Снижение теплового стресса

Снижение теплового стресса

When the content of livestock in climate rooms they created, usually, through the use of technical equipment (forced ventilation, heating), according to the type of animals and their age. The climate in the area is likely to differ significantly from the weather conditions beyond those. If the weather conditions are extreme, needed additional methods, to protect the health and life of animals.

Especially at high ambient temperature,, associated with a high solar radiation and high humidity, the temperature in the animal houses can rise so, that it will threaten the lives of animals. Also in unheated premises extreme temperatures negatively affect animals. As a consequence of global climate change in our latitudes to reckon not only with the more frequent mild winters, but also with periods of extreme heat in summer. This leads to targeted actions, according to the requirements of the Animal Protection Act (paragraphs 1, 2), to protect the life and well-being of animals. These activities include the appropriate management, and the application of additional technical equipment.

foundation thermoregulation farm animals

Farm animals maintain their body temperature constant, If the thermal load does not exceed certain bounds. Thermoneutral zone considered animal's environment temperature, which does not require the expenditure of energy on thermoregulation. In this zone are the best climatic conditions for the health and productivity. The thermoneutral zone is also in the area of ​​thermal well-being. Thermoneutral zone specific for different animal species and varies with age, with the change ratio of the volume of the body: body surface area. In young thermoneutral zone it is in a higher temperature region as compared with older animals. In addition to the ambient temperature at thermoneutral zone also affect humidity and air velocity. Three factors are combined into the above complex termogidralny. The content of total air heat termed enthalpy and includes sensibelnuyu (perceived) and latent (escaped through evaporation, I do not feel) warmth.

Farm animals have thermoregulatory mechanisms to cases, when the ambient temperature goes beyond the thermoneutral zone. If the temperature is above thermoneutral zone, increases the heat output from the body, and reduced formation of heat. This they compensate by thermoregulatory behavior, when the animals are looking for shaded areas or cool surface. Body temperature can be reduced due to heat (conduction), movement of air (convection), radiation (radiation) and evaporation (evaporatsii). Conduction, convection and radiation are possible only if, when there is a temperature difference. Evaporatsiya effective and without temperature drop, but increasing the relative humidity is less effective and stops, when the air is saturated with moisture. Animals without sufficient formation of sweat evaporation is carried out from the body primarily through the mucosal nasopharyngeal. Due to the frequent respiratory mucosal surface tissue is dehydrated, which leads to an increased demand for water. Bird increases its area of ​​the body revealing wings and uses the entire body to the heat output.

If the body can not give produced during metabolism warmth, hyperthermia occurs with fever, the consequence of which could be cardiovascular collapse, damage to brain cells and heatstroke. animals, affected by heat reduces food intake and locomotor activity, and water consumption, in front of, increases. If it occurs in the body fluid deficit, there is skin turgor, eyeballs sink, Surface vessels less filled and death often occurs.

Monitoring the climate in the livestock premises


Observation of the indoor climate should be carried out and documented periodically, and in critical situations - each hour, also at night. To control you need to use mechanical ventilation, as well as an alarm. Similarly, follow the recommendations on the use of ventilation equipment. Particular attention should be paid to the inflow of fresh air, which should be evenly supplied to the animal room. Near must be serviceable generator, in the event of a power outage to ensure the work of forced ventilation.

By constantly monitoring the weather on specialized sites or receive storm warnings helps to take timely measures to prevent animal losses. It is necessary, when the outside temperature rises above 38 ° C or indicator enthalpy rises over 67 kJ / kg. Particularly vulnerable to birds and pigs in the final stage of fattening.

General measures for the prevention of heat stress

It is recommended to plan emergency response in critical situations, eg, failure of ventilation equipment or extreme weather conditions. This requires additional devices, such as mobile fans of various modifications. Next measure to prevent heat stress - reducing the density of animals on the premises from May to September, for example at the end of fattening partially fill the space.

Great influence on the indoor climate of the building structure itself has (thermal insulation of external walls and roofs, window area). Especially the area of ​​the roof greatly affects the heating of premises, if it is not isolated. If it is true, air supply must not take place in the space under the roof.

Screening of direct sunlight can be done by planting trees, as well as partial shading of open areas and windows (blinds).

Lowering the temperature in premises could be achieved by increasing the air. care must be taken, to air intake grilles are free from contamination (dust, leaves). Increasing the air speed in the animal finding leads to an increase in convection heat recovery and greatly reduces the heat. For this purpose, it is recommended to use special air duct or install additional fans. The air velocity in the area of ​​animal finding may be promoted with 0,3 m / s 1,3 m / s, and in extreme cases up to 2,5 m / s. at 1,3 m / cooling effect is 3,3 ° C, and when 2,5 m / s - 5,6 ° C.

