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Studies were made of the effects of Vitamin A supplementation on the course of artificially induced lungworm infection in calves. Vitamin A deficient, Jersey bull calves, were infected with 2,000 D. viviparus larvae and supplemented with either 2 ug/lb/day or 60 ug/lb/day of Vitamin A. [...]

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This thesis explored the feasibility of training cattle to eliminate in specific areas of a barn and investigated cattle’s ability to generalise knowledge between different locations. In Chapter 2, all incidences of urination and defecation were recorded by group-housed female Holstein calves across 144 h. There were substantial differences between individual calves in the mean daily frequency. Calves urinated and defecated most frequently during daylight hours when they are more active and the location of voiding was likely related to the amount of time areas were occupied. In Chapter 3, calves were trained to urinate in a specific location via classical or operant conditioning. Classically conditioned calves were held in a stall for a set time and given no punishment or reinforcement upon urination, whereas calves in the operant treatment were immediately rewarded for urination in the stall. Classically conditioned calves did not urinate more than controls. Calves trained using operant conditioning had a higher frequency of urinations in the stall than their controls but did not seem to generalise this association; failing to urinate more than controls when tested again, 5 months later, in a new location (Chapter 4). The use of visual cues may be an effective way of helping cattle to generalise previously learned associations to a new location or context. Two experiments were conducted (Chapter 5) to investigate whether prior exposure to colour cues improves calves’ performance in a Y maze colour discrimination task. In Experiment 1, either both side and colour or colour alone predicted the location of milk reward in a Y maze. Our results suggest that calves overlook colour in the presence of more salient cues, such as location. In the second experiment, calves were first classical conditioned to associate coloured signs with presence of absence of milk (colours were randomised for controls) before testing in a Y maze discrimination task. Nine out of ten classically conditioned calves, but no control calves, achieved the learning criteria. Classical conditioning can be used to rapidly train cattle to follow colour cues and generalise these associations to new contexts or locations.

The goal of this research was to evaluate the effects of calf starter fermentation on rumen pH, metabolic adaptation of ruminal epithelia and growth of calves during the weaning transition. In study 1, calf starter consumption increased short chain fatty acid concentration in the rumen and changed expression of genes involved in ketogenesis and intracellular pH regulation but did not affect rumen pH. In study 2, decreasing dietary starch content did not increase rumen pH. However, feeding a calf starter that had the highest in situ dry matter disappearance lowered rumen pH without adversely affecting feed intake and growth of calves. These findings suggest that rumen epithelium can metabolically adapt to increased fermentation in the rumen at molecular level, and that sub-acute rumen acidosis may not adversely affect feed intake and productivity of dairy calves during the weaning transition. / Animal Science

Thesis (Ph. D.)--University of Wyoming, 2005. / Title from PDF title page (viewed on Nov. 15, 2007). Includes bibliographical references (p. 175-198).

Thesis (Ph.D.)--University of Adelaide, School of Agriculture and Wine, Disciplines of Animal Science and Biometrics SA, 2005? / "December, 2004." Bibliography: leaves 229-251.

Thesis (M.S.)--University of Wyoming, 2007. / Title from PDF title page (viewed on June 11, 2009). Includes bibliographical references.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 53-58). Also available on the Internet.