[Fleecewife]

I keep reading on here about not using permethrin type products before shearing, but that is exactly what they are designed for as the greatest risk of flystrike is when the wool is thick before shearing. As Twizzel says - we can't all get our sheep shorn at the same time and so have to use preventative methods.


Fleecewife actually mentions that the shearer "doesn't want to be bathed in Crovect" and that he/she will suffer a build up of the product"  Sorry but that's rubbish. For a start chemicals of this family have been developed from pyrethrum which is a natural plant product evolved specifically to kill insects. Its action is therefore lethal to insects but has not been found to affect mammals to anything like the same extent.  (I'm not saying it doesn't affect them and cats in particular can have a reaction)


So the permethrin family has low toxicity to mammals and I fail to see how the  shearer would get bathed in the stuff as no one is going to shower their animals in it just before the shearer arrives! I would expect it to have dried on the fleece pretty well before then. In addition, only 1%  of that which gets on the skin is absorbed through the skin in humans, and of that 50% is excreted within 24 hours. So the "build up of the product" is another myth.  I also very much doubt if commercial sheep farmers are going to discard their fleeces because they have treated for flystrike. So please lets keep things in perspective and not spread scare tales.
 

No landroverroy I am not spreading scare tales. People need to know the facts and even the rumours, so they can make up their own minds what to believe, rather than just accepting someone else's word.
 Pyrethrins are neurotoxins.  Yes they were evolved by plants as a defence system against insect attack. Now man has manufactured synthetic Pyrethroids as a purer form of the active ingredient.   Organophosphates were developed by Man also as a neurotoxin against insects, in the aftermath of the DDT disaster.  Organophosphates were hailed as perfectly safe because insect and mammalian nervous systems are very different, but in practice OPs were found to be toxic to humans, causing various serious physical and mental health problems. Now the Pyrethroids are hailed as the new safe product but in fact have been found to cause unwanted effects such as allergies and, perhaps far more dangerously, nervous system damage such as convulsions and loss of co-ordination.  These effects have been found with high doses, so I conclude that someone exposed many times a day to Pyrethroids, for example by shearing many sprayed sheep, or spinning a fleece for several hours a day until the whole thing is spun, will suffer a higher level of exposure than someone who touches just one sheep.


According to the literature provided by Elanco, who manufacture Crovect, Clik and the rest, Crovect prevents blowfies for 6 to 8 weeks, but is active against tick infestation for 10 weeks.  This tells us that the active ingredient is present in quantities great enough to kill ticks for far longer than it is present in quantities sufficient to prevent fly strike.  It seems improbable that the chemical suddenly evaporates at that point, but rather it will slowly dissipate over many more weeks, but will still be present in very small quantities for an unknown period of time.


Another problem I did not mention before is that wool processors could have a problem disposing of the effluent ie waste water from scouring fleece, if it contains above a certain concentration of any anti fly strike chemicals. I don't know the situation for large scale scourers, but smaller set-ups such as The Natural Fibre Co will charge the sender for the disposal of contaminated fleece, and it will be destroyed.  Otherwise they would be fined by, presumably, SEPA for contaminated effluent.  So this is not a scare story, it's real life and I mentioned it for the information of everyone on TAS.

[SallyintNorth]

And I will share some first hand experiences too.

When I first went up north, I was on a farm with 530 breeding ewes.  We used Crovect on the 60 hoggs against keds and lice, and on the 1000+ lambs against flystrike.  (In general we didn't find the ewes needed any treatment.)

In treating 1000+ lambs in a day, Crovect ate through my overtrousers (good ones - Flexothane), and even though we did the work outside, the fumes affected my lungs, and the amount in the air that landed on my bare arms I think also had an effect.  Anyway, I was wobbly and had breathing problems afterwards, which cleared up quickly, but I found after that that I was sensitised to the stuff and couldn't use it without full protective gear, including full face mask (like a welder's mask.)  It eats through latex gloves and Flexothane overtrousers so I also had to be very careful about how much I got on those things and go wash them off periodically.

If I got a whiff of it, or a splash on my skin, I would get an immediate reaction, akin to asthma, with streaming eyes and itchiness.

Once I had moved to the hill farm with ex-BH I was able to leave the Crovecting to him, and although I would help in the pens I made sure to be upwind of him when he was spraying.  We didn't spray all the lambs' fleeces every year, just the groups and body parts ex-BH judged to be at risk (if any), but we did do heads of all the lambs in certain fields as head flies were a problem on that farm. 

My last year there, we had had my sheep in for Crovect against head flies, as they were being particularly troublesome in the riverside pastures where my sheep were, and I had quite a few lambs with horns, which always increases the risk.  As usual, ex-BH did the spraying for me.

