Capital stock are a critical part of most production systems yet sometimes their importance is overlooked.
Al & Juddy take a farm systems approach in discussing forage and forage systems which feed this important stock class at critical times of the year.
Listen in to this general discussion on the principles of feeding next year’s production.
"Always focussing on driving pasture covers so that when we put a ewe with high energy demand into a set stock phase to be lambing, she's got enough feed underneath her with enough momentum to get to peak lactation as fast as possible." – Allister Moorhead
Juddy Hey Al
Al Hey, Juddy. How are you?
Juddy Yeah, you're looking well. That moisturiser obviously working. What are we going to hear about today?
Al Today, Glenn, we're going to be talking about the first in a series of podcasts we're going to do on farm systems. And the topic of today is looking at feeding capital stock.
Juddy Oh, great.
Al What we're going to look at is to define the system, the targeting, the key feeds for different parts of that system, focussing predominantly on autumn and the mating phase, wintering and looking at the pre lambing or calving time frame . And then we'll do a brief summary at the end. I think for the sake of the podcast the reality is that although capital stock and the cattle scene and the breeding cow are quite a big part of the capital stock footprint, the reality is she doesn't need a lot of specialist drivers inside the feed system. So predominantly this podcast will be focused on sheep and the ewe flock.
Juddy Excellent. So let's start right at the beginning. What do we class as capital stock? What physically are they on farm?
Al Well, that's the stock class that you have to carry to get your final product. They're not the final product until their last years in the farm system. And then they'll be sold as a cull for age type animal. But they are the producers of all your prime stock and all your sellable product, and they are the ones you have to carry for a whole calendar year. And quite regularly, you actually have to carry them as young animals until they reach their breeding maturity, their age. For some animals and some sheep systems in the industry, they actually consider hogget mating, which is mating a quite young animal. But that requires a lot of animals getting to a certain mass and size so they can actually take the ram. The other one is the scenario of just carrying the ewe throughout the calendar year. She's got a job to do is get mated, then be carried through winter, and then give birth to the lamb in the spring when food supplies are starting to kick in.
Juddy So we're basically talking about breeding stock. So whether that's the cow, the beef cow that we've got and we're getting calves or whether it's the ewe that we were getting our lambs from, that's what the stock we're talking about. We're talking about that breeding stock that is where you're generating all of your young animals from. And I guess from another point of view, in terms of feeding these animals, are we talking about strategic feeding? We're talking about tactical feeding or are we talking about both?
Al We are talking about both because on the scale of it, there are long periods of time that a capital stock unit can actually be treated pretty as a lower priority on a farm, which means they are opportunist feeders, they are often cleaners. And as long as they hit their key moments throughout their cycle, they can actually be fed quite a wide range of forages, I feel probably some of the drivers of the system are quite important just to discuss and what we've learnt in New Zealand over the years is that when you look at the sheep industry, particularly the two big drivers or the big drivers of sheep performance is fertility conception. So that's giving you the potential to not even optimise but almost maximise your sellable product, which is your lambs.
Juddy Yeah, really interesting because in a lot of the research, the weight of lambs weaned per ewe going to the ram is the one that's most highly correlated to profit. So you're absolutely right. So it's about getting big lambs, at weaning on the ground and as many as you can and if you work back from that, those two key periods around mating and through that lactation phase are the two ones you've got to get right.
Al And from today, we are actually going to focus on that lactation phase in another podcast, because we see that as an extremely important phase of weaning prime lambs off mum. The New Zealand farm system has taken that to a whole new level where we can get a carcass weight of between 17 and 18 or even 19 kilograms and a really minimal amount of time anywhere between 90 and 100 days. And therefore, that animal was really incredibly inefficient and the New Zealand system really takes that out. Some of the heavier weighted sort of schedules looking at more like the 20 to 22 kg lamb, really is a long season lamb, and we tend to find those in environments which cannot push them all in through that lactation phase anywhere near as much.
Juddy And I think the other point, we always talk about finishing lambs, but if you are in a sheep system where you are looking at mating hoggets actually having big lambs at weaning and those still moving on allows you to get into a body weight where they hit puberty and therefore mating hoggets is more successful. So it's not just about the finishing and the slaughtering of those, it's actually around getting those ewe hoggets up to a weight where they could take the ram.
