lamb deworming question and more

[laurie etc]

Ok - I finally got my 7 long-awaited (4 month old)Kathadin/Dorper lambs - and while I was at the trial this weekend, one of them up and died on me. He was fine when I left for the trial at 11:00(the biggest of the group) apparently my neighbor (who co-owns the sheep with me) found him down and almost dead an hour or so later. Unbeknownst to me, my neighbor had been offering the lambs corn, trying to coax them to become friendly (told him not to overdo it, but he's a Dr. Doolittle wannabe.) Anyways, the vet who looked at the virtually dead lamb diagnosed it as a thiamine deficiency (due to his "star gazing posture" at presentation- but it sounds more like overeating disease to me - since there were no outward signs and he was up and with the flock right until a couple hours or so before he died. The only outward sign I noticed was inordinant bleeting for a couple days prior, but I checked on him numerous times and he "seemed OK", moving around with the flock, otherwise. Anyone have any ideas - does this sound like enterotoxemia or thiamine deficiency? Or something else? (All of them were in good flesh, came from an immaculate farm, dewormed with ivermectin 3 weeks ago, and had their 1st Covexin-8 vaccine there- I gave the 2nd one yesterday.)

2nd question- This same vet told my neighbor that sheep need to be dewormed every three weeks - doesn't that sound really excessive? They are on fresh pasture (not lush by any means, but not grazed down at all)that has never held sheep before, and had horses on it more than a year ago. There are only 6 of them to about 6-7 acres.

[Bill Fosher]

Hi Laurie,

 

It's pretty hard to say, and I'm not one to second-guess a vet who has seen the animal. But my experience with thiamine deficiency is that it seldom comes on that quickly.

 

Under conditions of constant exposure to parasites, sheep should be wormed every three weeks. But your pasture should be just about free of worms, aside from whatever were in the sheep when they arrived. The big question in my mind would be whether ivermectin remains effective. There are some pretty large swaths of the mid-Atlantic region and Southeast where it isn't.

 

Here are the things that I have encountered that can take a lamb out in a hurry.

 

-- Pasteurella pneumonia. Often associated with stress or a change in diet or location, even if the change is for the better. Also known as shipping fever. A heavy worm burden would pre-dispose.

 

-- Clostridial disease. You mention a Covexin 8 program, but at four months old they were either given the first shot too late or too much time elapsed between the two. But I wouldn't think it would be enough to cause a failure.

 

-- Usually, maddeningly, it's not just one thing, but a combination of a touch of this and a whack of that. We had a few lambs die suddenly at about a month old that showed signs of white muscle disease. Not enough to be fatal, but once we addressed that issue they stopped dying. We never did find out what was actually causing them to die.

 

If I were you, I'd have a fecal sample done to determine the parasite status of the lambs. I'd try to regulate the corn. It's rare, but not impossible, that grain overload could be a sudden killer. Four month old lambs that have not been acclimated to grains probably shouldn't get more than a quarter pound of corn per head to start with.

[Pipedream Farm]

Laurie,

 

We still have success with ivermectin; I'd ask the producer if they still have success with ivermectin. If they don't then you won't.

 

Mark

[laurie etc]

Thanks, Mark - The person I got the sheep from is a vet tech - very meticulous - and does fecals on her own stock. She has had success with Ivermectin - only has a small flock of breeding ewes for "land use" (I bought her whole lamb crop of 7) and a handful of whethers she works. Again, they are on horse pasture that has not held sheep until a couple of years ago.

 

Thanks, Bill, I'll get a random fecal done before I start hitting them with anything. The "survivors" all look extremely healthy and in good flesh.

Urgh! It also urks me that this vet talked my neighbor into spending $83.50 for a 100 ml bottle of Dectomax dewormer (100 doses) that sells for $45 in the KV vet catalog. I'm taking it back to them.

What would you recommend deworming with, if the Ivermectin is not getting everything efficiently?

 

And re: the corn - I told my neighbor "No Mas!" I think he went through 50 lbs in a two week period. Originally, I told him he could put "a little corn" in a bucket and shake it to see if the sheep would come up to the barn for him. My idea of "a little" (a handful) and his (~5lbs!?!) were apparently not the same.

