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Ewes and fescue?

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Just did a post last night on hay and had one of those lightbulb moments! Oh crap, I forgot about my ewes! They've been eating fescue hay and seem to be doing fine. Do sheep have a sensitivity to the endophyte in fescue like horses and to some degree, cattle have? I don't remember finding anything about it. These girls are due next month and a couple of them are just beginning to bag up a little. Should I pull them off the fescue?


I pulled them in last evening and dewormed them with the higher dose of fenbendazole 10% (5cc/100lbs) and boosted their CD&T vax. Should I do anything else?

Thanks a bunch,


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Hi Lydia,


First off, please let me insert my obligatory "beware information, especially health information, offered over the internet from faceless strangers you do not know" disclaimer:


I'm not a vet. I am a shepherd with a small flock. I was a vet tech at one point in my life - and leagally and morally that does not qualify me to diagnose anything. I do live with a vet and so have had this very discussion in relation to horses and sheep. What I provide below is from three textbooks we have at home (author and publishers are cited so you can double check my lay interpretation).


Here's what the books say:


1. Sheep & Goat Medicine, 1st Ed., D.G. Pugh, Saunders Press, copyright 2002.


Dr. Pugh, in his discussion of fescue toxicity (tall fescue contaminated w/ an endophyte), states: "During winter months the toxins may cause a perpheral vasoconstriction leading to a gangrenous necrosis of th distal limbs and tail...sheep and goats appear to be less sensitive to the toxin then cows."


2. Current Therapy in Large Animal Theriogenology, Robert S. Youngquist, Saunders Press, copyright 1997.


Dr. Youngquist's ovine (sheep) chapter has one paragraph on toxic plants and does not mention endophyte infected fescue as a problem. However, there is chapter on reproductive toxicology in the bovine (cow) chapter that includes a lengthy discussion of fescue toxicosis. Dr. Stan Casteel wrote this chapter and notes "The most critical consequence of infected fescue utilization in cow-calf operations is diminished reproductive efficiency." (Lowered conception rates.) He also notes the problem is more severe when temperatures are hot (>90 degrees F), and related to the "decreased ability to disapate excess body heat...largely due to the peripheral vasoconstrictive effects of the toxic ergot..."


I can see two ways to intrepret this information: 1. only cows are affected, or 2. there is not enough data (interest, research $, etc.) to have noted the problem in the ewe.


(FYI, Theriogenology is the fancy term for reproductive medicine.)


3. The Veterinary Book for Sheep Farmers, David C. Henderson, Farming Press, copyright 1990.


Also discusses endophyte-contaminated fescue causing "dry gangrene of the lower limbs of grazing sheep..."


So, with all of that information in mind, IMHO, you are way beyond being able to do anything about it at this point (in terms of conception rates).


Did all your girls "catch"?


Hope the info helps.

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As Deb wrote,there isn't much information about Fescues.


Fescues,especially in pastures are the least likely grazed grasses by sheep. They'll eat everything around it but will leave fescues to grow tall where it becomes highly unpalatable.

Even in hay form,they'll pull the fescues out and will consume weedy grass.

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We don't have much tall fescue around here, but the fescues that we do have are not very palatable to sheep until they have been heavily frosted. My theory has always been that this perhaps killed the endophyte, leaving the grass palatable. I don't know if there's any basis for that conjecture.


Deb mentioned ergot in her post, and I think that's a different kettle of fish from the endophyte that infests fescue. (I mean, ergot can infest fescue, but it's not the run-of-the-mill fescue endophyte, I don't think.) Ergot can infest many species of grass, and it can be deadly to sheep.

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Actually Bill, it's the fungal endophyte that produces the ergot alkaloids, or, perhaps I should say in a more general form, "fungal endophytes produce ergot alkaloids."


The endophyte that infects tall fescue, per the references cited above (Pugh and Youngquist / Casteel) is called:


Acremonium {Neotyphodium} coenophialum , or A. coenophialum in the short form.