Al So to step back into this, what you achieve at weaning has and defines very strongly economic base in a sheep system and of course conception, the mating phase has a massive role in what you can possibly get at the end.
Juddy Yeah, it's the start.
Al And that's the start. And this is the whole point of this discussion today is recognising that although these stock classes aren't high priority stock for the calendar year, there’s two potentially massive timeframes and the first is in this capital stock feeding phase, and which is in the autumn when there's no sellable product, but you're setting the framework to have the best possible fertility outcome. And then the second part is this lactation feeding, which is actually feeding lactating ewes in the spring. Now we will separate that out and we'll discuss that another day because there are a lot of mechanisms and tools to talk about that lactation feeding and weaning phase. So, we're really focusing on what are some of the key drivers to get the best result from a fertility based situation, predominantly focusing on feeding, but not exclusively.
Juddy Cool. And so, I guess when you think about that mating period, that is where you set down the potentially the maximum number of lambs that you're going to get. It's from that point onwards that that number will only come down.
Juddy And so feeding around that period, maybe the six weeks prior to the ram going out is quite critical.
Al So just out of interest, what are we talking about with that? So talk to me about just what you said is that. It's not as simple as getting your feeding right when the ram goes out. We have to present, feed and create a plan of, you know what? What are those pre mating drivers.
Juddy So there's probably two things here. What we're after here is we're after elevations in body weight. So we want these ewes, if we're talking about ewes to be gaining body weight in that period six weeks out from putting the ram out. And what that does is it improves the success of reproduction. So we've got animals that are gaining weight and they are much more successful than animals that are losing weight, for example. So that's some quite old research proven time and time again that we want animals on a rising plane of nutrition, that we've got an increase in body weight.
Al Leading to the moment of mating.
Juddy So if you are thinking about nutrition when you put the ram out, right, you are probably too late to influence that particular mating. I think the other thing that's really important is the ability also to increase the protein intake of those ewes and that again, independent of the increase in live weight. But normally together, that also gives us improved ovulation, for example. So we're after a rising plate of nutrition with particular emphasis on protein for that period, six weeks out.
Al Then at least one, I'm mistaken. There's another significant challenge in the window of time we're talking about, and that's typically in that sort of late summer and mid-autumn and in some regions and will tease out the time of mating based on environments in New Zealand. But isn't this predominantly a time frame when parasitic worm burdens can actually have a big derailing effect in the sheep herd?
Juddy So there are a couple of issues here that can derail this. So what we've said is we want a rise in plain nutrition and more protein, and that largely is a time in some of our environments where protein is a real issue because we've got maybe drought affected pastures and our green leaf and therefore our protein is actually not as high as it could be. So that's a really important part for that. So the quality of the feed that's going in if we're looking at resistant pasture may not be good enough. Yes, Allister if we've got recent rains and we're grazing quite low the parasite burden going into those animals can be very high. And that is going to be a challenge because essentially what that does is even if those animals are just mounting an immune response to those worms, that's taking protein away from reproduction. So the internal parasite high internal parasite burdens, regardless of whether you are seeing the effects of those or not will have be having an impact on reproduction. I think the other important bit is it's also a time sometimes where we see endophyte issues and so there's a number of different.
Al And to tease that one out because our flock has been sort of more pushed on to the more extensive country in New Zealand as land values have gone up and as I say, the capital stock units of the farm can be used as tools for the majority of the year, apart from these really important times. They've been pushed out onto the less developed country, with varying topography. And in these environments we can still have endemic endophyte which is often quite toxic through January, February, and March, you can get a lot of leaf diseases kicking into old pastures at that time of year. So the loadings of facial eczema in the fight toxicity and things can really coincide to the lead into mating.
Juddy Yeah. So, I guess, you know, and we can talk about one of the ways of mitigating some of that is actually to provide feed that's free of those things. And so then we start talking about the use of summer cropping, for example, to drive this really important part of the sheep production cycle. Because really for those, if you can get those six weeks right, then you can probably do those, can be the lowest priority animals from then on, probably through to lambing. But it's getting those six weeks right. In a traditional pasture system, there are some real challenges, particularly in some environments as you've pointed out.
