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August 28, 2023

Mark Ferguson: Welcome back to Head Shepherd. This is one of those episodes that I think will get listened to a lot, this one we are about to record with Ginny Dodunski. Welcome Ginny. 

Ginny Dodunski: Thanks, Mark. Good to be here. I've been a long-time fan of the podcast, so it's cool to be on it. 

Some of the podcasts we record people get a lot out of and I think this one will be one of them, with worms being a fairly important topic. Before we get onto that, it would be cool to hear your background. You've been a practising vet for a long time; I'm keen to hear how you got into that and how you became a large animal vet, rather than spaying cats and dogs. 

Oh, I don't think I was ever going to do anything other than work with large animals. I didn't want to be a vet. I grew up in a rural district on a small block and I always thought that my friends who lived on commercial farms had the best lives and I thought it was some cruel stroke of fate that I hadn't been born onto one. So, it was just always something I wanted to do, to be involved in sheep and beef agriculture. 

I went to university to study agricultural science, I didn't want to be a vet. I had a bet with a guy in my class halfway through it to see who could get into vet school first. I identified, one, that I was interested in animal health because we'd done a paper on that and I found it fascinating; but, two, I could see the vet degree as a way to get into a good role in agriculture, kind of straightaway. 

So that was why I went to vet school. Having to sit through lectures on dogs and cats and emus - and ostriches were the other thing - back when I went through vet school. That was a bit of an industry in New Zealand and I spent my first year in practice doing quite a lot of work with those because I stupidly put my hand up. But then the industry collapsed and I'm pretty grateful for that, because deer are one thing, but emus and ostriches, they're on another level altogether. So it's good to be mostly just working with sheep and beef, and a bit of deer now.

And in the last 12 months, or so, you're now the Wormwise programme manager, which is a national role.

It's a national role. Wormwise was launched after there was a big national survey of drench resistance done in the early 2000s, which identified what, for most people, was a surprising level of drench resistance nationally. 

I'd been working with Trevor Cook at Manawatu Vet Services, who is very hot on parasite management and farm systems and all the stuff that I do now. So it wasn't a surprise to us, because we'd already been identifying a lot of resistance in the lower North Island. But this kind of turned it into a national issue.

Wormwise was launched as an initiative to help farmers manage this. It's a collaboration between Beef + Lamb, DairyNZ and MPI, who initially funded it, and APHANZ [Animal and Plant Health Association of NZ Inc], who are a collaboration of drench manufacturers, and the NZVA, the New Zealand Veterinary Association.

It is a collaboration but, at the moment, the only organisation funding it is Beef + Lamb. So big ups to them for listening to their levy payers who were telling them, in no uncertain terms, that parasites were becoming a more and more difficult thing to manage and that Wormwise needed a rocket under it. So, I got to be the person clinging to the rocket. 

Hopefully, it takes you somewhere nice. 

It is fantastic. I love it. I'm so lucky to do this job. It's great. 

So you travel around or it's answering phone calls? How does the role work? 

The role is supposed to be about managing the outputs from Wormwise - lifting the visibility of it, broadening the scope, more tools, better resources - lots and lots of things. So, I have to balance that, between the public side of it, which is a little bit of travelling around and speaking - there are Wormwise facilitators in every district of the country and we run workshops, which most people will probably be familiar with - but also, as the Wormwise programme manager, I get asked to speak at various things, which I think is important, because it keeps lifting the visibility of it. The other thing is our social media, which we again put a rocket under. 

My idea, when I took on the role, was to interview heaps of farmers who are doing a great job with worm management and go on to their farms and film it. I was totally naive because that stuff costs so much money and it's so time-consuming. So, I just went, man, I've got a limited budget here. I just need to get out my phone and start having conversations directly with farmers about worm management. It was just an easy way to get it going and the response has been great. It was good to get that underway and we'll continue to try and grow that.

Cool. So how do people find those things? We'll put the link in the show notes. Is it across socials, Wormwise? 

At the moment, its only social channel is Facebook. Identifying that our main demographic is sheep and beef farmers - who tend to, maybe, not be on TikTok - that slightly, I'm not going to say older, but more mature age groups that tend to be on Facebook. Beef + Lamb do share it on their Instagram and also on LinkedIn, but we don't have separate profiles for Wormwise. It's just about trying to keep it tidy and easy, so Facebook's the best way to find us. 

