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Item 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]Item 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 GrahamOne 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]Item 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 FrederickThe 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.Item 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, AlisonThe 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.Item 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.Item 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, WangxueThirty-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.Item 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 JohnAn 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]Item Analysis of farmer cognitive structures with respect to high fecundity sheep management systems: a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Agricultural Economics and Farm Management at Massey University(Massey University, 1987) Saunders, L. S.The object of the research presented in this thesis is to evaluate three multivariate techniques for representing and analysing farmer cognitive structures. The context involves representation of farmer belief and attitude relationships relative to their overall attitude towards high fecundity sheep production systems. Modelling of behavioural determinants positions this research within the soft component of management and is aimed at moving from the 'art' to the 'science' (as defined by Nix, 1979) of soft systems management research. Reviews of high fecundity production systems are presented such that the 'act' of high fecundity was defined as: "to maximise the weight of lamb weaned within flocks with a potential of 140% Lambs Born per Ewe Weaned. " The Fishbein and Ajzen ( 1979 mode of reasoned action is extended to incorporate the differentiation of input and outcome concepts. Galileo Methodology (Woelfe 1 et al, 1977), involving a system of interview methods and questionnaires in association with a Metric Multidimensional Scaling program, was used to measure the belief and attitude relationships and then spatially represent the cognitive structures of a sample of Western Hawkes Bay Farmers and a group of Experts. The extension objective of this research is to identify differing cognitive structures between groups of farmers with and without experience of the act relative to an Expert group. Increasing levels of farmer experience resulted in stronger overall attitudes to the act. Multiple Discriminant Analysis and Metric Multidimensional Scaling incorporating Procrustes rotations of spatial representations, identified the concepts of Maintaining Ewe Body Condition during Pregnancy, Reduced Stocking Rates and Multiple Lamb Survival as having the least degree of alignment. The cognitive structures of the Experts and Inexperienced farmers are in closest alignment, contrary to the predicted result from the experiential learning theories discussed. It is hypothesised that individuals with similar cognitive structures may have differing overall attitudes. The Management of the extension process is discussed relative to this hypothesis, as the extensionist may need to assist managers to learn the 'right' relationships not just assist managers to learn, if the efficiency of learning processes are to be enhanced. Extension messages for each group, derived by linear Aggregation theory (Woelfel and Fink, 1980), relating the act to the concepts of Multiple lamb Survival, later lambing, Multiple lamb Growth Rates and Summer Pasture Control are predicted to strengthen the overall attitudes towards the act for both farmer groups. A multiple regression version of the Fishbein and Ajzen model is presented as another means of predicting change in the overall attitude as a result of belief and attitude changes. The conclusion from this study is that Multiple Discriminant Analysis and Multidimensional Scaling offer significant opportunities to develop soft systems research in a descriptive sense, provided issues regarding measurement adequacy are resolved. The potential of muitivariate analysis for predicting cognitive change appears to exist but requires validation through time series data analysis, and resolution of the behaviour determinants and how these change through time.Item Studies on embryo transplantation procedures using Booroola-Merino x Perendale ewes : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science at Massey University(Massey University, 1987) Rangel Santos, RaymundoA study was carried out to develop an embryo transfer programme under farm conditions. For this embryos were collected from donor ewes 5-6 days after single-sire mating by rams of the same crossbreed as the ewes. Then the embryos were transplanted soon after collection or after they had been initially frozen and later on thawed before their transfer. To enable this study to be carried out, one hundred and sixty-one Booroola-Merino x Perendale ewes aged between 3 and 6 years and of 34-69 kg live weight were examined. These animals were classified as either carriers (F+) or non-carriers (++) of the fecundity gene on the basis of the number of ovulations recorded at laparoscopy carried out a few days after progestagen sponge treatment to induce oestrus synchronisation, and in a few cases on the basis of previous lambing data. The aims of the study therefore were also to identify ewe carriers or non-carriers of the fecundity gene, and to evaluate their ovulatory response to several doses of Pregnant Mare Serum Gonadotrophin (Tl=O, T2=350, T3=700 and T4=1050 i.u. of PMSG) given during the embryo transfer programme. On the basis of the criteria used to classify F+ and ++ ewes, 76 ewes were considered as carriers and 85 as non-carriers of the fecundity gene. Immediately after progestagen synchronisation treatment the incidence of oestrus and the distribution of onset of oestrus was similar in both groups of ewes, and also following PMSG treatment given in the succeeding cycle. Ovulation rate after the progestagen sponge treatment was significantly affected by genotype and age of the ewes, but it was not associated with the live weight of the ewes. The least-squares means for number of ovulations in F+ and ++ ewes and in 3 and 4-6 years old animals were 3.02, 1.73, 2.14 and 2.45 respectively. Higher sensitivity to