The next day, one of my lambs was completely paralysed, unable to get up at all.  We got her up to the farmstead and cared for her in a stable.  Two days later, another lamb was wobbly, and the day after that I could catch him very easily, so I brought him up too. 

Something made me look at the Crovect gun.  It was set for a full body adult sheep dose.  Somehow, the normally very careful ex-BH had not adjusted it down to the very small dose we would normally use for doing lambs' heads.  So they had got a huge overdose of Crovect, and the symptoms were neurological.

I worked with the two of them for many days, massaging them and putting them through the motions of walking.  After a couple of weeks they could wobble across the stable, and another couple of weeks they could go out into the small pet lamb pen for some sun and grass during the day, and come back to the nearby stable at night. 

Then one day we were out, away from the farm, and there was an unexpected very wintry shower.  (It was summer, but this was north Cumbria.)  When we got back, I found the wether lamb paralysed again in the middle of the pen.  The ewe lamb had gone into the shelter and was fine, but for some reason the wether hadn't, and the physiological shock had sent him back to how he was at the beginning.

By the time my move was imminent, the wether was still pretty wobbly but able to get about in the area around the farmstead.  The gimmer was not 100% but I think you wouldn't have noticed a wobble if you hadn't known her history.

Well, the wether wasn't fit for market yet, and no way would he manage the trip to Cornwall.  He had fought so hard to get better, twice, and he had a nice fleece, so I found him a forever home in a felter's flock in Co Durham and drove him and his mum (who was going to the same home) - very steadily! - across myself.

The ewe lamb came with me to Cornwall, and both are still alive and no apparent long-lasting effects.

And I have found that I no longer seem to be sensitised to it myself, either.  We do use a very small amount on some of the lambs here, and I have gradually dispensed with the mask and gloves when I do them, having found that just doing a very few hasn't caused me much in the way of ill-effects.

And one final story.  When I was on the upland farm with BH, I was given a fleece by a local farmer whose mum was a spinner, and who knew I would like their Jacob x Texel fleeces and picked me out one of the best.  I split the fleece with another local spinner, and did a quick spin with some of my half.  That evening I was very short of breath and felt weird.  I had a thought and rang the farmer to ask if the sheep had been Crovected, and yes, it had, about a month or six weeks earlier he thought.

I washed the fleece then (I often don't wash fleece before spinning, if it's clean, just give it an overnight soak in cold water and let it dry.)  Once it had had a good wash, I didn't have any reaction to spinning it - although I have to say, I never did long sessions with that particular fleece! 

[twizzel]

I think this thread has the potential to put maybe slightly more novice keepers off using fly control pour ons which is absolutely not the way I intended it to go. There is a fine line between keeping a shearer happy and withholding pour on use until after shearing, and withholding it totally because of scare mongering. Essentially if you follow the label instructions and observe the meat withdrawal you should have no problem. These products are so widely used that if there were issues with residues in meat they would have been found and the meat withdrawal increased. We’ve sent lambs off a few days after the withdrawal ended and never had any problem, likewise if we didn’t use fly control there would be serious animal welfare implications. We seem to have problems with strike around the shoulder blades/back rather than around the tail.

[SallyintNorth]

Sorry if you feel the thread has been derailed, twiz, but I for one couldn't leave llr's "So the permethrin family has low toxicity to mammals" unchallenged.

If anyone does read my post, they will see that despite having first hand experience of side effects from an overdose in sheep and of adverse reactions in an improperly protected human after treating 1000 lambs, I still use the product where necessary.  I am just careful about protecting myself and other humans, and very careful on dosage per sheep.

Everyone in their right mind would put animal welfare first, so there are a number of approaches a sheepkeeper can take if the shearer isn't imminent and there is a risk of strike.

First and foremost, if the sheep will have had Crovect on them in the four months before shearing, tell the shearer when you book and again when they arrive.  Some don't care and some need to be careful.

Secondly, if the fleece is destined for anywhere other than the British Wool Marketing Board or other commercial outlet, tell the potential buyer.  Some spinners don't want a fleece which had been Crovected in the four months prior to shearing, others will just wash it and not worry.  Small mills/processors may have a "no chemicals" rule, so check with them if you need to hold back any fleeces which were treated.

Thirdly, if you know your locale and the likely pattern of any strike, you can sometimes reduce the amount of product you need to apply to keep your sheep safe.  @Fleecewife wrote up once how they make up a diluted spray of Crovect and do the lambs' undercarriages, because experience has told them that that's the highest risk area with their sheep in their spot.  (And the belly wool gets discarded, not used, too.) 

Dag any dirty sheep and keep them clean.  If you have the choice, run sheep in exposed, windy, dry pasture during the fly season, rather than in a sheltered, moist one. 

