Which medication would be recommended for treating a Fasciola hepatica infection in a pregnant beef cow?

Clorsulon is the appropriate medication recommended for treating a Fasciola hepatica infection, particularly in a pregnant beef cow. This is due to its specific action against liver flukes, including Fasciola hepatica, which are significant parasites affecting livestock, especially in regions where wet or marshy environments promote their lifecycle.

Clorsulon works by inhibiting the enzyme systems that these parasites rely on for energy production, effectively leading to their death. Furthermore, clorsulon is considered safe for use in pregnant animals, making it a suitable choice for treating pregnant beef cows experiencing an infection.

While other medications like albendazole and ivermectin are commonly used for various parasitic infections, they are not specifically indicated for treating liver flukes. Praziquantel, while effective against certain types of trematodes, is not the first-line choice for Fasciola hepatica in cattle and does not have the established safety profile for use in pregnant cows compared to clorsulon. Thus, clorsulon's targeted efficacy and safety for use in pregnant livestock makes it the recommended option in this context.