[Music] good afternoon everybody so today I'm gonna speak about and a little bit I know about the question of extending the laying cycle in commercial hands so I came up with this snappy title at the time because I I thought we were starting to see an image of what the 100 week old 500 egg hen looked like and hopefully some kind of a unified message comes true at the end of that all great I have my I have my slides okay so extending the production cycle to 100 weeks makes a lot of sense and it's now a goal of breeding companies and nutritionists and the industry overall it makes a lot of sense because we can extend the utility of each bird so from a resource point of view and it's clever however we know that there are challenges associated with this there are challenges associated even at keeping hens to 75 weeks of age and we don't even have to look at the literature the the user manuals tell us to expect a decline a gradual decline in productivity and in percentage lay and also in egg quality as that relates to external and internal egg quality and also possibly egg safety there's welfare concerns associated with extending the laid to 100 weeks so we know that the longer the hen stays in lay various different metabolic issues arise for example in caged birds fatty liver liver hemorrhagic syndrome and also osteoporosis occurs later on in life in preparing for this talk I guess and some of you may be aware there's actually very little research looking at extending the lay beyond 70 weeks of age most of our tends to kind of finish up at that stage unless we're looking at white layers which is not the subject of today's talk and so in terms of what we have to go on there's very little looking at this sort of advanced all hands the applied research that's available is understandably mostly focused on nutrition and trying to alleviate some of the deficits that we see in older hands so looking at are trying to optimize macro mineral nutrition there's some interesting paper is also trying to optimize micro mineral nutrition for example providing a source of antioxidants which which makes sense and there's also more recently the application of functional ingredients and for anyone who is sort of keen to hear about that today I'm sorry to disappoint you I'm not going to dwell on us really much more beyond that and the focus of today is really to kind of give you some information about what we've been researching in the last couple of years at the University of Sydney where I used to work and I'm still associated and it's really just trying to understand the variation in these production traits that were concerned about trying to define them between individuals within the flock in early lay a point of Lai and then just following those birds on into lately and in the case of today looking at them up to a hundred weeks of age and trying to this link together what the individual bird looks like at point of Lai and what that bird then looks like I am at 100 weeks of age so the pathway to 500 eggs if we think about the product then you know in a bit of a fan of the laying hand I knew the area but I think they have this incredible output race they've been selected to have a very high rate of egg production egg mass per year they were decent feed efficiency and we assume that they are genetically very homogeneous as a group and but then myriads factors are involved after that when you deal with that product such as early life feeding regime disease status disease challenges a range of things which will impact the actual hand that lands on the farm to commence her laying career so our mindset is that a point of lay we have a uniform group of animals we expect that they will charge through the bulk of the laying cycle steadily and efficiently converting feed into eggs and by and large that that is the case however as we'll sort of see hopefully throughout this talk that's not the way it works for all hands and some of them deviate from the path of being truly efficient what we want to avoid is and in the post seventy five week periods hens which are have very low persistency have osteoporosis disease issues and poor quality eggs so really the focus today is to kind of dive into that a bit more so we know that like us all the age at time has an effect on the hand this incredible output that she undergoes in the first year of life and has consequences for percentage lay egg mass and small increase in mortality so we know that from the manuals that's what we expect there's an increased risk of metabolic and infectious disease depending on the system that's on that's being used so for example as I said earlier fatty liver hemorrhagic syndrome is can be present in caged systems and infectious disease might be an issue in free-range systems it may not necessarily be due to age it could be due to more time in the system so the longer the longer we live the sooner we die type of analogy there at Julie Roberts at the University of New England also showed and this is also well known that aged hens have a consequence for egg quality as well so she showed that in older flocks you get a reduction in translucency score although not in cuticle coverage a reduction in breaking strength and a reduction in how unit and this is one of the things which is limited extending the lay past 70 weeks in commercial practice I really like this paper it's nearly 20 years old now from a group Beru at all in in Japan and they show the changing immune status of the hand as she ages so they did this in leghorns and the basics showed this inability to effectively transfer immunoglobulins to the yolk as and as the hens aged and rather they accumulate that immunoglobulin in the plasma and this paper very eloquently then reversed that by administering Easter dye a