Hello, everyone. Welcome and thank you very much for joining me in this webinar on interest management in dairy cattle. The main focus will be on the occurrence of heat stress and on practical measures to reduce the negative effects of heat stress on cows and on young stock.
Let's go ahead. First of all, the objectives of this webinar. First, to clarify the occurrence of heat stress.
Present to discuss sciences and health effects, and thirdly, present practical management measures. I will follow the next procedure in this webinar in 5 chapters, some background. The occurrence of heat stress and the presentation of some test devices.
Then thirdly, risk factors and effects in dairy cattle, and 4, management measures and 5 conclusions. Background. Between the years 2003 and 2020, we have seen various heat waves in Europe and all over the world, I might say.
Sometimes it's accompanied by a high mortality rate in humans. For example, in France in 2010-2012, there were 20,000 people supposed to be dead caused by heat stress. With regard to the prevalence problems in cattle.
We don't have any national reports. We have case studies. I think there is still insufficient knowledge among dairy farmers about food stress and their negative effects.
Heat waves will occur more often in the coming years, given the climate changes. That's why I think the dairy farmers must be much more educated about prevention and control of the negative effects of heat stress, and the question might be raised. What about veterinarians?
The occurrence of heat stress. First of all, let's speak about the thermal neutral zone. Between 5 and plus 20 degrees in adult kettle.
Thermo neutral means in this range, cows do not need to address their reserves of energy. They can get rid of any heat as easy as you and me. Comfort zone is much more restrained, that's between + 5 and + 15 °C Celsius, where kettle, so to say, feel quite at at ease and they feel best.
Another definition is the upper critical temperature. Meaning, in this case, around 23 °C, meaning that above this upper critical temperature, the effects of heat stress start occurring. Note, and that's very important because there are not many people knowing these figures.
For calves, the thermal neutral zone is quite different from adult kettle. For example, neonatal calves between 10 and 25 degrees. Young calves up to 3 weeks of age, between 6 and 25, and calves.
More than 4 weeks of age, between 0 and 22 degrees. So calves should be addressed in a different way with regards to alarm situations than adult cattle. Finally, affecting cows may show a carryover effect, especially in the field of reproduction.
There are several devices for testing heat stress risks. Most known is the temperature humidity index THI. Sometimes used our heat index or comfort index, two names for the same principle.
There are smartphone applications usually based on THI. Another one. WBGT metre.
Is addressed a little bit later on, and other devices. In total, there are hundreds of devices and test procedures developed since the 1950s by the military in the US. For example, The temperature humidity index is based on this formula.
I will not go into too much detail, based on basically two types of temperature, the dry belt temperature and the wetb temperature. One is addressing the ambient temperature of the air, and the other one is addressing the relative humidity of the air. In the 60s, 70s.
Threshold values were defined. For example, If the THI is less than 64, it's OK. Above 64, there is already a sign of mild heat stress.
Above 72, moderate heat stress, about 77, severe heat stress, and 84 and more death risk. I've noticed on this slides that in the year 60s, in the 70s. The milk yield level of the average cow was quite less than these days, and that made the people decide to put the threshold value at 68 and not at 72.
Graphically, It may show like this, which the category is warm, very warm, hot, and very hot and extremely hot, and you see by the A and the B levels that at the same temperature. Say here 33 °C. At A the cow will have very warm, while at PB with a 70 degrees.
70% of relative humidity, the cow is already in the very hot area. So it's not a linear relationship. The smartphone apps, for example, on thermal aid.
Developed by the Missouri State University. This app is also dealing with THI. There is a heat index, which more or less.
It's T H I. I think more or less positive there is not a formula. And these smartphone apps provide heat stress indications for a given location, so you may enter the, the place where you are.
There are 3 classes, green is OK, orange is alarm, and red, there is a very high risk of negative interest effects. They predict for 3 consecutive days and provide the basic management measures to take. However, The clusters of green, orange, and red are rather rough.
