88,788 results

  • The utilization of lactose by the growing pig : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science

    Shearer, Ian John

    Thesis
    Massey University

    Irregular pagination: missing pages 131, 133

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  • A study of commercial embryo transfer programmes conducted with Texel and Awassi sheep : a thesis presented in partial fulfilment of the degree of Master of Agricultural Science in Animal Science at Massey University

    Pavitt, Andrew Edward Drummond

    Thesis
    Massey University

    The results of two commercial embryo transfer (ET) programmes conducted in Central Huwkes Bay, comprising 93 Texel and 78 Awassi donor ewes, were analysed to identify variables that affect the success of commercial ET programmes. The production of high quality embryos for export was the primary objective in the Texel programme, while the rapid multiplication of the Awassi was the sole purpose of the Awassi programme. Reproductive parameters such as; ovarian response to exogenous gonadotrophins, recovery and fertilisation rate of ova, yield of good quality embryos and embryo survival rate to scanning and birth were evaluated. The influence of age, ovulatory response, repeated flushing, the number of corpora lutea in recipient ewes and donor surgeon, on the reproductive parameters, were assessed. The Texel ewes were all purebred consisting of two-tooth and four-tooth animals. The Awassi ewes were either three-quarter or purebred, and included both ewe hoggets and mixed age ewes. Synchronisation of oestrus was attempted using a double CIDR-GTM regime. The super ovulatory programme differed in each breed but consisted of a series of FSHp injections in combination with PMSG. The ewes were inseminated intra-uterine with fresh diluted semen from a ram of the same breed after detection of oestrus. Embryo recovery was attempted 6-6.5 days after insemination using a standard flushing technique in which the oviducts and uterus were exposed by mid-ventral laparotomy. Two or three embryos were transferred into each recipient ewe within 1.5 hours (Texel) and 4 hours (Awassi) of recovery. Ovarian response to superovulatory treatment was not significantly affected by any of the variables recorded in this study, although the Texel programme provided a higher ovulatory response than the Awassi programme (8.89 CL vs 7.08 CL). The embryo recovery rates were 71.8% for the Texel and 78.1% for the Awassi sheep. Age of the donor ewes significantly affected (p=0.006) recovery rate of ova in the Awassi sheep, adult ewes and ewe hoggets recorded recovery rates of 90.7% and 65.2%. Fertilisation rate was not affected by any of the factors studied with 94.6% and 77.6%, of ihe Texel and Awassi ova, being fertilised. The overall yield of good quality embryos was 91.6% for the Texel and 80.1% for the Awassi. The yield of good quality embryos was significantly affected (p=0.03) by age in the Awassi, 87.5% of adult embryos and 64.4% of ewe hogget embryos were of good quality. Survival rates in the Awassi data set were significantly affected by the lower scanning and birth rates of the Awassi ewe hoggets than Awassi ewes (43.8% vs 65.9%: p=0.02) and (39.3% vs 59.4%: p=0.03) respectively. Each Texel donor ewe produced, on average, 3.89 embryos that were of sufficient quality to be preserved and therefore not transferred, resulting in 0.70 lambs being born per donor ewe in the Texel programme. The Awassi programme produced 2.10 lambs donor per ewe, however, this was significantly affected (p=0.03) by the age of the donor ewes, with adult ewes produced an average of 2.7 lambs per donor, and ewe hoggets, 1.2 lambs per donor. This work demonstrated the variable nature of embryo transfer programmes as well as the difficulty in achieving acceptable results from ewe hoggets. The Texel and adult Awassi results compared favourably to the other published reports and illustrate that on-farm commercial embryo transfer can provide acceptable results.

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  • Yields and quality components of maize hybrids for silage : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Agronomy at Massey University

    Villaver, Ronaldo C.

    Thesis
    Massey University

    Seven maize hybrids were evaluated at Frewens Block, Massey University, Palmerston North to determine the effects of hybrid and plant population on yield and yield components, nutritive value, dry matter (DM) partitioning and N%. The range of maturity of the seven hybrids varied from early to full season. The seven hybrids were P3902, Janna, CF1, Furio P3751, P3585 and CG900 each planted at 75,000; 100,000 and 140,000 plants/ha. Plant height, leaf number and yield were measured at 50% silking. Three subsequent samples were taken for estimation of yield, the final yield being at 30-35% whole crop dry matter %. "In Vitro" Digestibility and Kjeldahl N analysis was done by Animal Nutrition Laboratory, Massey University on the grain, leaf, stem and husk components for the 100,000 plants/ha population only. The effect of hybrid on crop development was closely related to relative maturity. P3902 and Janna, both early maturing hybrids were quickest to reach 50% silking and blacklayer, followed by medium (CF1, P3751, Furio) and late maturing (CG900, P3751) hybrids. Heat unit accumulation of each hybrid followed a similar pattern. Plant height and leaf number differed significantly among hybrids and was related to maturity ranking. Hybrid CF1 achieved the highest (20,046 kg/ha) whole crop DM yield at final harvest while Janna produced the lowest (15,776 kg/ha) yield. The 75,000 plants/ha plant population yielded significantly less than 100,000 and 140,000 plants/ha. There was no difference between the 100,000 and 140,000 plant populations. This study confirmed the present recommended plant population of 100,000 plants/ha for maize silage. Dry matter partitioning at final harvest revealed the highest proportion in the grain component followed by the stem, husk and leaf. Total metabolizable energy (ME) content ranged from 11.3 MJME/kg DM to 10.28 MJME/kg DM. The ME content of CF1 was significantly higher than all other hybrids. Final yield was not correlated with the relative contribution to yield in any of the components or with N % in the crop. However, total metabolisable energy content was correlated with its ME components in the grain, leaf, husk and stem. There were no significant hybrid differences in whole crop N % which ranged from 1.07 to 1.16%. Nitrogen % of total DM was strongly correlated to N% in the grain and moderately correlated to N % in the stem and in the leaf. NHI was highly correlated with % grain. CF1 was the best performing hybrid, having highest yield, metabolizable energy and N %. However, among six commercial maize silage hybrids (CF1 is excluded being a non-commercial hybrid at the time of experiment) tested, P3902, Furio, P3585 are the preferred hybrids for early, medium and full season, respectively. The performance of CF1 suggests that there is considerable potential for improving the agronomic characteristics of maize hybrids for silage production in New Zealand through local plant breeding programmes.

