[Music] hello this is uh dr brian sloan from addiso hello and welcome to today's webinar dialing down heat stress mechanically and nutritionally it continues the other sales smart science series that we started last year this series is designed to advance our understanding of the role of the essential nutrient methane as the series continues we'll learn more and more about how methane impacts not only production but health and reproduction you'll find other webinars in the series at feedchannel dot online heat stress is a perennial problem and just as hot humid weather wears us out it takes a toll on daily cows and their performance as a company we are continually being asked by nutritionists should they change in any way how they dial in amino acid balancing and the provision of other essential nutrients during the times of the year when dairy cars are subject to heat stress research is beginning to provide new and greater insights into the impact of certain nutrients to mitigate the effects of heat stress on dairy cow's production and well-being so with this new knowledge fortunately heat stress can be dialed down as we say both mechanically and nutritionally and that's why we're delighted to present today's timely discussion by two well-known university experts dr bob collier is the department head in the college of agriculture and life science at the university of idaho he has an extensive background in this area and thoroughly knows the mechanics of mitigating heat stress bob is an outstanding choice to walk us through how to dial down his stress via mechanical cooling his expertise spans environmental and lactation physiology endocrinology and molecular biology he has authored or co-authored numerous peer-reviewed journal articles chapters reviews and abstracts along with several industry articles and holds several u.s patents he has received he has received numerous awards and honors from industry associations and groups publications and universities dr phil cardozo is an associate professor in the department of animal science at the university of illinois phil is also extremely well known and listened to phil conducts research and provides very well received outreach programs in dairy nutrition and reproduction his experience with dairy farms both in brazil where he grew up as well as in the us give him a different perspective and set of management skills phil also has a veterinary perspective he too is well published phil will guide us in how to dial down heat stress via nutrition so just a few housekeeping egg housekeeping notes before we get started each of these experts will speak for 20 minutes then we will move into a 15 minute q a session along the way please be sure to type in your questions for bob and phil by getting your questions in during their presentations you can ensure that they are in queue and ready for timely answers from our experts today's presentations are being recorded we'll let you know when they are shared they'll be posted on the website www.channel.online and we'll even go one step further we'll share all the questions and the respective answers on the same website feedchannel.com watch for an email announcing their availability and now without further ado let's welcome dr bob collier collier from the university of idaho bob over to you thank you for that introduction brian thank you for that introduction and uh good morning or good afternoon everyone uh the electronic picture behind me is palouse in the spring and it is starting to look nice around here in moscow idaho but we know that warm weather is coming and with warm weather weather we get heat stress on dairy cows so today we're going to be talking about dialing down heat stress mechanically so i'm going to pull up my slides here and go to our slideshow stress uh is an external event resulting in strain on a biological system that strain is measurable typically on the dairy form as a decrease in feed intake or milk production but if we could measure some of the physiological responses we could see increases in respiration rate altered behavior such as more time standing up we know that if it's a true stress it'll change maintenance requirements so um that increases the the cost of maintaining the animal and eventually it'll lead to increased adrenal axis activation and secretion of cortisol and then subsequently reduced immune function now this is a pattern showing the seasonal changes in milk and milk yield and milk protein yield over 12 months here in the us and you notice that if we look at the blue milk protein line it comes down in the lowest point is july august which is when we have the highest temperatures but the milk yield curve actually doesn't bottom out until september october the reason for this is the fact that the effect of of heat on milk protein yield is direct and so as soon as it starts cooling off we have a milk protein starting to come back up but in the case of milky yield we have two things going on first the direct effect of heat stress on milk yield and then we also have the carryover effect of milk yield during late gestation on subsequent milk yield of the cow after cavity and so this seasonal pattern in milk yield is due to two things the carryover effect from heat stress during pregnancy and the direct effect of heat stress while the low protein yield is primarily the direct effect of heat stress on milk protein synthesis and we have looked at uh what kind of temperatures it takes