School of Agriculture, Food and Ecosystem Sciences - Theses

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    Performance recording of beef cattle in Victoria and adjacent regions
    Mason, W. E. (University of Melbourne, 1968)
    This thesis comprises four chapters. Chapters 1, 2 and 3 report scientific investigations involving performance recording of beef cattle. Chapter 4 contains conclusions and recommendations based on the investigations described in the first 3 chapters. My responsibilities in the preparation of this thesis included a detailed review of the scientific literature on subject matter pertaining to performance recording of beef cattle. This is presented in chapter 1 and this entire chapter was my complete responsibility. Chapter 2 describes the beef cattle breeding industry and the records which were available for this study. I am responsible for the contents and preparation of this chapter. Chapter 3 includes the analysis and interpretation of the records used in this study. Dr. R. G. Beilharz assisted with the statistical analysis. Chapter 4, which includes conclusions and recommendations resulting from this investigation, was entirely my responsibility.
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    The use & control of plants in Victorian irrigation & drainage systems
    Bill, S. M. (University of Melbourne, 1967)
    An account is given of the use of plants by the State Rivers and Water Supply Commission of Victoria to stabilize soils in Victorian irrigation supply channel and drainage systems. Chemical methods of controlling the growth of plants that occur naturally and create problems are also described, together with the principles that are observed when developing these methods. The importance of control of plant growth to achieve maximum channel and drain capacities, while at the same time ensuring maximum soil stability is discussed. The need for regulation of chemical usage where water supplies and irrigated crops can be contaminated is stressed. Research conducted in Victoria is described and compared with that in the U.S.A., and recommendations are made regarding the most useful avenues for future research. Publications describing various aspects of the use and control of plants in Victorian irrigation and drainage systems are attached.
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    The effect of water stress on the growth of the wheat plant
    Elliott, Brian Ramsay. (University of Melbourne, 1965)
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    Studies in animal production
    Tribe, D. E. (Derek Edward), 1926- (University of Melbourne, 1964)
    The papers presented in this thesis have been classified under four headings. Many of those in the Animal Behaviour group report work which was carried out while the applicant was a Scientific Officer at the Rowett Research Institute. All of these were planned and largely carried out by the applicant although in some cases authorship was shared with J.G. Gordan who was the applicant's experimental officer. The remaining rapers report work which was carried out while the applicant was on the academic staffs of either the University of Bristol or the University of Melbourne. Many of the pieces of work reported formed part of a post-graduate training programme and authorship is thus shared with post-graduate students. However in all cases the design of each experiment was the responsibility of the applicant and the work formed a continuing programme of study devised by the applicant. In all cases the applicant made a substantial contribution to the execution of the work and bore a major responsibility for the preparation of results for publication. The following list of papers includes those pieces of work which were carried out by post-graduate students under the supervision of the applicant but in which the applicant did not share the authorship.
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    The grazing intake of sheep and related measurements
    Vercoe, J. (John) (University of Melbourne, 1960)
    In Australia, animal production is dependent largely on pasture. A basic requirement therefore in studying the nutrition of the gazing animal, is a satisfactory measurement of grazing intake. Such a measure would be desirable at the level of the individual animal and although some techniques offer this possibility, the errors associated with them at present limit their application to the investigation of comparatively large differences. Fortunately, at the present time, research into pasture utilization and the nutrition of the grazing animal is at the developmental stage and is consequently concerned with investigating large differences. As these differences become smaller however, so the techniques must become more refined. The problems associated with the measurement of grazing intake are many. Under Australian conditions there is a marked variation in both the quality and the quantity of feed available to animals throughout the year and furthermore the changes which occur can be rapid. The situation is further complicated by the feat that in the first place measurements must be made under controlled conditions with sheen in cages where the ability to select a diet is restricted. Under grazing conditions however, the opportunity for selection may be greatly increased, depending on the level of stocking, and direct application of the information from caged conditions is therefore impossible. There can be little doubt in the minds of those interested in the nutrition of the grazing animal, that there is an urgent demand for a system of feeding standards for grazing conditions. Metabolism and respiration data for animals under controlled conditions are showing which factors influence the utilization of dietary energy and protein by the animal. For this information to be applied to field conditions, a measure of the intake of energy and protein b the grazing animal is fundamental. In Chapter 1, the various techniques described in the literature to estimate the qualitative and quantitative intake of the grazing animal are reviewed and in the subsequent Chapters an experimental approach is described. Chapter 2 describes the application of one such technique to cheep grazing an annual pasture; Chapter 3 describes an appraisal of the same technique used for irrigated pastures; Chapter 4 includes the effect of sudden changes in diet on digestibility together with some observations on the measurement of digestibility and Chapter 5 describes some features of the feeding value of M. tribuloides pods which form a substantial portion of the diet of grazing sheep over the summer months.