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  • Te hua o te pōkeka : he tuhinga whakatau mo te Tohu Kairangi Rapunga Whakaaro (Doctor of Philosophy), Te Pūtahi-ā-Toi, Te Kunenga ki Pūrehuroa, Papa-i-ōea, Aotearoa

    Malcolm, Joseph Te Pōroa

    Thesis
    Massey University

    Awaiting embargo

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  • The potential for out-of-season beef finishing systems on farms in the lower North Island : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Agricultural Systems and Management at Massey University, New Zealand

    Sherlock, Thomas Jon

    Thesis
    Massey University

    Beef production in New Zealand is strongly seasonal and reflects the pattern of pasture production on which livestock farming is based. Providing a more uniform supply of beef cattle to processors has the potential to improve returns to the New Zealand beef industry, first by increasing the market opportunities for New Zealand products, especially in the more lucrative markets requiring fresh (short shelf-life) beef cuts, and second by improving the utilisation of capital invested in processing. The primary aim of this study was to investigate the potential of Out-of-Season (OOS) beef finishing systems to reduce the seasonality of beef cattle supply to meat processors. The study focused on developing an understanding of the biophysical, social and economic factors that would affect the implementation of OOS polices for a sample of 14 farmers in the lower North Island. A Farming Systems Research (FSR) approach provided the framework for the field work and methods used in the study. A secondary objective of the study was to investigate the applicability of Farming Systems Research (FSR) methods for obtaining an improved understanding of the on-farm implications of OOS finishing systems and thereby enhancing the relevance of the findings to industry stakeholders. The first phase of the study involved semi-structured interviews with eight meat industry key informants. Their views were obtained on the effects of the seasonal pattern of beef cattle supply and the potential of OOS production systems to address this issue. Semi-structured interviews with 14 farmers with contrasting farming resources in a defined study region were then completed. Data was obtained from these farmers in order to identify the constraints, costs and opportunities they associated with OOS beef finishing policies. The final phase of the study included three in-depth case farm studies. The whole-farm computer simulation model StockPolTM was used to investigate and quantify the costs and implications of OOS finishing systems for each case farm. The seasonal pattern of beef cattle supply was confirmed as being a major disadvantage for processors and marketers in the New Zealand meat industry. Processing and marketing representatives believed that on-farm OOS beef finishing systems provided a realistic option for addressing the disadvantages. However, farmers believed that OOS finishing systems were less suited to, and more demanding of, their pasture-based systems. The effects of OOS polices on winter feed levels, summer pasture quality, and soil damage were identified by farmers as constraints to their adoption. The simulation of alternative production systems for the case farms suggested that premiums for cattle produced OOS would need to be about 20% above normal schedule payments in order to compensate for the lower biological efficiency of OOS systems. While it was difficult to formally evaluate the success of the FSR approach, the methods used proved successful in obtaining a detailed understanding of the constraints and impacts of OOS beef finishing systems faced by farmers.

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  • The effect of herbage availability and species choice on grazing preference of dairy cattle : a thesis presented in partial fulfilment of the requirements for the degree of Masterate in Applied Science at Massey University

