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Ethology of Risks Caused by Weaning in Pigs

HVOZDIK A
Veterinarni Medicina 36, 1991, 533-538

Regularities of social behaviour in sheep have been studied in large-scale production conditions. Efforts were made to work out an hypothesis and to determine the extent in which the biosocial relation mother-young one represent a limiting factor for animal sociability during their ontogeny. For this purpose, two forms of weaning were defined and compared: lasting 28 days (early) and 10 days (very early). Sociability of animals in a group and indexes of their sociability (IS) were criterions under study. The IS values in the first form of weaning varied within the values 3.24-4.09. An average IS value was xBAR = 2.68 and the dynamics of social hierarchy of the group was stable on the 8th day of their age (Fig. 1). The IS values varied within 1.21-4.30 in the second form of weaning. Average IS value of animals in the group was xBAR = 3.55 and the sociability was stable on the 28th day of their age. The study was aimed at analysing the social adaptation, eventually maladaptation as a potential consequence of deprivation resulting from very early weaning of pigs. Fig. 3 shows the results of research in the form of different indexes of sociability between simulated weanings of pigs, form I - 2.68 and form II 3.55. The IS difference is significant at the significance level alpha = 0.01 and alpha = 0.05. This fact confirms hypothesis of social maladaptation as a consequence of social deprivation of young animals very early weaned. In such numerous group of animals (21) in both forms of weaning, the IS varied so much, that no valid social structure of animals could be settled, i. e. to settle their social hierarchy. The dynamics of social hierarchy of animals was markedly affected by higher score of agonistic behaviour of the type of aggressive behaviour where infraspecific aggressive behaviour is stressed. Experience obtained confirm the true of sociability correlation and animal density for the benefit of lower concentration on the housing area. Conclusions of this study indicate the need of studying the problems in wider context, such as clinical ethology, behavioural genetics


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