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The profitability of beef production on some New Zealand sheep farms : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Farm Management at Massey University
(Massey University, 1971) Lowe, Kevin I.
New Zealand sheep farmers are currently receiving product prices which, when considered in relation to their farm costs, are the lowest they have been for many years. Wool prices appear unlikely to recover to levels experienced ten years ago and many sheep farmers are still relying on wool as a major source of farm income. There is an increasing awareness that beef animals can no longer be regarded as aids to good sheep husbandry and instead, must make a direct contribution to farm income. The increasing acceptance of animals of dairy origin as beef-producers, and continued confidence in the long-term market for beef, have helped provide a climate for large-scale moves toward beef-production on many New Zealand sheep farms. As a consequence, there has been a rapid increase in demand for economic information on all aspects of beef production and particularly with relation to established sheep enterprises. It is intended that this thesis shoud go some way towards meeting this demand. [From Introduction]
A study of the Romney fat lamb ewe, with particular reference to milk secretion and its effect on fat lamb production : thesis submitted by "392" [Alan Graham Logan] for the M. Agr. Sc. degree at Massey University
(Massey University, 1946) Logan, Alan Graham
One of the distinguishing characteristics of mammals, is the dependance of the young, during early post-natal life, on nourishment secreted by the mammary gland of the mother. Hence milk secretion is of fundamental importance in all our farm animals with the exception of poultry. The essential attributes of milk (viz., high water content and liquid state, high digestibility, high protein content of excellent biological value, high calcium and phosphorus and the presence of most of the necessary vitamins) are specially suited to the needs of young rapidly growing animals. In dairy cattle extensive study has been made of milk producing ability and conscious effort made to improve this by breeding, and nutrition. Comparison of the characteristics of modern dairy cattle (highly developed milking qualities but inferior meat carcasses) and of beef cattle (early-maturing and good carcass quality but often poor milk yield) clearly indicate the extent of improvement from the wild form and the variation in productive efficiency of different types. Valuable work on the milk-producing ability of other species, and its relationship to the welfare of the young has been carried out by Bonsma and Oosthuizen (1) and Donald (7) with Sows; and Ritzman (30), Fuller and Kleinhanz (10), Neidig and Iddings (24), Bonsma (2,3), 30a, Pierce (27,28) with ewes of non-milking breeds, and by several workers with specialised milking sheep, Scheingraber (31), Muhlberg (23), Maule (17). [From Introduction]
A study of the effects of plane of nutrition on milk secretion and lamb growth in Romney sheep, and the effect of weaning date on the growth of Romney lambs : a thesis presented in partial fulfilment of the requirements for the degree Master of Agricultural Science of the University of New Zealand
(Massey University, 1952) Murray, Paul Frederick
The productivity of an animal depends on two factors, its potentiality, which is governed by its hereditary make-up, and the extent to which that potentiality is allowed to develop, this being regulated by the environment that characterises the habitat. The effects of genotype are obviously shown by the differences between breeds of stock in the amount and quality of meat, wool and milk they produce; but within breeds these effects are not so apparent though they have been conclusively demonstrated, e.g. yield and quality between flocks of Romney sheep. Environmental influence on productivity is limited at the maximum level by the genotype, i.e. no matter how good the environment, the animal cannot produce more than the maximum ordained by the genes it possesses. Conversely, below the genotypic maximum, the environment can regulate the coiling level of production. This interplay of factors is well illustrated by the adaptability of different breeds of sheep to different habitats, e, g. the Romney is predominant in the North Island hill country while in the South the Merino and its crosses assume a greater importance. Within a population with approximately common genotype, e.g. a single flock of uniform breed, the effects of environment below the threshold set by the genotype can be widely varied, e.g. the growth of lambs in a drought can be severely set back. It is with the effects of a particular factor of environment, i.e. nutrition, on the milk production and lamb growth of such a population that this investigation is concerned.