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    The parotid salivary secretion of sheep
    Wilson, A. D (1938-) ( 1963)
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    Beef-cattle production in the Western District of Victoria : technical and economic relationships between beef cattle and sheep
    Wills, I. R ( 1965)
    Sheep-and-wool production and beef-cattle production are combined on many grazing properties in the Western District of Victoria. In the past beef cattle have generally been regarded as less profitable than sheep as a sole enterprise on a per-acre basis. In previous surveys it has been found that graziers believe that sheep and beef-cattle complement one another in a variety of circumstances because of the different effects of the two types of animal on pasture. It has also been found that sheep and beef cattle on grazing properties are frequently supplementary with respect to labour. The thesis has two main objectives. First it investigates whether the currently available analytical models based on static economic theory are adequate to solve problems of resource allocation between sheep and beef cattle grazing the same pasture. Second, it investigates whether many graziers carry beef cattle partly or solely to satisfy goals other than profit maximisation. The method of achieving the first objective was to compare the static economic theory relating to enterprise combination, and published work dealing with the problem of selecting the optimum combination of two enterprises, with the real situation existing on grazing properties carrying both sheep and beef cattle. The second objective was investigated by means or an interview survey of graziers running both sheep and beef cattle in six Western District parishes. A considerable amount of technical information about beef-cattle production in the Western District was collected in the course of the survey, and the more important points are summarised in the thesis. Of particular interest are the findings that very few graziers purchased cattle for fattening purposes, and that beef cattle were relatively more important on large properties than on small properties. It was concluded that static economic theory does not provide an adequate basis for the description of the situation where sheep and cattle graze the same pasture, or for the determination of the optimum allocation of resources between sheep arid beef cattle grazing together. Sheep and cattle graze pasture differently, and therefore different pastures result as the sheep-cattle ratio is altered. In this situation, the postulates on which the iso-resource function is based, that the shared input or inputs should remain homogeneous and constant in quantity as the outputs of the products change, are violated. Thus strictly speaking it is not possible to derive a valid iso-resource function relating the sheep and beef-cattle enterprises with respect to pasture when the sheep and the cattle graze the same pasture. However, if the changes in the pasture are disregarded, it is possible to design experiments to produce practical approximations of iso-resource curves relating sheep and beef cattle. Information obtained from graziers in this and other surveys, and the results of experiments, strongly suggest that for practical purposes it is reasonable to think of an iso-resource curve for sheep and cattle with respect to pasture as being concave towards the origin, that is, the sacrifice rate of sheep for cattle increases as more cattle are added on a sheep property. Farmer estimates and experimental evidence suggests that the marginal sacrifice rate on most properties may be lower than is generally assumed (nutritional standards imply a linear rate of eight merino whethers per 1,000 lb. steer). Almost all the survey graziers believed that the overall relationship between their sheep and their beef cattle with respect to their total feed supply over the whole year was a competitive one. Most estimated that their sheep and their cattle were complementary or supplementary with respect to pasture over a part of the year, including the Spring, and that their sheep and their cattle competed for scarce pasture at some time in the autumn and winter. The survey results showed that the most important reason for the presence of beef cattle on the survey properties was the value of cattle in controlling and utilising pasture and weed growth. However the value 0f cattle for that purpose appeared to decline as the sheep stocking rate increased. It appeared that on many properties the importance of beef cattle in pasture control was a consequence of a desire on the part of the grazier to maximise profits within the restrictions imposed by limitations on sheep numbers including the grazier's desire to limit his personal effort. Beef cattle were also frequently carried for the reason that they provided a means of stabilising income from year to year. Although the survey results tended to confirm previous findings that sheep and beef cattle are supplementary with respect to labour at certain times during the year, and that beef cattle generally require less labour per unit of return than sheep, few graziers said that they carried beef cattle for those reasons. It was concluded that substantial minority of the survey graziers did carry beef cattle partly or solely to satisfy goals other than profit maximisation. The most important of these goals was the minimisation of personal effort, which was shown not by giving labour as a reason for carrying beef cattle, but indirectly in the affirmation of the value of cattle (rather than additional sheep) in pasture control. A few graziers were motivated by a personal preference for beef cattle. In the situation where the available economic theory is inadequate to solve problems of resource allocation between sheep and beef cattle, and where a substantial proportion of graziers carry beef cattle partly or solely for reasons other than profit maximisation, there is little scope for sophisticated economic procedures. Given additional experimental data to provide indicators of probable "substitution rates", it seems that the allocation of resources between sheep and beef cattle on properties such as those in the survey can best be improved by budgeting possible adjustments.