The basic measurement measures. Are very general, and we have to bear in mind that management measures to counteract the heat stress effects should be tailor-made on each inn farm. But still, it gives a rough estimate of heat stress risks.
The last one The BBGT WBGT metre, wet bill globe temperature. You may choose between degrees Celsius and degree Fahrenheit. It's a handheld device, not more than 30 metres, centimetres long.
And Contrary to THI, it takes also into ground wind speed, shadow, and direct sun radiation effects. The WBGT provides the most reliable results on site. Costs are reasonable, I think.
And this might be a reason to have the WBGT metre as a standard equipment in the veterinary car. Other devices. Well known in the US are Castrel drops.
It's Is based on the heat index. Another one is based on TAHI and the so-called Tracker Pro is based on THI and WBGT. Prices are.
Maybe less affordable. One remark, because sometimes in the field we hear people using infrared imaging like the fleur pistol. Infrared imaging is not right for detecting heat stress.
It only gives the temperature of the skin and not the core temperature of the body, which is basically the key for detecting heat stress in the cow. There are quite some factors affecting the risk of heat rash for a cow. For example, the breed.
Parity. Young animals also in lactation, are more sensitive to heat stress than the older ones. The milk production level.
Lactation stage, feed intake. Russian composition, for example, protein level in the Russian will yield much more body heat than carbohydrates and much more than fat percentage. Pits of quality.
Pouring conditions, or whether there are shade areas, yes or no, whether it's sufficient drinking water and sufficient access, housing conditions. The presence of appropriate ventilation and the presence of cooling systems. Cow behaviour itself, aggressive cows.
Generate much more heat than the cow ones, and finally body condition score. The fat cows will have more problems than the thin ones. So we have to take into account this type of risk factors when dealing with management advice for the farmer regarding heat stress.
These pages are probably well known to many of you looking for a cool place in the water. And if it ends up like the picture below, we have truly a severe heat stress with all the problems coming with it. The sans A negative effect in Chaos.
First of all, a decrease in milk yield and decrease in feed intake. Between brackets, some percentages or information from studies on this issue. Cos spent more time idle standing.
They are less active. These are the first signs which should Put the farmer into alarm phase one, so to say. Other physiological phenomena are, for example, a decrease in serum collecting, vitamin C, dioxine, bicarbonate, potassium.
Very important is an increasing negative energy balance. Which leads to a reduced immune response, meritis, retained placenta, ketosis, ruin as ketosis, mastitis cases. All these incidences increase and not in the least, reproductive failure.
Or reproductive failure. We can see on the heat stress conditions all the negative effects of negative energy balance. Disturbed follicle development, disturbed steroid blood levels.
Far less Easter's expression. Decrease conception, more early am and death. And a medium dysfunction and involves a reduced sintogenesis.
Effects on milk composition. Often forgotten. Protein will decrease in milk.
Fat usually decreases. But some studies are contradictory. Anyhow, the lipid profile in the milk changes which affect milk quality.
It affect milk quality not only in nutritional value, but also in taste quality and in the milk for calves, for example. There are not only phenomena of decreasing, short chain fatty acids. Due to heat stress, but also the lipid profile itself is Confusing because for example, I have to look it up because it's a complex name.
Lysophosphateidylcholine, LPC decreases, which again affects largely the meal quality. Pregnancy rates As soon as the THI value. Increase above the threshold value of 68, we will see a pregnancy going down.
And above the 74 THI value, there is a great heat and animals suffer. Let's take a look to changes in dry metric intake, milk yield, and water consumption. At the left side, the ambient temperature, the first line.
Shows a dry me intake of 18.2 kilogramme 27, water intake 81 litres. In the lowest line with an ambient temperature of 40 degrees, the dry metal intake has dropped from 18 to 10.
The meal yield from 27 to 12 and water intake is largely increased with a mean of 135 litres per day, which is not fully, but nearly twice as much as in normal conditions. So we have to take care of these issues when addressing the management measures later on. A specific issue for calves, which are born to heat residents, they have lower IgG levels in the blood and a lower cell-mediated immune response.