Al I'm just going to tease that apart a little bit in New Zealand is that New Zealand is nearly 2000 km's long. We have a big change in latitude from the North to the South. And I always sort of describe if you're a tourist coming to New Zealand in our spring, you can get a pretty good gauge on how warm our countryside is based on how big the lambs are in spring. So we are in coastal Canterbury here in the Canterbury Plains, in the South Island of New Zealand. And against the coast, we can see lambs in this environment in the middle of winter because the pasture growth is actually starting to kick away, albeit slowly. But it goes really quite quickly through the last part of our winter and into the early spring. The key to this is in this part of Canterbury, we also got very, very dry in the middle of spring to the very start of summer. So the reality is our season is early. As you head up the Canterbury Plains as an example, we get up to about 300 meters above sea level on the top end of the plains and those lambs are coming later and later again because the environments are cooler and cooler. And then you'll get into some of our high country regions which will set between 300, maybe quite significantly higher. And you'll see some of those lambs are being born in the middle of spring, not even at the start of spring. So when you drive around seeing the size of our lambs, it is actually a really good indicator on, you know, how long a winter is, which covers off in the wintering part of this discussion in that the moving forage forward into lambing but also how warm the environment is as well.
Juddy Yeah, so let's come back to the mating period I think where we've got the ability to, you know, our risen pasture is of high quality and we've got some legumes in the air and we know the protein intake is going to be good. Then we can use that in terms of that flushing period where that's not the case I think then we drop to some of the summer crops and now in this region when it is dry.
Al Because we're mating earlier, which means we're closer to our true summertime for mating.
Juddy Yeah, we're closer to that heat. So things like forage rapes, some of the leafy turnips, even some of the, you know, crops like lucerne, for example, or high legume content like red clover, for example, can be used in terms of driving this change in both body weight and in protein. Now, it's interesting that some of those crops and I mentioned both lucerne and red clover also has some negative things associated with that mating period and photo estrogens can interrupt some of that. But my view here is that if you've got really high quality pasture outside of those, you should use that. But often what we've got is the alternative to, you know, things like lucerne and red clover are a brown hill and I would far rather.
Al Full of toxins and a pretty negative state to be fair.
Juddy Yeah and I'd far rather that the risk of a decrease in body weight and low protein far outweighs any risk of reductions from some of those other chemicals. So my view is that you know, even moderate pasture probably isn't good enough for a really good mating outcome. And some of these other ways of driving that particular requirement is we should take advantage of that. So once we've got those animals in lamb.
Al So actually before we do that, no, let's not leave the forages because not everyone will use crops on capital stock. So this is the point the cost structure around cropping would tend to focus us on getting a sellable product, a finished animal and that's the predominant use of summer cropping in New Zealand is to actually finish animals on one average. So let's step back a bit and talk about the role of body condition scoring of sheep as a mechanism to understand priority flocks that could be put onto specialist feeds. Because although you can't justify an economic outcome of that autumn, for example, on putting on a specialist crop, maybe on the third grazing of summer rape, you might consider putting on your light low body condition ewes as an example.
Juddy Yeah, and I think it's one of the common problems. I think when we talk about feeding capital stock is that sometimes we actually don't know what condition they're in. And so you can imagine the power from a management point of view of being able to put your hand on their back, particularly if it's sheep or in terms of cattle, it could be weighing those capital stock, but making an assessment of what condition they're in because you're right, we shouldn't be treating this as just a whole flock or herd. The sensible thing would be to do if we've got a finite resource in terms of some of the summer feed that we should be offering to the animals that are in the lowest body condition. And so we're trying to get those animals up to weight in terms of improving the chance of breeding. So I think, I like that idea of being able to identify which are your priority animals to get into some of these systems to drive that.
Al And Beef and Lamb New Zealand have amazing resources in this place and you know, there's a lot of actually very good support in the New Zealand farming sector to get your head around this. But the influence is dramatic it's got the potential to move lambing percentages by 15 to 25% by getting this moment right, just understanding who is too light and what levers you can pull. In New Zealand and in summer dry environments. It comes at a cost to the business and the industry. But we do pull the trigger on grain feeding at that moment for that exact reason of changing the direction of nutritional profile. But if we can do it as a secondary process of lamb finishing in the middle of summer, but the late summer you're actually putting light ewes through the crop. The multiplier is much more dramatic.
Juddy And just to reiterate that it is six weeks that you can get right, it is the six weeks that adds so much to your bottom line from that point of view. So once we've got these things in lamb, if we're thinking about the wintering of these animals. So, again, I think you're right. I think you've touched on before, Allister, these animals probably come down the priority list. They are not the highest priority.
