Only pregnant cows are affected. First trimester cows are not affected, only a small portion of second trimester cows are affected, and as the third trimester progresses, all cows are susceptible by eight months. All cows that abort will have a retained placenta. Treat these cows with systemic antibiotics to prevent complications. Cows so treated will breed back normally.
Graze cows in risk pastures early or until a problem is observed and then move to clear pastures.
This approach requires diligent observation. Clear-cut pastures for late gestation cows or selectively cut small trees and trim lower branches on larger trees. Remember, though, that dry needles on the ground are equally potent. Feed corn silage as a supplement. Avoid high protein supplements.