The mortality in those cars are much higher than normal prior to weaning. On average, they are born at a body weight 5 to 10 kilogrammes less. They show a decreased feed intake.
And a winning The body weight on average is 15 kilogrammes less, and the first calving age is at an age older than 24 months. These animals at the first lactation produced less milk. The conclusion is that the programming of the calves byed them has gone wrong.
See the other webinar on kind of rearing issues. Russian associated risk factors, point of particular attention. Crude protein, Laing content.
Ruin degradable protein. Concentrates fat contents, fat sources, and the use, yes or no, of yeast and fungi. These are the topics to be addressed when adapting the ration and the conditions of each dress.
The effects of pitch stress on calf performance is based here on the study. Including pairwise grouped cows under the same husbandry system, the same feet, same parameter levels as start. Some parameters on the left side.
The respiration rate. 35 versus 82. Body weight going down.
Dry metric intake was going down. Milk yield going down, milk protein going down, milk fat, and this was the study. In 2020.
Where milk fat was not very much decreasing or at least variable. Last but not least, stromatic cell count level. In the thermo neutral group, 286,000 per millilitre and in the heat stress group, 312,000.
So there are quite some. Important changes in heat stress cos as compared to the neutral ones. Practical management measures.
I have to stress beforehand that what I present here under practical management measures. Are Examples of suggestions. Which again should be adapted to the individual farm.
Generally The farmers should increase the number of meals per day in smaller portions and giving the largest parts during nighttime. We should reduce the effects of negative energy balance. To increase feed intake and provide a more nutrient-dense diet and a less concentrated high diet.
You have to check the vitamin and mineral status in the ration rather frequently, potassium, sodium, magnesium, carbonate. You should adjust the ration. And supply yeast or faecal culture if truly all other measures do not function.
With regard to drinking water. The farmers should provide up to 9 metres large drinking crafts per 100 cows. That is in the barn, but also in the pasture.
Although in the pasture, the drinking places should be kept with shade nets to avoid direct sun. If possible, The temperature for drinking water should be around 1015 degrees. There's another reason to put a shade net in pasture, and the, the water traps have to be cleaned daily to avoid all kinds of contaminations.
For example, on sulphates, chlorate and microbes, and that's why water quality should be checked frequently. With regards to the bond clan. If the feedback is in direct sun.
Shades should be created, let's say 5 square metres per cow. And they have to install the. The shade nets at 4 metres high above the floor.
You might, the farmer might consider installing tunnel ventilations if the barn design allows for it. Tal ventilation provides an equally distributed ventilation throughout the whole bar without any dead spots. It's not feasible on all farms.
In that case, maybe the farmer should install and use fences and sprinklers. What about mister? I come to that some slides later on.
Develop and adopt adequate cooling cycles also will be addressed later on. With regards to reproduction and other management issues. In heat periods, do not use natural surface bills.
Maybe a planned artificial insemination or synchronisation programme may do the job. Anyway, prostaglandins are not very useful because they do not yield any positive effects in those heat periods. Farmers should provide cooling for dry cows, at least the transition cows.
3 weeks. 4 weeks before starving. Create shade in the pastures.
Reduce the walking distance from bound to pasture, vice versa. You should reduce the time cows spend outside. Maybe the creation of milking groups is a good point to avoid waiting time before the milking power.
Milking groups where the cow density is not too high. And cops The IgG contents in cholostrum could be measured by cholestertrometer, and it counts themselves by refractometer. These issues have been addressed also in the webinar on cf health management.
In posturing. Shade areas, 10 square metres per cow, for example, using trees like in the left lower corner. But then not all trees are adequate.
You might use a mobile shading device. This shading device is certainly resistant. It's wind resistant up to 75 kilometres per hour.
And can be folded. Sorry. When it is folded.
It can be put behind a tractor or a quad to place to another position. Even in pastures, fences and sprinklers could be installed. Only if cows are used to those devices.