PMSG treatment was observed from the right ovary than from the left ovary (3.40 v. 2.82 ovulations respectively). No significant effect of dose of PMSG was found on the percentage of embryos recovered, the overall recovery rate being 66%. Of the ova or potential embryos recovered 78% had been fertilised and had developed to embryos. There were no significant differences between the 3 rams in the fertilisation rate in the ewes compared on a per ewe basis. The reproductive performance of donor ewes which had been flushed, was considerably influenced by the efficiency of the embryo recovery procedures, since every embryo not recovered represents a potential pregnancy and such a situation sometimes is not desirable. In this study 30% of the ewes that were flushed, subsequently became pregnant and produce lambs as a result of one or more embryos not being recovered at surgery. The number of ovulations after PMSG treatment was significantly affected by the dose-level of PMSG and the genotype, age and live weight of the ewes. F+ ewes recorded a significantly higher ovulation rate than ++ ewes. Their respective least-squares means were 3.61 and 2.31 corpora lutea. No significant difference was found between treatments 1 and 2 and between treatments 3 and 4. However, the response from the last two treatments was significantly higher than that from the first two treatments. Their respective least-squares means were 2.10, 2.01, 3.74 and 4.37 corpora lutea. Ewes 4-6 years old recorded a significantly higher number of ovulations than younger ewes (3 years old). Small significant effect of live weight was found on the ovulatory response of the ewes. Analysis within each genotype showed a similar trend in both genotypes, but small significant effect of weight was only detected in the ++ ewes. The pregnancy rate that occurred after the transfer of two fresh embryos (86%) was significantly affected by the genotype of the recipient ewe (F+ ewes 75% v. ++ ewes 96%). The number of ovulations in the recipients and whether or not they had received PMSG before transfer had no effect on the incidence of pregnancy. The pregnancy rate achieved after the transfer of frozen embryos (35%) was significantly influenced by the number of embryos transferred, but not by the ovulation rate in the recipient ewe or the time elapsing from flushing until freezing. Pregnancy rate was significantly higher after the transfer of 2 embryos compared to the transfer of single embryos (43% v. 0%), but only 8 transfers were made in the later category. On the basis of the number of ovulations, it can be concluded that ewe carriers of the fecundity gene recorded significantly higher ovulation rate after oestrus synchronisation and were more sensitive to PMSG stimulation than non-carrier ewes. There was an encouraging pregnancy rate obtained with frozen embryos, even although the small number of transfers carried out limits conclusions that can be drawn. However, the eighty-six percent pregnancy rate achieved after the transfer of two fresh embryos per recipient, shows the feasibility of the embryo transfer programmme under conditions where suitable recipients are available. Where recipients are limited then additional embryos might be frozen and stored until ready for transplantation.Item A study of the effects of nutritionally-induced bodyweight differences on ovarian function in the ewe : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science at Massey University(Massey University, 1987) Xu, ZhenzhongThe aim of this study was to investigate the mechanisms by which nutritionally-induced bodyweight differences(i.e.the so-called "static bodyweight effect") influence ovulation rate in sheep. Seventy Romney ewes (5-7 years old) were randomly divided into 2 groups of 35 each and differentially grazed on mixed ryegrass/white clover pastures for 12-16 weeks to generate two treatment groups differing in mean bodyweight by 14.9±1.8kg (mean± s.e.d.) early in the breeding season. Within each bodyweight (BWT) group, ewes were further divided into 3 blocks. Blocks 1 and 2 were used for the main experiment and only ovulation rate data were collected from ewes in block 3. The oestrous cycles of all ewes were synchronized by treatment for 14 days with progesterone-impregnated intravaginal sponges. Two weeks after sponge withdrawal, ewes in block 3 were subjected to laparoscopy to record their ovulation rate. After returning to oestrus following sponge withdrawal, ewes in block 1 and 2 were housed indoors and fed a maintenance diet of lucerne chaff until the end of the experiment about 16 days later. On day 12 of the synchronized oestrous cycle, ewes were injected with 150vg cloprostenol to induce luteolysis. Laparotomies were performed at 0, 24, 48 (block 1 only), and 76h after the prostaglandin treatment to study the patterns of preovulatory follicular development. The number of corpora lutea present on the ovaries at the time of the first laparotomy were also recorded. Ewes were blood-sampled by jugular venipuncture during the late luteal and follicular phases of the cycle and the plasma concentrations of FSH and LH were measured. After the laparotomy study, ovaries of the ewes were removed, fixed in Bouin's fluid and the left ovaries serially sectioned at 10vm thickness. Every 5th section was mounted and observed under a light microscope to study the populations of follicles 0.2mm or greater in diameter. Ewes in the high BWT group (H) had significantly higher ovulation rates than those in the low BWT group (L) (H=1.73±0.20, L=1.18±0.13, P<0.001). On average, ovulation rate increased by 3.1% for each kilogram increase in bodyweight. Significant relationships between bodyweight and ovulation rate also existed within treatment groups (PO.lO). It is concluded that variation in ovulation rate due to nutritionally- induced bodyweight differences is associated with changes in the number of follicles being recruited into the actively growing pool shortly after luteolysis and the proportion of the recruited follicles that become atretic at the time of selection late in the follicular phase of the oestrous cycle. However, large differences in bodyweight do not appear to influence the antral follicle populations in the ovary. FSH, which plays many important roles during follicular development, may not be involved in the control of bodyweight-induced variation in ovulation rate.