Al So very quickly, I'll ask a couple of questions though, you know, like if you're hogget mating, some of the big drivers are to get them to at something like a 45 kg body weight or above to take the ram and in nature weird things happen and we've seen quite light ewes like lambs even. But, as you know try to systemise it as a farm system to add value to more lambs in the final crop. Hogget, you know, keeping ewes for longer, hogget mating some of the few levers you can push or pull in the situation. So you know getting ewe lambs up to body weights by mid to late autumn is quite a big deal. And then so when we hit winter pregnant ewe lambs got a different priority to say well to an ewe and a twin bearing you or a triplet bearing ewe is who's got the priority at this moment?
Juddy I think if you were looking at the priority stock, I would still say those young animals have the highest priority and we don't. None of those animals, when I say they come down the priority list, none of those we want to drop in a big hole. But what I would be saying is we'd be looking after our hogget’s first and I'll be taking advantage of the technology around scanning for example.
Al Scanning plays a big role in this discussion because to be fair, an ewe carrying just one lamb has a whole different energy of demand through winter.
Juddy Absolutely. So we're looking at in lamb hogget’s, particularly those with twins and there might not be too many of those, but we do really need to look after those in terms of maybe the two days I'd be looking after those with twins.
Al That's the ewe that's either going to lamb for the first time, that's two years of age, or a hogget that's going to lamb.
Juddy Yep. And so, and then I'd be looking at the multiple bearing older ewes, mixed age ewes and they'd be the order that I'd be doing them. And, this is really once we've got through that mating period, it's really about daily intake here and making sure that we've got enough for the youngest sheep to continue development, but for those older animals to maintain body weight through that winter period.
Al And just to tease out and just supply our listeners with a broad, incredible generalisation of, you know, the need for the concept of scanning to understand multiples particularly and be able to separate and manage them differently. If we had 3000 ewes in the average New Zealand flock, for example, which is a pretty moderate size sheep flock with a fecundity and lambing percentage of anywhere between 165, right up to 180. We could be dealing with anywhere up to 3 to 400 sets of triplets inside that. Which is actually a really significant group of animals to see as being different. Because the energy demand from a group of ewe carrying triplets to again a ewe carrying a single is quite dramatic.
Juddy Is quite dramatic. And really one of them requires almost no effort. And in those mixed days, ewes with singles, you know, really can look after themselves right up to, you know, a young sheep having triplets, her energy demand is high.
Al And also, you don't want to overfeed it, so you actually want to be managed.
Juddy Very managed system there. So I think that's where the scanning becomes really critical because that allows you to make those management decisions that can make all this work. You know, I think if you've done a really good job at the mating period if you don't scan, I think you've lost an opportunity.
Al Yeah, absolutely. And looking at the feedstuffs for wintering in the New Zealand farm system, we run basically for the ewes across New Zealand we run pretty much two predominantly forms of wintering in the colder regions we do tend to take our capital ewe flock off on to crop. Because our pastures do not accumulate fast enough to actually get enough grass ahead at the time of lambing and just to put the flag up that actually what we're targeting is about a pasture cover of about 1200 kilograms of dry matter per hectare at lambing which you know might be about six or seven centimeters of height. And it takes a bit in some of our colder climates to actually get to that critical mass, which is an important mass for you to successfully lamb down on to and reach peak lactation within 14 days of when she lambs.
Juddy In some of our environments the cover that you leave when you come off in your autumn is about the same cover you go on to and so that's where their crops are really important, making sure that we can come off and they can be on crop knowing that you've got that cover on farm ready for that spring.
Al And then parallel to that is the slightly warmer country where in all likelihood ewes are going to be managed on existing pasture cover on a long rotation, really tight grazing, to move around and to lengthen the rotation to get that cover. And then another proportion of ewes will be carried on autumn sown cereal and ryegrass based pastures and crops. And they are sort of the three predominant systems you have your base pasture that's been set up in the autumn to create a long rotation in a slightly warmer environment where you stay on your normal traditional pasture and just rotate it at long rotation lengths. The second one would be deliberately sowing shorter term crop. For example, rape and grass is a very traditional East Coast winter crop sown in late summer and utilised at the start of winter. And with the target of having the Italian ryegrass or annual ryegrass regrow underneath the rape and then or using oats and Italian ryegrass or just Italian ryegrass as one of those feeds to break fence across through the winter. And then the last one would be setting up winter crops which are based from taking spring moisture from the previous year, sowing in late spring and early, very early summer are trying to capture a little bit more moisture through summer because often these crops are in cooler environments that have a little bit more summer moisture. And then stocking them on both either swedes or some of the shorter kales to get through winter and maintain whole farm pasture cover for lambing.