    Torres-Rodríguez, Alberto

    Thesis
    Massey University

    Herbage intake is one of the factors determining animal performance. Intake and quality of the diet consumed by animals are both determined by selective grazing. The motivation to graze selectively is in part a function of dietary preferences. The study of diet selection requires knowledge of what animals prefer to eat when there are no or minimal constraints to them obtaining their diet. This experiment aimed to investigate the effect of relative availability of a preferred species on dairy cattle response at grazing, and to evaluate the feasibility of the use of monocultures of pasture species for studies of preferences of dairy cattle. Three species-contrasts each composed of two adjacent 1-ha monocultures of either White clover:Ryegrass (W_Rye), Lotus corniculatus:Ryegrass (L_Rye) or Lotus corniculatus:Red clover (L_Red) were used. White clover (W) and lotus (L) had been previously determined as preferred over ryegrass (Rye) and red clover (Red). Each species-contrast was subdivided into four plots and the height of the preferred species was set at 4, 6, 8 and 10 cm, whereas that of the less preferred species was set at 10 cm across plots. Groups of yearling Holstein heifers grazed the plots, and observations on grazing behaviour were made by recording grazing activity and species location at 10-minute intervals during daylight hours for three consecutive days, twice in summer and twice in autumn during 95/96 at the AgResearch Flock House Research Centre, near Bulls. During summer, a second week of grazing followed each period of observations for grazing activity, where attempts to estimate herbage dry matter intake and diet composition using the alkane technique were made. From the species-location information, total grazing time (GTt), expressed in hours, and distribution of GTt between preferred (GTp) and less preferred (GTI) species was obtained. The proportion of GTt allocated to grazing the preferred species was considered as a measure of preference. Statistical analysis was performed by GLM procedures of SAS. Regression analyses were carried out for grazing activity parameters on actual height of the preferred species. Animals showed preference for a mixed diet with partial preference for the legume component (W, 67 %, and L, 70 %) over grass, whereas partial preference in the L_Red species-contrast was close to indifference (L, 55 %). However, this partial preference differed between seasons, being in general stronger in summer than in autumn. Partial preference decreased with decreases in height of the preferred species. However, herbage bulk density (BD) appeared to be important also in influencing preference since more marked responses to height were observed in autumn when sward had lower BD compared with summer. Botanical composition of the sward upper stratum was also considered to influence animal preferences. Diet composition estimation from herbage and faecal alkanes suggested that animals consumed the preferred species at higher proportions than indicated by the proportion of GTt allocated to the preferred species. This was possibly due to differences in rate of intake between herbage species. However, more research is needed in this area in order to establish more accurately the relationship between these two techniques. It is concluded that animals respond to changes in herbage availability of a preferred species and to species choice by adjusting grazing time between preferred and less preferred species. It would be appropriate to research the potential animal performance benefits of increasing the availability of a preferred species in proportion to that preferred by the animals. This works confirms the use of monocultures of pasture species to be useful in the evaluation of preference of dairy cattle. Inclusion of a wider arrangement of species-contrasts is recommended.

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  • The use of breath hydrogen testing to evaluate carbohydrate malabsorption in dogs : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Science in Small Animal Medicine at Massey University

    Bissett, Sally Ann

    Thesis
    Massey University

    The use of the breath hydrogen test in this thesis has focussed primarily on the study of carbohydrate assimilation in healthy dogs and in dogs with gastrointestinal disease. The gastrointestinal handling of dietary carbohydrates and the rationale, applications, and limitations of the breath hydrogen test have been reviewed. Studies were undertaken to investigate the effect of food particle size on carbohydrate digestion and the effect of dehydration on breath hydrogen concentrations in healthy dogs. In addition, breath hydrogen testing was used to assess the assimilation of four commonly used commercial carbohydrate sources in dogs with gastrointestinal disease. In each study, expired breath samples were collected at regular intervals after the ingestion of a carbohydrate test meal. The excretion of hydrogen in the breath was compared between groups, mainly by analysis of the areas under the breath hydrogen concentration versus time curves. The reduction of food particle size was found to cause starch granule disruption and significantly decreased the amount of malassimilated rice. The assimilation of corn, however, did not appear to be altered by reducing the food particle size. Instead, an earlier rise of breath hydrogen concentrations occurred, indicating more rapid orocolic transit and/or fermentability of the smaller corn particles. Five percent dehydration, induced by food and water deprivation, was found to significantly elevate breath hydrogen concentrations and was associated with a significantly greater number of flatus-contaminated breath samples. This increased breath hydrogen excretion associated with increased flatulence in dehydrated dogs was attributed to a greater "net" production of hydrogen within the gastrointestinal tract. Finally, breath hydrogen concentrations were not found to vary significantly between four different extrusion cooked carbohydrate sources (wheat, potato, corn, rice). However, it could not be concluded that these carbohydrates were assimilated to a similar extent as in vitro fermentation results revealed marked differences in the amount of hydrogen produced per gram of carbohydrate fermented at different fermentation times. Individual dogs with gastrointestinal disease appeared to differ in their ability to assimilate the four different carbohydrate sources. In addition, dogs with exocrine pancreatic insufficiency were found to malabsorb significantly more carbohydrate than the dogs with mild inflammatory bowel disease. In conclusion, food processing to reduce carbohydrate particle size appears to increase the assimilation of rice. Methods to reduce the particle size of rice should be considered in the formulation of veterinary therapeutic diets for the management of diarrhoea. Mild dehydration appears to increase breath hydrogen excretion. This suggests that breath hydrogen tests should not be performed on animals that are suboptimally hydrated until their hydration deficits have been restored. The marked individual variation of carbohydrate assimilation noted in dogs with gastrointestinal disease, suggests that clinicians should consider altering the carbohydrate source offered to dogs with intractable malassimilation. with the aim of finding the carbohydrate best tolerated. Finally, direct comparison of breath hydrogen concentrations should not be used to compare the digestibility of different complex carbohydrates unless an accurate means is available of comparing the amount of hydrogen produced per gram of substrate fermented in vivo.