I suppose what we want to do now is a Wormwise workshop in a condensed format. A lot of people, down in the south anyway, in the last 12-24 months, have discovered resistance in their worm populations to most of the chemicals available. And that puts chills up most people's spines, particularly with intensification and irrigation. We've seen a real spike in worm populations generally, and therefore everything's starting to break down.

The other fear that's making some people lose sleep at night is the limited supply of capsules this year. The concept of farming without slow-release capsules is something that people haven't wanted to contend with before - even though a lot of people have been told not to use capsules for a long time, because of the potential resistance issue. 

So a few people would be keen to hear your wisdom on how they go about managing worm populations with restricted chemicals.

Just taking a step back, a lot of your audience follows you because they're interested in genetics and anybody who's got a basic understanding of genetics is going to realise - and our parasitologists have been telling us this since the first drench chemicals were released in the sixties and seventies, which was thiabendazole and levamisole - that you've got a host population, the sheep or the cattle, that breed once a year which is comparatively slow compared to the parasites that can breed, in ideal conditions, every three weeks. And the level of variation or polymorphism in those parasite populations is massive. 

So the maths is stacked against the drugs. Parasites were always going to evolve resistance to drugs, and it depends on how we use those drugs, and how much we use those drugs, and over what percentage of the animals on our farms we use those drugs, as to how quickly that's going to develop, right? The more days in the year that your worm population is exposed to the drug, the more days that they've got to breed and get around that. To put it as simply as possible. 

As we intensified, we've found it very easy to continue to use more anthelmintics because, until resistance came along, it has taken the visible signs of parasitism out of the equation. 

Just taking a step back from that though, I think one of the key points in Wormwise workshops is the cost of larval challenge to stock. We do some exercises and show data around that, which brings it into really strong focus for people: the cost of daily intake of worm larvae. Just using drugs doesn't necessarily get around that. 

The one place that does get around that is the use of those long-acting capsules or injections. They will knock the larvae out as soon as they're coming in and stop that immature population from developing into more and more worms in the animal

But when we've got animals, say lambs on a 28-day drench rotation, other than probably the two days after that drench, every other day those lambs are being exposed to some sort of larval challenge - unless they're on clean feed. The cost of that to our systems is actually bigger than the cost of the clinical parasitism that we see when the wheels really fall off. So, I think understanding larvae on pasture and how you can minimise that in your system is the key - the most important thing. 

It does become difficult in systems where there are young animals around all year. It becomes difficult in systems where they are sheep dominant and in systems where it's difficult to provide cleaner feed (i.e. new grass crops or areas that have been grazed by different species for a long time).

So, if you're sheep dominant and largely permanent pasture - particularly unfortunately, if you've got fine-wool sheep (because they are more susceptible) - then you are in a situation where you're quite reliant on anthelmintics. And, as the parasitologists have told us from the dawn of time, that - at some point - was always going to fail. So, we're getting to that point now, we need to have a real sort of systems think about how we now go forward and deal with this.

Ironically, people think of high rainfall in New Zealand and therefore, worms. But also in the Mediterranean environments where I grew up, there was a great concept of the “double summer drenches”. But nothing selects a worm population faster than drenching them when all the worms are in the sheep, essentially. And so you're putting massive pressure on that chemical when there are no, or very little larvae on the pasture or there's no pasture and it's hot and dry. So you whack two drenches into them and that kills a lot of drenches pretty quickly. 

Indeed. I do think from a resistance point of view - no, just from a worm point of view - sometimes those systems where there is an environmental break, it's either a really, really cold winter or it's a big lot of crop in the winter, or it's a very dry summer or a big lot of crops somewhere where you create a break in that worm challenge/exposure cycle, from a worm perspective, those can be easier to manage.

And, as you've alluded to, from a resistance perspective, you've got to be careful about how you use the drenches going onto that clean feed that results from that system or that environment. So, I totally agree with you. 

Interestingly, talking to farmers in Hawkes Bay in the last couple of years, where they've had unseasonably wet summers - I lived and worked in Hawkes Bay for four years and the farmers in the dry parts of that district would always say, as we'd come from Manawatu, "Oh it's so easy farming over there, summer safe, like you just keep cruising, growing grass all the time. It's a piece of cake.” - and now they sort of see what it's like in terms of the worm challenge and the bug challenge. Summer safe isn't necessarily easy on a farm, because those worm cycles just keep going all year. And you ask anybody who farms in a moist part of Northland and the worm challenge is just a constant thing.  

