Ventilation and Thermal Comfort

Pigs do not have functional sweat glands and cannot cool themselves by sweating like humans or horses. They rely on panting, wallowing in water or mud, and air movement to reduce body temperature. When temperature rises above 25°C, pigs begin to show heat stress — they stop eating, lose weight, and reproductive performance drops sharply (Singh and Prasad, 2014).

According to ICAR (2016), the comfortable temperature range for growing pigs is 16–22°C, and for adult pigs 15–20°C. In the hot Indian summer, it is very difficult to keep temperatures this low without shade, ventilation, and cooling devices. The following measures help maintain thermal comfort:

Open-sided construction: The upper part of the side walls should be open (with wire mesh) to allow natural air movement. Ridge ventilators (openings at the top of the roof) further help hot air escape. Sprinkler systems: Overhead sprinklers that wet the roof and walls can reduce inside temperature by 3–6°C in summer. Wallowing area: A shallow water pool (30–40 cm deep) in the outdoor run area provides great relief to pigs in summer. Trees and shade: Planting trees around the pig house provides natural shade and can reduce surrounding temperature significantly (ICAR, 2016).

Category

Optimum Temp (°C)

Upper Critical Temp (°C)

Signs of Heat Stress

Newborn Piglets

30–32

35+

Huddling away from sow

Weaners (8–16 weeks)

22–26

30+

Panting, not eating

Growers (16–24 weeks)

18–22

28+

Reduced feed intake

Finishers

16–20

25+

Weight loss, aggression

Pregnant Sow

16–20

25+

Reduced litter size

Boar

15–20

23+

Poor semen quality

Table 7: Temperature Requirements and Heat Stress Thresholds for Pigs (Source: ICAR, 2016; Singh and Prasad, 2014)