Most mornings, when I wake up and take that first glorious sip of coffee, there are 25 ewes starring back at me.
We installed a temporary paddock for our ewe lambs to grass a portion of our yard this summer. The piece of grass is directly across from our kitchen’s large picture window. Most of the time, I have the thought that the scene is idyllic; crisp white and black sheep grazing the green grass while the sun floats over the horizon. But, there is a danger among those blades of grass.
That may sound dramatic to some but is the wholehearted truth. By worms, I’m actually talking about a variety of parasites that, if left untreated, can severely decrease the growth of affected animals and can even cause death. We have had ewes die due to parasites. Parasites affect all grazing species.
When sheep graze, they can ingest parasites which then pass through the body, leaving parasite eggs in the manure. The eggs then hatch and go through several larval stages before reaching an infective stage. This cycle can complete itself in as quickly as six days, which is why it is recommended to graze a pasture in sections. This allows the sheep to move off a piece of grass before the larva reach the infective stage.
Larva are tricky to control as the larva can survive for long periods. The larva’s survival also depends on weather patterns; larva will thrive in lush, growing pastures but will die when the pastures become hot and dry. Graziers have to balance having adequate feed available in a pasture with the health of the pasture and its ability to rest and grow again.
There are many specific methods to control larva in sheep, from the height of the grass in a pasture to intensive rotational grazing; even grazing cattle with sheep helps as the parasites that affect sheep do not affect cattle. Grazing the two species together helps break up the life cycle of the parasites. There are also a variety of oral solutions and injectable medications which kill internal parasites.
From lung worms to stomach worms, liver flukes to tapeworms, sheep producers have some mighty microscopic enemies to deal with.