The Accidental Smallholder Forum

Livestock => Sheep => Topic started by: Womble on September 26, 2019, 01:11:38 pm

Title: Wormer Resistance?
Post by: Womble on September 26, 2019, 01:11:38 pm
This is one chapter of a wider and more confusing story, but I'll do my best!

We have a few of this year's lambs which haven't been putting on weight and have been very squitty for some time. This has happened the past few years and despite trying all sorts of things like vitamin drenches and boluses we've never really gotten to the bottom of it.

So, as an extra check, I had an FEC done two weeks ago on a sample from the worst affected. This came back with a mixture of nematodirus and strongyle eggs at 300 epg. We then wormed with a group 3 ML wormer (Molemec ivermectin) and retested him two weeks later. This new sample has come back with 150 epg, and all nematodirus.

So now both the vet and I are confused. Shouldn't the wormer have knocked out the nematodirus also?  My understanding was that the one good thing about nematodes is that they haven't figured out how to resist wormers yet (hence why we use white wormers against them specifically, even though they're not much use any more against most other types of worms).

I'm still working through this with the vet, but in the meantime, does anybody have any ideas? 
Title: Re: Wormer Resistance?
Post by: twizzel on September 26, 2019, 03:29:20 pm
Could they have picked up the nemo worms since worming? The wormer won't be persistent and nemotodirus hatches can occur in autumn  :thinking: 


What was the cocci reading from the fec? The other thing I would maybe do is blood test for mineral deficiency.
Title: Re: Wormer Resistance?
Post by: Anke on September 26, 2019, 05:06:04 pm
So you think you may have species specific resistance? As in only nematodirus resistant to ivermectin, but not strongyles? I would treat with different wormer class (either Levamisole or Zolvix) and see if it makes a difference? And also do some FEC's for other individuals (like non squitty ones) and see what their level is?


Title: Re: Wormer Resistance?
Post by: Buttermilk on September 26, 2019, 05:59:12 pm
I too would use another wormer but would use the white one as you are not trying to knock out anything but nemotodirus.
Title: Re: Wormer Resistance?
Post by: Womble on September 26, 2019, 08:02:59 pm
Thanks all. I've attached a photo of the lamb in question - as you can see, he'll not be ready for eating any time soon  :-\ .

I guess he (individual sample of the worst sheep) will have been ingesting eggs continually, but I didn't think they reached maturity (to start dropping eggs of their own) for more than 2 weeks, hence the timing of the two samples?


I found this online though: "Like many parasites, this nematode has shown an ability to adapt its behaviour and in some areas some outbreaks of disease are now being seen in autumn. This occurs when eggs on pasture develop to the third larval stage – without overwintering – and hatch in the autumn, with a ‘mass hatch’ potentially occurring in the warm, wet period following a dry summer. Lambs that avoided exposure in the spring are particularly at risk."
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I wonder if this guy is just a particularly poor doer, due to some other issue, which then means he never developed any natural immunity to nematodirus?  Then if we are having an autumn hatch, I guess that might explain it to some extent?

The thing that's confusing me is that I didn't think resistance was common in nematodirus? (Hence the recommendation to use a white wormer, since they're still effective against nematodirus even though lots of other worm species are resistant to them).

Does anybody know if it's common to have nematodirus which are resistant to group 3 (ML) wormers?


Twizzel - I didn't get a cocci reading I'm afraid. Also blood tests to follow. My plan now is to worm this one with a white wormer and then take another sample in 2 weeks time to check. I'll also take a pooled sample from some of the healthy ones to check too - good idea Anke.
Title: Re: Wormer Resistance?
Post by: Tim W on September 26, 2019, 09:56:31 pm
Nemo hatch patterns have changed a lot in the last few years, we regularly pick up nemo eggs throughout the year (i take FEC samples most weeks)
Out of 124 individual FEC samples done last week only 18 didn't have nemo eggs present

I have a farm on which nemo are resistant to clear (@ 90 % efficacy) drenches at some times of year

It may be that some nemo are getting resistant to white drenches hence the rise in later hatches
It may also be that some eggs are hatching later than the ''traditional'' spring hatch and hence not getting killed off by early drenches
Either way i find them fascinating

Title: Re: Wormer Resistance?
Post by: Womble on September 26, 2019, 10:00:08 pm
I have a farm on which nemo are resistant to clear (@ 90 % efficacy) drenches at some times of year


Thanks Tim, that's really useful. I'll try the white drench and see what happens.

Title: Re: Wormer Resistance?
Post by: Buttermilk on September 27, 2019, 08:24:51 am
If the lamb keels over and dies I would get a post mortem done so that both you and the vet know what you are dealing with for future reference.  I had this scenario a few years ago and it was a combination of worms and fluke so we changed our regimes and not had a problem since.

It started with one lamb failing to thrive one year and losing 7 lambs the following year.  I wish I had had the pm done on the first lamb.  Hindsight is wonderful.
Title: Re: Wormer Resistance?
Post by: Rosemary on September 27, 2019, 09:05:01 am
Our tup lambs have been the same - but the ewe lambs have been fine. Wormed them with Zolvix on the advice of the vet and they're pretty much OK now but not good enough to go to the abattoir on Monday as planned. As I say, the ewe lambs are fantastic.
Title: Re: Wormer Resistance?
Post by: Tim W on September 27, 2019, 09:40:16 pm
Our tup lambs have been the same - but the ewe lambs have been fine. Wormed them with Zolvix on the advice of the vet and they're pretty much OK now but not good enough to go to the abattoir on Monday as planned. As I say, the ewe lambs are fantastic.

Ram lambs always have a higher worm count especially at this time of year (puberty)
20th August i did FEC on mixed sex lambs running together (same management) ---ewe lambs 320 epg, ram lambs 690 epg
Same applies to adults ---rams always run higher than ewes
Title: Re: Wormer Resistance?
Post by: Womble on October 10, 2019, 04:40:41 pm
Update:  Wormed with Albenil white wormer 2 weeks ago, and the repeat FEC this week has come back clear.

So, on one hand it's bad news that we have group 3 wormer resistant nematodirus, but on the other hand at least the cheap bullets still work against them  :thumbsup: .
Title: Re: Wormer Resistance?
Post by: Scarlet.Dragon on October 10, 2019, 05:59:30 pm
Let's hope Bioworma gets the green light for use in the UK fairly soon... it will be a phenomenal new tool in the armoury against resistant worms if we can get it!
Title: Re: Wormer Resistance?
Post by: Backinwellies on October 10, 2019, 06:39:11 pm
Update:  Wormed with Albenil white wormer 2 weeks ago, and the repeat FEC this week has come back clear.

So, on one hand it's bad news that we have group 3 wormer resistant nematodirus, but on the other hand at least the cheap bullets still work against them  :thumbsup: .

It gets more complicated by the day!  …. and FEC's are great but for a few sheep it costs a fortune!
Title: Re: Wormer Resistance?
Post by: Buttermilk on October 11, 2019, 08:19:49 am
Oops had problems with the quotes.

My land also has clear wormer resitance but white ones work.

Get your own microscope and slide it saves a fortune in FECs.