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    The carboxyl terminal sequence of sheep heart phosphofructokinase : a thesis for the degree of Master of Science in Biochemistry at Massey University
    (Massey University, 1980) Colls, David Selwyn
    The aim of this project was to investigate the carboxyl terminal sequence of sheep heart phosphofructokinase. Existing methods for the preparation of the enzyme from sheep heart proved to be unsuitable because of the insoluble nature of the purified enzyme. Consequently it was necessary to develop a suitable purification scheme before sequencing work could be commenced. Purification strategies involving magnesium ion precipitation of phosphofructokinase, DEAE-cellulose chromatography and agarose chromatography were tried before a suitable method was found. The carboxyl terminal sequence of phosphofructokinase was investigated by the tritium labelling method of Matsuo, by carboxypeptidase Y digestion and by isolation of the carboxyl terminal peptide generated by tryptic digestion. Digestion of phosphofructokinase by carboxypeptidase Y resulted in the release of leucine, isoleucine and phenylalanine. However attempts to characterise the carboxyl terminal residue by tritium laberling, and to isolate the carboxyl terminal peptide were unsuccessful. The carboxyl terminal sequence suggested by these results and the possible amidation of the carboxyl terminal residue are discussed.
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    Measurement of ovine plasma androgens by a competitive protein binding method : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science
    (Massey University, 1971) Torrey, William James
    A method has been developed for measuring plasma testosterone in sheep using competitive protein binding (CPB) techniques. The procedure requires column chromatography on LH-20 Sephadex gel of a methylene chloride extract of plasma, and final determination of plasma testosterone by the CPB technique using salt precipitation of the protein bound fraction. The sensitivity of the assay has allowed application to the measurement of plasma testosterone levels in normal male, normal female, Klinefelter and freemartin sheep. It has also enabled the monitoring of the effect of stimulation - with intravenous pregnant mare serum gonadotrophin and human chorionic gonadotrophin (HCG) - on the plasma testosterone levels of normal male and Klinefelter sheep. A modification to the method, borohydride reduction of the initial methylene chloride extract, has enabled the plasma androstenedione levels to be determined, simultaneously with plasma testosterone, in two of the HCG stimulation studies.
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    A study of the inheritance of some productive traits in Perendale sheep : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science at Massey University
    (Massey University, 1975) Elliott, Kenneth Hamilton
    Genetic parameters were estimated using 3,313 half-sib records from 62 sires and .1720 daughter-dam pairs. The data used were obtained over the period 1957 to 1972. The estimates of heritability by paternal half-sib and daughter-dam regression analysis were respectively:- weaning weight (0.20 and 0.16); hogget body weight (0.27 and 0.44); fleece weight (0.32 and 0.30); quality number (0.26 and O.31); fibre diameter (0.54 and 0.47); staple length (0.49 and 0.35); character (0.23 and 0.23). An estimate of 0.03 was obtained for lambs weaned/ewe lambing (Lw/EL) by the daughter-dam regression analysis from 665 daughter-dam pairs. Estimates of genetic correlations were in the following ranges;- Medium negative (-0.4 to -0.6) Low negative (-02. to -0.4) Low positive (0.2 to 0.4) Medium positive (0.4 to 0.6) High positive (0.6 and over) Hogget body weight with character. Quality number with staple length. Weaning weight with quality number, fibre diameter and character. Quality number with fleece weight and fibre diameter. Hogget body weight with weaning weight and quality number. Staple length with character. Fleece weight with fibre diameter and character. Fleece weight with staple length. Phenotypic and environmental correlations were also estimated. Phenotypic correlations generally agreed with the genetic correlations. Important exceptions were hogget body weight with fleece weight, staple length and fibre diameter. Among the environmental factors studied, age of dam and rearing rank effects for the wool traits were generally small. These effects had a marked influence on weaning weight and hogget body weight. At weaning, singles were 4.2 kg heavier than twins, while at 14 months, this difference had been reduced to 2.1 kg. When comparing a two-year-old and mature age of dam effects, a 1.44 kg difference at weaning in favour of the mature age of dam reared animals, was reduced to a 1.11 kg difference at 14 months. The estimated parameters and environmental effects were discussed with reference to their implications in selection programmes. Relationships between hogget traits and the ewes lifetime production (four consecutive years) were analysed. Records from 458 sheep were used. Correlation coefficients indicated that hogget fleece weight, quality number, fibre diameter and staple length were good indicators of lifetime ewe performance for these traits. The results indicated that a poor relation exists between hogget body weight and number of lambs weaned by the ewe over four lambings. A regression analysis of hogget traits on life-time economic value of the ewe indicated that fleece weight and hogget body weight were the most important variables influencing life-time economic value. Implications of the results were discussed with reference to selection and culling programmes at the hogget age in ram breeding and non-ram breeding flocks.