So, it's addressed by management, but also genetics absolutely have got to have a role to play in the long term. As we've selected for more and more high-performing sheep in our crossbred flock, we have consequently ended up with animals that are more reliant on drench to continue doing that performance. So, we've got a backpedal out of that. I know there's progress being made in fine wool, I think that's awesome. We've got to start taking that more seriously, and I think there's going to be some good tools coming down the pipeline in terms of helping select those animals a bit more easily, fingers crossed. 

Sounds like you know something I don't, so that's good! Everyone loves the concept of a wet summer until they farm in one, everyone in the dry areas  anyway. I grew up in the Mallee in Victoria, which has a pretty tough summer and we'd go to see the grandparents who were on irrigation, and you'd sort of think, “Jeez, it would be amazing if we could have some of this.” But once you're dealing with the worm build-up from that and everything else that comes with it, it becomes less amazing or not quite as amazing as you thought it might be.

I think genetics definitely has a role to play, but it's not going to be the only tool. It's about making sure we are selecting for those resistant animals and they act a bit like a capsule in the sense that there's always a mechanism to slow down that challenge. Whereas short-acting anthelmintics only knock off what's in the animal. 

And you talk to people and they think that the job is to kill all of the worms, but you're never going to kill all the worms. It's about managing that larval population and having the animals in the right spot at the right time. And, for resistance management, refugia is a massive part of it and making sure you're not drenching everything all the time. 

Correct. Refugia, I think, can be a little bit confusing for people. Put very simply, the farms I see and the data I see from around the country, the farms that still have no drench resistance or very minimal drench resistance have a long history of not drenching their ewes. [In] the work that Dave Lethwick began in the early 2000s down at Flock House, looking at the various regimes and how they did or didn't select for resistance, they identified back then that the undrenched ewe flock was absolutely key to maintaining refugia easily on a farm. 

I think it's really easy to get bogged down with little details of refugia in terms of how we manage this paddock or how we manage this mob of lambs, just getting really granular about it. But, at a farm system level, that undrenched ewe flock is massively protective in terms of not creating further drench resistance on a farm. I think it's going to be difficult to backpedal out of severe resistance situations - just by having an undrenched ewe flock - but I can already see some progress on farms that I'm working with where that has become something we've instigated.

The other thing about my role is that, for Wormwise, I do that 20 hours a week. And then the other 20ish, or sometimes more, hours a week, I'm still doing private consulting, which I was doing when I was in veterinary practice anyway. So, it's not just worm consulting, it's whole farm systems, because you can't have one without the other.

Dealing with farms that have diagnosed multiple drench resistance - triple drench resistance, in recent years - even if the ewe flock previously has had a lot of drench use, putting in place a best-practice system around that ewe flock, in terms of feeding and body condition and making that ewe flock the priority, instead of pinching feed from the ewes by trying to finish animals that probably should have been gone - that sort of thing - that, in itself, has been helpful on a lot of these farms, in terms of apparently winding that resistance back a little bit.

It's probably quite a big topic to get into, in terms of reversing resistance on a farm; but, having a high-performing, well-fed, well-conditioned and then undrenched ewe flock - that's just a really powerful thing from a farm system and profitability point of view, completely aside from the drench resistance stuff. But that undrenched ewe flock is super protective - and provides great refugia in systems - and we know that from these farms that have got a long history of an undrenched ewe flock and also no drench resistance. 

And we've seen the good practitioners being able to bring drenches back with really effective use of all these tactics. 

Just to that point about bringing the chemicals back. If we'd gone in and treated a whole bunch of animals and then slaughtered them and counted all the worms left behind, even when we first started using our combinations, we had that much background resistance to the individual actives that there would've been worm genotypes there already that were able to survive those combinations. It's just that we didn't see them because they were at such a low level. 

But over the years, using these combinations, we've selected them up. Now they're so prevalent on many farms and winding that drench resistance back, it'll never go back to a hundred per cent, because it probably wasn't a hundred per cent to begin with. But we can get it back to a point where it's in the nineties, where we can then use those combination drenches in a limited way, with a whole lot of management change or system change, and also some use of those novel drenches.