Most of us find that adult ewes are unlikely to get struck, especially if healthy and clean, and very young lambs are also fairly resistant.  Lambs which have a decent amount of wool growth are more susceptible, and much more so if dirty.   

If your lambs are squitty so keep getting dirty, worm them.  If it's a rich grass thing, give them a mineral drench as you move them onto the lusher pasture. 

if the areas where the sheep lie up are fairly soiled, so they get soiled as they lie down, and are lying amongst a lot of poo, especially if it's wet poo, move them to another field if you can.

But yes, if you need Crovect (or Clik or Clikzin or other autrhorised product) to keep them safe, use it.  Tell the shearer, but use it.

[Buttermilk]

My shearer would rather I treated with crovect a week before he clips than risk flystrike.  However as a handspinner I am reluctant to do so.

[landroverroy]

Can I also point out that I said in my original post that it is an irritant and that I dilute it 10 times and still find it effective. I answered a simple question by vfr400 and then people started going off at a tangent and pointing out withdrawal periods as if this was a reason not to use a product for the purpose for which it was intended. All this is clearly stated on the product bottle and instructions, and I (maybe wrongly!) normally credit people with the intelligence to be able to read that for themselves.   

[Fleecewife]

The whole point of TAS is the sharing of information I believe.  To my mind this information should be as balanced as possible. When we are using chemicals we should be as aware as we can be of the pros and cons, for our own protection, that of our livestock and of the environment - this is backed by the Government's rules too.  We should never be blase about the use of chemicals.  On the other hand, by using certain chemicals correctly we are ensuring the wellbeing of our livestock.


My approach is to ensure that any new users have as full a picture as possible so can decide for themselves what is their chosen approach.


My own belief is that fly strike is such a hateful event that, in spite of working generally in line with 'organic' principles, we have always used Crovect against fly strike - we have never had any of the other ectoparasites it can treat.  I have seen some awful cases where people have not used the available chemical anti fly strike products and their animals have been cruelly afflicted.  I have also seen cases where shepherds choose not to use chemicals but their animals are well cared for and without strike.


I did not intend my earlier comments to be taken as advice not to use these products, far from it, but to let a new user know that there are two sides to their use.

[landroverroy]

My shearer would rather I treated with crovect a week before he clips than risk flystrike.  However as a handspinner I am reluctant to do so.

Out of interest Buttermilk - do you not wash the fleeces before spinning, and would you not expect it to be then washed out?
I did look up all the warnings about the use of Crovect and Spot on  and could not see any guidelines or special instructions on how to use wool that had been treated with these. However, as the effective period on the sheep is up to 8 weeks, I would imagine that if you kept your fleeces for a couple of months before using them, then the chemicals would have by then degraded. [size=78%]  [/size]

[SallyintNorth]

I don't think the Crovect or whatever would necessarily degrade in a stored fleece.   The 8 weeks is a reasonable estimate of how long it takes weather to wash the product off the fleece

[twizzel]

We had more maggots tonight so on our shearers advice have treated all our ewes with Clikzin  we’ve never had to use pour on before shearing before 

[Buttermilk]

My shearer would rather I treated with crovect a week before he clips than risk flystrike.  However as a handspinner I am reluctant to do so.

Out of interest Buttermilk - do you not wash the fleeces before spinning, and would you not expect it to be then washed out?
I did look up all the warnings about the use of Crovect and Spot on  and could not see any guidelines or special instructions on how to use wool that had been treated with these. However, as the effective period on the sheep is up to 8 weeks, I would imagine that if you kept your fleeces for a couple of months before using them, then the chemicals would have by then degraded. [size=78%]  [/size]

I sell my fleeces to other hand spinner to process and as I do not know if the recipient has any allergies ect it is better safe than sorry.  I am allergic to sheep/suint for a start and would not like to add anything else into the mix.

[Twotwo]

I think this, to certain respect fails into two separate issues.
1)the effect of the chemicals on the environment, whether it be food, fleece or or greater environment. Once the withdrawal guidelines have been adhered to it becomes one’s own choice whether to consume/use the product or not (of course the wider environmental issues are something we need to think about).
2) the effect on the handler - I have become sensitised to 2 part epoxy resin through my work and therefore cannot use it or come in contact with certain chemicals without having a eczema flare up.. most people can quite happily glue a broken jar together with Araldite with no ill effects, so I feel that someone with only a limited amount of sheep using the fly prevention products once or twice a year .... (having informed their shearer and wool buyer) probably is going to benefit from using crovet/ clik.
Becoming sensitised to something is horrible- one of the things that cause my eczema to flair up is cobalt.... bloody nuisance - soil/ fertiliser/ sheep feed/drenches / blue dyes ....... but I still