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  • Effect of maternal nutrition during early and mid-gestation on fetal growth : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science (in Animal Science) at Massey University

    Cooper, Kate

    Thesis
    Massey University

    It is generally assumed that, because the fetus has a small nutritional requirement relative to that of the dam in early gestation, differential maternal nutrition at this time is unlikely to influence fetal growth. Hence the dogma that females in early gestation need not be provided with nutrients additional to those required by comparable nonpregnant females. However, the effects of nutrition during early gestation on fetal and placental growth and development, and hence birth weight, have not been studied extensively. Nor does the current dogma take into account the fact that the placenta has a different pattern of growth from the fetus. Hence this study sought to further examine the effects of maternal nutrition during early and mid-gestation on placental and fetal growth. The first study was conducted over two years, with crossbred heifers managed for High (H, 0.6 kg/day) or Low (L, 0.1 kg/day) liveweight gains from mating until day 140 of gestation. Treatments were then reversed so that effects of nutrition during early gestation were not confounded by differences in maternal live weight at calving. Averaged across years, maternal live weights (kg, Mean±SE, n=60) were (H vs L) 393.5 ± 4.3 vs 362.1 ± 4.3 (P0.05) at term. Calf birth weights were 31.1 ± 0.5 vs 31.4 ± 0.5kg and weaning weights (average calf age = 90 ± 14.4days) were 91.3 ± 2.0 vs 89.7 ± 2.0 (both P>0.05). A second study using breeding ewes was designed to determine more directly whether early placental development and fetal growth may be modulated by nutritional manipulation of the female during early and mid-gestation, and so eliminated the potential for the dam to compensate for earlier treatments during late gestation. Mixed-age Romney ewes (average live weight 54.5 ± 0.4 kg), pregnant to a synchronised oestrus, were allocated to three nutritional treatment groups (n = 20/group), Low (L = 0.5 maintenance (M)), Control (C = 1.0M) and High (H = 1.5M) from days 21 to 101 of gestation. Maintenance requirements for a 50 kg ewe were assumed to be approximately 0.9 kg DM/ewe/day (10 MJ ME/day) at a concentration of 11 MJ ME/kg DM. Ewes were weighed weekly, slaughtered at the end of treatment, and fetal and placental measurements recorded. Live weights were significantly (P<0.05). Low levels of maternal nutrition did not significantly influence these parameters (L vs C). It is concluded that high levels of maternal nutrition in early and mid-gestation enhance fetal and placental growth and development in sheep, while low levels are without effect compared to ewes fed at maintenance. Thus there may be advantages to high levels of maternal nutrition in early and mid-gestation though the possible effects of compensation in later gestation, as may have occurred in the beef cow trial, are yet to be studied in sheep.

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  • An economic analysis of least-cost layer rations : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Farm Management at Massey University

    Ryan, Oliver Patrick

    Thesis
    Massey University

    Fifteen treatments, replicated once, each containing eighty four birds of three strains of White Leghorn layers (White Base a, White Base b, M. Line) were fed rations ad libitum of five different metabolisable energy levels (2315, 2535, 2756, 2976, 3197 k. cal. M.E. per kg.) and three different protein levels (16, 17, 18 gms. per hen per day, based on an energy intake of 305 k. cals. per hen per day) to obtain quantitative estimates of the physical input/output relationships of layer production. Three other treatments, plus a control, were fed to obtain data on the response of laying hens to restricted energy intake and improved protein quality. All rations were formulated to least cost using Linear Programming. Least Squares multiple regression was used to obtain linear response functions for feed intake, egg number, egg weight and liveweight gain (the variables included in a net revenue function for layers under New Zealand production conditions). Feed intake was expressed in terms of dietary energy concentration and initial liveweight. Statistical problems encountered dictated that predicted nutrient intakes were used as the independent variables in the estimation of the egg number and liveweight gain functions. Predicted energy intake and methionine intake accounted for differences in egg number, particularly for White Base b layers. Predicted energy intake, methionine intake and isoleucine intake accounted for differences in liveweight gain. There were no significant differences between average egg weights. There were significant strain differences in ad libitum feed consumption, egg number, average egg weight and liveweight gain. A net revenue function was estimated in terms of the endogenous variables (dietary nutrient concentrations) which were included in the layer response functions. This was analysed in terms of the endogenous variables for the then current egg and feed prices.

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  • Beef cattle production in northeast Thailand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy in Development Studies

