requirements for protein, vitamins and minerals. If the base diet is not balanced or adequate, that will change her requirements.
Bottom Line
We looked at widely available supplements targeting broodmares. Futurity Blend 30, Triple Crown 30, and Gro N' Win were the only ones we felt addressed both the increased protein/amino acid and mineral needs of pregnant and lactating mares. Of these, assuming you start from a base of balanced nutrients that at least meets minimum needs for maintenance, Buckeye's Gro N' Win gets the nod as best all-in-one product.
