Hi, folks. Good to see you. Alex, hello to you all.
Thanks for joining me at this webinar on heat press in horses in general and in sport horses in particular. In this webinar, I will address the occurrence of heat stress, the different tools to determine the severity of heat stress, each with their advantages and, more important, their disadvantages and the signs and diagnosis. The topics that I will address I first of all, the background and occurrence of heat stress.
Tools for assessing the interest, severity, impact factors and consequences for horses, signs and diagnosis. And as an annex, I will address a short note on electrolytes. Get rid of its surplus of body heat.
By convection. It's sweat, evaporation, and respiration. Since 2003, the periods of heat are recurrent every year.
Tropical regions experience great heat every year. These hot periods lead to increased mortality in humans. The question, however, is, what about sport horses?
With regard to the horse, there are several factors. Impacting the heat accumulation in the horse, for example, solar radiation. But also ground thermal radiation.
The soil temperature may be very high from 50 °C up to 30 °C or in Fahrenheit from 1 to 2 to 158. All those factors. Can disturb the balance between getting rid of heat accumulated in the body and what the environmental conditions will do to the horse.
As a reminder Body heat production is basically Focused on body core temperature. Body core temperature is impacted by missile temperature, of course, during the performance or intensive training. It's rectal temperature.
38 + or minus.5 degrees Celsius or 99.5 to 101.3 °F.
Body heat originates from biological maintenance processes. Metabolic heat caused by digestion. Level of training and performance.
In general, and in normal conditions, body heat is eliminated by sweating, 75%, about respiration, about 50%. Convection and some minor factors, 10%. In an energy balance equation, there are several factors impacting on that heat accumulation.
Radiation, convection, heat loss by fluid ingestion. Heat loss by respiration, heat loss through the skin, evaporation, and of course, the external workload, such as the performance and the metabolic rate. The latter factor, metabolic rate is new amidst all those factors because there is hardly done any work regarding metabolic rate in horses or even in the rider.
The thermal neutral zone of horses is between 5 and 23 °C. The comfort zone of a horse is between 10 and 20 °C. Mhm.
We define an upper critical temperature, UCT of about 23 °C or 73.4 °F. What is thermal neutral?
That's the temperature range in which the horse has no problem at all to keep its core body temperature at normal values and has no problem to get rid of the body heat. Above the UCT, the horse is physiologically not able to get rid of body heat easily, so there is a problem there. How can we assess the heat stress severity?
There are about 150 different tests going around since ages. I have put on this slide the 3 main indexes. Comfort index or R index.
Which comprises the air temperature and humidity, which leads to a figure. However, air temperature and air humidity are non-compatible units. It's like comparing apples and peaches.
There are several factors neglected. So this heat index or comfort index is not reliable. The temperature and humidity index.
It is often used in animal production, but again, also in this index, factors are neglected. Advantage is that it provides a, a graph which is easy to read for people. The 3rd 1 is the redb globe temperature WBGT index, which will be addressed a little bit further down.
Heat index. Or conflict index. In this graph, there are two options.
A. And B. At a temperature level of 32 °C.
And about 10% of your humidity. The horses may be warm, but there is no problem. Commend However, if air humidity increases, going to the right.
To 50% humidity or even 80% air humidity, then the horse is entering the hut. Sector and even at the right side, the very hot sector. There we have a severe, utmost severe heat stress.
Seems nice to use this kind of index because it's rather easy to read. However, wind speed. Sun radiation shadow effects are not accounted for.
The temperature and humidity index. Does not take into account these factors neither. Classification Mild heat stress, moderate heat stress, severe heat stress, and risk of death.
Causes several alarm. The arm area one indicates that you have to be careful or already. Without taking too many.
Control measures. But at 2, there is truly an indication to get things done with the horse to cool down. The WBGT index is also based on air temperature and relative humidity, but it takes also into account wind speed, solar radiation, cloud cover, and sun angle.
It's most accurate. The error level is between 0.31 °C and 0.61 °C, or in Fahrenheit, it would be between around the 32 °F.
A choice, it can be expressed in degrees Celsius or in degrees Fahrenheit. At this slide on the left side, we found the individual parameters for the WBGT index in different colours, relative humidity, shade temperature. Wind speeds And solar radiation.