    McKenzie, Philip James

    Thesis
    Massey University

    Northeast Thailand, a large plateau of relatively infertile soils, is an area of traditional beef cattle farming. The region has undergone a rapid process of physical, social and economic change in the past forty years. Clearing of forests during this period and the development of new infrastructure, particularly roading, has increased the level of human settlement and opened new agricultural areas for cropping. Agricultural growth has been maintained by opening up new land areas, increasing the production of rice, the predominant crop and diversifying into new commodity crops such as cassava and kenaf. While agricultural growth has been substantial during this period, industrial growth has been higher. Increasingly, many farm families from the Northeast now work for part of the year in urban employment often temporarily migrating to Bangkok, the centre of industrial activity. The government has sought to diversify agricultural production away from rice and other commodity crops towards more intensive and high value agricultural activities. One focus of diversification activity has been in the promotion of beef cattle farming to meet increasing demand for beef from urban consumers. This thesis reviews some of the several projects which have been implemented to do so and the socioeconomic context within which they have occurred. Detailed research was carried out in six villages in Northeast Thailand during the period 1993-1995 with a follow up visit in June and July 1997. Changing patterns of land use, social and economic conditions have altered the way in which cattle are farmed. Cattle now have less access to common grazing land and are farmed as an adjunct to cropping activities. Their ability to utilise crop by-products and act as a store of future income are seen as important by farmers. Two critical issues were identified that have relevance to this region and elsewhere. The first is the identification of the appropriate role of beef cattle within agriculture and within local and national systems of development. The second is the development of structures to assist both farmers and governments to meet their objectives. Within these two issues the ways in which resources, technology, culture, and institutions interact and are modified as a result of the process of change is extremely important to the success of development initiatives.

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  • Epidemiological aspects of feline hyperthyroidism in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Science at Massey University, Palmerston North, New Zealand

    Olczak, Joanna

    Thesis
    Massey University

    A questionnaire-based case-control study of 375 cats was conducted in New Zealand over a 14-month period from 1996 to 1998 and then used to identify possible risk factors for feline hyperthyroidism. The owners of 125 hyperthyroid cats, 125 age- and sex-matched and 125 random control cats were asked 64 questions, about their cats' exposure to potential risk factors including: cat and owner demographics, each cat's medical history, the indoor and outdoor environment, the cat's diet and feeding practices. For the clinical cases a questionnaire of 10 questions completed by the attending veterinarian provided the demographic data, the cat's medical history and clinical signs before, and at the time of diagnosis of hyperthyroidism. A range of statistical techniques was employed to analyse the data, including univariate odds ratio and chi-squared calculations, stepwise forward unconditional (case-random controls) and conditional (case-matched controls) logistic regression, frequency analyses and Cox regression (proportional hazards model) for case-random status. Kaplan-Meier survival analysis was used for hyperthyroid cats to evaluate the effects of a number of different treatments, including medical, surgical and radioactive iodine treatment, on survival time (months) of the cats after the diagnosis and up to the final date of the study. Variables that were positively associated with feline hyperthyroidism from the ease-random control comparison included age, breed, sex, age at desexing, history of any oral cavity diseases, sleeping predominantly on the floor, regular use of anti-flea products (in particular applied to the cats' bed/bedding) and eating more than ½ of the daily diet as a commercial canned food. Older cats were more likely to develop hyperthyroidism. Siamese cats were found to have a lower risk for developing hyperthyroidism. Females were three times as likely to develop the condition as males. With cat's age at desexing, the category "don't know", which indicated either that the cat had had a previous owner or was of unknown origin, was associated with increased risk for developing hyperthyroidism. Although oral cavity diseases were controlled for age, the occurrence of dental disorders was associated with a five-and- a-half-fold higher risk of developing hyperthyroidism. A 6.6-fold increase in risk of developing hyperthyroidism was calculated for cats sleeping predominantly on the floor. Cats eating half or more of their daily food as a canned commercial cat food were shown to have twice the risk of developing hyperthyroidism as those cats whose diets excluded canned food. In order to focus on factors which might influence occurrence of the disease in cats at similar constitutional risk of feline hyperthyroidism a second investigation was conducted in which each case was compared with a control animal matched on sex and age (± 1.5 years) for the case. In this comparison, cats with episodes of diarrhoea were seven times more likely to have hyperthyroidism. The use of fly sprays in the cat's indoor territory was also associated with an increased risk of developing this disorder. Cats eating a variety of flavours of commercial canned cat food had 3.8-fold increased risk of developing hyperthyroidism compared with cats whose diets consisted of a single flavour of canned food. The interaction between drinking water from puddles and the regular use of animal/plant origin fertilisers (sheep manure, compost, commercial blood and bone fertiliser) in the cat's outdoor territory was associated with a 5.3-fold higher risk of developing disease. Other variables that appeared to have some protective effects included "more than one cat in the household" (from the case-matched model) and the previously mentioned protective effect of breed, for Siamese cats only, from the case-random control comparison. The questionnaire completed by veterinarians provided information on history and clinical findings in affected cats. The frequencies for the clinical signs weight loss, polyphagia, hyperactivity, tachycardia and palpable thyroid gland(s) were 92%, 68%, 34%, 62% and 56% respectively. Skin changes, episodes of vomiting and decreased activity had the following frequencies: 49%, 26% and 11% respectively. The increased number of feline hyperthyroidism diagnoses in the warmer six months of the year, from October until March, indicates seasonality of recognition of disease, but may not represent true elate of onset. The relevance of the identified risk factors to the aetiology of feline hyperthyroidism is discussed, bearing in mind that some of the potential risk variables mentioned earlier could be the result of the disease itself. The analysis of this study suggested that further investigations should be undertaken into the molecular basis of the disease, into dietary factors and Other potentially important risk factors such as insecticides, breed and sex susceptibility.