to reduce milk production recently by a rosemary virgo zimmerman um using high producing dairy cows because the original thi uh chart use cows that average about 70 pounds a day so these guys are producing over 100 pounds of milk a day and or near it and we see that they began declining in milk yield at a thi is 68 which is about four points lower the original thi was 72 but as i said earlier these are higher producing cows and therefore more sensitive to heat stress and so you can see we have different levels of stress from the stress threshold the mild to moderate moderate to severe and then severe stress and all of these come with increasing reductions in milk yield and reproductive performance and reduced growth rate of calves but we also have the um impact on death rate which a lot of people don't appreciate but um it doesn't take much of a change in thi to increase death rate in holstein cows this is a data set from italy from bernabeu and bernabucci and co-workers over a million hosting records and we see that in the thi minimum of 70 the lowest point if it reaches 70 or if the highest thi reaches 80 you start to see massive inc or increases in death rate now if you look at a thi of 80 would correspond [Music] if you look over here uh be about 90 degrees with a 50 relative humidity that would equate to increases in death rate or if the minimum temperature thi of only 70 which is a temperature of 76 degrees fahrenheit with a 30 relative humidity so death rate starts increasing relatively early on when heat stress begins to increase and the the cows that are dying are not the healthy cows most of these cows that are going to die during heat stress are going to be found in the sick part because stresses are additive and if you've got a cow that's already dealing with mastitis or metritis or metabolic disease and you put heat stress on top of that those are the cows that are likely to succumb to their combined stressors but i often go into these sick barns or hospital barns and very few of them have any cooling and i've never understood why because uh these cows the sick cows are the ones that need cooling the most because they're the most stressed and the most likely to die if you have an increase in heat stress on the dairy so remember to take a look at your sick barn and see if there are ways you can reduce heat stress on animals that are located in that facility and i think you'll get a payback uh when you invest in some cooling there this just shows uh it's a it's a table from uh smith and co-workers and it shows different levels of milk production loss per day from 2 to 12 pounds a day lost milk for different periods of time during lactation 90 days 120 or 150 and you can see that that these losses even small amounts of milk loss two pounds or a kilo of milk a day can over 150 days an 18 milk cost you 54. per cow which if you've got a couple thousand dairy cows that's that's a lot of milk and of course at 10 pounds a day you're talking really large amounts of loss in income so cooling does have good returns on investment and the question is how to go about that cooling what are some of the mechanical things we can do and before we do that we need to talk about how cows lose heat and uh on this uh schematic here on uh the y-axis we got heat lost or produced and over here on the uh x-axis is the ambient temperature around the animal or the heat load as you can see the cooler it is uh the more heat that is lost from the animal and therefore the more heat needs to be produced and so um as if you look here at this lower and upper critical temperature in between those two is called the thermal neutral zone where the cow is not expending ener energy to heat or cool itself but below this uh cows must increase their heat production and or energy in in other words maintenance costs has increased to keep up with this heat loss and of course when you get into heat stress above the upper critical temperature animals have to expend energy to dissipate heat you also notice that the upper critical temperature is always below the body temperature now the reason for that is once the ambient temperature reaches body temperature you cannot lose heat by conduction convection and radiation which are three of the four routes of heat loss and so actually when ambient conditions rise above 101 or the body temperature of the cow then that animal is going to start storing heat and the only way for that animal to lose heat at this point is evaporative heat loss we all know the cows are not good sweaters so this places the cows in a precarious situation where they're producing tremendous amounts of heat and uh their ability to lose that heat is greatly diminished or even reduced to zero excuse me and so um we have to find ways uh to alter the environment around the cow to make sure that she can still access these three major routes conduction convection and radiation in order to lose heat or we have to try to evaporate water for the cow by wetting it and evaporating water directly from its skin surface temperature and so we'll look at some of these from a practical standpoint and another thing that goes along with this uh just point out that surface temperature which is the skin temperature of an animal is a very good indicator of what kind of uh state it's going to be because from a from a heat loss standpoint if the surface temperature of the animal is above 35 degrees centigrade then that animal cannot lose heat by