HOT WEATHER PROBLEMS by: Dr. John Walton and Dr. Oliver Duran, The University of Liverpool

Just recently the outdoor temperature has been very high indeed and this has resulted in almost unbearable indoor conditions also. This type of weather presents many difficulties for both black and white skinned pigs who do not have the opportunity to find shade or a wallow.

The ideal living condition for pigs outdoors is a wooded area with hollows and hills giving direct protection from the sun, wind and rain. Fallen leaves and branches provide good bedding and there will be lots of “goodies” to eat as well. Many domestic pigs are kept outdoors and the only protection they get from the elements may be a tin shed or a wooden hut. In the summer, both these can be extremely hot so the pig is forced to go outside in an attempt to get some cooler surroundings which of course will probably not be available and there will be the added risk of hot direct sunlight. These conditions will soon give rise to sunstroke which can be fatal if the pigs remain outside in the sun without shade.

If a pig is suspected of having sunstroke then it must immediately be provided with shade, kept quiet and hosed down with cool water. If the pig starts having convulsions then the vet must be called to administer a sedative, but one word of caution…pigs with severe sunstroke may not recover. If the sow is pregnant then an attack of sunstroke often leads to an abortion with all the litter being lost.

Pigs kept indoors during very hot conditions run the risk of heat stress because of prolonged exposure to a hot atmosphere. Lots of drinking water must be provided for both indoor and outdoor pigs and if possible a wet wallowing area provided. Alternatively a water shower or dripping water from a length of hose can be made available to enable the pigs to cool down.

Do not attempt to mate pigs during the heat of the day – wait until the cooler evening time but remember prolonged hot weather can cause boars to become temporarily infertile so try and keep them cool by providing a shower or a drip hose. You may only recognize that your boar was affected by the heat when mated sows return to estrus 21 days after service.

Appetite may be somewhat irregular with prolonged hot weather but you must make sure that fresh drinking water is always available especially for pigs that are normally given a wet mash feed. Do not let uneaten food become sour or moldy as this might produce future health problems if it is eaten at a later date.

Of special concern will be the extremely overweight pig. As you know pigs do not have sweat glands on their body except in a very few places such as around the nose with heat being usually lost from the body by panting through an open mouth. It is most important to provide these very heavy pigs with shade, a wallow or a shower. If they are getting over-heated then try and cool them down with water from a hose or use an electric fan to blow air over them. Do not make “hot” pigs take physical exercise ….just allow them to rest as much as possible in a quiet, cool place.

Another major problem with hot weather is sunburn. Remember that just as with ourselves, skin can burn even on overcast days when there is not any direct sunshine. Obviously the best course of action is to prevent sunburn. So just like the advice above provide lots of shade in a cool area, sun screen lotions can be applied but never use oils such as motor oils or cooking oils. Both of these will damage the skin and neither do they keep out ultra-violet “sun burning” rays.

Often indoor pens or boxes have no mechanical ventilation and even though a half door may be left open often the temperature inside can be very high indeed. If no system is available to produce some air movement then a drip or shower hose is needed to enable the pigs to get wet and then cool down by evaporation. Open as many windows and half doors as possible. Provide some form of shade if direct sunlight is entering the box and it would especially help if a fan could be fitted to move the air about inside the pen.

Points to Remember During Very Hot Weather:

For outdoor pigs: Provide shade out of direct sunlight and a wallow big enough to allow the whole pig to get in but not so deep that it covers the snout when the pig is lying down. Do not force exercise. Make sure fresh drinking water is always available.

For indoor pigs: Provide shade from direct sunlight and provide a drip or shower hose and if at all possible give some air movement by attaching a fan to the wall. Avoid mating during the heat of the day. Make sure that fresh drinking water is always available.