[Rosemary]

I think we need to be clear about what "clean grazing" is. According to my vet, clean grazing has had no sheep on it for several years - NOT pasture that has been rested for 21 days or so. A 21 day rest will reduce the worm burden but the grass is not clean. Clean grazing is probably only possible as part of an arable rotation.

The advice I follow from my vet is to worm all breeding sheep at lambing (I do tups and any retained ewe hoggs at the same time), because at lambing, the ewes' resistance drops and the worms "see" the opportunity to quickly multiply and shed eggs to infect lambs. Healthy adult sheep have a resistance to worms. Worm test adult sheep before tupping and worm only if necessary.

Lambs - worm test and dose as required. I test mine at shearing or 2nd Heptavac (end May / early June) and weaning (end August).

My understanding of turning out on to dirty / clean pasture is the same as jaykay's, with the proviso about what constitutes clean pasture above.

I read the disease stuff from NADIS and if I am concerned about nematodirus or fluke, then I'll phone the vet and do what he advises.

[lachlanandmarcus]

I agree, and I do. Egg counts are a good thing. Hang on a mo, what I said was meant tongue in cheek, hence the grin? I never intend to offend, and if its taken that way, I am sorry. But what happened to debate, banter, and freedom of speech??? Didn't realise we were running on BBC guidelines! Am I not entitled to my own opinion anymore 

I haven't been offended, it got deleted before I got the chance to read it    I probably sound a wee bit stroppy in my post which might have provoked, if so I didnt mean it to. 

[thenovice]

No , no fair play, I was a bit too tactless. No offence taken, and again, none intended. Im gona shut up now, I never know when to stop 

[gulli]

I think we need to be clear about what "clean grazing" is. According to my vet, clean grazing has had no sheep on it for several years - NOT pasture that has been rested for 21 days or so. A 21 day rest will reduce the worm burden but the grass is not clean. Clean grazing is probably only possible as part of an arable rotation.

The advice I follow from my vet is to worm all breeding sheep at lambing (I do tups and any retained ewe hoggs at the same time), because at lambing, the ewes' resistance drops and the worms "see" the opportunity to quickly multiply and shed eggs to infect lambs. Healthy adult sheep have a resistance to worms. Worm test adult sheep before tupping and worm only if necessary.

16 weeks at the very minimum

I would even be wary of routine drenching at lambing without egg counts to check. just because there is often a rise doesn't mean there always is, especially in ewes in good condition on land that hasnt been sheep grazed for a few years

[SteveHants]

I think we need to be clear about what "clean grazing" is. According to my vet, clean grazing has had no sheep on it for several years - NOT pasture that has been rested for 21 days or so. A 21 day rest will reduce the worm burden but the grass is not clean. Clean grazing is probably only possible as part of an arable rotation.

The advice I follow from my vet is to worm all breeding sheep at lambing (I do tups and any retained ewe hoggs at the same time), because at lambing, the ewes' resistance drops and the worms "see" the opportunity to quickly multiply and shed eggs to infect lambs. Healthy adult sheep have a resistance to worms. Worm test adult sheep before tupping and worm only if necessary.

16 weeks at the very minimum

I would even be wary of routine drenching at lambing without egg counts to check. just because there is often a rise doesn't mean there always is, especially in ewes in good condition on land that hasnt been sheep grazed for a few years

The nice thing about FECs is I realised that in a 'normal' year (not 2012) - my ewes dont need worming, and its worth the £6 every 6 weeks to find that out.

[sh3ph3rd]

Healthy adult sheep have a resistance to worms. Worm test adult sheep before tupping and worm only if necessary.

I'll be the first to say, I've got a LOT to learn about sheep, farming, etc, the whole thing in general, but what specifically is this worm resistance? As in, I'm not questioning its existence, but what are the mechanics of it? The physiological side of things, etc... I hear about it a lot but have never heard a good explanation of what exactly makes an adult more worm resistant than a lamb.

