Parasite management

[lilipansy]

I see questions about this topic ALL the time and everyone has an opinion. Some of the opinions given are scary to me especially because there are so many new people reading this stuff. Here's what I've learned that have worked well for me.

Proper parasite management entails (a) understanding the different classes of dewormers available (i.e. the method in which they kill parasites), (b) knowing what type of worms you need to treat for and at what level (FEC), (c) understanding when and how to treat and (d) know how to evaluate the results. Here's a great article on the subject: https://www.sheepandgoat.com/testresistance.

You don't just treat animals with 2 or 3 classes of deworming ALL the time (as I've seen suggested). That protocol is just for when the levels are sky high and you need the additional help. Doing so on a regular basis causes the dewormers to be ineffective quicker and leaves you without any recourse. Do fecal tests so you know what is affecting your animal and at what level. Do fecal test reduction test so you can evaluate the efficacy of your dewormer(s). Every region is different so what works for one are may not for another. Educate yourself so you can appropriately guide yourself on how to manage your herd.

 

[The Old Ram-Australia]

G'day lilipansy,a very worthwhile post IMO.The other path we take is to select for "worm resistance",currently we run about 200 breeder ewes over 10 female breeds and 5 male breeds .The only time we mass drench is when we wean the lambs ,it's a broad spectrum + tape and we are moving toward this as being the only drench during their lifetime....T.O.R.

 

[Baymule]

I see questions about this topic ALL the time and everyone has an opinion. Some of the opinions given are scary to me especially because there are so many new people reading this stuff. Here's what I've learned that have worked well for me.

Proper parasite management entails (a) understanding the different classes of dewormers available (i.e. the method in which they kill parasites), (b) knowing what type of worms you need to treat for and at what level (FEC), (c) understanding when and how to treat and (d) know how to evaluate the results. Here's a great article on the subject: https://www.sheepandgoat.com/testresistance.

You don't just treat animals with 2 or 3 classes of deworming ALL the time (as I've seen suggested). That protocol is just for when the levels are sky high and you need the additional help. Doing so on a regular basis causes the dewormers to be ineffective quicker and leaves you without any recourse. Do fecal tests so you know what is affecting your animal and at what level. Do fecal test reduction test so you can evaluate the efficacy of your dewormer(s). Every region is different so what works for one are may not for another. Educate yourself so you can appropriately guide yourself on how to manage your herd.

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I just started using fecal sample under a microscope. The results slammed me up against the wall. What I thought were healthy sheep are in fact, the wormiest of the bunch. Nothing like real truth staring back at me on a McMasters slide. I now have a cull list. A promising ewe lamb is on the slaughter list. Her count is high, as is her other family members going back to one of my original ewes. It will hurt to sell one of my first sheep, but if I keep her, even if I never keep her lambs, she will be in the flock, shedding worm eggs in the pastures. Farming makes one make tough decisions.

I use Garlic Barrier monthly and have done so for a couple of years. I did a worming several times a year with chemical wormers, but it was a stab in the dark. Eye membranes were medium to bright pink. From this time, moving forward, I will maintain my flock based on fecal exams, culling for worm resistance. I will continue to use Garlic Barrier as a wormer, using chemical wormers, after fecal testing, when Garlic Barrier fails to keep the numbers down. I am still VERY new to FEC and am learning. In no way am I setting myself up as some kind of expert, just relating my stumbling towards doing things a better way.

@lilipansy in your climate, you have conditions all year that contribute to worms. At least most of us get a winter break. How do you cope with it and what is your strategy?

 

[lilipansy]

G'day lilipansy,a very worthwhile post IMO.The other path we take is to select for "worm resistance",currently we run about 200 breeder ewes over 10 female breeds and 5 male breeds .The only time we mass drench is when we wean the lambs ,it's a broad spectrum + tape and we are moving toward this as being the only drench during their lifetime....T.O.R.

Aloha TOR,

Yes, selecting and developing a resistant line would be the ultimate goal and I intend to do that with (FEC) testing tools we are so blessed to have learned and applied to our herd. We are currently working on bringing our numbers up and will cull heavily and only keep the best. I have some stock that has only been dewormed at weaning and have done extremely well given that we had such a wet season last year. We are quite happy with the results. I guess the main point in my post is to educate people, especially newbies that you need accurate data in order to make decisions about your herd and not just blindly do what everyone tells you is right.

 

[frustratedearthmother]

What I thought were healthy sheep are in fact, the wormiest of the bunch. Nothing like real truth staring back at me on a McMasters slide. I now have a cull list. A promising ewe lamb is on the slaughter list.

Here's my question: If you think they are healthy.... maybe they are? If they can carry a high parasite load but, look healthy, and produce nice lambs... they might be doing ok. Some animals can tolerate a higher load just fine.

Just throwing it out there...

 

[Mike CHS]

Here's my question: If you think they are healthy.... maybe they are? If they can carry a high parasite load, look healthy, and produce nice lambs... they might be doing ok. Some animals can tolerate a higher load just fine.

Just throwing it out there...

There is a lot of truth to what you wrote. We have three ewes that were on our cull list because of parasite load but they have maintained great body condition even after raising twins while others were losing condition. Two of those we did not worm other than garlic but have done fecals on and they have not increased the egg count. They will be staying as it is now.