It absolutely bamboozles me that I still see farms out there that know they've got triple resistance and are just continuing to use triples and won't move to a bit of Zolvix and Startect at targeted times. You're driving yourself into a hole really quickly doing that. 

You and your sheep, generally; it doesn't bode well. 

Obviously young sheep are where most of the chemical is required, because they are born with no natural resistance and develop that over time. Regardless of genotype, they need to build up their immunity and get better at it. So, that's where we're throwing a lot of our chemicals. With people that are facing resistance - when managing refugia in those young sheep, do you do it at a systems level or do you run some old girls with those lambs? What's the best practice there? 

I think running older ewes or two-tooth ewes, or hoggets that have weaned a lamb and that are ageing up to a two-tooth, they're a great source of refugia. We've got plenty of farms now doing that in the North Island and they always comment how quickly those girls pick up when you put them on lamb feed with the lambs and give them a bit of space from each other. A sheep's worst enemy is another sheep; the more space you can give them, the better.

It's amazing how those hoggets, or ewe lambs that have reared a lamb, don't actually need drenching, they just need a really good feed quite often - with older ewes, same thing. I know Dave Robertson down in Oamaru - he's got a really good case study of a lamb finishing block, where they've largely turned a resistance issue around, by introducing grazing ewes into the equation.

There are other ways of doing it. You can leave some lambs undrenched every time you treat. You can monitor and extend your drench intervals. All of those things work well when you've got your eye on the ball and your staff have got their eye on the ball and everyone's on the same page and everyone's watching - because those situations can turn around quite quickly sometimes, and you can have animals that are clinically parasitised within a short time, if you haven't got your eye on the ball. 

I think that stockmanship is really important, if your refugia is by leaving lambs undrenched, whatever way that is, you've really got to be on the ball with your stockmanship and your feeding and trying to provide them with as much what I call ‘clean’ feed (there's never such a thing as ‘clean’ feed really, that has absolutely zero worms on it), but as low-challenge a feed as possible.

But the ewes are a really easy way of doing it. 

I guess we’re lucky in New Zealand, as compared with Australia, where a lot of farms (well, it’s not luck…it’s by design!) have beef and sheep and, so obviously, running cattle and sucking up some of those larvae is a good tool that can be utilised - rotating species around a farm - what is the impact of that rotation? Does it have a significant impact on the larval population?

That's a great and very interesting question and it's probably a question that we could do with a bit of quantification around. But, from a gumboot observation, from what I see with my own hill country clients here in the North Island and talking to other practitioners around the country, I think the closer that you go to a 50:50 sheep-cattle ratio or even more cattle than sheep, those farms just have a much more significant ability to manage the worms in their sheep without drench. 

I appreciate that on our steep North Island hill country, a lot of it just doesn't lend itself to having that many cattle, so that's not always practical, unfortunately. And, again, that's where the ewe flock and the system that you're running becomes just as important.

But, in terms of grazing rotations, there are two broad ways of doing it. One is that you've got a truck and trailer going around, where your most susceptible and vulnerable animals (i.e. lambs) are out the front getting the pick, and then you've got something else following them, and something else following them, with sort of a vacuum cleaner thing going on. 

Where farms can get quite long rotations going, it is possible to substantially reduce the worm challenge to lambs. I'm not sure that, on a lot of those farms, they're necessarily doing a lot less drenching of those lambs, because a lot of those farms are big stations where leaving lambs undrenched for a longer period, or leaving proportions of lambs undrenched, is risky. But, it still reduces the worm challenge to the lambs well enough to get good performance and then we are relying on the ewes to provide that refugia as they follow the lambs around.

When you do that though, you do have to manage your ewes carefully, because those farms, where lambs are weaned back onto the lambing country, where you're lambing over most of the farm, the worm challenge on those farms is still pretty high and there'll be a proportion of those ewes that don't handle it because of that.

So having a split in your ewe flock, where you're looking after those lighter ewes (and they might be going around ahead of the main mob or on their own little rotation, with some young cattle or something), I think that's really important. Just having all your ewes in a big mob and hoping for the best, that's not usually a good recipe for success. 

Your comments on nutrition are obviously really true and we see it firsthand all the time. There are two ways to kill worms, or restrict their impact on your system, and one is chemicals, but the other one is just having the immunity of the sheep cranked up and that's obviously when they're well-fed and in good condition and high protein tucker and everything going well. 