An investigation into the structure and function of the ileocaecal junction of the sheep : a thesis presented in fulfilment of the requirements for the degree of Master of Science by thesis only at Massey University
(Massey University, 1992) Murphy, Peter Grant
The sheep ileocaecal junction has been shown to have sphincter-like properties, fulfilling the criteria for a gastrointestinal sphincter identified by Fisher and Cohen (1973). However the short zone of elevated pressure within the lleocaecal Junction (ICJ) could be due to venous engorgement rather than tonic muscular activity, as the tip of the ileum examined histologically reveals an irregular musculature interspersed with a vascular loose connective tissue. A similarity is suggested to the human ileocaecal sphincter as described by Quigley, Borody, Phillips, Weinbeck, Tucker and Haddad (1984). This short (less than 5mm) zone of elevated pressure in the sheep would appear to work in conjunction with a valvular action as described by Kuman and Phillips (1987) for the human ICJ, preventing retrograde digesta flow from the caecum to the ileum. EMG recordings of the ileocaecal region in the conscious sheep showed approximately 70-80% of the MMC phase 3 activity that reaches the distal ileum progresses as far as the ICJ. This appears to be the main motility pattern present in this region in the conscious sheep, and very little coordination was observed between patterns of caecal and ileal activity. Feeding was found to decrease the amount of MMC activity in the distal ileum by lengthening the interval between successive MMC phase 3 patterns of motility. This effect of feeding on MMC activity appears not to be due to the levels of circulating gastrin, and could be due to either a reflex inhibition such as an intestino-intestinal reflex mediated by noradrenaline as has been described for cats, or humoral mechanisms involving another. agent such as cholecystekinin, VIP or Substance P. Both the latter substances were shown to be present in nervous tissue within the ileum, though their role remains unclear.
A comparative study of defoliation in Holcus lantanus and Lolium perenne pastures grazed by sheep : a thesis presented in partial fulfilment of the requirements for the degree of Master in Agriculture at Massey University
(Massey University, 1993) Hu, Yankai
Objectives of this study were (i) to extend limited information on the assessment of relative defoliation of grass and legume components in mixed ryegrass/white clover and yorkshire fog/white clover pastures, (ii) to test whether the balance of preference between ryegrass and clover differed from that between yorkshire fog and clover, and (iii) to compare the behaviour and the potential reaction of the two grass species under grazing conditions. Observations were made on plots of ryegrass/white clover and yorkshire fog/white clover grazed by sheep at high (12% live weight) and medium (6% live weight) herbage allowance. There were four replicates of each treatment, which were grazed in rotation over a four week period. Detailed sward measurements were made before and after grazing. Measurement of herbage mass, sward height, sward components, pasture structure and defoliation are reported. Sward surface heights were very similar for the two swards both before and after grazing. The sown grasses formed the dominant proportions in both swards, while white clover proportions were similar. The proportion of dead material was higher for yorkshire fog/white clover pasture than ryegrass/white clover pasture both before and after grazing. Tiller populations were higher for yorkshire fog than ryegrass (10355 vs. 6505 ±919 m·2). Mean stem length was greater for yorkshire fog than ryegrass (62.3 vs.35.0 ±2.8 mm), and the distribution of stem length showed a stronger positive skew. Yorkshire fog had a shorter leaf length than ryegrass. The population density of white clover nodes was similar in the two swards. White clover nodes in the two swards were quite similar in leaf weight, number and area both before and after grazing. The defoliated heights for clover in ryegrass/white clover and yorkshire fog/white clover swards (3 cm and 5 cm respectively) were similar at both low and high grazing allowance. The proportion of grass in the grazed stratum was higher for ryegrass than for yorkshire fog pasture before grazing, but the proportion of white clover was lower. Three parameters estimated from pre- and post-grazing measurements on individual grass tillers and clover nodes were used in the interpretation of pasture defoliation: namely defoliation frequency, defoliation severity and defoliation pressure (frequency x severity). In ryegrass/white clover pastures, the defoliation of leaf was significantly higher for ryegrass than white clover for all three parameters. In the comparison within yorkshire fog/white clover pastures, the defoliation frequency was not different between grass and clover, but the severity of defoliation and defoliation pressure were significantly higher for grass than clover. Ryegrass stem was grazed more severely than white clover petiole in ryegrass/white clover pastures. Defoliation parameters for yorkshire fog stems and white clover petioles in yorkshire fog/white clover pastures showed smaller and not significant differences. There was a highly significant effect of allowance on leaf defoliation in ryegrass/white clover pastures, but the effect was less marked in yorkshire fog/white clover pastures. More ryegrass leaf was grazed per day than yorkshire fog leaf. The proportion of leaf removed and the pressure of defoliation were higher in ryegrass than in fog. When white clovers were compared between the two swards, there were no differences in any of the three defoliation parameters. Leaf defoliation effects were greater at medium allowance than at high allowance. For all parameters, allowance effects were greater for grass than clover. The fact that grasses were defoliated more severely than the companion clovers in both swards reflected the effects of vertical distribution of sward components. However, the much lower defoliated height for clovers in both swards strongly suggested that sheep actively selected clover in the mixed swards despite the fact that clover was distributed much lower in the sward canopies. The greater defoliation of ryegrass than yorkshire fog leaf was attributed to greater preference of the animal for ryegrass than yorkshire fog in comparison with the companion clover.