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    Measurement, mathematics, and mechanisms of mammalian growth : a thesis presented in partial fulment of the requirements for the degree of Doctor of Philosophy at Massey University
    (Massey University, 1978) Clark, Ross Graham
    Longitudinal growth experiments using rats, lambs, and heifers were analysed by establishing linear relationships between ages, live weights and body lengths in individual animals. Various analytical methods were investigated. Statistical and biological reasons forced the logarithmic transformation of weights and lengths, a three parameter logarithmic metameter was used if means and standard deviations were correlated on a two parameter logarithmic metameter. Age was transformed to give linear relationships. Changes to the experimental design and analysis of growth experiments were suggested. Effects were demonstrated in individual animals that were previously only shown for grouped data and the techniques' sensitivity produced novel findings. Rats were ovariectomised at three ages and/or treated with oestrogen and slaughtered at four ages. The rat ovary inhibited growth pre-pubertally, and the response to ovariectomy or oestrogen was negatively related to the pre-treatment growth rate. Compensatory growth occurred following weaning in rats and following birth in ruminants. Estimated initial weights explained more of the variation in subsequent growth rates than did observed weights. In rats pre-weaning growth lines diverged (compensation being negligible), birth and weaning weights being positively correlated, post-weaning growth rate was strongly negatively correlated with weaning weight. Estimated birth and final weights, and weaning and final weights, were unrelated; compensation being nearly complete. Two sets of pre-weaning lamb live weights (collected by others) were, for individual animals, linearised. Pre-weaning compensation occurred, as it did in two independent sets of weighings from monozygotic twin heifers (also collected by others). Compensatory growth, between and within sets of twin, occurred rapidly to weaning, then slowed. The efficiency of identical twins for experimentation, using these methods, was shown, as were the disadvantages of using average daily gains. The linear relationships did not explain all the systematic variation, short- and long-term oscillations in growth rate occurred. Long-term oscillations were related to live weight rather than to age. Neo-natal testosterone treatment of female rats transposed and advanced the pattern of growth. Both Sex and Strain affected the pattern of growth. The possible use of these techniques in animal breeding was discussed. The logarithms of lengths and weights, assumed by many biologists to be linearly related (allometry), showed curvilinear relationships. A technique of carcass analysis was developed and applied. Ovariectomy increased rat body weight and length but did not produce obesity (assayed by percentage composition and by allometry). Oestrogen stimulated fat deposition but inhibited linear growth. Body weight's response to oestrogen was adaptive,bone growth's non-adaptive. Similarly there was a large pre-pubertal sex difference in body length but a small difference in body weight. This separation of the mechanisms controlling bone growth and body weight increase was discussed. Part of the increased size of ovariectomised rats was attributed to increased skin size (and altered composition) and decreased tail length, giving decreased heat loss, and improved energy utilisation for growth. Body growth occurs in two overlapping phases, of cell hypertrophy and cell hyperplasia, represented by different growth equations, and controlled by different mechanisms. A possible mechanism controlling cell hypertrophy, and directing compensatory growth, based on cartilage growth, would explain some of the effects described. The endocrinology of the mechanism, and oestrogen's interaction with it, were discussed.