 

[lilipansy]

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I just started using fecal sample under a microscope. The results slammed me up against the wall. What I thought were healthy sheep are in fact, the wormiest of the bunch. Nothing like real truth staring back at me on a McMasters slide. I now have a cull list. A promising ewe lamb is on the slaughter list. Her count is high, as is her other family members going back to one of my original ewes. It will hurt to sell one of my first sheep, but if I keep her, even if I never keep her lambs, she will be in the flock, shedding worm eggs in the pastures. Farming makes one make tough decisions.

I use Garlic Barrier monthly and have done so for a couple of years. I did a worming several times a year with chemical wormers, but it was a stab in the dark. Eye membranes were medium to bright pink. From this time, moving forward, I will maintain my flock based on fecal exams, culling for worm resistance. I will continue to use Garlic Barrier as a wormer, using chemical wormers, after fecal testing, when Garlic Barrier fails to keep the numbers down. I am still VERY new to FEC and am learning. In no way am I setting myself up as some kind of expert, just relating my stumbling towards doing things a better way.

@lilipansy in your climate, you have conditions all year that contribute to worms. At least most of us get a winter break. How do you cope with it and what is your strategy?

Aloha Baymule,

Have you actually tested the efficacy of using Garlic Barrier? I'm always skeptical of things like that. We've been very fortunate with our herd given the wet season we've had last year. We don't have a lot of choice here when it comes to breeds because this is an island and bringing new lines is difficult and cost prohibited for the most part. Also, mainland animals have a hard time adjusting to our environment and succumb to heavy parasite loads. Most sheep here come from Dorper/Katahdin cross with a little bit of Barbados Black Belly and/or St. Croix. These are all tropical breeds that are inherently resistant so genetics helps a lot. I sit with my sheep daily and make sure everyone looks good and are eating and acting normal. I keep good records on fecals, who had it, when, levels, etc... and run through the entire herd every other month or so. The most susceptible ones are mommas (right before and after lambing) and lambs younger then 4 to 6 months. I provide them with free choice minerals with a sprinkle of Decoxx and baking soda. Here's the mineral shed in one of the paddocks (on the right), my beautiful boy Abacus and our newest addition Penny Waddlebutt. We also rotate the herd every 5 to 7 days depending on how well they have grazed the paddock. We grow mainly so we don't have to mow and to eat.

 

[Baymule]

Here's my question: If you think they are healthy.... maybe they are? If they can carry a high parasite load but, look healthy, and produce nice lambs... they might be doing ok. Some animals can tolerate a higher load just fine.

Just throwing it out there...

If I have a choice of healthy sheep with good worm resistance and healthy sheep with high worm loads, I'd rather have the ones with worm resistance. I understand what you are saying, but what's the point of keeping sheep that are worm incubators, dropping them all over the pastures? While the sheep may be able to keep up, even with a high worm load, won't they need to eat more, both to feed the worms and themselves? Not being obnoxious, just discussion.

 

[lilipansy]

Resilience in animals is good (ie. they do well regardless of the high count). The problem lies in all the eggs they shed, affecting the rest of your herd. I cull those.

Here's another thought. Make sure you understand what is causing the high count on your sheep. Is it the season? Is it their age (older and younger animals are more susceptible). Are they lactating or pregnant? Are your grounds clean? Is it your grazing practices? If it's none of the above and they just have weak genetics, then cull hard. If it's caused by something or condition you can fix or control then it's not their fault. Fix it and you can keep them.

 

[Sheepshape]

Worming practices vary with breed, climate,age of sheep, availability of land, and elevation above sea level over here (Britain)......and also, some folk do what they have always done, which may not be best practice by any manner of means.An approximately 10 minute webinar is available on line which forecasts what the weather is likely to be and following on from this what parasites are predicted to be a problem......a useful monthly 10 minutes. Faecal egg counts are done for a very reasonable cost and kits are available for those enthusiastic to do their own counting. Pre and post worming faecal samples are helpful to ensure that the wormer has been effective and that resistance isn't present/developing. Our vet practice is always willing to give advice on worming which is specific to the our geographical location.

Resistance of an individual animal to many types of worms increases with increasing age of the animal, but resistance to liver fluke does not occur. Older animals therefore usually need to be wormed less often. I'm in a high-fluke area and have to use flukicides annually. Wormer resistance (and therefore ineffectiveness of that wormer) rises in flocks where all animals are treated with anthelmintics. Best practice dictates that approximately 10% of the flock are not treated at any one time that the majority of the animals are treated in order to avoid selection for wormer resistance. I usually choose the approximately 3 year old in good body condition who has no diarrhoea to omit from the 'worming run'.

Ewes have a lowered resistance to worms in the 4-6 weeks run-up to lambing. Nature lowers their bodies to recognition of 'foreign bodies' at a time that cells from the foetal lamb may cross the placenta and the foetus be seen as 'foreign' to the ewe. Without this lowering of resistance, foetal rejection could occur. A side effect of this lowered resistance is an increased susceptibility to worm load and worm proliferation. All but about 10% of my ewes are wormed at lambing and are turned out with their lambs onto fresh pasture at 2 days after lambing when most of the eggs/worms will have passed through their systems.

Periods of high ambient temperature in the summer can lead to hatching of many worm eggs and nematodirus can occur proving fatal to lambs, so I watch the webinars to see if this is likely to occur and discuss with my vet the best wormer to use.

So, in practice....I'm worming 2 or 3 times a year, rotating the wormer types, listening to webinars and vet advice, moving animals to clean pasture when possible, getting faecal egg counts when indicated, leaving about 10% of the target group without wormer to avoid resistance and checking that growth rates and body condition scores are as expected. Sounds a lot, but, in practice, it's far from onerous.

I've never had to cull an animal because of parasites.