I think a good case of that at the moment is in the central progeny test merino hoggets. Will [Gibson] is getting quite frustrated trying to get their egg count up [as part of a controlled worm challenge] - and, it sounds strange, to be saying you've got fine-wool sheep that are on irrigation and we can't get worms in them, but that's what's happening. They'll get up to 250-300 or whatever and then, because they're on pretty good tucker, the numbers start dropping back again.

That is such a great point - to your question before, about managing refugia or parasitism - the challenge in lambs. We know that in the lamb's first year of life, they're going to develop their immunity to worms. And they can do that very quickly and very effectively and efficiently, just at a low-trickle challenge of worms. 

There's an exercise we do in the Wormwise workshops where we show some data of lambs that were dosed with 5,000 Ostertagia larvae a day, (God, who had to do that?!) versus lambs that were dosed with 1,000 Ostertagia larvae a day. The ones that only got 1,000 larvae a day grew at the same rate as lambs that were completely unparasitised during the trial. So, the fact that at a low-trickle level they can still grow at a very high rate, while developing their immunity and actually not need a drench, that sounds crazy, right? Not need drenching at all.

Be careful of that please, everyone. I'm not telling you not to drench your lambs. But, with that low-challenge feed, they don't have to be getting much of a worm challenge to develop their immunity. And what you described there with the egg counts going up to a low-to-moderate level, and then dropping off, that's perfect. If all of our farm systems in New Zealand could replicate a system like that, where the young stock were just allowed to develop their immunity under low challenge, it'd be so different. But it's just not that feasible on everyone's farm. 

It's quite bizarre that we're the only farm, or the only people managing sheep in New Zealand, that actually want the numbers to go up, and we're the ones that can't get it to happen!

I do see that talking to some of the worm FEC breeders who've now been breeding animals for two decades or more for low FEC. Talking to a number of them when they try to do FEC reduction tests (i.e. drench efficacy tests on their farm to see where they're at), they will find that their lambs in the summer can't get their egg counts up high enough to do a FEC reduction test. That's an indication of some pretty good progress there, I would suggest. 

That's right. And when we think about what the breeding values equal - like a minus 80 is an 80% lower egg count - so, you end up under drench thresholds quite a bit once you get those resistant populations; often they won’t get up to drench-threshold egg counts because they don’t get as high as they would if they were the other half of the population (or the other 80 percent of the population, in some cases).  

Really interesting. I think in all of this, everything we're talking about, and what you are talking about, is ‘well-monitored’ is the only way to be really. You can't do any of this if you're shooting blind and think “Oh they’re scouring a bit, so I'll whack a drench into them.” Some people use it, rather than give them a feed, thinking "I'll just whack a drench in them because they get energy outta that drench," or whatever. 

The scouring, particularly in ewes, they don't always need a drench - sometimes that's just feed. A classic one is the lambs that, when you go to shift them, there's two sitting down in the gateway and there's three or four panting and "Oh shit they've got barber's pole." So, we run them in and we drench them all and one or two more die and then they stop dying. And so it must've been the drench. 

But, when we get an opportunity to do post-mortems on those lambs, or when I get clients to open them up and send me photos of those lambs, so often it's not barber’s pole; it was viral pneumonia, it might've been leptospirosis. There are a few other things that'll tip lambs over like that. And if you're just looking at them sitting in the gateway, they basically all look the same. It's not until you do a bit of a closer look that you can actually make a call. 

But then the thing with barber’s pole is that, it happens to me one day, so I go down to the pub that night and I tell everyone in the bar, “Shit, lambs are tipping over with barber's pole.” And then suddenly the whole district and the trading manager from the local store hears about it, so he drives around and tells everybody "Oh, you've got barber's pole, you need….” For goodness sake! 

Barber’s pole is a lot less prevalent in New Zealand than we imagine. The other thing about barber's pole in ewes is that we know, from the northern parts of New Zealand, that there are plenty of ewe flocks that don't ever get drenched and they don't do any routine treatments for barber's pole. It is all about condition, nutrition and genetics. So anyway, I'm going to stop on my soapbox about barber's pole now, sorry. You just set me off. You triggered me Ferg! 

It's so true. We often shoot from the hip with our solutions because it's the one that might have worked before. But we need to make sure, in every opportunity, we're making a well-measured, well-managed or well-thought-out decision based on some sort of data. 