[jaykay]

There are two sorts of resistance being talked about here.

The first is of worms to worming medicines. The second is of sheep to worms.

The reason that adult sheep are less bothered by worms than lambs are is that their immune system has had chance to build up against the worms. The same sort of thing as to why human kids get chicken pox, measles etc but adults tend not to. Specifically, it's immunoglobulin E and eosinophils that get involved in immunity to worms - in sheep and in us.

But when ewes are in lamb (or any other mammal is pregnant, same thing happens in humans) in order to avoid the immune system attacking the foetus, which is half 'foreign', the immune system is 'turned down'. So in-lamb ewes are more susceptible to worms - for the same reason pregnant women are more susceptible to things like Listeria, which most of the rest of the time, their immune systems would deal with.

[bizzielizzie66]

Hi Jaykay -

You have a real knack for explaining things - resistance to worms, wormer resistance and the "in refugia" explanations are all really well done!  Vets & pharmaceutical companies should employ you if they don't already

[Bionic]

Thanks jaykay 

[jaykay]

Thank you  I think it helps that I need things to be very simple in order to understand them myself!

[Rosemary]

Excellent explanation 

[VSS]

I think we need to be clear about what "clean grazing" is. According to my vet, clean grazing has had no sheep on it for several years

16 weeks at the very minimum

Don't need to have kept sheep for very long then before "clean" grazing is something you only get to dream about!

[gulli]

I think we need to be clear about what "clean grazing" is. According to my vet, clean grazing has had no sheep on it for several years

16 weeks at the very minimum

Don't need to have kept sheep for very long then before "clean" grazing is something you only get to dream about!

yes, but it varies with climate, for instance in very hot countries like australia, parts of new zealand, the sheep are always moving onto clean pasture, which combined with drenching means that the only eggs which are shed are resistant to wormer, which in turn means that the only worms that are picked up by the sheep are resistant (in simple terms, obviously not all worms are resistant)

clean grazing can be useful, but its not the end of the world, if you dont have any, and often you are better off without

[sh3ph3rd]

Thanks jaykay, that's the bit I was curious about, in a nutshell. 

Specifically, it's immunoglobulin E and eosinophils that get involved in immunity to worms - in sheep and in us

for instance in very hot countries like australia, parts of new zealand, the sheep are always moving onto clean pasture

Wow gulli, you must live in the outback or something, if you're a fellow Australian, because the majority of herds I know of in the greener areas are literally never moved off the same paddock, year in year out year after year. The only time I saw sheep continuously moving onto new 'pasture' was in the desert, and you can't call that pasture, lol. Not to make any stupid claims that Aussies aren't aware of and practicing the usual industry standards of ovine husbandry, especially the commercial ones. Just haven't seen as many big scale sheep operations as some, I guess, and a lot of the smaller shepherds do it differently.

[gulli]

Thanks jaykay, that's the bit I was curious about, in a nutshell. 

Specifically, it's immunoglobulin E and eosinophils that get involved in immunity to worms - in sheep and in us

for instance in very hot countries like australia, parts of new zealand, the sheep are always moving onto clean pasture

Wow gulli, you must live in the outback or something, if you're a fellow Australian, because the majority of herds I know of in the greener areas are literally never moved off the same paddock, year in year out year after year. The only time I saw sheep continuously moving onto new 'pasture' was in the desert, and you can't call that pasture, lol. Not to make any stupid claims that Aussies aren't aware of and practicing the usual industry standards of ovine husbandry, especially the commercial ones. Just haven't seen as many big scale sheep operations as some, I guess, and a lot of the smaller shepherds do it differently.

talking about rotational paddock grazing mainly, although it stands to reason that the massive flocks arent on the same patch of grass all the time or it wouldn't be a patch of grass... what I was trying to get at was that the period between 'dirty' and 'clean' pasture is shorter because of the heat
no im not an aussie, could have been if my grandad had decided to leave home though