lot of hormones that were responsible for orchestrating this process so to sum up this slide really what we're saying is that you see these these changes occur and generally they're they have negative consequences for productivity so when I became interested in this subject we started asking different questions about flocks of hands and traditionally as nutritionists I guess we feed to the average of the group so we measure traits but we measure them on groups of animals and we assume that there is a bell curve of distribution and if our enzyme or our calcium tweak is going to shift that bell curve left or right but we don't really know much about what animals are being affected and that's something that I'm really curious about so we set out on this project which was funded by Australian eggs and just asking some very simple questions so in addition to knowing about what the body weight spread in a flock is what's the variation for voluntary feed intake in an ad-lib system and same questions for egg mass feed efficiency also when we understand the efficiency or we've measured the trait of an animal in early life how long does that persist for is it a plastic trait or is a quite stable does it does it persist for further into the delay period and we know from other animals that and there is a bit of plasticity in these traits and they can become efficient or inefficient and change these parameters question I'm interested in as a nutritionist is what are the consequences of being inefficient for the hands so if a hen is inherently inefficient what's the toll that that place is if an e on that animal as it goes through its life if an animal is very efficient or very inefficient or to make that bit more simpler if they have a high-value feed intake or a low voluntary feed intake is there any link with egg quality and again one of these things that we can't really measure we can't linked the egg to the hen and so we were missing a vital piece and in the puzzle there and trying to understand what the underlying biology is that that that causes these effects is something I'm also very interested in and I guess the moneymaker question is can we manipulate these traits and improve the system so we do know that this variation in body weight this is a really nice image from a Highline manual I think it just shows the sort of expected spread and body weight that we should see in a young flock of bullets during the rearing phase and generally this bell curve distribution is what we we come to expect and so for example for the the poet's that we use in this study that I'm going to talk about today at 21 weeks of age we see this sort of similar bell curve distribution of the average is 1,800 grams but there's lighter and heavier animals so I guess so we were interested to find out about was you know what happens to those hands which are a little bit heavier at the point of lay what do they look like apart from being heavier and vice-versa for these very lighter animals what what happens to them as they go to the laying cycle this is a really interesting work that was carried out by Julie Roberts and Greg Parkinson and Riley horn in Australia and they looked us the they sampled caged farms and looked at the average flock weighs I think all for the same stunt for the same breed but what they found was that in comparison with the breed standard which is the canoes the black line on the graph generally hens tended to be heavier in point at point of lay and they got heavier as time went by so that they to quote the report they were on average 200 to 250 grams heavier than the breed standard so from that really interesting and it was the it was the I guess seed material for the project that we commenced with Australian egg and Sydney University we were lucky enough to have these individually caged hens something like I wouldn't get away with in the UK and we came up with a highly sophisticated automated weighing system and we actually had a student who was assigned to sampling those bottles contents those bottles that was their only job but the point of it was that we were trying to capture consumption rate per day and build up a profile of these hens over time daily basis and obviously on the longer period so this is anneka complicated slide I'll just touch on it briefly we essentially started with this group of 450 hens they entered the cages at around 18 weeks of age and started laying in the weeks after that we were interested in the entire flock and the plan was to dip in and out during the delaying cycle and take same measurements again on the same birds if they were still in the system but to try and kind of separate them out a little bit we also rank them based on a range of parameters one of being feed intake egg mass percentage lay and feed efficiency so for the case of this in this talk today I'm going to present that the data ranked as and the basis of feed efficiency so what we did was take the first third and fifth quintiles so the most efficient animals the animals which were sitting around the center of the bell curve and the most inefficient animals and basically retrospectively assigned them to a feed efficiency ranking and then looked at what what they were doing at 35 to 40 weeks 45 weeks of age at seventy-five weeks and then we even managed to do some work at 90 weeks of age so the the first period was a characterization period allow us to assign them to ranks the 35 to 40 weeks was when we focused in more detail on those birds we'd ranked on the basis of feed efficiency so a bit more sampling and involved analysis the idea being that we could understand when we based on the rankings that we'd assigned in early life did they maintain those rankings later on in mid lay and in lately and so we had a follow-up at 