No description available.

Two trials were conducted in order to assess the efficacy of microbial phytase supplementation in improving the bioavailability of certain nutrients in the diet of early weaned piglets. In trial I, a low-phosphorus, corn-soybean meal diet supplemented with phytase significantly improved the apparent digestibilities of phosphorus (P, p = 0.0004) and calcium (Ca, p = 0.04). The average daily gain (ADG) and feed conversion ratio (FCR) were also improved by supplemental phytase. In trial II, addition of acetic acid to the low-P plus phytase diet further improved the apparent digestibilities of P and Ca (gp = 0.01, p = 0.02, respectively). Furthermore, the apparent digestibility of copper was also significantly improved by acetic acid addition. As a consequence, the piglets fed this treatment showed the best growth performance. Acidification of a diet which provided the NRC recommended levels of available P significantly improved the apparent digestibilities of protein and most of the minerals (P, Fe, Zn, Cu and Mn) but it was not reflected in improved growth performance. These results indicate that microbial phytase not only released P from the phytic acid molecule but it also cleaved other minerals bound to this complex.

No description available.

No description available.

The objective of this study was to derive new selection indices for swine production in Quebec. First economic values were derived as change in profit per market pig for a one unit change in a trait while all other traits remain unchanged. Production figures and prices used were taken from Quebec figures. Comparing with the currently used economic values, the responses showed the same range for the sire line with a higher emphasis on age to 100 kg for the new values. The same trait, response in age to 100 kg was much smaller in the maternal line for the newly derived economic values but showed higher responses for backfat and litter size. Lean yield was found to have higher responses if used directly as a selection criterion for carcass composition instead of backfat. Feed intake was found to have unfavourable responses in the maternal line but did not change the responses for the paternal line. Including farrowing interval in the maternal line resulted in favourable responses for lean yield and litter size. Regulating the backfat level using a restricted index in the dam line had no effect on the other traits in the index.

The objective of this research was to determine the nature of hog supply response in Quebec, Ontario and Alberta over the period 1968-1986. Special emphasis was placed on the role of government stabilization programmes. The research examined the development of the North American hog industry and described the various federal and provincial assistance programmes that were available to hog producers over this period. Using an adaptive expectation framework, separate linear equations for each province and three pooled data equations were specified. The equations were estimated using four procedures namely, Hildreth-Lu, instrumental variables, quasi-generalized least squares and augmented least squares. Results indicate that (1) stabilization programmes exhibit positive effects in Quebec and negative effects in Alberta and Ontario, although in no province are these coefficients statistically significant and (2) that response to risk varies across provinces. This research concludes that other factors including vertical integration and western grain market conditions may have been important factors in production shifts during this period.

Graduation date: 1992

Includes list of papers and publications by the author / Includes bibliographical references (leaves 198-231) / [12], vii, 231 leaves, 6 p. of col. plates : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Reports on studies aimed at increasing the efficiency of livestock transgenesis programs. Overall the experiments provide an improved basis for understanding the application of animal biotechnology to the pig. / Thesis (Ph.D.)--University of Adelaide, Depts. of Obstetrics and Gynaecology and Animal Sciences, 1991

Thesis (M. Sc. Vet. Sc.)--Faculty of Veterinary Science, University of Sydney, 2005. / Bibliography: leaves 165-172.

Thesis (M. Sc. Vet. Sc.)--University of Sydney, 2005. / Title from title screen (viewed 27 May 2008). Submitted in fulfilment of the requirements for the degree of Master of Science in Veterinary Science to the Faculty of Veterinary Science. Includes bibliographical references. Also available in print form.