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  • Some economic and nutritional aspects of different grower and layer rations in egg production : a thesis presented in partial fulfilment of the requirements for the degree Master of Agricultural Science in Animal Science at Massey University

    Swan, Stephen Edgar James

    Thesis
    Massey University

    Preface: Chapter One of this thesis presents background information on the rearing of laying pullets and describes an experiment evaluating a series of rearing rations (with continuous variation of the levels of three major ingredients) in terms of overall profitability. Chapter Two looks particularly at the layer phase, and considers possibilities of reducing feed costs in this phase. An experiment evaluates a series of layer rations (with continuous variation of the levels of three major ingredients) in terms of overall profitability. The final chapter presents an appraisal of the methods available for economic analysis of livestock rations, and discusses the problems associated with their application in layer nutrition. A profit function is suggested as a means of economic evaluation.

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  • Facilitating learning : enhancing dairy farmer competence through workshops : a thesis submitted in partial fulfilment of the requirements for the degree of Masters of Applied Science in Agricultural Extension, Massey University

    Stantiall, John Douglas

    Thesis
    Massey University

    Agricultural extension in New Zealand pastoral dairy farming systems has traditionally comprised a mix of technology transfer, education and consultancy. Activities have been targetted at individuals, discussion groups and farmers mostly through the mass media and group activities. It has been assumed that the provision of information (technology transfer) will lead to individuals being better placed to make sound decisions, be innovative and make appropriate changes to their management practices. Individuals were assumed to benefit through a mix of improved profitability, more efficient use of resources and the achievement of non-profit oriented goals (e.g. personal satisfaction, lifestyle/family, land stewardship). Due to ever-changing circumstances, managing a viable farming business in the future will, however, require a different way of thinking compared to the past. This study focused on the provision of learning tools tailored to the future needs of dairy farmers. Agricultural extension has evolved over the last two decades from "Transfer of Technology" to a paradigm of participatory action learning. The learning process involves the building of knowledge. Two areas of dairy farmer learning needs were identified using a competence questionnaire and workshops were then designed to meet these needs. The facilitated workshops "Northland Dairy Cow Nutrition" and "Preferred Future" were piloted and evaluated with dairy farmers The latter showed that as well as achieving specific learning outcomes and applying new knowledge to their farming business, participants also gained confidence in their ability to learn. The outcomes for the "Preferred Future" workshop were comparable to those reported for "Dairy-MAP" (Pennsylvania, USA), "Smart Move" (Queensland, Australia) and "Farm Finance" (Pennsylvania, USA) workshops. Reasons for a lack of enthusiasm for formal learning in the farming community have been outlined in the literature. Knowledge construction has rarely been acknowledged as an outcome of agricultural extension or education programmes. If, however, farmers become more aware of their learning needs through the application of a competency framework, they are in a stronger position to demand learning experiences that are relevant, timely, convenient and effective for them. The major implication arising from this research, for both agricultural education and extension workers, is the need for a paradigm shift from the Transfer of Technology model to one of facilitated learning. This will require education and extension professionals to learn new skills themselves in order to provide leadership in facilitating learning. This will require competence in designing materials and tailoring activities to the learning needs of farmers. Positive learning experiences occur in facilitated workshops where there are: clearly identified learning objectives; a course design that builds participants' knowledge to meet these objectives; and facilitation that utilises the principles of adult learning and creates a non-threatening, non-judgmental and enjoyable learning environment.

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  • PCR probes for ammonia hyper-producing bacteria in the rumen of New Zealand ruminants : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutritional Science at Massey University, Albany campus, New Zealand

    Manickavasagar, Shanmuganathan

    Thesis
    Massey University

    Competitive PCR (cPCR) primers were developed to detect and enumerate 5 hyper ammonia-producing (HAP) bacteria previously isolated from New Zealand ruminants, and 3 previously described HAP bacteria, Clostridium aminophilum, C. sticklandii and Peptostreptococcus anaerobius. Primers were designed by aligning 16S ribosomal RNA gene sequences and identifying unique site for each bacterium. Primers were matched as closely as possible in terms of length, G+C content and Tm to either the universal eubacterial forward (fdl*) or reverse (rdl*) primers to anchor the PCR at either the 5' or 3' end of the 16S rRNA gene. Primer specificity was tested in amplification reactions with DNA extracted from 35 bacterial isolates, mostly from the rumen. The primers designed for isolates C2 and D5 produced amplified PCR products only with their respective target DNAs. Primers developed for isolates S1, D4 and P. anaerobius also amplified DNA from closely related species, P. asaccharolyticus, Fusobacterium necrophorum and isolate D1, respectively, in addition to their respective target DNAs. Internal controls were developed for each of the chosen primers by creating deletions in the amplified target DNA using restriction endonuclease digestions and religating the terminal fragments. The deleted internal control fragments were reamplified and cloned into the PCR cloning vector pGEM-T. Cloned internal control DNAs were coamplified with known amounts of their respective target DNAs to generate standard curves so that unknown samples could be quantitated. DNAs extracted from rumen samples from sheep fed a diet of chaffed lucerne and infused with either monensin or buffer were probed for HAP bacteria using the cPCR probes. The results showed that isolates C2, D5, S1 and C. sticklandii and C. aminophilum were below the detectable limits of the cPCR technique and their population could not be enumerated. The absence of any PCR amplifiable DNA of these organisms in the rumen samples was confirmed by conventional PCR in the absence of internal control DNAs, by additional purification of rumen DNAs followed by reamplification, and by preamplifying rumen DNA with the universal eubacterial primers fdl* and rdl* prior to PCR with primers specific to each organism. However the D4/F. neewphorum and D1/P. anaerobius probes showed detectable populations in the samples. In vivo the D1/P. anaerobius population in the rumen ranged from 3 to 7x108 cells ml-1. Monensin showed no inhibitory effect on the D1/P.anaerobius population, which maintained steady levels throughout the sampling period. D4/F.necrophorum populations ranged from 3x108 to 1.4x109 bacteria ml-1". Monensin had little effect over the first 48hr compared to control sheep but after 72hr D4/F.necrophorum populations increased and finally reached 1.4 x109 bacteria ml-1 at 96 hrs.