Aspects of the biology of Campbell Island feral sheep (Ovis aries L.) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Zoology at Massey University
(Massey University, 1986) Ballance, Alison
The feral sheep population of Campbell Island was studied between April and August 1984. Data were collected from 2529 of the 4000 sheep killed in the south-east of the island, and the population described. Productivity and timing of lambing are examined. A survivorship curve and the age:sex characteristics are plotted to illustrate mortality and population structure. Changes in population size and lambing rates since 1895 are presented. Attributes such as wool colour, occurrence of horns, body size and lambing dates are described. In several respects these differed significantly between localities, and the existence of distinct sub-populations is suggested. The presence of these sub-populations is related to home range behaviour. Observations were made of 70 tagged sheep in the area around Menhir during April-June 1984, and it is suggested that they adhere to a home range, the mean size of which was 43.3 ha. Sheep were found associated in groups of up to 65, although mean size was 6.31. There was no constancy in group composition, although several hogget:dam associations were noted. Groups comprised both rams and ewes. Time activity observations showed that in winter the sheep spent 70.2% of the time grazing, and 16.6% ruminating, with ruminating peaking around midday.
Some aspects of the bone-muscle relationships in New Zealand lamb and mutton carcasses : a thesis presented at Massey Agricultural College in partial fulfilment of the requirements for the degree of Master of Agricultural Science in the University of New Zealand
(Massey University, 1961) Russel, A. J. F.
The three main constituents of a meat carcass are bone, musele, and fat, and of these the lean meat or muscle is of greatest interest and importance to the consumer. Bone represents an almost total waste and is hence considered as undesizable and as something which must be accepted with the desirable muscular tissue. In the words of Robert Bakewell, "You can't eat bone, therefore give the public something to eat." (Dawson, 1957). The Physical properties of muscle and bone are markedly different. Muscular tissue is compressible and hence difficult to ensure with accuracy on a linear scale. The intimate association of skeletal muscle with other tissues makes its complete removal for accurate weight estimation both difficult and tedious. Bony tissue, on the other hand, lends itself more readily to the measurement of linear dimensions and weight.
Experimental pneumonia induced by a Bordetella parapertussis-like organism in the ovine and murine lung : a thesis presented in partial fulfillment (70%) of the requirements for the degree of Master of Philosophy in Veterinary Pathology at Massey University
(Massey University, 1987) Chen, Wangxue
Thirty-four specific pathogen-free (SPF) Swiss mice were intranasally inoculated with a suspension containing about 3 x 10 7 colony-forming units (CFU)/ml of a B. parapertussis-like organism isolated from pneumonic ovine lung. Eleven per cent of the animals died between 2 and 3 days of inoculation and over 90% of infected mice developed a subacute bronchopneumonia morphologically similar to early lesions of naturally-occurring ovine chronic non-progressive pneumonia (CNP). The sequential pulmonary changes were examined by light microscopy and transmission electronmicroscopy from 12 hr to 29 days after inoculation. The early stages were characterized by alveolar septal congestion and oedema, focal intra-alveolar haemorrhage, and intra-alveolar and septal infiltration by neutrophils and macrophages. Later, hyperplasia of perivascular and peribronchiolar lymphoid tissue and the deposition of collagen in the interalveolar septa were prominent. The bronchial and bronchiolar epithelium remained intact throughout the experiment, but bronchiolar lumina became occluded by inflammatory exudate at an early stage. Ultrastructural changes consisted of the degeneration of the alveolar type I and type II epithelial cells and marked degeneration of alveolar macrophages. Pure cultures of the B. parapertussis-like organism were consistently recovered from mouse lungs 12 hr to 6 days after inoculation. Both intact and degenerating organisms were found free in alveolar spaces and within phagocytic vacuoles of alveolar macrophages. However, replication of organisms was not observed at any stage of infection and no special association was observed between organisms and the ciliated or non-ciliated respiratory epithelium. Injury to ovine respiratory tract was demonstrated when a similar bacterial suspension to that given to the mice was given by intratracheally to colostrum-deprived lambs. The lesions produced in the pulmonary parenchyma of the lambs were similar to those seen in both early naturally-occurring ovine CNP and the experimental infection with this organism in mice. They consisted of an acute mild tracheobronchitis, severe alveolar collapse and acute bronchopneumonia which developed within 24 hr and was most severe at 1 to 3 days after inoculation. Ultrastructurally, the alveolar epithelium exhibited extensive degenerative changes and necrosis of individual epithelial cells. Topographical studies revealed extensive coverage of the infected tracheobronchial epithelium with a dense layer of inflammatory cells mixed with mucus, and focal extrusion of ciliated cells. Occasionally, moderate numbers of the B. parapertussis-like coccobacilli were seen closely associated with cilia. Inoculated lambs showed a marked elevation in the numbers of cells in bronchoalveolar lavage 24 hr after infection. Up to 93% of the cells in the lavage at 24 hr were neutrophils. However, no close interation between phagocytic cells and the organises was detected. Many of the macrophages in the lavage exhibited cytoplasmic vacuolation from five days after inoculation onwards. Blood leucocyte and neutrophil counts in infected lambs gradually rose to reach peaks at five and three days after inoculation, respectively. The B. parapertussis-like organism was recovered in pure culture from the nasal cavity of lambs killed on days one, three, five and nine. The viable bacterial count in bronchoalveolar lavage fluid decreased from 24 hr to 5 days with almost complete elimination of organisms nine days after inoculation. The retention of the B. parapertussis-like organism in the mouse trachea was compared to that in the mouse lung from 0 to 48 hr after intranasal inoculation. Although there was greater bacterial deposition in the trachea than the lung there was a faster clearance from the trachea. At 48 hr after instillation, almost all organisms were eliminated from the trachea but about 45% of organisms were retained in the lung. The current investigation has shown that the B. parapertussis-like organism can infect SPF mice and colostrum-deprived lambs and induce a subacute bronchopneumonia. The morphological changes seen suggest that this organism has the potential to predispose the ovine respiratory tract to further infection by other microorganisms and that the organism itself may also be able to cause severe pulmonary damage. The relevance of these observations to the problem of CNP in sheep in the field has yet to be determined.