In the upper right corner, you'll see another example of how one farmer is cooling down cows in pasture with big I would say cannons of water being Positions Imposor always provide fresh cool drinking water with an easy access for everyone under a shade net. About shading. Shading reduces the heat load by up to 30%, so it's worthwhile to provide shading.
Water should not be far away from the shade area. There are different shade materials on the market. You have to inform yourself what would be feasible financially and what would be optimal with regard to their effect.
The cheapest, of course, are trees with or without shade nets between them. Below the 4 pictures show two types of trees which are quite capable to provide optimal shade. It has to do with their foliage, dense foliage, while in the right pictures.
These trees will not provide very much shade. Wooden slats, sometimes used, are not effective. Shade nets are much more effective.
And with regards to the materials, aluminium, sm sheets, or white painted material are not too poor to use for shading. Shedding area Two graphs The shade area surface, which is available for each cow is determined for use by the cows. The smaller the surface, the less cows are using it, like is shown by these different groups.
24 versus 9.6. The sufficient shading areas reduced the respiration rate of cows, especially in the afternoon, which is shown by the 3rd group with the squares.
So shade area is truly contributing to a lowering of the heat stress load. Water has a much greater cooling effect than fans. In hot and humid climates, you will need sprinklers and fences, fences with a speed 5 to 7 kilometres per hour, and a shade to enhance evaporation of heat from the skin as much as possible.
However, in hot and dry climates, you need fans at the speed of up to 15 kilometres per hour and shade to get rid of body heat. In dry climates, you don't need sprinklers exactly because the ambient area is dry. General management issues.
Avoid kettle handling in hot periods of the day. Let's say between 2 and 6 p.m.
You better do it between 6 and 8 a.m. Likewise, avoid cattle loading or unloading during these hot periods of the day.
Again, do it between 6 and 8 a.m. Or at night.
The same is valued for veterinary treatments. Cows to be treated, for example, to be trained for artificial insemination, veterinarian intervention should not stay longer than 30 minutes in the stall. They are already excited to be put in the stall.
The intervention will excite a more causing an accumulation of Body heat due to heat stress conditions. Maybe the farmer could provide the processing area with sprinklers and fences, 1 for 5 cars. In pasture, the farmer could eliminate windbreakers like bushes.
And not in the least the farmers should control flies, biting flies. Some examples. Left upper left corner.
A bo With lets In the wall and the ventilation through the flats is strongly reduced. In this barn there will be a strong accumulation of heat with a lack of ventilation. The lower left picture.
Shows openings in the roofing, which are far too small to allow proper ventilation. An alternative is in the right upper corner. Where parts of the world can be opened.
But it should be operated properly, meaning I don't leave it open for day and night, depending on wind, depending on the sun direction. There is always a risk of direct sun radiation, which causes an increase in body heat. So an inventory on a farm should be made.
What is present. What should be done to improve ventilation and to get rid of the barn heat. Other examples.
Shade roofing is provided for these cattle, so they can hide from direct sun radiation. The idea is nice, especially on the height of, say, 4 metres. But the roofing should be larger.
At each site. The upper right picture. The installation of fences.
Know the number and the inclination. This is a part where cows exercise. And that's the reason that France are put.
All along the roofing at about 1 to 1.5 metre distance. The windbreaking curtains in the side walls may very well assist in avoiding direct sun radiation in the bi, for example, at 4 p.m.
Or 6 p.m. About cooling equipment.
I will speak about fences, sprinklers, and shades. And they asked the question, what about using misters or foggers, you know, the, the fence, which provides at the same time a cloud of fine droplets of cool water. They are not feasible to cooling down camps.
Only to cool the barn air, which makes the cows more comfortable. So Mr. Sfoggers are not compatible for cooling the cars.
Friends. And again, these are suggestions. Equipment and installation should be tailor-made for each individual farm.
Friends of a diameter 76 to 90 centimetres. One at each 9 to 12 metre bar lengths. Or 1 cent per 10 cows or 13 square metres.