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  • Some aspects of growth rate as it is related to reproductive efficiency in dairy cattle : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy in Veterinary Science at Massey University

    Tan, Kim Sing

    Thesis
    Massey University

    The purpose of the study reported in this thesis was to evaluate whether liveweight, measured in Friesian yearlings immediately before the breeding season commenced and in parous cows of the same breed just beforecalving for the herd began, was related to reproductive performance during the first four weeks of the mating period. Should such a relationship be confirmed 'target weights' which would ensure a high level of reproductive efficiency could be established for animals of this breed under normal husbandry conditions in New Zealand. A pre-requisite to the investigation was thatthe method(s) used should be easily applied in a commercial farming situation. Body weight measurements for 184 yearlings (5 herds) and 288 parous cows (4 herds) which were at least three-quarter bred Friesian were taken at the times indicated above and related to submission rates (S.R.) and pregnancy rates (P.R.) during the first four weeks of the following breeding season. The cows were bred by artificial insemination with heat checks being made by experienced stock men; yearlings were mated to young bulls fitted with chin ball mating harnesses. P.R. and the dates of conception were confirmed by both pregnancy examinations at the conclusion of the breeding period and by subsequent calving information. Reproductive performance in the yearling heifers was high with S.R. averaging 94% (range 88-100%) and P.R. 86% (range 71-100%) for the five herds. The majority of the heifers were judged to be in good body condition with mean body weights for the herds ranging between 231±27 and 277±22 kg (mean ± S.D.). Differences in liveweight between herds were probably related to management during rearing although age variation and minor differences in the amount of Friesian 'blood' in each herd could have been contributing factors. When individual herd effects were removed a positive but non-significant linear relationship between liveweight and S.R. was achieved with the yearlings. From the six points plotted on the regression it was noted that the lightest group of animals had a submission rate of 76% whereas all other groups had submission rates in excess of 94% thus suggesting a threshold effect. The minimum liveweights for the lightest yearling groups exceeding a 90% submission rate varied from 204-229 kg depending on the herd. While a positive relationship between liveweight and pregnancy rate was noted in the yearling data this was neither linear nor significant - further investigations seem warranted to resolve this particular issue because of its importance in breeding management. The significant differences noted between herds in yearling pregnancy rates may have been due to differences in fertility of the bulls used. The reproductive performance of the three year-old and mature age groups of parous cows was satisfactory (S.R. averaged 87 and 86% and P.R. 69 and 65% respectively) but that of the two year-old cattle poor (S.R. 67% and P.R. 56%). Marked differences occurred between herds. Apart from the possible influence of liveweight before calving on these parameters of performance analysis of the reasons for herd differences was beyond the scope of this study and not attempted. Differences in liveweight of the different age groups of cows both within and between herds was marked and, apart from the relationship with age, could most likely be attributed to management during the late autumn and winter period before calving began. Any association between liveweight and subsequent reproductive performance was however generally poor and inconsistent and in retrospect it was concluded that the method that had been used for investigating any possible relationship was unsatisfactory. A future investigation in which variables are more effectively controlled has been suggested. Two year-old heifers experiencing their first lactation continue to be a problem group particularly under New Zealand dairy husbandry conditions. Careful management commencing during rearing and extending through first mating, calving and second breeding is required if a high level of reproductive efficiency in this age group is to be achieved.

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  • A study of fertility in a herd of sows : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science at Massey University

    Hermann, Kaspar Michael

    Thesis
    Massey University

    Irregular pagination. Missing pp 68-69

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  • Cortisol metabolism in the sheep (Romney breed) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science

    Langford, Alan Keith

    Thesis
    Massey University

    The metabolism of Cortisol in the normal Romney ewe was investigated by analysis of the radioactive metabolites excreted in the urine following intravenous (I.V.) administration of 4-c14 cortisol. The metabolite glucuronic!os were hydrolysed with b-glucuronidase and extracted from the aqueous medium with ethyl acetate. The neutral fraction was divided into c-19 and c-21 metabolites by sequential elution from a florisil column. Extensive use was made of T.L.C. for the separation and analysis of each fraction before the quantitation of individual components. A series of experiments was performed with, surgically modified sheep involving collection of bile and urine both after I.V. injection of 4-c14 cortisol, and after intraduodenal infusion of radioactive biliary metabolites obtained from I.V. administration of 4-c14 corticol. The metabolites collected at each stage were analysed both qualitatively and quantitatively. The urine collected each hour for 18 consecutive days from a normal sheep, was subjected to colorimetric determination for a-ketol and 17-ketogenic steroid content. The data obtained was analysed for diurnal variation in chromogen output, and the daily secretion rate of cortisol was estimated.

