The relationship between social facilitation and feeding
behaviour was studied, using growing and finishing pigs. The
results showed that the pigs' feeding activity was influenced by
their social environment.
Both positive and negative social facilitation was found in the
feeding behaviour of pigs kept in groups. The factors which caused
these different types of social facilitation were studied.
Moderate competition in an 8-hour feeding regime may produce positive social facilitation of feeding behaviour while serious competition, eg in a newly founded group, can cause negative social
facilitation of feeding behaviour.
Pigs with different social ranks show different reactions to
the stimulation from their social environment, which produces different results with regard to social facilitation. The dominant
pigs reacted more strongly to the social environment than the
inferior pig in the present results.
The group size of the pigs may also cause differences in social
facilitation, but results are not clear on this point. The feeding
speed of a companion pig seems to be unimportant in causing differences in social facilitation of the feeding behaviour of the subject pigs.
The physical character of feeds may play an important rôle in
influencing social facilitation in some circumstances. The present
results demonstrated that, if the feeding drive is the dominant
drive, it can be positively facilitated by social environment, but
when the feeding drive is a subordinate drive, then social
facilitation can be decreased by the social environment.
The pigs showed strong allelomimetic behaviour in feeding
activity. The food intake and eating speed of the pigs increased
with increase in body weight but the total feeding time decreased,
or kept constant, when the body weight increased. The eating speed
may vary according to the following factors: the individual pig,
the pig's body weight, competition, the length of the period of food
availability and physical characteristics of the feeds. The pattern of feeding behaviour changes with increasing body weight. The
present thesis also strongly indicates that the food in the form of
meal is not as easily ingested by pigs as pelleted food.