Juddy Yeah. And I think from an animal perspective the aims here is to maintain. This is a maintenance feeding and the strategy around here is this is not about, you know, excessive intakes and high growth rates, for example. This is about maintaining animals through that period and the number of lambs, particularly through that winter period, doesn't have a huge impact on the energy requirement of those animals. Probably a big effect is in terms, of environmental temperature. Those animals in very cold environments will need a little more than those that are in energy and more energy than those in warmer climates. You know, there's bit of shearing going on. So if we're shearing, we're going to be requiring a higher intake. So really that period is matching the quantity with the demands of the animal. And you know, animals in low body condition probably need a little more but it's so much less than what we were thinking about prior to mating. So it's really a period where we're taking stock, we are holding those animals but feed budgeting is important to make sure we get through because it's in the third trimester that we need to start ramping that feed up again. In terms of that's when the third trimester is about where two thirds of the growth of the fetus happens. And it's where we need to start putting energy into that.
Al So we've got a bit a history Glenn with the use of different species through that, you know lamb and set stocking phase. We've done quite a lot of work and have worked with farmers throughout New Zealand looking at lambing onto plantain, red clover, lucerne across the country depending on the time of year and the location. One of the species we've probably got the most experience with that late trimester timeframe with is the plantain and do you want to highlight some of the experiences we've had there, which shows you the subtle awareness that you need to understand some of the requirements of your feedstuffs at about that time?
Juddy Yes, it is really interesting so when you think about coming into that last trimester, and in that early stage of lactation, what you're actually after is this is probably where the animal has the highest energy demand and highest protein demand if you to be fair. And so this is where we are growing the fetus and then we get lactation and there is an enormous amount of energy that's required. And so if you thinking about those periods, what we're after from a forage point of view is one that's on hand.
Al Whether it meets those targets.
Juddy Meets those targets of, you know, 1200. And I think the other important thing is that we probably want that forage to be growing early enough so that we're not having to pull a whole lot of cover from autumn all the way through winter ready for lactation. So having something that is inherently cool season active and starts early from that perspective relative to your lambing date. I think the other really important part of this is knowing that there's a high energy demand for having a forage that is easily grazed. So can you get, you know, the three and a half, four kilograms, particularly maybe for a ewe down a throat a day of dry matter? Can you actually physically do that? And that where that 1200 cover, 1200 comes because at 1200 we take away much of the harvesting problems with ryegrass. So if we had a forage that was easily harvested and the other one that's really important I think is the retention time of that material in the animals rumen because if it's sitting there for a long time and the processing speeds quite low, then those animals aren't going to be able to eat as much as they could in a day.
Al Especially when they're carrying all those lambs as well.
Juddy Especially when rumen size is constrained by the number of lambs they've got and particularly in that late, late gestation. So that's where we had some relative success with the likes of Ecotain. And so we've got a plant here that's winter active or cool season active, quite active in that period around about lambing, big broadleaf, easily harvested because it's a dicotyledon and the way the plants constructed we're getting a far faster throughout through the rumen. We've got low rumen resilience times. We don't have as much rumination, for example, and some of our work suggests that maybe up to those ewes are able to consume up to a third more a day. And you can see how important that would be when you've got when you're an animal with high energy demand. So that's one example, Ecotain can be used for that. I've seen this being used with red clover as well. Maybe not quite as early, but certainly if you are lambing hoggets slightly lighter, then red clover is a really useful forage as well. Again, from a protein point of view, really good. It's also break down speed is high, so animals are consuming large amounts of that or have the ability to do that. I just want to give a bit of a warning, just going back to the plantain one, one of the problems specifically with plantain is that it has quite a high calcium content and at about two weeks prior to lambing is about where and we see that a really high demand for calcium and a ewe that is about to lamb. I suspect when she's starting to think about producing a lot of colostrum and the demand for calcium is quite high. One of the problems with wintering on plantain and then maybe getting two weeks out from lambing and going back out into ryegrass, is that the animal because it had so much calcium in its diet has not even started the process of mobilising skeletal calcium. And so when the demand comes on and you shift a feed to a ryegrass, for example, she is well away from being self-sufficient in terms of calcium and we run into a lot of hypercalcemia in terms of that.
