Is there a specific kind of feed and medication for pregnant cows?

No and no. Definitely no medication unless the cow is actually sick, and the same kind of feed that she'd get if she were not pregnant or suckling a calf. Be mindful, though, that a cow that is in mid-pregnancy and not suckling a calf (or "dry") doesn't need as much protein and energy as if she were in late pregnancy, or lactating. When a dry pregnant cow is in her second trimester and needing to gain or lose some weight, that's typically the best time to do it. Add straw to her ration if she needs to lose some or maintain weight. To get her gaining, feed with a good source of energy, like grain or beet pulp or something similar, to be fed along with her usual diet of grass and/or hay.