Heat stress on farm

This dossier aims to support welfare inspectors and other stakeholders in the field of climate control on pig farms, in particular at high temperatures. The dossier is updated periodically by the EURCAW-Pigs team. The text is not legally binding.

There are hardly climatic legal requirements for pigs in the EU-regulations. However, on a national level rules can be stricter, but often formulated as “open norms”. Directive 98/58/EC states that the accommodation should “not be harmful” to the pigs, which can only be checked by animal based indicators. However, legal limits are not available in most countries, with difficult enforcement as a consequence.

Measures to prevent heat stress can preferably be combined with the weather forecast to prevent heat accumulation in pig buildings. The main measure is to regularly check indoor temperature and relative humidity and to use a table on corresponding temperature-humidity-index values to assess the heat burden of animals and to start with countermeasures before the threshold is reached (see ‘Show more’).

With increasing global temperatures, the risk of heat stress for farm animals is growing. As pigs are not able to sweat and in livestock houses they generally do not have the opportunity to wet themselves, an ambient temperature above the upper critical temperature (UCT) leads to reduced welfare and performance.

When visiting a pig facility it is necessary to have a toolbox of indicators to detect heat stress. There are many indicators available, both environmental (risk factors) and animal based, of which some show an acute, others a longer term effect (pen fouling) of heat stress. Individual indicators are not sufficient as a signal for heat stress, a combination of indicators is a better proof. The most useful and proven indicators are described in more detail in three indicator factsheets (see ‘Show more’).

In collaboration with national training bodies and national reference centers on animal welfare, EURCAW-Pigs develops training guides for the different welfare topics as standards for national training in EU Member States.