70 to 75 weeks of age just to see how persistently where and if one group had started to decline quicker than the other and then finally a look at 795 weeks of age as well so essentially what we were doing was just zipping in at different times and seeing if in our flock of hands did individuals and the group decline in performance as we would expect so I'm just going to show the data for the the entire group initially and I guess as you would expect you see a slight decline in production performance over time but I would suggest not quite as bad as we would expect and this probably reflects the fact that they are an environmental model yeah environmental conditions i experimental conditions with a very high level of control I should have said that these birds were all kept under the exact same circumstances so they were fed a wheat soybean meal formulated Dyess formulated to commercial expectations so it had enzymes phytase as it expect and I guess what we saw was that probably not a huge tail off in production performance but certainly an increase in variability as the hand as the hen staged so you're getting an increase in the rate of lay at 75 weeks of age but not really much of a difference in for example feed intake or feed conversion ratio so we found this really interesting I guess one of the questions we had was about the variability in those traits and why some hens were able to maintain persistency and other important measures later on in to lay egg quality also declined as we would expect so we got a reduction in harness an increase in shell thickness but overall a reduction in eggshell breaking strength so again more that's what you'd expect but interestingly in the 75 week cohort looking at them as a group you're getting this really interesting range of hall units so some are pretty lousy but other are maintaining the high high units at that very advanced stage of lay and similarly as it expects overall low egg breaking strength but some of the birds having quite having quite high levels of egg breaking strengthened so there's a lot of detail here but I just want to sort of draw your attention to kind of what what the ranking the hands on the basis of feeder fish she showed us we have a broken open to daily feed intake egg ways egg mass and percentage lay and so the variation in feed efficiency that we saw was really mostly derived from an increase in voluntary feed intake so possibly because of the genetics the percentage lays is really high across the flock egg weight is pretty much it has very little variation in it because the hands are very uniform but the capacity for variation and feed and feed intake is quite significantly different between the efficient and the inefficient hens so I guess if we look at the time periods we can kind of see that hens that had low voluntary feed intake in early life tended to have low Vons if he didn't take throughout life and vice-versa inefficient hens consume more early in life and that carried on to later on this graph possibly shows that a little bit better so if you look first at the continuous line this is the s your ranking of the hands at these three different time periods I'll get to the 95 weeks a little bit later on so these were artificially ranked or they were very blocked at the start of the study and we can follow the progress of this these groups of hands as they go to the cycle and what you can kind of see is that feed efficiency is separate at the starix and a remain separate that the whole way to the delay cycle it doesn't cross over so it's more or less that you like fixed or very stable from a very early age and as far as we know at that point of layer earlier body weights as you'd expect is also different and we didn't control for this but it's the inefficient hens were heavier and tended to get heavier over time vice first of the efficient hens were lighter and also gradually increased in weight over time so this MFE group is really the average of the flock and this just sort of shows you the variation in line with Greg Parkinson and Julie Roberts research we found that our hens tended to be in excess of the breed standard more or less the whole way true through the through the study and it worsened over time so having kind of identified these very distinct groups we focused on the to do a subsample on the efficient hands and the inefficient and so at 45 weeks of age we we took a sample and necropsy does bt idea being to look at sort of gross organ morphometry and some biochemistry and just really I guess gain an understanding of what an efficient hand looked like so probably as you'd expect the inefficient hand so that's the the bars on there the columns on the right hand side were heavier animals they had an increase in abdominal fat pad so rather than producing more eggs or having a more efficient process the excess feed that they were consuming some of that was ending up in the in the body in the in the carcass so an increase in abdominal fat pad also had quite a significant increase in liver waste when we look at the composition of that liver weighs proportionately more crude fast and less moisture and lipid peroxidation so measuring T bars for that liver and also more systemically at the muscle we see that these inefficient hands have higher levels of lipid peroxidation so i guess that kind of that question all right that results makes me question if you know they are eating more feeds but are they actually getting enough antioxidants to to to maintain liver function and true enough we got an increase in fatty liver score as well i'll show you a picture in the next slide of that so essentially these inefficient hands these heavier animals now bear in mind only about 200 to 250 grams heavier than the breed standard suggests a point