Monday, October 1, 2007

Whys and what fors

Back on Sept 25th I wrote about how one of our sheep was sick. As I said then---it is something that occurs to every farmer and every species of animal. Most people, without livestock, assume that it can be as simple as giving an antibiotic to treat a sick sheep, goat or cow. However---it's not always that easy. In our case it wasn't anything close to being that easy.
We started out not knowing exactly what was wrong with our girl and finally settled upon "thiamine deficiency" also known as: Polioencephalomalacia (PEM)
This disease can occur because of many different reasons but can be summed up best as a "disease" that has to do with the ruminants stomach not producing vitamin B1 also known as thiamine.
Chances of our ewe recovering were medium---but not for sure---and she could have been left with a bit of neurological damage. However in the course of treating her for this disease we found she lacked the two major symptoms that everyone I spoke with said she should have: a "starry eyed/going blind look" and a neck that was very stiff and "pulled backwards". My ewe did not have either of those----so back to the research I went even though most people DID still think that thiamine was the problem. For some reason I just didn't feel it "fit" correctly.
To make this story a bit shorter we finally figured out our problem. Our ewe---and a few more of our sheep---were slowly becoming effected by "Dallisgrass Staggers". And though the name doesn't seem to say this, basically they were slowly being poisoned by a fungus. A fungus that was growing on the seed heads of a variety of grass in our pasture--dallis grass.
"Grass Staggers" or fungus poisoning is a fairly common problem among livestock but is much more known to happen with fescue or perennial rye grass or a few other types of grass. I had even originally thought it was grass staggers but I do not have that much fescue and the drought had pretty much killed of all the rye grass so when the vet said "thiamine deficiency" that's what I went with.
Treatment is as simple as pulling them off the affected pasture and giving them different grass or forage to eat. That helped the rest of the sheep, though one of our younger sheep also seems to be still struggling with it a bit but not nearly as much as our ewe Princess.
Princess still is bothered by "leg cramps" maybe even a bit of an upset stomach, so twice a day she gets a banimine shot which is a pain and inflammation reducer to help her move around and eat and drink. Yesterday she finally got to go back out on pasture and seems to be doing o.k. She is eating and drinking and moving around with the flock.
I do believe not only was she glad to be back with the others (remember they are social animals) but they had missed her too. Usually when two sheep, even ewes, have been in different pastures for a while they will butt heads to establish who is "top". This time however instead of putting horns together or butting---they rubbed cheeks with her :-) Very nice---I like to think they were telling her they are glad she made it. I know I am.

So here are a few pictures of Dallis grass with fungus on the seeds and also a bit of information about Dallisgrass Staggers for information. Note the comment on the "sticky" sap of the seeds----we have that every where and have never before had that. Also one other thing I learned was that if you have mushrooms growing in your yard/pasture then you have prime weather for any fungus that grows on any variety of grass. So just watch those seed heads---they aren't always good for the animals to eat.

Dallisgrass poisoning (also known as Dallisgrass staggers) occurs several days after cattle ingest a significant amount of dallisgrass seedheads infected with an "ergot-like" fungus called Claviceps paspali. The seedheads typically are infected with the fungus in the fall, as the seedheads age. Rather than flat looking seeds on the heads, the infected heads have gray to black swellings that have a sticky sap material on them. Some observers say it looks like little popcorn (see photos of normal and infected seedheads). Usually not all the herd is affected, and it appears that it occurs when some animals develop a preference for the tips of the seedhead.

The infected seedheads contain three primary toxins, paspalinine, and paspalitrem A and B, which are tremorgenic alkaloids. The affected animals show neurological symptoms, including trembling of the major muscles and the head, jerky uncoordinated movements, and they also are spooky and sometimes aggressive. The animals will startle and run, and often will fall in unusual positions. In bad cases the animals will go down, and may stay down for several days. Convulsions and death can occur in extreme cases. The symptoms are somewhat like grass tetany, and this is often misdiagnosed, but they don't show the sudden death characteristic of grass tetany, and don't immediately respond to treatment for grass tetany.

There is no treatment for the malady, except to get the cattle off the affected grass, and provide them with high quality forage. If possible they should be put in a field with no ponds, steep slopes, etc. as they commonly stumble around and end up injuring or drowning themselves. Usually cattle can completely recover from the poisoning.

In late summer we often have reports of dallisgrass poisoning, and it seems to be getting more common now because there is more dallisgrass in pastures in North Carolina. Toxicity usually is reported on farms with rank dallisgrass seedheads and the fungus present. In many cases producers had stayed off the pastures hoping to let the grass get a little more growth on it, and as a result the seedheads got old. In other cases, there are only a few cattle in large pastures, so the Dallisgrass grew faster than the cattle could consume it. Rarely do we get a report of a case were there deaths of the affected cattle. It also seems that in many cases the younger cows are affected, which suggests that cows may learn to avoid eating too much of the seedheads after getting too much (cattle are known to learn to avoid poisonous plants in this way).

Dallisgrass is becoming a more important part of many pastures in the piedmont and coastal plain. It is a very good quality warm season perennial, and provides great benefits to pasture systems, but the one drawback is the potential for Dallisgrass staggers. By rotational grazing the grass after seedheads emerge but before the fungus grows on them the problem can be avoided, because cattle will readily eat the immature seedheads unlike some other grasses we are used to. If the seedheads do become infected, clipping them off at about 12" before grazing should

help prevent the problem. Hay with high amounts of seedhead can also be a problem, so feeding Dallisgrass hay along with other hay is advised, especially if infected seedheads are present.

For more information concerning dallisgrass poisoning contact, your extension agent or your veterinarian.

1 comment:

maggie said...

I'm glad you found the cause of the problem. Ruminants can be so difficult. There's only one vet in the area that deals with small ruminants. He's a busy man. I wonder if goats face the same problem as they are mainly browsers, not grazers?