In a study conducted by Wallgren and Lindahl (1996), evidence pointed towards a classification of pig tail wounds: mild, moderate, and severe. Regardless of what degree the wound was ranked, the ventral side of the tail contains direct access to major veins that can spread infection throughout the whole body; concluding that any measure of wound can have a detrimental effect to the bitten pig (Getty & Ghoshal,1967). .
Tail biting behavior is more commonly observed in earlier stages of pig production such as nursery and growing phases, because of the decreasing activity pigs have as they age (Stolba & Wood-Gush 1989). During these phases, pigs are let loose in their own pens to do as they please (increasing pathogen production). Studies have shown that along with increased movement, this time of production is when pigs will show increased interest in bloody objects, stimulating a large increase of more tail biting among their pen-mates, thereby increasing infection rates dramatically (Fraser, 1987a). These instances of outbreaks make producers having to deal with those who begin the outbreak, and make sure it can be controlled before it expands. With a large concern apparent within the industry, scientists have been driven to explore what causes this behavior. .
Several hypotheses have been proposed to provide explanations as to why tail-biting behaviors occurs. A logical reasoning that justifies why scientists are unable to discern the cause of tail biting is because this behavior is a natural behavior of the pig. Without pigs being able to speak, they are unable to voice their motivation, making scientists conduct intensive studies to figure out this riddle. The issue lies within predisposed neurological functions that all pigs are born with, and all point to a reason why this behavior is seen across all pig populations. Present-day pig production is also a major contribution to this biting behavior, due to early weaning of piglets being most desirable so the sow can become pregnant again sooner.
