## Section: Stockmanship Standards

### Thermal Control

Pigs lose heat by four natural methods
1. Conduction to the floor
2. Convection to the air
4. Latent heat (or moisture) mainly by respiration
This is illustrated in the drawing

This is useful as it allows us to calculate what extremes we can achieve by the four methods of heat loss.

For Example (From Y. Choiniere and J. Munroe 1994):
A 7 kg weaner on a wire mesh floor produces around 29.5 watts of energy which it needs to lose. In order for the animal to be kept within its thermal neutral zone without chilling in a standard nursery at 30?C.

Latent heat = 10% Conduction to the floor = 17% Radiation = 44% Convection = 28%

If we placed the weaner on a heated surface, so that the conduction to the floor was 0%, the pig still has to lose 29.5 Watts. The Latent heat does not change, so we must allow the pig to loose more through radiation and convection to maintain it within the thermal neutral zone.

For example:
Latent heat = 10% Conduction to the floor = 0% Radiation = 57% Convection = 32%

The room can now run at 23?C and the air flow can be increased providing a better environment particularly in the winter.

 BACK TO PIG STOCKMANSHIP STANDARDS CONTENTS PAGE Extracted from Garth Pig Stockmanship Standards* written by Dr John Carr. You can buy this book HERE *Published by 5M Enterprises Limited