Effects of Ostertagia circumcincta larvae and adult parasites on abomasal and intestinal tissues in sheep : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Physiology
(Massey University, 1994) Hodgkinson, Suzanne Marie
Ostertagia circumcincta parasites infect the abomasum of sheep causing damage to the abomasal tissues and significant production losses to the sheep farming industry. Ingested larvae enter the gastric glands and emerge as adults which live in the abomasal lumen. The effect of adult parasites on the abomasum has not been systematically investigated. In the present study, sheep raised to be free of helminth parasites were given either adult O. circumcincta parasites via an abomasal cannula or larvae per os. Adult as well as larval O. circumcincta parasites stimulate hypergastrinaemia, a decreased abomasal pH and elevated serum pepsinogen concentrations. While the concentration of G cells did not change in the larval parasite infected sheep compared with the non-infected control sheep, the total number of G cells was increased due to an increase in mucosal thickness. There appeared to be fewer G cells present in the adult parasite infected sheep compared with the non-infected control sheep, which was most likely due to a depletion of their gastrin content due to overstimulation. The hypergastrinaemia observed during ostertagiasis is not due to a change in the ratio of G:D cells. The lumen dwelling adult O. circumcincta affect the mucosa of the abomasum resulting in an apparent inflammatory reaction, demonstrated by the presence of eosinophils and neutrophils in the lamina propria. Mucous production and/or secretion is also affected, shown by the presence of large mucus-secreting cells in the mucosa. The total wet weight of the abomasum/kg body weight is increased in sheep infected with O. circumcincta, with an increase in the total size of the abomasum. The larval parasites evoke a hyperplasia in both the antral and body mucosae with little change in cell size. In sheep infected with adult parasites, the thickness of the abomasal mucosa is increased in the body, but not the antrum. This increase is most likely due to hypertrophy. Either the larval O. circumcincta or the hypergastrinaemia have trophic effects on the upper duodenum, with an increased mucosal thickness which did not occur more distally. This did not occur in the adult parasite infected sheep. The larval parasites or hypergastrinaemia provoked a hyperplasia in the jejunal mucosa. This did not occur in the adult infected sheep. The larvae and adult parasites did not appear to exert a hypertrophic or hyperplastic effect on the ileum, caecum or colon. Those results indicate that adult O. circumcincta parasites have substantial effects on the ovine abomasum.
A study of pasture pattern in relation to microtopography : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science at Massey University
(Massey University, 1966) Rumball, Peter John
An important aspect of the science of plant ecology is the determination of the nature and causes of variation in vegetation. Reflecting the controlling influence of the physical environment, this variation is continuous both in space and in time. The most rewarding means of unravelling the intricate relationships between vegetation and habitat is through the detection and analysis of pattern. In an ecological context, pattern may be defined as the non-random distribution of vegetation units within a defined area. This means in effect, that the distribution is either more contagious or more regular than could be expected, if chance was the only factor which influenced the distribution. Greig-Smith (1964) described a random distribution as one in which the presence of one individual (unit) does not either raise or lower the probability of another occurring nearby. The existence of pattern in vegetation is apparently a universal phenomenom. It may be manifest on a very wide range of scales and intensities; from broad global-wide belts of vegetation, down to the variable performance of a single species over a small are.. Causes of pattern may be either intrinsic, (e.g. method of dispersion, competitive ability) or extrinsic, (e.g. variations in the effective physical environment). [From Introduction]

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