According to Dr. Casteel, in relation to the inability to dissipate excess body heat "...due to the vasoconstrictive effects of the toxic ergot peptide alkaloids (primarily ergovaline) produced by the endophyte fungus, A. coenophaialum." So, this is the same beast.


There is more then one kind of fungal endophyte, and so there can be more then one kind of ergot alkaloid. Although I am a loss for a specific name at the moment, rye and the Salem witch trials comes to mind.


Now, if there is a veterinarian or a closet toxicologist lurking out there, it's time for them to jump right in. I have a degree in biology, but my interests are more towards zoology...

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I'm on an advisory committee for one of the Univ of MO research farms and Dr. Dave Patterson has done a lot of research involving the endophyte fungus and how it affects reproductivity in cattle (yeah, I realize this discussion is about sheep but thought this info might be useful here as well).


The highest concentration of the fungus will be around the seed. Check your hay, if it has seed heads visible that's where the culprit lies. If the hay was put up early before the seed head appeared, the toxicity of the fungus will be MUCH lower.


Also, as far as the seed itself, the fungus dies in storage but it's useless to reseed with this endophyte free seed unless you've killed the existing fescue and row-cropped the field for at least one year, (to make sure that all of the seed left in the soil has germinated and been killed off). Then it's still not totally recommended to seed with endophyte free seed as livestock tend to overgraze this (studies show consumption will increase approx. 40%) and kill it out.


Now a new strain of freindly or beneficial endophyte has been found in Europe and is being marketed here under the name "Max Q" and I'm sure there will be others. It has the limit feeding characteristics of the traditional endophyte infected without the vasoconstriction, increase in body temps, etc. and so far the reproductive studies are looking much better on this new beneficial endophyte infected fescue.


I believe the palatability of fescue increases after frost because of the conversion of some of the starches(?) to sugars (?) (or something like this, really, I'm not joking here!) not to mention the seed should be on the ground by this time as the plant reached maturity long ago and the seed was dropped soon after it ripened.


There's much too much info for me to remember it all but it is very interesting if you have as much fescue as we do.


just my contribution


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Well, now. This is very interesting.


I have some sheep that came from a farm where they had lost ewes to ergot poisoning and the shepherds there told me it was entirely separated from fescue endophytes. The ewes went lame, eventually went down, and once down never came back up. Some of the lame ones, if pulled off mature (seeded out) pasture would recover.


It took two years for them to figure out what was happening -- fescue toxicosis was ruled out because there was no fescue in the fields where this was happening. It was orchard grass, primarily.


Learn something new every day.

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Guest PrairieFire

"I believe the palatability of fescue increases after frost because of the conversion of some of the starches(?) to sugars(?)..."


That might expalin why my ewes won't eat the taller fescue until late in the season...thanks, Angus...

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I failed to mention this in the earlier post--one thing you can do to help, but it won't eliminate the problem altogether, is to clip your pasture and get the seed heads on the ground. I'm not that familiar with the grazing habits of sheep, but with cattle, that does help. It also helps cut down on eye irritations from seeds and hulls getting in the eyes if the animals are reaching down through for a bite of undergrowth. We try and clip low enough to get even those stems that are in the late boot stage as they will be seeding out soon, but don't clip too low and destroy the leaf portion of the plant.

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Another thing I remembered about this case: on close examination of the forage, they saw a black smut, which was what got them to test in the first place.


As far as I can remember, the endophyte that causes problems in fescue is invisible to the naked eye. Is that correct?


And do we know how these endophytes travel from field to field?

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The endophyte fungus is invisible to the naked eye. In a photo from a microscope, it looks like a squiggly red line but the color could be from stains or dyes commonly used to highlight things like this, I just don't know.


The means of transport for endophyte I haven't heard, but could surmise it could be any number of things from seeds in the haircoat, to wildlife, to manure, to wind, ... possibly many things.


As for the "black smut", that is very common here but I don't have any knowledge about it other than it appears during times of prolonged rain/high moisture and appears to me to be somewhat like a mold or mildew substance. Since we "process" all of our hay, this gets "blowed/knocked" loose and we have no appearent problems from it.

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