conduction convection or radiation um the reason for that is that the the surface has to be cooler than the core of the cow for heat to flow down to get out of the cow and so if the surface warms up at or above the actual body temperature it's going to start storing heat so here we can see that when the surface temperature or skin temperature of the cow stays below 35 we can keep that cow body temperature constant between around 38.5 once it goes above it then it's going to start storing heat and you see heat stress cows over here on the right whether body temperature rises from 38.5 all the way up to 41.5 and of course the skin temperature in these cows is around 40 degrees centigrade so if you have a uh infrared gun you can just walk around your uh animals and you don't have to touch them you can do this from 10 feet away take the surface temperature of the animal if if they're above 35 degrees centigrade skin temperature they're going to need some additional cooling in order to maintain their body temperature so strategies for reducing heat stress in dairy cows we need to reduce heat gain by providing shade reducing the air temperature or reduce the skin temperature of the animal by evaporative cooling wetting the cow and using wind speed to increase evaporation we can reduce the air temperature by evaporating water directly into the air and then of course providing shade prevents solar radiation from heating the skin surface we can also help maximize heat loss by increasing wind speed around the animal increase evaporation of water from skin and decreasing air temperature which maintains those thermal gradients for the cow and then we can finally reduce environmental variability by maintaining a constant environment in the barn using a cross-ventilated approach cross-ventilated barns have a tremendous ability to minimize environmental variability and this maximizes output productive output of the animal and then cross-ventilated dairy barns you see a huge reduction in that seasonal pattern in milky so the first requirement is always shade it's the cheapest and it's the first thing you have to do because remember the air temperature does not measure the solar radiation coming from sunlight so if it's 90 degrees in the shade which is the air temperature then if there are animals standing in the set it's going to be more like 120 or 130 degrees which is is going to be very stressful so cows always seek shade and they'll move to follow the shadow as you see here in this picture of this shade which is oriented north south now if there was feed and water or fans or other cooling machinery in this structure the cows would still follow the shadow and so if you want to maximize cow behavior you want to make sure that you uh orient your shade so that you've maintained the cows where you want them to eat and drink and to stay cool because they'll walk away from cooling systems if that exposes them to sunlight so always remember when you're building uh shade facilities if you want the sun under the shade to dry out the floor that's fine use a north south orientation but if you intend for the animals to stay under there um you'd better build it east-west or you're going to be spending money on curtains to keep the shadow under the shade structure and the cows there as well now if you if you look at the data and this is from rodriguez and co-workers in 2006 on whether animals prefer uh shade alone or misters alone you might think that a mister might cool animals more than a shade but you can see here the the blue uh dots and line or cows that are under shade only and they are considerably cooler during the hot part of the day than those cows that have no shade but are being sprinkled to cool their skin surface so if you ever wonder what's the best investment it's shade structures by by far so we have a very a variety of cooling systems in this example we've got a reverse chimney cooler it's called a coral it pulls air down through the shea of this cooling tunnel and there are fans in here that increase wind speed and also nozzles to spray water there's 12 different combinations of wind speed and water supply and so these are very effective at cooling animals that are fixed they don't rotate and the animals need to stay under them and so you'll notice that we have curtains here because this sage structure is oriented north south which come down to keep the cows under the shade if those curtains didn't come down these cows would still follow the shadow but since they're under these coolers you'll notice they're mostly lying down and uh that's a good sign because heat stress cows usually are standing and that's because they have to stand the pant so another quick observation you can make in addition to skin temperature is see how many cows of yours in your facility are standing and if there are a lot of cows or majority of them are standing you can count respiration rates and if the respiration rates of those cows are above 60 breaths per minute which is half maximal they're stressed they're they're being heat stressed this is a another approach and it's an oscillating system that also follows the shade and so you can see these systems are blowing air and these are not effects they're rotating oscillating back and forth and when the shadow moves they have solar detectors on the cooling system so they'll rotate and blow the air out where the cows are now um so this this has advantages that you have the ability to