And then already from this graph, you can see there's a whole mixture of values of individual parameters, which at the end, at the right side, provides the WGT index. As you can notice, the impact of shade temperature, wind speed, and solar radiation is bigger than the impact of temperature and humidity alone, which is very important as a corrective factor. The WBGT index is not new.
It was developed in the 50s for the US Army because there was severe heat exhaustion among soldiers in World War 12. Nowadays, WBGT index is a common tool for underground miners. Industrial workers and also high-levels supporters.
For sport horses, it was adapted by David Marlin for every use at great international competitions. Like the Olympics or the World Equestrian Games, but this too is lacking the metabolic rate as an impact factor. The WBGT is available as a handheld instrument.
It's about 10 inches, 25 centimetres long. And it accuracy has been evaluated. Quite accurate.
The price is affordable. And I think it should be a must for veterinarians, horse owners, riders, and officials. The reading out of this instrument.
In degrees Celsius or degrees Fahrenheit is not the same as ambient temperature. That's the only thing you have to be taken care of. Most of the other indexes largely overestimate the thermal comfort of the animal or of men.
The WBTGT does not. WBGT readings need interpretation. The FAI, for example, presented in 2018 general recommendations for three-day competitions based on WGGT values.
However, These FAI threshold values need adaptation for individual horses. Each horse is not the same as another one. And different countries or competition organisers may use different critical threshold failures.
You have to be aware of that fact. Difference between comfort index and WBGT index readings are enormous. For example, the worst time predicted by the comfort index.
At a certain competition. It's not at all comparable with the worst time predicted by WBGT in the middle, the red arrows compared to the green arrows. It's me that the comfort index is surely not the best parameter to predict whether or not a competition can go on.
These are the recommendations of the FAI. The reading out is in degrees Celsius. In different classes.
The first class, less than 28, no changes in recommended format for the competition. To the 32, 33 class hazardous climatic conditions for horses to compete. So measures should be taken already and in the last class.
This is probably an area where no competition should be held. But it goes further. If you compare.
In the last column, the Values of the WBGT readouts. As determined by the FAI. And in the four last column, the risk of horses individually.
There is not much. Risk difference between the two. Although for the individual horse.
The risk where action are truly needed, very high risk. Is slightly more specific than the FAI. The same is valued for, for example, extreme risk and death risks.
To notice for you that the FAI gives for death risk and WBGTR readouts more than 33, while the index normally is about 32, there is already a difference. For men That's the column. In the middle There are differences in risk for men of being impacted by heat stress.
Riders should take care of that and should be aware of the risk they are occurring. The main factors impacting heat stress are listed here. There are 10 Animal-related issues.
Management-related issues, 567, and 8. And other factors, 89, and 10. The impact again of the metabolic rate of the animal.
And or the rider are still not taking into account. Poor conditions, resin composition, for example, carbohydrates produce more heat than proteins and fat. Something management of the stable can take into account.
The ventilation of housing conditions, shadow and cooling applied yes or no, or other factors. This list of 10 main factors is something that stable owners should take into account. What happens in the horse's body and his threats.
But first of all, there is a lot of body, a loss of body fluids, leading to dehydration and hence loss of electrolytes. This loss of body fluids causes blood circulation problems. As a result, there is less blood going to the skin.
So less heat evaporation is possible. Cooling of the horse itself is hampered. There's less blood going to the muscles.
Causing a less of energy influx and heat is accumulating, less blood is going to the intestines. Less water intake, electrolyte intake, sometimes even colic. This causes a slow recovery and less recovery, unless something is being done about it and being done on the right time.
The consequences of heat stress for the horse is of course an impaired welfare. But different health problems are possible. Cole has been named, respiratory disorders, heat function, liver function problems, cell function destruction, cell memory problems, and increased susceptibility for infections.
And of course, anytime the horses heat stressed, there's a loss of performance. Economic losses, sometimes even death of the horse. So it's quite worthwhile to do something about.
A heat stress horse. And the problem is right now is that heat stress in horses is a highly underestimated phenomenon. Causing problems of all kinds.
