Don't stop feeding hay too soon. Keep hay available until cattle completely stop consuming it. Use the highest-quality hay for lactating cows. Provide grain supplementation. A supplement containing a high percentage of cereal grains will provide the energy that cattle need to overcome energy deficits.
Corn is often best.
About 3-6 pounds of a supplement containing a high percentage of corn h elps cows regain conditioning for rebreeding. Consult your veterinarian for recommendations. If cattle are nutritionally stressed, make certain that the dewormer works against the brown stomach worm without causing much stress to the cattle. Pay special attention to first-calf heifers. Provide extra supplementation to these cattle.