Just back to that monitoring. I do appreciate that it's not logistically easy for everybody to do faecal egg counting. That said, there's a great automated solution available where you can do bulk egg counts yourself. That provides you with some level of information and, if you do them regularly enough and get your eye in with the data, then they're a great solution. So, for those isolated people who are like, “Well, I can't drive samples to the vet clinic every week,” you don't have to. It's just learning to interpret that system. 

It’s really interesting, actually. Massey University, on behalf of Beef + Lamb, has done a series of interviews with farmers who use less drench than the average called the ‘Low Drench Use Project’. And all the farmers in that group talk about monitoring and how they do it. A lot of them started off doing a lot of egg counting or a lot of maybe weighing or whatever they were doing. But all of them, there's a sort of pattern, over time, where they get their eye into what the stock looks like and what the grass looks like and what kind of feed they need to be on to not be pushing the envelope and not end up with parasitised animals.

And a lot of them do note that over time, they do less of this formal monitoring once they get their head around using less drench. So the monitoring's really, really important. Over time, I think people can develop their own eyeometer to not have to do as much formal monitoring. But, I do think when you first start, it's super important. 

Whether you're monitoring egg counts or monitoring condition scores or monitoring pasture, you're in a higher level of information-based decision-making, even if it's not actual egg counts, you're still more attuned to what's happening.

Definitely, you've got that algorithm in your mind of grass growth, grass height, what the FEC is, or what it might be and then what the stock look like and what's coming up in terms of environment and management on the farm. And you're just making calls around whether we need to drench or not, based on all that information.

Capsules are the biggest silver bullet probably to sheep agriculture, ever, in terms of when you whack 'em in - and as you said - that means no larvae impact, and they do act like magic and the animals look amazing and everyone gets addicted to them.

There's a restricted manufacture of capsules now and I don't know what that looks like in the future. But, what we do know is that they're going to be in limited supply this year, so there's going to be a lot of farmers out there using less or maybe none at all. Going into lambing, what's the best practice if you can't whack a capsule in your twin and triplet ewes? What's the next best plan? 

I actually contacted Boehringer when they first announced that. I think it might've been before Christmas in 2022, just to say thank you so much for letting us know now that these things might not be available. Because, at that point, people in the North Island anyway, have either weaned, or they're about to wean in the South Island. In terms of being able to farm without them, when you have been very reliant on them, it's really scary and probably dangerous to pull them all out in one year. But I think, in the end, it has to be the aim, because the parasites are at the point where they're evolving so much resistance to them that they're not going to work. 

And I've heard cases in the South Island of merino ewes with capsules in the last season getting sick and dying with the resistant worms that are there now. So, that's the endpoint and you don't want to wait till you get there. But pulling the whole job out in one year is scary and there are a lot of management changes that need to happen. And probably policy changes on a lot of those farms, to make sure that those merino ewes have got access to enough high-quality, cleanish feed and that they've got enough condition on their backs to withstand not having a capsule.

I think for a lot of farms, they probably do need to look pretty critically about which animals are going to be the safest - and I'm speaking about fine-wool now, because I'm pretty confident that most strong-wool people, with a bit of attention to body condition and getting someone to help you do a feed budget, if you're not familiar with that, and sorting your rotation out for the winter, most strong wool farms can get through and lamb very successfully without capsules. But, with fine-wool, I do think, talking to the people that I know in the South Island who know more about it than me, I think it would be a dangerous thing to tell people just to pull them all out in one year.

There's probably going to be some compromise around leaving the least vulnerable animals untreated and really focusing on the feed and the condition for them. Then looking, maybe, for some alternatives - for a year or two - for those more vulnerable animals, while you keep critically looking at your system and seeing where can you take that larval challenge out, where can you stop contaminating the farm - if you're carrying a whole lot of fine-wool hoggets through the winter as well, to finish or whatever you’re doing there, and then lambing back on that same country. 

We've just got to think about managing larval challenge on our farms quite differently and I think a lot of farmers don't even think about it at the moment. It's looking for ways to minimise the larval challenge to those lambing ewes, whatever that looks like. But you just can't wake up in the middle of May and go, “Right, snap, I'm going to do that!” That started two months ago. And I think some people will probably need quite a bit of support to get there.