cool the cows where the shadow is located if it moves and second the other thing about it is because it's rotating it doesn't stay fixed over a single animal for the entire cooling cycle and so in extremely hot uh weather this approach of an oscillating system doesn't cool quite as much as a fixed system where the cows under the cooling stream constantly and this just shows this was an air at southern arizona you can see that the oscillating fan and the kraut cool system shown in yellow and red and you notice that the coral cool system is slightly better than the oscillating system until uh the monsoon begins and here you see the moisture coming up when we have our monsoon rains now we have high temperature and high humidity and uh the coralco system loses its advantage so there's no difference during hot humid weather between the two systems and obviously because it's now human as well milk yield also declines more during this period um another approach is using conductive cooling and an original approach is uh just cooling ponds which were are found in florida and some southern states um the disadvantage is that you have contamination of the water so you can't use a moving water source that's going to be going uh outside of the dairy it's got to be fixed in the water contained on the dairy but it's a very effective way of cooling and as you'll notice uh mainly cools the bottom one-third of the animal about 20 percent of the animal gets cooled by this approach but it's a fairly effective way to move heat out of the animal um if you know we've done research on cooling pads for cows to lie on which would be very similar and they do increase heat loss but there are not any commercial commercially available systems now or as of yet that have been shown to be cost effective and and finally i mentioned that maximum environmental cooling is through uh use of cross-ventilated barns here you can show the the uh exhaust here and then the intake water is pulled through these pads that have water coming down across the pad to evaporate so you effectively cool the air inside of these facilities and then during the winter it reduces heat stress so they they've been very effectively used in texas panhandle and the upper midwest to protect against both heat and cold stress and because they reduce that environmental variation they have very little seasonal pattern in production in the animals of higher milk yield during across the year and as you'll notice these are very large structures so big capital investments and it really depends on the milk price and and whether the number of animals you can get into a facility whether you can get cash flow the cost of doing this but certainly it has been demonstrated to be cost effective in a variety of locations including florida so um just looking at this overall we want to protect animals with shade first that's a least cost approach next we want to increase wind spree with fans and if we need to drop the air temperature we can blow water into that airstream to reduce the air temperature increase convection or we can cool the animal directly with water and then evaporate the water off the animal shade gets rid of that direct solar radiation there may be some infrared heat that comes down on the animal from the shade metal structure but this can be effectively reduced with insulation and finally there's an opportunity to use conductive cooling of bedding material to improve heat loss of animals to the bedding material and studies have shown that sand is a very effective uh bedding material for this use and driving air not so much because driving air holds water and water holds heat and therefore it's more difficult to cool using dried manure than it is sand bedding so we want to reduce heat load with shades increase heat loss by increasing wind speed lower skin temperature by wetting cows directly and evaporating the moisture with fans lower ambient temperature by evaporating water sprayed into a fan and then increase increased conductive heat loss through cooled water beds if available and these have all been shown to be effective and the effectiveness really depends on the location and the environmental conditions the animals are facing thank you very much and i'll be happy to uh answer questions thanks bob for that excellent presentation and we uh certainly appreciate the opportunity to have you with us today you gave us many great take-home messages and i know that you're waiting uh till after the next presentation to help answer uh some some some questions just want to remind the audience that please stop posting your questions and so that we can make sure we have uh some good questions to ask ask both speakers after the next pre er the next presentation so next up is dr phil cardozo from the university of illinois who will share insights and research to help guide us in mitigating heat strength through nutrition phil the floor is yours hi everyone i would like to start by thanking addisio for inviting me to be part of the smart science series webinar i feel very honored to be here and it's a pleasure for me to talk about this topic uh that it's some strategies to nutrition strategies to alleviate heat stress of all those nutrients out there if i had to focus a little bit and throughout the literature we can find some of these nutrients associated with heat of abatement we can find a pretty good amount of literature on how they would impact or how they would help with