Also room humidification roof, the room itself or the air helps to reduce the temperature of the air. For evaporation requires energy. It is taken from the heat sensibelnoy, which results in lowering the temperature. Part sensibelnoy temperature becomes latent temperature in this process, which means an increase in relative humidity, but the enthalpy remains constant. In spite of this it is important to control the rise in the relative humidity of the air, because at very high temperature (30 ° C) and a relative humidity of more 80% can occur extreme thermal load (heatstroke), when heat is terminated. Therefore, the enthalpy - is a suitable option for situation assessment.

Spraying water on site can be done in different ways depending on the type of floor covering. In stables without litter (concrete, slotted floor) this can occur by a hose or plumbing system with outlet openings or spray nozzles. The water may be directed to the floor or directly on animals. When spraying pressurized (pressure 50-80 bar and sprays with very small holes) cooling effect is from 8 to 10 ° C, without them - 4-5 ° C. In poultry houses and poultry wet litter must be avoided. Therefore, there can only supply air humidification (adiabatic cooling). Whereby the inducted air can be chilled to 3-5 ° C. Here, the inlet air is passed through the moist material with a very large surface area.

Cooling of inlet air is also possible using a so-called geothermal heat exchanger. This uses a temperature in the deeper layers of the ground, air of which is fed into the room through the pipes.

Losses due to thermal stress can be avoided thanks to the feeding and management. Reduced feeding the hot and the increase in the cooler times of the day (associated with the reduction of the dark phase) and uninterrupted provision of drinking water to help cool the. Surveillance of livestock and technical equipment in an emergency shall be constant (day and night).

On pasture for all animals should be able to hide in the shadows (thermoregulatory behavior). If there are no natural sources of shade (trees, bushes, building), We need to build artificial shelters.

Summarizing we can say, that the reduction of heat stress is, to reduce heat and increase the impact of heat due to various measures.

Special measures to reduce the heat stress
Heat stress in poultry

The symptoms of hyperthermia and its prevention methods are similar for different species of birds. Therefore, they are described in detail in section 5.1.1. (broilers and laying hens).

Heat stress in broilers and laying hens


All the bird begins to breathe through the beak, and the number of breaths may exceed 250 in a minute. To return the heat the animals stand with spread wings. Feed consumption is reduced, Water consumption increases. Raise the feeders in boilers is not recommended, because the animals do not always avoid food. If the temperature rises above 35 ° C at a humidity of more 75%, when the body temperature rises to 42 ° C., which leads to deaths. Dead animals are, distributed over the entire area. The naked skin on the head bluish, of the beak often follows a liquid or liquid feed porridge.

The air velocity at the end of fattening (live weight 1,5 kg) в 4,5 m³ / head per hour at high rates of enthalpy (>67 kJ / kg of air) It is insufficient. It should be increased to 6,75 cubic meters / head at a time (corresponds to 4,5 cu / a 1 kg body weight), if you can not reduce the density of animals in the house.

By increasing the air speed twice with 1,25 до 2,5 m / s cooling effect can also double. Air from the higher rate to be supplied only on the part of the room, that the animals had a choice. Well established air "soul" in the third of the floor space. Air velocity at a temperature of 26 to 35 ° C may be from 3 до 6 m / s, respectively,.

Humidification of the supply air should be administered before the expected high temperature. This will reduce the house temperature 3-5 ° C and at the same time binds the dust particles. But we need to keep an eye on the humidity of outside air, which should not exceed 50%. Humidification animals and litter should be avoided, relative humidity indoors should be below 80%. It also helps moisturizing uninsulated roof, especially if the air ventilation of the area served by it.

To avoid additional stress on animals, you need to take care of a particularly quiet caring for them. Positively acting cottages additional vitamin C in drinking water.

In poultry houses with a free ventilation (Louisiana) it is recommended to install additional portable ventilators, which include temperatures in excess of normal.

Heat stress in turkeys

The minimum air velocity in closed poultry houses in the summer should be at least 4,0 cubic meter / kg live weight for turkeys and a minimum 5,0 cubic meter / kg live weight for turkeys, in extreme climatic situations 5-6 or 6-7 m³ respectively. This can also be achieved by reducing the population density premises.

If the air is humidified, We need to ensure, the relative humidity does not rise more 70%.

Through raising feeders prior day's heat is reduced feed intake and thus unloaded metabolism. When the temperature in the evening and at night the animals are able to unlimited food consumption.

Avoiding trouble in the house makes it possible not to create a bird excess stress. During regular rounds to familiar birds employee, it stimulates the birds to stand, so that the heat accumulated beneath them was removed.

