Most pasture farmers know that endophytes are hard on animals, causing problems ranging from pregnancy issues to staggers.  Other ailments include slow growth, hoof gangrene, and a hard time handling hot weather.  But what are endophytes?

If you're a ryegrass or fescue plant, endophytes are the coolest thing since sliced bread.  These symbiotic fungi --- Neotyphodium coenophialum in fescue and Neotyphodium lolii in ryegrass --- spend their whole lives inside a single grass plant, eating sugars the plant hands over willingly.  In exchange, the endophytes produce alkaloids that deter insects and keep grazers like deer, sheep, cattle, and horses from gorging too much on the grass.

When scientists discovered the dangers posed by endophytes, they got to work breeding endophyte-free grasses.  However, they soon learned that plants share their sugars with endophytes for a reason --- without the endophytes, fescue and ryegrass tend to die out quickly.  (The paired photos show an ailing stand of endophyte-free fescue on the left and a thriving stand of endophyte-infected fescue on the right.)  Now scientists have changed their tactics and are trying to breed endophytes that produce the alkaloids that keep bugs at bay (peramine) without making ergovaline (which is the most problematic alkaloid for livestock).  If you haven't planted a special (read: expensive) strain, though, chances are your ryegrass and fescue are infested with the common endophyte varieties.

Luckily, you can work around endophytes in many situations, giving your grasses the boost they need to thrive without hurting your livestock's health.  The trick is to understand the life cycle of an endophyte-infected grass.

The red lines in this diagram show the general location of endophytes within a plant.  (No, you can't actually see anything with your naked eye.)  The fungus comes along for the ride when a seed drops off the parent plant, spreads up into the lower portion of the leaves, and then heads up the flower stalk to infect new seeds.

As a pasture maintainer, this life cycle tells you how to ensure your livestock don't munch on too much of the problematic fungus.  If you don't overgraze your pastures and do graze often enough that the grasses don't want to go to seed, your livestock probably won't get enough endophyte into their systems to cause problems.  No wonder endophyte-related illnesses tend to show up in summer or fall, when our cool season grasses are declining and we're forced to graze them down to nubbins.

My final endophyte-related question was --- do endophytes harm chickens?  A quick search of the internet doesn't turn up much definitive information.  Chickens fed on a diet of endophyte-infected fescue seeds did worse than those fed on a diet of endophyte-free fescue seeds, but other sources suggest that, in the wild, chickens don't eat enough grass to get sick.  Fescue is generally too tough for chickens to digest, but I did plant some annual ryegrass in one of our pastures since these tender leaves are supposed to be much more palatable to non-ruminants.  I'll make sure to treat the ryegrass carefully and will let you know if I see any problems.

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About us: Anna Hess and Mark Hamilton spent over a decade living self-sufficiently in the mountains of Virginia before moving north to start over from scratch in the foothills of Ohio. They've experimented with permaculture, no-till gardening, trailersteading, home-based microbusinesses and much more, writing about their adventures in both blogs and books.



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