heat abatement right all those nutrients but today i would like to focus on minerals and protein as well that we have done some research that i would like to share with you here today right like i said that evaporation if you ever wonder why our sweat is salty uh there is something related to eliminating some of those minerals through sweat or evaporation especially co2 through cows what can lead to also some reduced rumen ph and potential for ruminositosis and there is some research out there and that's what i show you here the rumination in minutes per cows and you can see the high yielding cows as they start experiencing a higher thi what happens is that rumination drops dramatically right so there is an impact of the environment on rumination or at least here measured by minutes of rumination per day and that can lead to another source of problems like for example the acid-base balancing cows right and if you look into the nrc right our recommendations for the this minerals in 89 and then updated in 2001 most likely we're going to get a new one in 2021 let's see how it goes but we always had here in illinois uh our recommendation and would say hey you know what during the summer we've seen we've experienced that increasing magnesium sodium potassium on those diets have added some benefits and based in what so that goes back to evaporation and some of those minerals that are being lost through the summer through heat stress uh but also through some kind of a older research that we can look here if we look into this response surface graphs on dry matter intake sodium and potassium specifically here right so we can see that in the winter as we add more potassium or we add more sodium there is a limit so or in other words there is a pick where you have maximum dry matter intake for those minerals so if i add too much sodium at some point cows are going to stop eating and the same thing would be with potassium however when they did the same aspect of that research the same response surface but now they did that in the summer what they realized that is that as they increase potassium that intake never stopped increasing right that was not the same with sodium sodium so is too good to control and not feed too much otherwise you're going to have reduction in dry matter intake you still have a peak to that point 4.30 however potassium there isn't this indication of hey feeding more potassium in the summer may be beneficial for intake and then of course you can relate that to milk yield and everything else right and cow's health and maybe we are going to if we look into potassium sodium they are all positively charged ions and comes back to that decade idea that it's very popular in pre-doing pre-partum during the negative d-cad right but what we want to talk now it's about lactating cows and them being positive is that any effect of adding more positive or the cat ions in that diet like potassium for example uh would that be beneficial it seems to maximize feed intake at all that concentration between 250 and 400 when they put the data together uh improve milky and dry matter intake of those cows and it could be useful in heat stress conditions right uh because of that increase in those minerals and then when i pick some of those graphs and i plot here for you you can see that dry matter intake meat healed milk fat even though linear and right there is like an optimal range where we should be right so i think increasing those minerals during the summer during a heat stress moment uh i think it's important and i think it's it co-harborates with this meta-analysis showing hey we may not be feeding enough uh cations or a positive decath to those cows specific especially in the summer but this would be worth this data for the whole time right summer or uh winter so that cow in heat stress there is that fire but there is also that fire that comes from her right and there's a very nice review i really suggest you guys to go ahead and read it from bear bradford in 2015 where he's talking about this fire the flame that is inside the cow and actually he talks about some of those responsibles for the flame to being heat stress and also oxidative stress right through this uh reactive oxygen species or ross right uh and through heat shock proteins through heat straps right so he focused a lot on the inflammation and actually there is data uh research showing that yeah heat stress increases the amount of those uh reactive oxygen species ross and i'm showing you here some of them this peroxide superoxide or hydrogen peroxide i think are the most common ones when we talk about it and also similar to oxidative stress because of some of the genes that are expressed during heat stress are very similar to the ones when we have oxidative stress right so there's a comparison there but how that look inside the tissue of the cow so you have ferritin there is responsible for restoring iron right very important uh and we know that during heat stress that ferritin now starts releasing some of that iron in a form that we call now transition mineral ions and i'm going to refer here to tmi so you have the increase of this tmi that now you have ferrous in steropharic there are also other minerals that are encompassed to this tmi right this transition mirror ions but they are also then gonna create some of those uh peroxides and also they can damage the dna of the cells inside the liver so the hepatocytes right uh and what happens what