Heat stress in ducks

Minimum air velocity must be summer 4,5 m³ / kg body weight per hour, at the end of fattening it should be increased to three times. If this can not be achieved by means of ventilation, We need to reduce the density of animals in the room.

Humidification animals and litter should be avoided. If the house is already high levels of humidity, extra moisturizing it will be critical. If the relative humidity is over 70%, possibility of return of heat through the breathing becomes limited.

Restriction of food intake should be also possible, as described for turkeys. Especially important, that water was freely available at any time.

straw bedding should be done quietly and gently, We need to avoid a flock of birds in one place.

Heat stress in pigs


Pets weighing up to 30 kg can compensate for high ambient temperature. But heavier specimens at a temperature of over 28 ° C, begin to breathe heavily, drink more water and reduce food intake, that is, to show the first signs of heat stress. Especially with increasing fat thickness complicated heat output. The high density of animals at the end of fattening causes, that animals can lie only touching each other, which significantly limits the heat. This can be minimized, selling the heaviest animal in the first place. Most animals can give heat lying in a corner on the wet or possible other heat-absorbing surface. This requires a minimum area 1 quarter. of the head. If this is not ensured, it is necessary to take care of another method of cooling. The headquarter inseminated, as well as in the mother liquor in high temperature areas has a negative impact on fertility indicators.

moisturizing floor is especially recommended for pigs (hose, stationary water) or installing showers, which are included in time and can be used for a long time). Particularly effective water spray tiny droplets in the mist. For this purpose water supply low and middle pressure water unsuitable, because so drops are too large. But the high-pressure setting gives the ideal size droplets with low water. But in the room relative humidity should not exceed 80%.

Avoid heat stress and allow construction activities (thermal insulation of walls and roofs), corresponding air supply in a pigsty, and additional equipment for cooling the supply air by humidifying the air or deep tank.

Вы знали ?

  • Свиньи почти не потеют. Поэтому они не могут использовать механизм теплоотдачи для испарения избыточного тепла, что делает их очень чувствительными к высоким температурам.
  • Современная генетикапрогрессивна. Однако и она бессильна в создании животных устойчивых к тепловому стрессу.
  • Порог толерантности к тепловому стрессу варьируется в зависимости от физиологической фазы, чем тяжелее животные, тем они более чувствительны к избыточной температуре.
Heat stress in cattle


Also cattle suffering from high temperature. Metabolism in the RNC forms a lot of heat, which arises from the activity of the rumen flora and formation of milk. Release of heat is limited due to the low volume ratios of the body to its surface area. Already at temperatures above 25 ° C feed consumption is reduced, and with it, milk production and weight gain. When the content of dairy cows and bulls at the end of fattening indoors necessarily sufficient to ensure animal drinking water and additional ventilation. It is also recommended to open the gate in the barns. When the content of the meadows animals use trees and other shelters as a source of shade. If animals are kept in the meadow is only partially, you need to take care of shelters, if there are no trees or buildings, forming a shadow. In the heat period it is also recommended to drive the animals in the barn at lunchtime.

Heat stress during transport of animals

Each transport leads to significant motor and mental stress animals, more aktivnomuenergeticheskomu metabolism, and therefore, an increased heat production. This is even more aggravated by the fact, that each teplovoj_stress_pri_transportirovketransporting precedes trapping or distilled. Therefore, these activities during the summer months should be conducted during the night. It is particularly important due to the very careful preparation ensure the most relaxing treatment of animals and the use of suitable equipment for reducing stress. Animals should not be fed before transport, but it required access to water. Depending on the expected temperature in the street and the duration of transport loading density should be reduced to 10-20%. Need to check, whether ventilation is working. If there is, you must open additional ventilation holes. It is particularly important at high temperature to go quickly and avoid stoppages.

car fan should be examined already at startup. It is important to, so that it can operate independently of the vehicle engine. Recommended availability of additional fans, which are cooled during transport download. In certain situations, it is recommended internally spraying pigs with water.

If the stop is loaded transport is inevitable, it must not stand in the sun. Additional ventilation before unloading, how it is organized in slaughterhouses for poultry, brings its positive effect. Also transport ride without stopping to avoid heat stress. But poor management at the slaughterhouse to the overcrowding of poultry can bring all of these measures is not.

If traffic gets stuck in traffic or an accident, the driver must contact your company or the police, to bring your car out of traffic jams and ensure traffic on the other road or overload animals.


Guidelines developed by a working group 1 (livestock) Veterinarians for Animal Protection, 2010 year, Germany. Responsible for the release of Dr. Bodo Bush, Professor Gerd Schlenker. Translation Elena Babenko, especially for

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