of lay had a greater incidence of fatty liver score so this is images from the 45 week period and you can see this sort of spectrum of pathology and if we think about extending the lay to 100 weeks if in caged animals you start to see this kind of pathology at this early stage it begs questions about the persistence ease of these animals which have obvious pathology in midlane now the egg did not escape consequences either so when we we looked at the eggs associated with these efficiency rankings we note we saw that generally the efficient hens have higher albumin heights more albumin waist and overall a higher high unis so the reverse is true for the inefficient hens where they had a greater proportion of the egg was composed of yolk so you're seeing this kind of shift and the eggs are essentially the same but you're seeing this shift in the components and obviously or I guess it seems to me that the albumin would be cheaper and require less energy to synthesize than the energy-rich yolk when we examine the yolks of those inefficient hens we tended to find a parallel with the lipid peroxidation so these inefficient hens produced yolk with higher lipid peroxidation and when we did a fatty acid profile more saturated fast and less unsaturated fatty acids so a very different animal and a very different egg you can see the consequences are for the high unis so the efficient hens have to have the best high unit so bear in mind these are animals which consume less would have a similar rate of lay in a similar egg mass and that sort of tends to worsen during storage compositionally the albumin has less amino acids in the inefficient hen so ignore all that data the main message is that these inefficient hens in addition to having producing eggs with less albumin the actual concentration of amino acids is also less so again thinking about from a nutritional point of view is there some way is there some reason why these hands are consuming you know more feed to try and satisfy the requirements for egg synthesis heard a really interesting question as the hens aged then is you know if there's lower protein in these eggs is there a greater risk of contamination if the albumin and these various different proteins are very important anti spoilage mechanism so that brings us to a midway point I guess we have to bring this back towards extending lay in some way but the point of it really was that we found these very strong differences in hens from a very early age and what we generally observed was those changes stayed with the hens for life so if they were life in early lay our point of lay they would end up probably being lice at 75 weeks of age the differences are mostly driven by an increase in voluntary feed intake so I guess in systems where feed intake is controlled this may be a much more muted effect I'm not sure it's very hard to kind of you have to recognize the limitations of a singly caged experimental model and be very conservative about drawing conclusions from that the presence of fight liver hemorrhaging syndrome syndrome of 45 weeks I think is a concern because I think it could be something which may not necessarily manifest as more increased mortality or morbidity but most certainly affect productivity and an egg quality so what about the next stage if we go on from 75 weeks up to 100 weeks has anybody got their money on the heavier hands making a spectacular comeback later on in lay so we were really interested in this question and I guess we've got some preliminary data which I was still sort of crunching on the plane on the way over here so surprisingly the heavier hands the ones which we'd ranked as being lifetime inefficient had a height slightly higher rate of lay at 95 weeks but generally after that they tend to fall down so for example for example her unit is still markedly lower egg breaking strength at this stage is now worse in the inefficient group compared to the efficient group whereas we hadn't actually seen that true outlay and you have to take this final measurement with a grain of salt because it's not really a very much unified overview of the skeletal strenght and structure of the hens but we did get this reduction in leg break straight leg breaking strength of the femur bone in lately so that sort of is interesting I think collectively to wonder what's happening in these heavier animals or inefficient animals as they reach the advanced stages of lay ok I think I'm doing ok for time just kind of summed this so I guess for me to try and understand how we bring hens to a later stage of lay it's really about understanding what the components of the flock are and I think there's lots experimentally to be done in that area to try and understand which hens are sort of underperforming and how do we deal with them from a management from a disease and from a nutritional point of view and what you know can we also perhaps improve the efficient animals today also have capacity for improvement if you understand what what their characteristics are certainly setting off on a higher higher waste and I say that when I mean going beyond the target suggested by the breed manual in this case the eyes of Browns seems to have negative consequences it may be something that's an important strategy in different systems but from a cage point of view it doesn't seem to be beneficial and so our ongoing work is really simple where we were trying to now go back and see can we intervene an early life by just doing some simple feed restriction both transient and throughout life to try and put some of these inefficient animals back on track so I guess I probably have raised more questions and I've answered and extending the lay psycho but hopefully it'll provide some thoughts on the subject thank you very much [Applause]