The sidestep, the effects of heat stress on reproduction in stallions, and in mass. Installing the stogenesis, less libido. Problems with semen collection, a lower number of spermatozoma, abnormal sperma.
May last for 70 days. Doing some moderate exercise with the stallion has no extra effect, not negative, not positive. In mass, we can see a disturbed oversight development and maturation, disturbed embryo development, disturbed foetal and placental development, and As a difference with the stallions, exercising a mare may have an extra negative effect.
And the effects are greatest around ovulation and conception moments. As general risk factors, we can name the heat itself, the stress of stealing or mouse, exercise, transport, handling, or changing environment, and so on. What are the signs of heat stress?
Intensive sweating or no sweating at all? An increased respiration frequency, panting like a dog. Decreased feed intake, decreased mortality.
Ataxia, muscle tremor, and of course the decreased performance and also deviating behaviour. Secondary swellings on the skin. A decreased skin elasticity.
Deviating colour of the gums should be pink growth. A rise in rectal temperature. If rectal temperature is above 40 °C or above 104 °F, called the wet.
Increased heart rate. This bundle of signs can be used to set a diagnosis. We call that the primary clinical checkpoints.
Sweating. If not sweating at all, check the hind parts of the horse. You can see it.
Elasticity of neck skin folds. Normal is that it should not stand longer than 6 seconds. The gun scholar test with the stamp.
It should be pink rose again in 2 seconds. Rectal temperature. Abnormal in Cases where it is above 38.5 °C or 99.5 °F.
Heart rate. Respiration state and behavioural changes, including nervous signs. For example, The next skin test.
In the neck, you take with thumb and finger a fold. Tear it out and if it stands for more than 6 or 10 seconds, then there is dehydration. Do the test on different places.
The Gump's nest Push your thumb well on the guns. And then release. After release, the pink rose colour should be back in 2 seconds.
Easy to perform clinical. Tricks Action by the vet is particularly needed when the horse is panting severely. Largely over 30 BPM.
If the pills has increased in rest, largely going above the 65 BPM. A high rectal temperature as we named. Dehydration signs can be noticed by grim test and skin fold test.
The horse is severely under sweat. Or in some cases, not sweating at all. A depressive or a tactic horse.
Often showing nervous signs, irregular and high heart rate. And premal treatments are predominantly predominantly present, other signs may be detectable such as colic. These are 9 easy to understand and in, easy to observe.
Phenomena which the owner or rider can do by himself or herself. What to do for a rider. When he's waiting or she's waiting for the vet.
Continuously hosed the horse with large volumes of cool cold water. Put the horse in the shadow and if possible, in a stream. Give the horse often small volumes of cool cold water to drink.
If the horse wants to. You may add apple juice to increase attractivity. Who at least inside legs and belly.
If available, not easy, install fence in front of the horse. Walk quietly for 5 minutes, then rest for a few minutes and repeat it. Some examples.
Transporting horses. Under heat stress conditions. Can lead to aggravated problems of the horse during transport.
Competition I was talking about large volumes of cool cold water. This means not by throwing buckets of water on the. Or because it takes too much time to have an effect.
It's too much from a human point of view, acting. And it's counterproductive for the horse. Below In the middle Hosing the head of the horse, but in this case in this case, particularly the head with a hose of water.
Its counterproductive, and again, I would call it window dressing. The horse will not be helped in any way. Another issue At the bottom right.
The infrared Thermography of a horse. Shows in fact the skin only. Can be convicting to see that the horse indeed has a a hot skin.
But doesn't say anything about core body temperature. It's not fit for a diagnosis. On the scraper on the right top.
I will come back shortly. Because there is discussion going on, yes or no, using a scrape to get rid of the warm water from the horse. There is a particular situation in thoroughbred racing horses.
These are pictures from Margaret Brando. After a race Where at the top left corner. The horse is.
Aggressive, this cannot be seen. The skin of the horse is attaining 50 °C. Below this horse is not only a tactic, but is going mad.
They can run through fences. At the right side, this horse. Can be cooled, but this is not large volumes of cool cold water that the horse cannot get on the feet again.
