Background and historyExtreme temperatures and water shortages take their toll on pig herds in particular, with heat stress and heat stroke being prominent causes of weakness, diarrhoea and acute distress. Droughts result in restricted water use across all agricultural businesses and in swine herds, water shortages can be catastrophic – continuous access to clean water is critical for pig health. Wallows (mud baths created through pumping water into shallow mud areas) also provide pigs with some relief from the heat but water use restrictions can prevent the maintenance of such areas. Show According to advice published on the website of Western Australia’s Department of Primary Industries and Regional Development, “Most animals can transfer internal heat to the outside of the body by sweating and panting – these are the two most important tools for the maintenance of body temperature and form their inbuilt evaporative cooling system. However, pigs do not sweat and have relatively small lungs. Due to these physiological limitations and their relatively thick subcutaneous fat, pigs are prone to heat stress.” Responsible use of water and keeping your pigs cool are essential to maintaining productivity and welfare in your herd. This usually occurs where ventilation has failed or in extremely hot weather. Clinical signsWhen a pig’s internal temperature increases, it reaches a point where it can no longer increase moisture loss through increasing respiration and sweating – the ‘heat stress emergency’ point. The animal may pant harder but without relief; this cycle can lead to death. In cases in which heat stress occurs only for a short period of time (two to three hours), no lasting harm has been observed in most individuals.
PreventionIndoor housing and ventilation
Outdoor housing
To keep water cool and clean... keep water storage and water troughs in the shade, and use blocks of ice or frozen tubs of water to bring the water temperature down and reduce evaporation. PigletsPiglets need continuous access to water at two weeks old and, if left in direct sunlight or in poorly ventilated barns can suffer heat exhaustion, potentially resulting in mortality. SowsBreeding herds are particularly susceptible to an array of reproductive issues, including decreased farrowing rates, smaller numbers born per litter, a reduced number of piglets born alive per litter, higher embryonic deaths during early gestation, a larger number of stillborn piglets and miscarriages. Heat stress is also responsible for increased mortality among sows. BoarsHeat stress and dehydration in boars can result in lethargy and reduced libido, increased irritability and aggression, and can degrade semen quality. The same measures must be taken for the boars as for sows during periods of high temperatures, ie provision of wallows and shades, ensuring adequate resting space, and provision of ample fresh, cool water. ProteinIn prolonged hot weather, consider feeding pigs the lowest safe level of protein, ensuring the correct essential amino acid balance is maintained. The higher the nutritional protein consumed, the more water pigs require to stay hydrated, therefore reducing protein intake will reduce water required and reduce risk of dehydration. How do you tell if a pig is overheating?Overheating can cause your pig to pant rapidly and excessively, drool thick, rope like saliva, the eyes may have a glazed over look to them and obviously may be excessively thirsty. His gums may become very dry and even a bit crispy from dehydration.
How hot is too hot for a pig?Heat Stress Index
Mature pigs are most comfortable when air temperatures are between 50-75°F. Once temperatures exceed 80°F, pigs over 100 lbs. (grow-finish pigs, developing gilts, and mature sows and boars) can very quickly move into life-threatening levels of heat stress.
How do you cool down an overheated pig?Cool water helps reduce the pig's internal body temperature, as well as replace water lost from elevated respiration during periods of heat stress. Provide market hogs with plenty of access to water.
Are pigs sensitive to heat?Pigs are more sensitive to heat than other animals because they can't sweat. Thus, high temperatures can lead to heat stress, which causes poor performance.
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