Support in predicting heat stress

The thermoneutral zone, i.e. the wellbeing zone for individual poultry species, varies greatly and depends on age and weight. For example, laying hens prefer temperatures below 20 °C, while fattening poultry favour higher temperatures, especially early on in the fattening process. Flock management during the summer months, in particular, always requires a great deal of finesse from poultry farmers.

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It is not unusual for there to be major differences, firstly between the day and night temperatures, and secondly, between individual days. Moreover, the heat produced during the digestion process also affects the body. The birds can control thermoregulation through convection (releasing heat through the skin). However, this mechanism only works if there is a drop in temperature between the body and the ambient temperature. If the ambient temperature is higher than approx. 33 °C, thermoregulation predominantly occurs through 'beak breathing'. This situation causes a lot of extra stress for the bird due to an increased breathing frequency and, eventually, puts considerable strain on the animal. In this case, an increasing number of free radicals build up within the body of the bird, which can have a negative effect, especially on the cardiovascular system.

Moreover, days with high temperatures and humidity can cause increased lactic acid production in the blood. The result is a diminishing blood pH value, which in turn lowers the blood's capacity to transport a sufficient amount of oxygen. Over time great strain is placed on the body, which can in turn lower the performance level. The worst case scenario is a significantly increased mortality rate within the flock.

In order to counteract this risk, poultry need adequate support during these phases. Firstly, it is vital to monitor the stable climate in the henhouse, sufficient water supply and the functionality of the emergency power supply. Secondly, the flock needs additional support in the form of supplement feed during heat stress situations. The combined use of Miravit AscoStabil and Miravit Hydrolac has proven to work in past years. A combination of ascorbic acid and polyphenols, like the ones found in Miravit AscoStabil, supports the body's anti-oxidative ability to bind free radicals, thereby making them harmless. Amongst other things, the polyphenols in this combination help to make the daily feed ration more stable than it would be using other, similar ingredients. The selected electrolytes, like the ones contained in Miravit Hydrolac, compensate for loss of electrolytes – which can occur as a result of beak breathing – and act as a buffer substance in the blood, meaning that the pH value can return to the physiological level. Both products should be administered in combination in the drinking water on the day of the heat, and the following day.

The Miravit Concept Miravit Concept is also offering the Thermotool app for smartphones this year as a free service tool. This can either be downloaded via the Google Play Store Google Play Store or via the iTunes store iTunes store to smartphones or tablets. After the address and species of animal have been entered, the app calculates a heat stress index from the respective temperature and humidity level. This is depicted on a scale in colour, and the risk potential for the current day and a forecast for the coming five days can be obtained. The 'What To Do' button leads to a variety of management recommendations for each risk assessment, which firstly refer to customising the climate in the henhouse, and secondly to providing additional support for the flock in the form of vitamins and electrolytes.

In past years, extreme heat stress phases have frequently occurred without warning, meaning that there was limited time in which to take action. As a result of this experience, all technical elements of the air conditioning in the henhouse should be maintained, and there should also be a supply of supplement feed, such as ascorbic acid, polyphenols and electrolytes, available at the poultry farm in order to ensure that the situation can be dealt with quickly. Thanks to its ability to predict heat stress phases, the Thermotool app certainly facilitates efficient farm management.

More information on the hygiene and vitalisation concepts can be obtained from Andre Stevens, telephone +49 (0)175- 2958357, and at