Al And so this is a pretty important point because the key to this is this happens immediately. It happens within 24 hours. And it's a consequence of perceiving that these plantain paddocks are just pastures and you've rotated into it and you rotate out of it, but you're doing it at an uncomfortably critical time where this calcium, this high calcium loading has really collapsed our ability to actually mobilise our own. However, this is an important point to tease out. It's only if you shift off it. There is nothing inherently wrong with grazing it up to lambing. It's when you move off it that it becomes the problem.
Juddy Yeah, and so the question is often asked, well, how soon before or if I'm on it and I want to come off, how soon before lambing? And I would say, you know, with a high calcium diet, I'd like to think that if you were coming off, you would come off at least a month before the start of lambing.
Al Even longer from what I've seen.
Juddy And so it can't be just before lambing remember two weeks out is peak calcium load.
Al My attitude to this is that if you use it as a general pasture inside of a wintering program, you use it at the start of winter. You literally come into winter as one of your first rounds and then you're off it because the value is keeping a cover at the point of time and the other value as if it's a priority stock class and we do recommend gummy ewes, twin bearing hoggets, triplet bearing ewes. I personally would be recommending set stocking them early at an appropriate stocking rate and never taking them off.
Juddy And I think the other interesting point that we've got to make here is that we are talking about pastures with high contents of Ecotain, for example, in those.
Al Almost pure to be fair.
Juddy If we're talking about if it's a third or a species with clover in grass.
Al Up 10%, 15%, 20%.
Juddy This is not a problem because essentially those diets aren't necessarily that high in calcium. So we're really talking about the Ecotain dominant swards that we need to be careful of.
Al Plantain and clover, but because it's winter, it's mostly plantain.
Juddy Yeah. So I think it's the critical part about that in terms of the red clover, and as you know, we've been quite successful in terms of lambing down on that. One of the questions that often get is, so what about those lambs that have been lambed down onto red clover? If they don't see anything else apart from red clover, is there any chance that we may impair reproductive performance?
Al Future fertility
Juddy So I would say for me, this a risk profile we've done a couple of times where we've had ewes, lamb down on red clover and taken those ewe lambs through to mating weights on red clover and had quite successful matings. So I don't think there's an inherent problem there. Males, particularly if you are dealing with stud stock, right. There has been some reported literature that suggests that as we reach puberty, if we're having high concentrations of phytoestrogens, they can cause problems for males. So my thought here would be this is probably not where you've got to stud operation and these males are very important to you. This may be a risk that you don't want to take, but largely what we're saying, we think that risk is relatively low because and it's likely to be, you know, if the plant is growing well and we've got one of the varieties such as Relish which is low in phytoestrogens, that the risk is relatively low. But I think it's a risk it's just what your risk profile is. Stud animals I probably wouldn't take the risk even though it's low.
Al Yeah, when you look at the wintering on brassicas, you know, we've been wintering on swedes, rutabaga, another name for it, swede crops for a very, very long time, very successful in some of the southern parts of New Zealand. Iodine plays a big role in that because unless I'm mistaken, swedes are quite low on iodine and it does actually have a bit of an impact and has had a long history of understanding that iodine around the start of wintering has a really big impact on lambs and lamb survival post lambing.
Juddy So, the type of iodine here is really around the thyroid gland. So iodine is really important and the enzymes by which the thyroid communicates to the rest of the body. And thyroid is really important in terms for young lambs is an important in temperature regulation. So it's really interesting brassica crops in North Island could be suffering from this as well. It's just that environmental temperatures don't get to a point where those lambs have or need to get some really clear signals from the thyroid about increasing their core body temperature for example. So where we've got where were feeding brassicas we know that there's a set of plant compounds in brassicas, glucosinolates, which block iodine uptake. And that's where we're getting some of the problem. We get a essentially a subclinical goiter, which is an enlargement of the thyroiditis.
Al We've done a bit of work on this it's not exactly the most pleasant job on the planet to do but thyroid deficiency, unless I'm mistaken, it's the weight of the thyroid against the weight of the lamb.
Al So to define it. And I got blown away when I watched you do these measurements over the years at, you know, as a layman, you would never know a thyroid deficient or a lamb that had subclinical thyroid.