So, that said, the Boehringer capsules, it’s been indicated that they won't be on the market, other than what people have got in stock now. There is another brand of capsules and there are also long-acting injections. Wormwise doesn't advocate the use of any of those on a routine basis in ewes, because they're a known risk factor for making your resistance worse.

But, at a practical level, I think pulling the whole job out in one year with fine-wool sheep could be very dangerous and I have heard of cases where that's been done and it hasn't gone well. So, get some help. Focus on everything you can around body condition, good feed levels and minimising larval challenge. But, those are system things that sometimes take three to four years to put in place. And obviously genetics, that genetic change is a decades-long thing. So, we can't, again, just wake up in May and decide to change that. 

That's right, it's a slow burn. But every year they get slightly better so it's all wins in the long run. I guess those skinny twin-bearing or skinny triplet-bearing ewes are your high-priority group in any mob of sheep. They're the ones that need to be identified and treated differently. And if there are any capsules around, they're the ones that they'd be going down the throat of first.

Yeah, I agree. And most of us are still well in advance of mating at the moment. And I think you should think carefully about what you're doing with flushing ewes if your ewes are in light condition - because why do you want to put more twins and triplets into ewes that aren't going to start the winter in good condition? Because those are the ewes that die. They're the ones that have low lamb survival and they're the ones that are more likely to be impacted by parasitism. So just be careful of that. 

I think my holy grail is either weaning ewes that are already in the condition that you want them in at tupping, which I know is quite difficult, but getting them up to that weight straight away, ASAP, straight after weaning. For the genetics we've got in the North Island anyway, in terms of these very fecund crossbred animals that we've got now, flushing them to poke more lambs into them - I don't think that's something that's really serving anyone nowadays.

Yeah, really good point. I think flushing generally needs to be really considered well, because what flushes best are skinny sheep. You get your biggest response from the skinnier sheep. I'm always saying over here to save that feed for once you’ve pregnancy scanned and you've got some skinny twins; that's where any feed that's going in to try and flush the mob should be going into making sure you get viable lambs out of the lighter twin bearers - it is going to be where your highest return is for that feed. 

A hundred per cent. I've got a friend who farms on very flat country in the Manawatu, which probably should be a dairy farm; but they have a very high performing ewe flock on it. And, when they take the ram out, because most of their ewes have got twins and triplets on board, any ewes that are condition score two or less - they have a reasonable area of winter crop - they just poke them into the winter crop and they just go and get lost in the jungle, in the winter crop, for the entire winter. And not all of them pick up to be beautiful, fat things. In fact, most of them don't. But they get through and they rear a lamb and then they get rid of those ewes. 

But those ewes that you've priority-fed all summer and are still light at mating and are still light at ram removal, they've got something wrong with them. And all you can do is either put them on a truck then, or just give them as much space as possible, as small a mob as possible, and much feed as possible. Don't leave them in the big mob and you will surprise yourself how well they can perform. But those are the ones on our hill country, that they're either dead or missing. You just don't see them, they just go down and die in a hole somewhere. 

We have big discrepancies in the North Island in our tallies from tally time to tally time. We know from the data that Trevor Cook and I collected - from some work on light ewes that we did in the mid-2000s - we know it's those skinny ewes that are gone. There are a couple of really cool bits of data. One was ours, which was that of the ewes that started the winter at a body condition score under two, only 17% of them, on five or six farms that we studied, were present at weaning. And Kate Griffiths did a PhD looking at something similar, with a much larger number of sheep, about 13,000 sheep I think, in the North Island, and her number was 16% of those light ewes. 

So, ewes that start the winter light are just not in good shape to still be there at weaning. It frustrates the heck out of me when I see farmers talk about restricting ewes in the name of preventing bearings, for instance; or ewes getting too fat at lambing and then getting cast - those cast are the ones you see - the ones that you don't see are all the ones that are costing you because they just go and die somewhere and you didn't even see them. 

Excellent, Ginny, we better wrap it up there. We really appreciate your time, you've been a great supporter of neXtgen. We love having you in the network and commenting on The Hub and, when we're running the Growing Ewe Masterclass, you're a key contributor to that. Thanks for all your support and thanks for coming on today and sharing your world of knowledge.

Thank you. It's been a pleasure. 

Dr Mark Ferguson
Article by:
Dr Mark Ferguson

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