are the mechanisms that the cow has to prevent that one of the things is two main enzymes that is the antioxidant so remember you have the ross in one part of the scale in the previous slide and then you have the antioxidants so that's where we need to bring the balance right so glutathione peroxidase right and again that's where i bring the point of nutrition and i bring selenium is being extremely important on this antioxidant system here is that selenium is going to be part of this glutathione peroxidase enzyme and this enzyme is the one that is going to be able to first deal with this tmi this minerals and excrete them in a chelated form but also it's going to act directly to hydrogen peroxidase or in the case of the oxides that's going to be more the styrofoam oxidase dismutase that also depends on some trace minerals or sod for short they are going to be able to chelate or to oxidize this transform to water and then alleviate the cows or the impact of heat shells in the cow however when you have a elevate or a continuous heat stress then what you're gonna have is too much of those compounds and you're to have a lack of those components or those and antioxidants to deal with the cow so imagine if cows are deficient or they don't have a good source of selenium or trace minerals what's going to happen is that that enzyme now is going to be deficient and that is going to be an impact in the liver and that impact was measured throughout different uh the research trials and there's dna damage heat shock proteins but there is some cell death that is happening especially at the level of the liver right what would that could that mean in response from the cow well this very interesting research by gal and others in 2017 right what they saw is that uh when they have cows during a period without heat stress right this is the protein yields that the cows are produces was pretty normal protein yield coming out of them and then whenever they induce those causing heat stress the protein yields drop drop dramatically and the other group of cows that they call the par fat thermonutrial what they did was they fed the cows the same amount that was reduced from the intake of the heat stress calcium the heat stress costs dropped intake they dropped they offered in uh uh dry matter for the cows in the par fat group that's what's par fat to the heat strascow so we take out the intake confounding from that uh question on the impact of heat stress so they didn't drop as much right so meaning there is something that is not being as efficient in the heat stress cows on how to partition those nutrients they realized that nun nuclear nitrogen was higher on those cows so again alluding to some inefficient in nitrogen utilization that could be leading to lower protein yields right milk drop as well and when they did the analysis in blood or plasma again bun correlated pretty well with what happened in the mun mucurian nitrogen right but they showed something a tendency for glucose to be lower in the heat stress cows that means that the cows are preferring to use glucose then nifa for example when cows reduce the intake on the perfect group nifa goes up meaning these cows are a little bit starving however during heat stress this doesn't happen right they prefer to use glucose than to use nifa and something very related to protein yield now they show that total amino acids in plasma was reduced in calcium heat stress right remember they ate the same thing as the parfait but something was happening that they didn't have enough total amino acids circulating in the blood is that showed elsewhere well here what i want to show you now going from what that research showed right with the decrease in protein yield and i want to share with you from the last six or seven years last six years the protein yield in the book tank of our farm here at the university of illinois and as you can see that's a lean a line that is going up luckily right we get paid by protein yield for example so it's good for us we're making more money but you can see it's not a straight line and you have some deep some valleys and you have some peaks there right and you're right that's summer right so the summer especially in our old facilities when you have a farm that isn't from the 30s or 40s we have a limited amount of resources on how to uh work with heat abatement so we do see a reduction of those new protein whenever we have december but interesting enough uh one of the things that we've been doing since 2015 roughly is to start formulating for amino acids so remain protected methionine room and protected lysine right uh well i don't see any difference well we also collect information from the farms on our route so there are 30 farms around us that the same truck is collecting so they give me the data as well and you can see that they also have the impact of summer however you can see now that especially after we started to formulate four amino acids this blue line start to detach from the orange line that means we are getting more protein in the book tank than those of other farms and where compared to all the farms that are sending to the same factory prairie farms then you can see that very similar to our route but it's still below our number so again from the perspective we start seeing that well we start feeding for amino acids our book tank our protein from our cows nuclear protein is not suffering as much as the other ones we do have problems in the