SOCIAL-ORGANIZATION STRUCTURES IN INTENSI VELY KEPT PIGS .1. ETHOLOGICAL INVESTIGATIONS ON THE SUCKING ORDER

In intensively housed pigs, the sucking order of piglets is a social o rganization structure based on territoriality. Following some introduc tory considerations on the problem of ethological investigations, the present paper deals with the characterization of the sucking order wit h relation to early postnatal piglet vitality (n = 523 / n = 876) and to its stability and importance (n = 1136) regarding different udder r egions. Several parameters have been developed allowing these facts to be described in a more transparent and comprehensible way. As to post natal parameters, only the teat positions of first milk intake had sig nificant effects on the teat positions within the later sucking order (alpha = 0,05). It could be proved that the distribution of piglets wa s shifted towards cranial teats within the established sucking order ( alpha = 0,05). The sucking order, on the whole, was characterized by h igh stability (single teat = 67,5%; teat pair = 82,5%; udder region = 91,3%); compared to sucking at cranial (73,5%) or caudal (70,1%) teats , however, sucking at median teats (61,4%) was the most inconstant. Po ssible reasons for these results are discussed from an ethological poi nt of view.