To choose depending on one design. Fence should be placed at 2.5 metres high at each 2 metre lengths.
Inclination 30 degrees towards the floor. An airspeed between 7 and 15 kilometres an hour. So it should start operating from 22 °C onwards.
And last, not the least, the large ceiling fans of 120 centimetres diameter or even more, covering up quite some surface. You know, up to 8 metres of diameter. Again, Some examples of their installation in the lower left picture.
The fans are inclined to watch the floor installed above the cubicles to provide the cows with a comfortable air when they are laying down. At the Right. Pick your own.
The lower level, a ceiling trend. In a spacious mind. Sometimes mine are not as spacious as this one.
So we have to adapt the installation to the individual farm. The air speed under a fan like here on the left, upper left corner with a diameter of 70 to 90 centimetres. Should have a speed of 7 to 15 kilometres per hour.
Easily Testable By using simple devices. Sprinklers or sprayers. For example, those who provide 18 litres of water flow per hour at a low pressure.
The nozzles yield 1.25 litres per minute per square metre. This already is sufficient.
Like friends. Sprinklers start operating from 22 °C onwards. Together with the fence or prior to the fence.
Remember, water has a greater cooling effect than fences, but fans enhance the evaporation of heat from the skin. The duration of the operation is largely between 5 and 15 minutes. Remember that sprinklers or sprayers are providing large droplets which easily attain the skin.
While misters provide very small tiny droplets which remain on the surface of the hair. Never direct the water flow to cow's head, nor into the feed bank, nor into the cubicles for obvious reasons of hygiene and mastitis problems. Some examples.
Some of these installations are, so to say, homemade, do it yourself, as long as the criteria are met. Behind the feed bank on the upper left picture. Behind the feet wreck.
In the upper right picture. In the lower left picture. Sprays are not feasible.
But trends are. Here, the fans are positions. In effect behind the feeding on the cow's body.
At the middle lower picture, the combination. Barn and mistres and ventilation. Throughout the whole bond.
Mors to cool the barn air should be operated in a very professional way in order to avoid all kinds of problems in their rendering the cubicle bedding. Too humid To render the cows. Aggressive because sometimes they don't like it at all.
Cooling cycles. A cooling cycle refers to the duration of spraying and fanning and the frequency of repetition. For example, 5 minutes of spraying, followed by 10 minutes of fanning, to be repeated each 30 minutes.
That's one example. Another example is a minimum of 2 to 3 cooling cycles per day, one just before noon, the second before the evening milking, and maybe a 3rd during a hot night. Note that there are many variations of cooling cycles possible, again, depending on the farm and the herd.
Where to put them? For example, behind the feet track parallel to cubicles, or in the waiting area. In the milking parlour, but without sprayers and one exits.
Again, the farm design. Should dictate what is feasible and what is acceptable. Veterinarians still may play a large role in that respect.
The alternative is to create a shower area in the bar. Walk through the type activated by the cows themselves. Spraying and fanning is done here at the same time.
So here cows make their own choice whether they want to have a cooling or not. This is maybe the least expensive option. Which cattle are to be cooled?
Of course, the fresh cows because they are the high yielders. First, lactation heifers should not be forgotten. They're highly susceptible.
Tory cows, especially the close up ones, the transition cows. Then other milking cows. And don't forget the young stock.
Be aware of the Different thermal neutrality levels. With regard to cooling the young stuck. What happens does he trust a youngsters?
From 24 °C onwards, body heat production increases. Water is lost from respiration. When night temperatures are low.
The heat stress effects are less. That means that the farmer has to check repeatedly what's going on with regard to temperatures. Young stocks too.
Show an increased respiration rate, a drop in feed intake, a feed efficiency. There will be a daily weight gain loss. The manure will be too firm.
Women development, especially in the younger ones, will be poor and meaning performance will be poor as well with regards to gross, rate and body weight. At a level of 42 °C or more body temperature, there is a risk of mortality. Moreover, Youngst Under heat stress conditions already may be born from dams under heat stress, you'll have a poor Prognosis for future life expectancy.