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    Endocrine cells in the gastrointestinal tract of sheep : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Histology at Massey University
    (Massey University, 1985) Gurnsey, Michael Peter
    Previous investigations have shown that the digestive activities of the mammalian GI tract are controlled, in part at least, by biologically active compounds released from endocrine cells in the mucosa of the GI tract itself. Despite this, comparatively few studies have been made of the endocrine cells in the GI tract of sheep. There is also a paucity of information about the suitability and reliability of histochemical and immunohistochemical methods for the identification of GI endocrine cells in sheep. The aims of this study were to: (a) establish reliable techniques for identifying endocrine cells in the GI tract of sheep, (b) use these techniques to investigate the effects of age on the distribution and densities of various GI endocrine cells, and (c) investigate possible changes in endocrine cell densities due to infection with the helminth parasite Trichostrongylus colubriformis. Initially, various histochemical and immunohistochemical staining techniques were investigated for their suitability for identifying endocrine cells in mucosal samples from reticulum, rumen, body and antral regions of the abomasum, three duodenal sites, ileum, colon and caecum, as well as the pancreas, of adult animals. As a result, the De Grandi technique was selected to estimate argyrophilic cell densities, EC cells were identified by the fast garnet technique, and ECL cells by their silver staining and morphological characteristics. The PAP immunohistochemical technique was used to identify G, S, and A cells, using antisera to gastrin, secretin, and pancreatic glucagon, respectively. No endocrine cells of any type were found in the reticulum or rumen. Argyrophilic cell densities were greatest in the abomasal body and proximal duodenum, then decreased distally. EC cell densities were highest in the duodenum, although, like argyrophilic cells, they were found throughout the abomasum and intestines. In contrast, ECL cells were confined to the abomasal body. Greatest densities of G cells occurred in the abomasal antrum and proximal duodenum; they were absent from the abomasal body, ileum and large intestine. S cells were confined in their distribution to the small intestine. Pancreatic islets of Langerhans contained A cells, as well as cells with slight argyrophilia; the identity of the latter cells was not determined. A cells were also found in exocrine acini, but these were the only cells in the exocrine portion of the pancreas that were stained by any of the histochemical or immunohistochemical techniques used. No A cells were identified in the mucosa of the GI tract. These studies also clearly established that ovine G cells are not argyrophilic. This finding is in contrast to those reported for most mammalian species with a simpler form of stomach. The effects of age on endocrine cell densities were studied using the tissues from 100 - 110 day old foetuses, 2 week and 24 week old lambs, and adult sheep. All endocrine cell types identified in adult sheep were also present at the other ages. However, in the foetuses, endocrine cell densities were lower than in other age groups. The most notable age-related trend was that antral G cell densities increased with increasing age. In contrast, from 2 weeks of age, there was a decrease in intestinal G cell densities with increasing age. It was also clear that D cell densities were much higher in 2 week old lambs than for any other age group. Possible explanations for these age-related changes in endocrine cell densities are discussed. D (somatostatin containing) cells were located throughout the abomasum and intestines of all nonadult animals and in pancreatic islets of 2 and 24 week old lambs. The effects on endocrine cell densities of an experimental infection with 40,000 T. colubriformis larvae was investigated in 40 week old lambs. Although the resultant infestation was mild, there was a significant (P<0.001) increase in argyrophilic cell densities in the proximal small intestine. Specific identification of the argyrophilic cell type(s) which had increased was not possible, however, the most likely candidates were D1, X and K cells. It was concluded from these studies that endocrine cells, similar in morphology and staining characteristics to those of other mammalian species, occur within the mucosa of the abomasum, small and large intestine of sheep. Greatest densities of endocrine cells occur in the abomasum and proximal duodenum. Cell types identified in the GI tract included EC, ECL, G, S and D cells, while D and A cells were identified in pancreatic islets. It was demonstrated that endocrine cell densities change with age and that significant changes in cell densities can occur in mild trichostrongylosis.
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    Energy metabolism, ranging behaviour and haematological studies with Romney Marsh and Cheviot sheep : a thesis presented for the degree of Doctor of Philosophy in the University of New Zealand
    (Massey University, 1958) Cresswell, Eric
    Youatt (1776-1847 a) in commenting on British breeds of sheep, writes:- "In all the different districts of the Kingdom we find various breeds of sheep beautifully adapted to the locality which they occupy. No one knows their origin; they are indigenous to the soil, climate and pasturage, the locality on which they graze; they seem to have been formed for it and by it." Some present day students of animal husbandry are now examining the characteristics of these various breeds in the light of the particular environment in which each originated. Their object is to discover what characteristics can fairly be ascribed to particular sets of conditions, or in other words, what possible functional adaptations to environment can be revealed by study of this unique collection of soil stable breeds. Interest in the background of the development of these breeds and its possible influence on them is not however limited to the United Kingdom as British breeds of livestock have been taken to all the corners of the world in the wake of the migratory movements of the British people. For example, in New Zealand, at the time of writing, attention is being focused on the Romney-Cheviot crossbred ewe which is competing against the Romney Marsh for certain hill country and this has prompted consideration of the parent stocks (Plates 1 and 2) from the standpoint of their original habitats. This project was undertaken to augment what has already been done in New Zealand on this subject.