Fescue toxicity

[Pohney]

I’ve been digging around trying to get information on how much fescue is too much… We have not yet been able to renovate our pastures and I suspect - but have not been able to confirm - that at least some of our grass is fescue and that, given that it would’ve been seeded in 2006, it was either endophyte infected or has converted over as I understand earlier varieties were not as robust as today’s which are just infected with a non-toxic endophyte. In short, I plan to eliminate fescue hay three months prior to foaling and transition to Timothy. However, I don’t have a practical way of completely eliminating pasture access. My pastures right now are overgrazed - the horses put their heads down and pick at stuff, but walking through it you’d be stretched to even find enough grass leaf to do any sort of forage analysis. How much risk am I still incurring at this stage? I can restrict her to a smaller paddock to ensure it remains heavily overgrazed and offer hay as a preferable option.

To add - I may be able to restrict to a smaller pasture and then spray the secondary one and plant with a summer annual. Realistically though, I won’t get a summer annual established until at least mid-late May at best. I do also plan to throw down some clover seed while its still cool and see if I can get that coming up to create a preference for that forage variety.

[SusanO]

There is always Domperidone ( sp?). I would ask my vet about that. Fescue is hard to eradicate.

[JB]

When is she due to foal? Is this a this-year foaling?

Winter-dormant pasture is unlikely to have the infected parts of the grass. You can even pull samples to have it tested.

Keeping a small paddock over-grazed, with lots of yummy hay so she’ll want to eat that and not choose to pick at short sweet grass, can work.

And yes, even then, I would plan in starting Equidone about 3 weeks (I think that’s the desired timeframe, it’s been a while) out from foaling, and THEN you should plan on getting frozen tested colostrum as soon as you can - don’t wait to scramble to find it. If supplies are low/non-existent , they should start picking up as foaling season goes on. You’d also then plan to have that be the foal’s first milk, no playing around waiting to see if the dam’s milk was good enough.

[Hillside_H_Ranch]

Our pastures are entirely fescue in my location. We pull the mares off pasture at the time of the nine month rhino vaccine, and use small paddocks + fescue free hay to limit exposure. We don’t use domperidone, and this has worked for us for the 15 years we’ve been here. I would use your small paddocks and make sure your hay is fescue free. As long as you see some udder development, I would hold off on the domperidone.

[Montanas_Girl]

The simplest solution would be for you to section off a small portion of the pasture for her, deliberately graze it down until it is essentially a “dry” lot, and house her there for the final 60-90 days of her pregnancy. There really isn’t a hard and fast rule for exactly what the toxic intake of endophyte-infected tall fescue is for pregnant mares - there’s too much variability in alkaloid concentration and individual susceptibility to set a single limit. But, since the toxin is most highly concentrated in the seedhead of the plant, keeping your turnout grazed/mowed down to nothing is the best way to go in this case. Over time, you can try to renovate your pasture to another forage type, but that is a VERY expensive, labor-intensive process, and it rarely lasts long. Equidone (domperidone) is the treatment for fescue toxicosis, but most vets do not prescribe it unless toxicity is strongly suspected/indicated, as it can reduce colostrum quality.

[IronwoodFarm]

^This. I have fescue in all my fields. It is not going anywhere. I keep my mares in fields that have been eaten down and I keep the fields mowed. The seed head is the real issue. It serves a dual purpose since I have a breed that gains weight by looking at a blade of grass. This way the grazing muzzles do not have to be used. I only use domperidone post foaling if the milk supply is insufficient. Usually it isn’t and once it starts, there are no further problems.

[Real_Rush]

This discussion got me thinking about what-ifs. Say a mare was left on fescue pasture and wasn’t pulled off until within a few weeks of guesstimate foaling. If she was given any other kind of hay except fescue, would she still probably bag up like normal? Would there still be the likelihood of a red bag delivery, etc? Luckily, my current broodie has been in a drylot, so not worried about her. I’m just curious if there’s a "point of no return ", so to speak.

[JB]

The more you can dilute the fescue, the better. Coming off the endophyte does start reducing the problems it can cause.

[Montanas_Girl]

@Real Rush

Say a mare was left on fescue pasture and wasn’t pulled off until within a few weeks of guesstimate foaling.

While we always advise mare owners to remove their broodmares from fescue pasture and hay 60-90 days prior to foaling, experimentally, 30 days is usually plenty of time. So, depending on exactly where “a few weeks” falls in that timeline, it might or might not be fine. The main problem is that gestation length in the mare is so variable that you can’t reliably pinpoint that 30 days out mark, so 60-90 days leaves plenty of room for error and miscalculation.

[Guilherme]

The early growth Tall Fescue carries little, if any, of the endophyte. Meaning that it carries little risk. The more mature the grass the mare mature the risk.

You don’t note where you are. That is important information. If you are in the Southeast you are surrounded by Tall Fescue as it is the “money crop” for all sorts of livestock production. Eradication, once recommended by the UT Knoxville ag. experts, is no longer the case. Management of vulnerable stock is now the advice.

Take a paddock, hit it with RoundUp, wait for the plants to die, the put your gravid mare there and hay her. Keep the Domperidone ( sp?) on hand if recommended by your vet. In the event that she gets a dose you’re ready to counteract it. Or, for a more sure solution, put the mare in a stall and hand exercise her every day. You will control the feed she gets and that should do the job.

More than 20 years ago, before the problems with Tall Fescue were clear, we lost three foals in less than a week. That was NOT a happy time. But we learned and never had another problem once we figured out what the problem was and some university level help in devising a sound management plan. We shortly thereafter moved to our present farm and tried to maintain some “non-fescue” pastures (according to UT directions) to no avail. It is a difficult grass to eliminate and all our neighbors were running cattle and they loved it. So we surrendered to the inevitable and instituted management practices which were successful.

Talk to your County Agent and see what the current guidelines in your area are.

Good luck as you go forward.

G.