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  • Effect of sward surface height on herbage intake and performance of finishing beef cattle : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Plant Science at Massey University

    Realini, Carolina

    Thesis
    Massey University

    This study examined the effects of sward surface height (SSH) on the herbage intake, ingestive behaviour and performance of steers finished on ryegrass (Lolium perenne) /white clover (Trifolium repens) pastures during summer. The influence of this initial treatment contrast on subsequent cattle performance under common grazing conditions during early-autumn was also studied. Twenty six month-old steers with an initial liveweight of 522 ± 7.6 kg, 14 Angus x (Hereford x Friesian) and 10 Angus x (Hereford x Jersey), were set stocked on swards maintained at SSHs of 5 and 10 cm (L vs. H) from 18 November 1996 to 4 March 1997, with 3 replicate groups of 4 animals per treatment balanced as far as possible for "breed". Six steers from each treatment balanced for "breed" were slaughtered on 4 March and carcass and meat quality characteristics compared. The remaining animals were grazed for another 5 weeks on common pastures until the final slaughter on 8 April. Over the SSH control period, the 5 and 10 target swards averaged 4.8 ± 1.36 and 10.0 ± 3.24 cm. Herbage on the H swards contained more dead material, less crude protein, lower dry matter digestibility and live:dead tiller ratio than that on the L swards. Estimates of herbage dry matter intake were higher for steers grazing at 10 cm than for those grazing at 5 cm SSH (8.0 vs. 4.8 kg DM d-1 from 2 estimates and 2 alkane pairs, P < 0.05 for each comparison). Steers were unable to increase their grazing time in response to limiting sward conditions sufficiently to compensate for lower intake rates in short swards, resulting in reduced herbage intakes. Daily liveweight gain over the summer was higher on the 10 cm than on the 5 cm SSH (1.10 ± 0.23 vs. 0.32 ± 0.21 kg d-1, P < 0.01) and carcass weight at first slaughter was significantly higher for steers on the H swards (332 ± 10.6 vs. 287 ± 7.5 kg, P < 0.05). SSH treatment did not affect other carcass or meat quality characteristics of steers. Liveweight and carcass weight gain per hectare were 71 % and 43 % greater (318 vs. 186 kg and 166 vs. 116 kg) for steers grazing at 10 cm despite the lower stocking rate (2.86 vs. 5.80 steers ha-1) maintained by the tall swards. Over the common grazing period previously restricted steers had higher intakes, greater grazing and ruminating times, lower resting time and grew faster compared to steers previously grazed at 10 cm SSH. However, none of these parameters were significantly different between the steer groups with the exception of resting time. Increased autumn growth rates by previously restricted steers did not compensate for the differences in liveweight established during summer, and significant differences in carcass weight were still evident at the end of the compensatory period between the steer groups (335 ± 9.4 vs. 297 ± 9.4 kg, P < 0.05). There were no significant differences in meat quality characteristics with the exception of meat brightness which was higher for previously restricted steers. These results suggest that maintaining a sward height of 10 cm offers advantages in terms of individual animal output and output per hectare compared with grazing at 5 cm and that compensatory growth does not seem to be an important phenomenon in heavy (over 500 kg liveweight) finishing steers.

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  • A geographical study of some factors that affect the location of deer farms in New Zealand : a thesis in partial fulfilment of the requirements for the degree of Master in Arts (Geography) at Massey Universit

    Mawson, Ian Darcy

    Thesis
    Massey University

    This study of the rapidly-expanding industry of deer farming does not claim to be an economic treatise on the commercial viability of farming deer, nor does it claim to be a practical manual for prospective and established deer farmers. It is, however, a document designed and written to help the farmers of deer understand themselves, and their infant industry, a little more fully, and to help other interested persons gain an insight into the development of the exciting new enterprise of farming deer. The underlying theme of the study is that the present distribution of deer farms throughout New Zealant after some eight years of development within the industry, is explainable. Such explanations are expressed in terms of the past and present cultural attitudes within New Zealand to deer, the resultant legislation and official actions taken, the major modes of diffusion of both the underlying notion involved and the successful, practical methods that have evolved, the characteristics of the deer farming operation itself as well as of the people involved in it, and the relative productivity of the land employed for the farming of deer, particularly in view of man's changing knowledge of deer. Regional variations in the distribution of deer farms, and in other related phenomena, are examined, and possible explanations for these are sought. Trends that have evolved within the industry up to the present time are examined, particularly in the light of more recently-gained scientific and empirical knowledge on both productivity and profitability. The future of the industry is then viewed with reference to these trends and to marketing outlets.

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  • Some investigations into the larval development assay and trichostrongylid nematodes of sheep : a thesis presented in partial fulfillment of the requirements for the degree of Master of Veterinary Science at Massey University

    Hoza, Shaaban Bakari

    Thesis
    Massey University

    Irregular pagination

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