Iowa ag leaders and lawmakers were cautiously optimistic that an executive order by President Donald Trump to keep meat processing plants operating during the COVID-19 crisis would help ease growing pressure on livestock farmers. They also emphasized the importance of guidelines issued by federal health and safety agencies designed to better protect pro­­cessing plant workers from contracting the virus.

The executive order, the ag leaders and lawmakers said, will help restore an orderly market for hogs and cattle. That will, in turn, help stabilize supply chains that have been badly strained during the COVID-19 crisis, reduce the pressure on farmers to depopulate livestock herds and ensure that consumers will have adequate meat...