So everything should be done to have the neonatal cows born from Iris cows. As good as possible, but also after the replace of milk period, it should be taken care of in a very particular way to reduce the negative aspects of a reduced life expectancy. Specific actions for Youngst.
There are some examples here. If calves are in hutches. The farmer should at least install an exercise pen in front of it.
The hutches should be positioned in the direction of the predominant wind. The third one, not very known, I guess, is to install a 20 or 30 centimetre high concrete block under the backside of a hutch, because this will increase the ventilation inside the hutch. So lower the temperature.
Between individual hutches, the farmer should leave 1.25 metre distance and between rows of hedges, 3 metre distance, all that to facilitate the wind or the air movements between hutches. If there are truly hot areas where cops are housed outside, for example, Farmer could install a fence and run them during daytime at a speed of 7 to 15 kilometres per hour.
The calves will tell themselves whether they appreciate it or not, if they are outside. In the fan air, they like it, otherwise, they stay inside the hutches. If cows are housed in a barn, open the windbreak curtains and operate fence, the same principle as with the hutches.
Ms, I've put a question mark because it's not always certain that misters will do a good job. Again, depending on the design of the car barn. Always ample cool fresh water from day 2 onwards, available throughout the day.
Buckets should be cleaned daily. A clean, dry, thick straw layer, daily. Replace it Grain by the handful repeatedly on the day.
That b too should be cleaned every day, and if painting is seen in Jost stock, you might, as a farmer, increase milky replace for energy to 7% or even 11% depending on the outside conditions. Flight control measures should be implemented because flights increase body heat generate production. An example, windbreak curtains installed at 4 metres above floor, with large spacing to let the hot air out and a free wind movement.
If there is no wind, but still hot. Fences can be installed and operated. You don't need to have a big farm with many animals to do this, because even with 20 cows or 50, you can do the same installation.
Problems I encountered in the field when cooling, just to give an idea what to look for in case of problems. The diameter of water tubes is too small. In that case, the water pressure is lost.
There are too few water tubes present or too many 90-degree angles are present in the system. Again, Loss of water pressure. The nozzles or sprinkler sprayers are too small, meaning that large droplets are not produced.
If the droplets are very fine, too much wind will disperse the water droplets. Inside, the water recollection might be too difficult. You have to take care of that as well when designing a cooling installation on the farm.
Friends may be poorly located on directed. For example, a poor inclination or maybe poorly maintained. Here too, the the veterinary may play a substantial role.
Farmers are tended to put the air speed of the fence far too high. A fan is not Put on the farm to cool the cow or the calf. It's there to enhance hot air evaporation.
So 7 to 15 degrees, 7 to 15 kilometres per hour is sufficient. The electrical installation of the farm is not sufficiently powerful, causing breakdowns of the electricity. This issue should be addressed before even talking about which installation, what and how.
Too many cooling cycles are applied by the farmer. Causing poor hygiene, wet bedding material in the cubicles, and so on, increasing the risk of metastitis. Conclusion is that one farmer needs an expert technician for a tailor-made plan for the individual farm.
Conclusions. There exists a wide variation between breeds in susceptibility. Maybe there is room for genetic selection.
I know the Brazilian breeds is, for example, . A resistant breed. Heat stress effects on reproduction have a multifactorial background.
Hence, a multi-arm domain approach is needed. Vets should be aware of the fact that hormone injections like PGFT alpha do not work in heat stress periods. During each stress period, the veterinarian must continue his routine heart monitoring.
Routine monitoring. Is addressed in another webinar in this congress. There is no single blueprint approach for managing heat stress.
Each individual farmers have a tailor-made system for cooling cows and calves. The expert technical support is warranted before installing any device. And if the farmers think that the investment is rather high, losing a lot of milk or even cows to heat stress is more costly.
So be prepared. Thank you for your attention and good luck. Stay safe.
Stay healthy.