Juddy Yeah. So you're looking at the ratio of the combined thyroid rates to the body weight of the animal. And yes, we did quite a lot of work, particularly from feeding different crops, but also some lambs out of those colder regions. And looked at it in terms of diagnosing subclinical clinical iodine deficiency and yes, you wouldn't know.
Al Because I mean the horror stories and I have personally seen this when I was young enough we had where, you know, the thyroid of an individual couple of lambs would have been the size of a table tennis ball almost to a tennis ball in size and so that's clinical thyroid deficiency.
Juddy And so sometimes what you see is the only symptom that you've got at a flock level is a few more dead lambs. And so that can be brought on by the fact that you're deficient in iodine and that can be a symptom of the amount of brassica that you've got in your diet. So you can imagine if you've been through a summer where you've been offered a summer brassica crop and then you winter in a winter brassica crop, then you've been exposed to some of those antagonists for quite some time, and you may run into that. You know, some of the injectables are able to get past that. So it's not something that's insignificant but I would say it's something to be mindful of when you think about the length of time that you might be on a brassica.
Al So when we sort of coming to the end of the description, the farm system's been, you know, defined pretty heavily by the fact that we've got a stock class that is this really important time for the financial outcome of the property. It is predominantly around that mating phase, and we've described that as a plane of nutrition. There's that time of year, which is pretty much the last months of summer in the start of autumn or fall. And at times you can be quite limited on feed strategies around there. But we've discussed that the key is to keep a rising plane of quality, both energy and protein. We've discussed the role of parasitic internal parasites and watching for this are external feeds, toxins, micro toxins. They all play a role at this point of time and sort of point us towards feed systems that moderate this. I look at it and think to myself that at this time one and two year old perennial pastures are some of the best pastures we have on our farms. And they would fit into this mating phase very, very strongly. And this is this whole concept that when you plant new and young pasture for the first eight months or two years, they are not normal. They can be used to really leverage the whole farm. And you tend to find they can be used for finishing through their first seasons, but also this mating phase for young pasture. They are very logical places to put underweight or low body conditioned animals on to as your youngest and most vigorous pastures.
Juddy And you might argue, actually, from a farm systems point of view, if you are looking at what's the best thing you could do for autumn pasture in terms of trying to finish off a few more lambs on a declining schedule or knowing that you've got the whole of winter to do that for your winter lamb trade for example that by far the biggest priority is around those that capital stock because that's your lamb crop for next year. So I'd say once we get into the autumn phase, anything still left over never lose sight of the fact that this is your next year's lamb crop and you need to be doing everything you can from a nutritional point of view with your capital stock to get as many of those on the ground as you possibly can.
Al As I say, young pasture, one or two year old pasture makes great mating feed residual summer crops leftover leaf turnip. The Hunters of the world are rapes, Mainstar, Spitfire, that type of product that are on their second grazing, sometimes even their third being allocated to underweight ewes or hoggets, you know, the success of mating on brassica crop, for example, residual brassica crop is actually quite outstanding. You've always mentioned in your red clover stands or lucerne. Lucerne for me is a classic, I mean, you don't want the lucerne to be too old because black spot is one of the leaf diseases that elevates the phytoestrogen levels in lucerne, but as you pointed out, that's all relative to the landscape and your other choices and we're lucerne it's normally hot, dry and brown. And so your choices are very moderate, and I would be putting them on lucerne and getting body condition changes every day and then worry about the risk of phytoestrogen. And so, you know, those are the big drivers, we're sort of discussing setting up for winter, recognising that we've got probably three primary crops. One is your natural pastoral land, whether you can get out on a long rotation 60 to 80 days depending on exactly where you are and rotate around. We looked at specialist autumn sown feeds that may take on a class of stock for longer, probably focused on hoggets. So you keep growing your hogget on the way to lambing in the spring and then winter cropping and predominantly bulb crops. We didn't mention turnips but winter turnips and swedes would be a predominant sheep feed through the colder parts of New Zealand, always focusing on driving pasture covers so that when we put a high energy demanding ewe into a set stock phase to be lambing, she's got enough feed underneath her with enough momentum to get it to peak lactation as fast as possible.
Juddy Well I reckon that's a pretty good summary, Alister. I'm off to shift my hoggets so we might catch you next time.
Al Thanks, catch you then, bye.