 

Ahhhhh - the learning curve...

[Valhalla]

Bill, do you rotate what you use for de-worming or stick with the same type all year?

[Bill Fosher]

So far I have not encountered any resistance, so my strategy might be very different from one that would work for those of you in the mid-Atlantic and deep South.

 

Having said that, I use one kind most of the year, with an occasional hit from a different family.

 

For instance, this year I'm using ivermectin for the first time in about five years. Shortly after the lambs are weaned, I'll hit everyone with ivermectin and levamasole, then back to ivermectin for the rest of the year.

 

I'll use that strategy for a couple of years, then switch and use albendazole as the main wormer with an occasional hit of either levamasole or ivermectin, then after a couple of years, I'll go back to using levamasole as the main dewormer. So far a six-year cycle seems to be doing the job.

 

Usually there's at least one time during the year when I use albendazole for tapeworms in addition to whatever other strategy I'm using.

 

I have not started to use Cydectin because I don't have the need as yet. If ivermectin starts to fail me, I'll replace it with Cydectin in the rotation.

[Shoofly]

That's pretty much the strategy i use too and i'm in NC. I use cydectin as my main wormer (have for several years now) but hit the flock with tramisol about once a year, usually around now. And i hit my lambs with valbazen once or twice to clear up tapes when i start seeing them.

[Deacon Dog]

^Same here but with Prohibit as the main wormer and Valbazen once or twice a year.

[tucknjill]

I was told by a VERY successful local shepherd to stick with one wormer till it starts to fail you (ie gain resistance) then switch to something new...shepherd in question has been to all the local classes at VA Tech and such like that...I was told to use Cydectin when I purchased my new flock as they had come from a flock that had been treated with Tramisol for many years...every three weeks sounds excessive but I guess it depends on how many sheep and how many acres. When I lived in Richmond and had about 120 sheep on about 10 acres, yep I wormed every three weeks thru the summer but now that I have about 170 on 50 acres, I worm about every 7 weeks in the summer months and about every 3 months in the winter (to coincide with lambing and breeding etc)

 

Past that I can offer no other ideas, I am still new in my sheep education!

[Bill Fosher]

Sam,

 

The problem with the advice of using a wormer until it starts to fail is that it appears that most resistance traits are dominant. Once they're there, they will remain. So if you keep using ivermectin until it fails, wating five or 10 years to go back to it might make no difference whatsoever.

 

I believe that levamasole resistance is not dominant, but I could be mistaken about that.

[tucknjill]

Heck, I wouldnt know one way or another...Just going on their advice...???? I am going to take some of the sheep seminars and such at Tech or wherever they are offered locally...You can never have too much learnin'

[Bill Fosher]

Sam,

 

The latest thinking is to stay away from Cydectin unless and until you have ivermectin resistance, as worms that develop resistance to Cydectin will also be resistant to ivermectin. The inverse is not true, however.

 

If ivermectin is already failing on your farm, then go to the Cydectin, otherwise, hold off.

[tucknjill]

It was totally failing the times in the past when I used it.. as it was on the farm where these sheep came from unfortunately.

[Valhalla]

Ivermectin is already failing here in VA. I used the Cydectin Pour-On for years and now am using the new Cydectin sheep drench, both with success.

[Bill Fosher]

It's worth testing if you're not sure, though. Not every farm will have resistance to ivermectin, even if many of the surrounding areas do.

 

With so few choices, it's best to keep an ace up your sleeve if you possibly can.

[Deacon Dog]

It appears levamisole (Prohibit, Levasole, Tramisol) may be less susceptible to resistance:

 

"Although levamisole has been available as a sheep dewormer for a long time, it remains effective in many flocks. Research suggests that only H. contortus worms that are homozygous recessive for levamisole resistance are resistant. This is analogous to the spider lamb syndrome where mating of two carriers of the recessive gene results in spider lambs only one-fourth of the time and mating of a carrier with a normal animal results in 50% of the progeny being carriers but no spider lambs are produced. This may at least partially explain the reason that levamisole appears to remain effective in many flocks.

