A mineral mix of two parts calcium to one part phosphorus is helpful to insure adequate phosphorus intake. You can mix a third of trace mineralized salt with two-thirds mineral mix to encourage intake since mineral mixes are unpalatable. If pasture is of poor quality or nonexistent, feed hay and even grain. About one and a half pounds of high-quality legume hay per 100 pounds body weight or one and three quarters to two pounds of similar quality grass hay will meet the maintenance requirement. Do not forget water, trace mineralized salt and the mineral mix.
Many owners feed one to two pounds of grain daily.
With maintenance, there is no gain or loss of weight. But, broodmares gain about 70 percent of the weight of pregnancy during the second trimester. Pregnant broodmares in an Australian study were more efficient than non-pregnant broodmares. As noted, broodmares should be in good body condition with a score of five and a half or higher at this time of year with one being emaciated and nine being obese. And, broodmares fed a high-quality maintenance ration should maintain appropriate body condition and weight for this stage of pregnancy.