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    Quality of potatoes for processing
    Wilcox, Andrea M ( 1966)
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    The physical and functional development of the forestomachs of the lamb
    Wardrop, Ian Donald ( 1960)
    In this thesis a study of the physical and functional development of the forestomachs of the lamb is presented. The experimental work can be divided into three main fields as follows:- a) Studies on the physical development of the fore- stomachs. b) Studies on the functional development of the reticule-rumen. a) Field work in which the above studies have some direct bearing. The main findings of these studies have a) PhysicaI development of the forestomachs: In grazing lefts the four stomachs have reached their adult proportions by approximately 8 weeks of age. The type of diet can markedly influence the rate of growth of the forestomachs, and in general, it would appear that plant food is needed for the normal development of the forestomachs, and It plant food is excluded from the diet the development of the forestomachs is retarded at about the level found in the 3 week old grazing lamb. The main changes in the histology of the forestomach walls takes place during the last third of foetal life, and the adult his histological features are all present at birth. The major post-natal histological changes are complete by 56 days of age. It would appear that age is the main factor controlling the histological development of the forestomachs, and that plant material is necessary for the full development It of these organs. It was also shown that different diets can cause differences in the appearance of the rumen mucosal surface, stratum granulosum and stratum corneum. b) Funcational development of the reticulo-rumen: It was postulated that the functional development of the reticulo-rumen of the grazing iamb could be divided into three phases - a non ruminant phase (0 - 3 weeks of age), a transition phase (3 - 8 weeks of age) and an adult ruminant phase (8 weeks of age onwards). If plant food was excluded from the diet, the lamb remained in the non- ruminant phase, however, once plant food was fed to these lambs the reticule-rumen function reached the adult levels within one week. c) Field studies: As the forestomachs of the grazing are qualitatively and quantitatively fully developed by approximately 8 weeks of age, it is possible to ween lambs of this age with no check to their growth rate, provided the pastures are relatively high in protein and are not at the late flowering or seeding stages. The milk yield of the grazing ewe measured by the oxytocin technique gave consistently higher recordings throughout Iactation than the conventional lamb suckling technique. By the tenth week of the lactation the milk yield, as measured by both techniques, had fallen by half. There was a high correlation between the milk yield of the ewe and the lamb live weight growth up to seven weeks of age.
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    Studies in animal nutrition : the intake and storage of dietary nitrogen and energy
    Vercoe, John Edward ( 1963)
    This thesis is divided into two parts. Part I consists of three chapters. Chapter 1 is a critical review of the literature which deals with the nutritional factors which influence nitrogen and energy retention in animals. In the light of these factors, the effect of dietary composition on the relative storage of energy as fat and protein is discussed. The review concludes by discussing the effect of energy storage as fat and protein on changes in liveweight. There is an extremely large volume of literature on this subject and no attempt has been made to cover it exhaustively. The more important contributions to the field have been mentioned and the review investigates the variety and complexity of nutritional factors which may influence the composition of energy storage, and discusses their likely effects. Chapter 2 describes two experiments where four diets, which differed in their levels of protein, were each fed at four levels of intake to adult guinea pigs. The effect of the level of dietary protein on the energy and nitrogen balance of the animals was investigated. Chapter 3 reports an experiment in which the change in liveweight of penned sheep, fed diets which varied in the levels of protein and energy, was interpreted in terms of the nitrogen balance of the animals and their metabolizable energy intake. The contents of Chapters 2 and 3 are to be submitted for publication shortly. Part II of the thesis consists of four published papers dealing with the food intake of grazing sheep. Chronologically the work reported in Part II preceded that reported in Part I. Chapter 4 and 5 deal with the faecal-nitrogen technique for measuring the intake of grazing sheep for both annual and perennial pastures. Chapter 6 reports the results obtained when faecal-nitrogen techniques were used to estimate the intake of a group of grazing sheep and Chapter 7 uses the results of Chapters 5 and 6 to present a hypothetical model which suggests the importance of dietary composition, with respect to digestible organic matter and digestible nitrogen, in determining the liveweight change of sheep grazing annual pastures.