That's a chapter of different, different content which will be addressed later on. About the impact of water scraping. Last year, there was a publication by William Chuck Kang.
Saying that water scraping is a waste of time when it is done in between coolings. Water scraping after cooling is worse than cooling alone. But unfortunately, in the discussion.
Nothing was said about what about water scraping during water cooling. What about fanning at the same time as water cooling? And what about water cooling, plus fanning, plus escaping all at the same time?
I would say we don't know enough to make a proper statement about water scraping. Anyway. Fanning and large volumes of cool cold water is the most important component of a cooling procedure.
Some ideas to master heat stress at the stable. 1 may install temperature and humidity logos and read out every week. One can sample semen from stallions every week and evaluate the quality to see how severe the heat stress impact is.
Evaluate the semen quality data for each stallion to find out which horse is more able than others to adapt to heat stress situations. Improve ventilation in the stables. Let hot air not be stagnant, but it should be moved and of course, moved out of the state.
Maybe the owner is able to provide ample shade in paddocks or pet pasture. If there are trees, what kind of trees, it would be densely leafd and at least 5 metres high. 1 may graze stallions during the night and stabling during the daytime.
The last points stabling during the daytime may be a point for discussion. It depends on ventilation, the air temperature in the stable, etc. Or another option, grazing the stallions from 7 to 11 a.m.
And 4:30 to 9 p.m. The rest of the time indoors.
Breathing every other day under ovary monitoring. So you have an idea about what's going on. And whether it's useful to breed the mare.
Please note that resting after AI is sometimes . Advised has never had a proven, proven positive effect on embryo recovery. About the electrolytes, some major issues.
The most important thing for the horse in electrolytes is sodium chloride and potassium chloride. There are many, many products on the market with mainly sugar as first component. Rationals vary greatly in sodium chloride.
So you have to be careful which one to choose. Also, grass hay varies greatly in sodium chloride. You can check that by doing or advising a forage analysis.
A good supplement of electrolytes provides 6 grammes of sodium, 12 grammes of chloride, and 4 grammes of potassium. It should be listed on the label. If the horse refuses to drink because he or she doesn't know it, add some apple juice.
Better is to train the horse in drinking electrolyte fluid. The alternative is table salt, 2 tablespoons per day of salt licks, but even then, the horse should be trained throughout the year. Some riders give electrori gel to the horse after an a performance.
Again, electrolyte gel has sugar as first component. This gel is mostly used by human marathon athletes. But remember, a 600 kilogramme horse would need 600 gel tubes to substitute the sodium loss in sweat.
Note that endurance horses under heat conditions may lose 10 to 15 litres of body fluid per hour in sweat. So in that case, gel is not indicated at all. And even if a horse has light work, he may lose 5 litres of body fluids in warm conditions.
This represents 50 grammes of body salts in these 5 litres. So forget about electrolyte gel or even the riders should forget about it. Finally, there are 2 major different heat stress situations.
Heat stress in a hot, dry climate and heat stress in hot, humid climate. The treatment procedures for cooling are completely different between the two. The most problematic of the two is the hot humid climate, because in a hot dry climate, the horse can get rid of heat by evaporating.
And in hot, humid climates, the horse should be assisted. By a forced evaporation of heat from the skin. We come to that in another webinar.
This webinar addressed the heat stress in sports forces. I bundled all the practical management issues in the booklet. It's not a big one.
It's like this. Easy to handle, easy to put in a pocket. It's available from the UK context publications.
Other versions are in preparations. And I I would advise you to take a look at it because given the many tables, instruction figures, and photos explaining the text. It's 55 pages, so not a thick book.
It's a practical guide for riders, horse owners. And even veterinarians, I would say. This is the end of webinar one on dress in sports horses.
Please feel free to contact me by email for further inquirements if you'd like to. My email address is listed. And keep in mind that we envisage to organise webinar too on the control and preventive measures regarding heat stress at the home stable and at competitions.
This webinar to also would address innovative cooling equipment such as the equine cooling unit and an equine cooling carousel. The latter. Is where 12 horses can be called simultaneously.
Especially for competition or mass, Large stables, I would say. Thank you for your attention.