Pre-slaughter exercise, a prolonged on-farm fasting period (more than 18 hours), long journeys and long lairage periods provoke the use of muscle glycogen to produce energy. This reduces muscle glycogen content at slaughter.
At low temperatures animals tend to group together, creating a microclimate and increasing the surrounding temperature; this depletes energy reserves in the muscle, especially if the animals shiver.
When providing pigs too much space during transport animals can be thrown around and get bruised as a result of unexpected movements of the lorry. Also, if pigs can move around they may be involved in fights causing glycogen depilation.
Entire males tend to fight more