Co-grazing helps control parasites by which approach?

• A. Allowing two different species to graze together to disrupt parasite life cycles
• B. Increasing stocking density on a single pasture
• C. Relying solely on chemical dewormers
• D. Grazing only in the shade to avoid sun exposure

Answer: (A)

Co-grazing uses host diversity to interrupt parasite transmission. When two different species graze together, parasites that infect one species aren’t as able to complete their life cycle in the other. The shared pasture becomes a less favorable environment for parasite development, so fewer infective stages survive to reinfect the animals. Over time, the overall parasite burden drops, reducing reliance on chemicals. The other options don’t leverage this interruption—more animals on the same pasture increases exposure, relying only on dewormers can lead to resistance, and grazing in the shade doesn’t affect parasite life cycles.