School of Agriculture, Food and Ecosystem Sciences - Theses
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ItemBody composition studies in the sheep( 1957)When he was Senior Lecturer in Animal Physiology and Production at Melbourne University, Dra T.J. Robinson initiated a series of experiments concerned with the body composition of fat lambs. This study was carried out by the following team of workers under Dr. Robinson's leadership: Mr. Blair-Weste Physiology School; Dr. Binet, Statistics Department; and myself from the school of Agriculture. The aims of this study were to determine: (1) Whether the quality and conformation of a fat lamb carcass could be defined by external body and probe measurements. (2) Whether the antipyrene technique could be used to estimate the total body water in lambs and hence their body composition in terms of total waters fat, and fat free tissue. (3) What relationships might exist between the specific gravity of a lamb carcass and its fat content. (4) Whether sample joints in a lamb carcass were representative of the whole carcass in terms of total bone, muscle, and fate and therefore of total water, fat, and fat free tissue. The first part of the investigation was carried out by Drs. Robinson and ninety and I was in no way involved. The other experiments were carried out jointly by Dr. Robinson, Blair-West and myself. In October, 1953, Dr. Robinson divided 8 newly-born Suffolk cross lambs (all singles) into four similar pairs, and fed each pair on a different plane of nutrition. The lambs, which were made to grow along predetermined growth curves, were weighed fortnightly and antipyrene determinations were carried out monthly. Thus the growth curve of each lamb could be drawn and split up into its component parts - i.e. H2O, fat and fat-free tissue. All lambs were killed when they reached 80 lbs. live weight, and the carcasses deep frozen. When I joined the team, in January, 1955, the carcasses were removed from the cold store and I carried out the specific gravity determinations on them. In order to test the worth of both the antipyrene and specific gravity techniques some standard methods of estimating body composition had to be used as a comparison. It was hoped that the specific gravity of the carcass would give a measure of chemical fat content of the carcass and that antipyrene estimations would give a measure of the total body water in the live sheep. The standard technique used for assessing these estimates was a complete chemical analysis of each lamb into total water, fat protein and residue. One side of each carcass was dissected into total bone, muscle, subcutaneous and intermuscular fat. It was then possible to assess the relationships between the physical and chemical composition of the carcass and the relationships between the physical and chemical composition of sample joints in the carcass and the total carcass. I was responsible for carrying out both the carcass dissections and the chemical analysis. During the course of this work (February, l956), Dr. Robinson took up a new appointment as. Professor of Animal Husbandry at Sydney University. I remained in Melbourne to complete the work under the direction of Dr. D.E. Tribe, the newly appointed Reader in Animal Physiology and Production. The experimental work reported in this thesis is limited to that part of the study for which I was responsible. It will be appreciated therefore, that its full significance lies in its relationship to the work of the other members of the team.
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ItemThe effect of the level of nutrition during pregnancy and lactation on the production of grazing sheep, and the interaction between levels of fertility and nutrition( 1956)The livelihood of the sheep farmer depends upon the success with which his ewes produce and rear healthy lambs. This is of particular truth in those areas where fat lambs are produced. It is well known that the production of lambs in large number and in good health depends very largely upon the standard of feeding of the ewes during pregnancy and lactation. however in most areas of the world sheep are restricted to those marginal localities in which the agriculturist finds it difficult to produce milk, eggs or vegetables. Under these conditions, the feeding of pregnant and lactating ewes becomes a task of some difficulty. Where food is in short supply it is very necessary to know at what stage of pregnancy or lactation the plane of nutrition should be raised. Thomson and Thomson (1949) have shown that in Scotland the sheep farmer should feed a supplement to his ewes during late pregnancy. Coop (1950) on the other hand has shown that under his New Zealand conditions, the supplement was best reserved until lactation has commenced. It was thought important to know the effect of different planes of nutrition on pregnant and lactating ewes under the conditions of sheep farming in South Victoria. It was for this reason that the present investigation was undertaken. In addition it was thought to be of interest to determine the interaction "if any" between the level of fertility and that of nutrition
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ItemEndocrine interactions in the oestrous cycle of domestic animals with particular to the sheep( 1956)A full knowledge of the hormones involved in the oestrous cycle and their interactions, is essential for an understanding of many of the problems associated with fertility of domestic animals. This knowledge is most essential for the study of the control of reproductive phenomena in practical animal husbandry, such for example as the successful breeding of the anoestrous ewe, and the synchronisation of oestrus and ovulation in the cyclic ewe and cow for the purposes of artificial insemination and ovum transplantation. Until recently fundamental studies of the hormones involved in the oestrous cycle have been almost completely confined to laboratory animals. Now, with relatively cheap sources of large quantities of steroid hormones, experimental work is possible using the larger domestic animals. This paper is a report of such studies in the sheep. The fact that most of the literature on this topic is concerned with the small laboratory animals necessitates a brief account of the more pertinent findings for these animals.