Thesis (Ph. D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 90-98). Also available on the Internet.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1957. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 157-172).

The behaviour, welfare and reproductive efficiency of sexually mature pigs kept in groups rather than singly has recently become important because of new EU legislation to ban sow stalls and tethers. Four studies were undertaken to examine the behavioural, welfare and economic implications of a Dynamic Service System (DSS) for gilts. The DSS is a semiintensive variant of 'group mating'. In DSS, the female population is changed on a regular basis while the boars, forming a team, are resident. In total, 1402 gilts and 38 boar teams were used to establish behavioural parameters and reproductive output (i.e. conception rate and litter size) in such a system. The behaviour of the sexual partners was continuously recorded for 6,288 hours (i.e. 262 days). The results indicated that male sexual behaviour differed significantly between and within boar teams. Social dominance failed to significantly affect male sexual behaviour and a comparison of the male social and sexual hierarchies showed that they were poorly correlated. Gilt reproductive behaviour and performance were not affected by the number of heat periods experienced prior to service, at a controlled age. There were no detrimental influences on gilt productivity of halving the size of the boar teams from 4 to 2 individuals. Overall, the reproductive performance of gilts in a DSS was at least as good as in other conventional mating systems. The Dynamic Service System was shown to be compatible with good welfare and acceptable behavioural patterns, and is clearly a valuable alternative in future pig production.

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Thesis (Ph.D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (February 27, 2007) Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Queensland, 2002. / Accompanying CD-ROM catalogued separately. Includes bibliographical references.

Thesis (M.S.)--Ohio State University, 1968. / Includes bibliographical references (leaves 42-43). Available online via OhioLINK's ETD Center