 

This is unlike the situation with ivermectin (and its chemical relatives) where we believe that resistance in H. contortus is expressed as a dominant trait making a worm with only one copy of the gene effectively resistant to ivermectin. In this situation, a mating between a resistant worm, with only one copy of the resistance gene, with a non-resistant worm still results in 50% of the progeny being effectively resistant to ivermectin. All progeny of a male or female worm homozygous for the resistance gene will be resistant. Australian researchers speculated as early as 1996 that resistance of H. contortus to ivermectin might become common rather quickly as a result of this mechanism of inheritance. Our observations in sheep and goats now seem to bear this observation out, and we must ask ourselves here in the USA to what extent the extra label use of this class of compounds has contributed to this problem."

 

http://muskingum.osu.edu/ag/pg1.htm

[Caroline Reichard]

In our region (I'm in north central MD) the biggest threat for me is Barbour pole worms. I have been told that these parasites can kill a sheep within 5-7 days of the initrial infestation. My own experience would tend to back this up, as a few years ago we lost about a dozen to fifteen sheep to these parasites. At that time they were on a regular, frequent program of Tramisol, which had absolutely no effect on these worms. My vets report that Levamisol and Cydectin are effective against them, and both have proved helpful on our farm. The Cydectin, though, is amazingly expensive, so I am grateful that the Levamisol is working. In this kind of weather, whenever a sheep dies the first thing I look at is the eye: white mebranes= parasites, and I don't take any chances with the rest of the flock. My experience was that the first to go were the nrusing ewes. The lambs did not start to die until quite a bit later. That summer we suffered from those worms for about 2 months, and I believe that they left much of my flock at that time permenently weakened. On my vet's advice I was, at one point, worming several times a week for about 2 weeks; that was the only thing that finally knocked them out.

[Bill Fosher]

HI Caroline,

 

It's interesting that Tramisol wasn't working but you've had good results with levamisole, as Tramisol's active ingredient was levamisole. It has been off the market for some years now; perhaps your supply was out of date?

 

As far as I know, the only way levamisole is available now is under the Prohibit brand name from Agri-Labs. Schering-Plough owned both the Tramisol and Levamasole trade names and has discontinued both as sheep drenches. They may still be making Levamisole Oblets for sheep, but I don't think so.

 

You also need to be careful about conclusions that you draw from looking at eyelid color. All that palor proves is that the animal was anemic. Parasitism -- specifically infestation with Haemonchus contortus or barber pole worm -- is probably the most common cause of anemia in sheep, but it's by no means the only one. There are also lots of parasites that don't cause anemia. So white membranes don't mean it is parasites, and pink ones don't mean it isn't.

 

Also, upon death the blood breaks down very quickly. I'd be pretty surprised to see color in eyelids on any dead sheep.

 

We had a hyperacute outbreak of HC in a group of freshly-weaned lambs last summer, and it's truly a trying time. Lambs were pale and even dying within 10 days of being treated.

 

We had to bring 430 lambs into the barn in high summer, put them on hay and grain, and deworm them three times in 21 days. We were then able to turn them out into pasture that had not had sheep on it for at least 25 years, so they were no longer being reinfested. They turned around and finished quite nicely, but it was a hard lesson to learn -- and expensive too.

[Caroline Reichard]

Hi Bill,

 

This is what happens when you post a response before FINISHING the first cup of coffee in the morning.

 

The eyelids I'm talking about aren't the dead sheep's, of course, but those of the rest of the flock. I know that anemia can be caused by many things, but I worry about the Barber pole worms since autopsy has showed I have lost so many sheep to them.

 

I have not had a problem with that parasite since I started using levamisole. I looked up my records and was using Valbezan when my rash of deaths ocurred. Once again, blame my mistake on the lack of suffient early morning coffee. I should also add that the place from which I purchased that medication was not air conditioned, and it can get very hot in there during the summer (over 90 degrees). I have wondered if the integrity of the Valbezan was compromised by over-heating. The levamisole powder is labeled to tolerate a higher temperature than many liquid drugs. Any thoughts?