summer but even though we seem we seem to have a better results than other farms could that that be amino acid formulation well that's something that we want to explore there right here is uh russo pate my former phd student did an awesome job in this paper again i'm gonna highlight some of the outcomes of this experiment but all these papers that i'm talking about i'm glad to share uh with you guys so this is the the paper so we have this baseline for nine days and then you have this phase trial or where we're collecting some of those samples and we collect a bunch of data to make sure the cows are in heat strass or try to decide which level and then we are collecting a lot of samples that i'm gonna share with you some here right but one thing that we wanted to do is to talk about the difference right so show how different was phase one to phase two so we did a pair analysis so how does that mean well we get for example an average for what the cal did on that first phase and then we compare how it was different when we did the heat stress or the parfait thermal neutral right so for example if on average the cow was producing 30 kilos of milk on that first phase and then she produced 30 25 and 20 those were the values so the value was minus five zero or minus ten uh okay so that to highlight the difference i'm not so much worried about uh the absolute number in this case right so just want to share with you uh the diet that was uh the ingredients the chemical analysis of that diet it came out at 15 protein nothing very special pretty common here in our area in the midwest very corn silage based diet and here more specifics on the amino acid nutrition some of the numbers we can talk more about it well what we can see here is that we had cedars with buttons that could measure uh the temperature of the cow through the vagina you can see yes cows in heat stress they had increased vaginal temperature and also increased rectal temperature so there was a difference off core temperature of those cows saying to us that yeah your method worked do you induce heat stress uh the other thing is the respiration rate like i showed in that first video you can see another video here yes the respiration rate went up and heart rate went up as well with the environmental treatments right a dry matter intake they drop pretty similarly even though uh you can catch statistically but if you see numbers that's uh minimal that was the same thing that others found in the past and for us here when there was a different was that we saw this different by environment where milk yield uh was higher for the cows in the heat stress than it was or the difference was lower so we're talking here about two kilos of milk perhaps and then there are some uh discussions that we do on this and how different we did comparison to other trials uh milk protein that's where we start seeing some very interesting results uh as expected in heat stress cows reduce uh the milk percentage and cows under the rumen protected methane reduce it less right so saying that hey if you feed that amino acid more uh saying that if you feed that most limiting amino acid in this case methionine you may maintain that um protein yield and also then the same thing happened with casein right so part of that milk protein 80 roughly 78 to 82 percent is made of casein and that's actually what's going to originate cheese right so when we see cheese yield cows that received protect and defining they would yield more cheese i don't have it specifically which casing it is but total casing that's what we were able to measure here when looking to the milk fat we saw that rumen protect and methyl increase the amount of fat in milk under heat stress compared to control and when we analyze what type of fatty acids was there there was no difference between room protection and thinning and control but between par fat and heat stress you can see that cows under heat stress they have a decrease in the amount of the novo versus the par fat again talking about the utilization of field from nephi versus glucose like i've mentioned before and when we look into the mammary gland uh we got the biopsies and through immunostate chemistry we are able to see tunnel cells and key y 67 that are pretty much their value lies they are dying or they're velyze in that memory gland they are proliferating and we can do a relationship or a ratio between them right and what we can see is that when we see the apoptosis apoptotic cells you have this relationship where in the summer it seems like control had more of those cells and when we do the ratio the same story more cells dying than cells proliferating saying that perhaps methionine as an essential amino acid had the capacity to protect or induce some of those cells not to die not to go under apoptosis and perhaps to have more secretory cells what would be my take home message here i think there is no magic pill uh as the nutrient that is gonna uh avoid heat stress or prevent heat stress in dairy cows i think the ones that we talked today especially increasing the decade selenium through glutathione peroxidase methane have been proven to improve the cows ability to maintain homeostasis or recover right i do think that heat stress abatement mechanically can be achieved in a more efficient way but we should never disconsider all the nutritional aspects as well with that i'd like to say thank you again for making me part of this the webinar [Music] series you