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The physiological effects of etorphine, and etorphine combined with xylazine and etorphine combined with azaperone on respiratory and cardiovascular function were determined in. Boer goats. The goats were habituated to the experimental procedures allowing the determination of respiratory and cardiovascular function while the animals stood quietly at rest. This resulted in the physiological changes induced by the three immobilizing drugs being measured and compared with those obtained prior to the administration of the immobilizing drugs. The: effectiveness of diprenorphine and atipamezole in antagonising the physiological changes induced by the immobilizing drug treatments was also determined. All three immobilizing drug treatments depressed respiratory function resulting in a decrease in PaO2and an increase in PaCO2. Etorphine caused limited changes to these blood gases as a result of decreases in respiratory minute volume and alveolar minute ventilation caused by a fall in respiratory rate. The administration of etorphine / azaperone did not decrease the efficiency of respiration more significantly than when etorphine was administered on its own. Etorphine injected in combination with xylazine resulted in a severe decrease in respiratory function. The decrease in PaO2 and the increase in PaCO2 were much greater than the changes to these two blood gases following the administration of either etorphine or etorphine in combination with azaperone. Compared to etorphine administered on its own, etorphine combined with xylazine caused more significant decreases in tidal volume and alveolar minute ventilation, and more significant elevations in both physiological shunt fraction and percentage dead space ventilation. The administration of etorphine, etorphine / xylazine and etorphine / azaperone caused three different sets of changes to cardiovascular function. The injection of etorphine resulted in significant increases in both total peripheral resistance and systemic mean arterial blood pressure, and a significant decease in cardiac output. The administration of etorphine / xylazine resulted in a rapid and significant decrease in the systemic mean arterial blood pressure, followed by a decrease in cardiac output. The peripheral resistance remained unchanged. Etorphine / azaperone caused a progressive decline in the total peripheral resistance. As the cardiac output did not change significantly, the systemic mean arterial blood pressure fell progressively. The administration of etorphine resulted in a gradual and limited decrease in the oxygen consumption index. Following the injection of etorphine / xylazine a rapid and significant decrease in the oxygen consumption index resulted, which was significantly lower, when compared to the goats immobilized with etorphine, at 5 and 35 minutes PDA. The injection of etorphine / azaperone resulted in a gradual decrease in the oxygen consumption index which reached a minimum value at 35 minutes PDA. At this time, the oxygen consumption index due to etorphine / xylazine was not significantly different from the value due to etorphine / azaperone. Diprenorphine effectively reversed the respiratory and cardiovascular effects due to etorphine. The physiological changes induced by the administration of etorphine / xylazine were partially and temporarily antagonised by the administration of diprenorphine, it was only following the injection of atipamezole that they return to the values measured in the goats prior to immobilization. Diprenorphine effectively reversed the respiratory depression induced by etorphine / azaperone, however a mild acidosis persisted until the end of the trial period. The cardiac output and systemic mean blood pressure improved dramatically following the injection of diprenorphine but there was no immediate change in total peripheral resistance. / Dissertation (MMedVet)--University of Pretoria, 2010. / Animal and Wildlife Sciences / unrestricted

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-10-18T11:49:54Z No. of bitstreams: 1 2014 - Ramon de Sousa Rego.pdf: 1491511 bytes, checksum: 746021e21f53b13713de3e8e94d03121 (MD5) / Made available in DSpace on 2016-10-18T11:49:54Z (GMT). No. of bitstreams: 1 2014 - Ramon de Sousa Rego.pdf: 1491511 bytes, checksum: 746021e21f53b13713de3e8e94d03121 (MD5) Previous issue date: 2014-08-26 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / The protein quality of milk of goats and digestibility of the lipid fraction are important factors that stand out when compared to milk from cows. The ?-lactoglobulin is the higher abundant protein in whey ruminants being produced in the mammary gland during lactation. It may represent up to 12% of the total protein. We seek to present work was to evaluate the gene ?-Lactoglobulin (BLG) with their genetic polymorphisms in the promoter regions 5 'and 3' UTR and associate them the characteristics of milk production in experimental goat herd. For this 150 goats (Capra hircus) of Saanen and Alpine, genotyped for polymorphisms of the BLG gene were used. For genotyping 10 mL of blood per animal were collected. The blood was used for DNA extraction and amplification of two fragments of the BLG gene by means of polymerase chain reaction (PCR). The amplified fragments were submitted to electrophoresis on polyacrylamide gel and evaluated by by restriction fragment length polymorphism (PCR-RFLP). The SmaI and SacII enzymes were used for the promoter (promoter + exon 1 region) region and the region of exon 7 (exon 7 + region 3 '), respectively. The differences in cutting patterns were visualized on a polyacrylamide gel. In the promoter region of the single nucleotide polymorphism (SNP) at position -60 (C/T) was identified and was associated with the percentage of protein in milk. This result suggests a relationship between genotypes of the promoter region of the BLG gene and the protein level of the milk. The presence of two polymorphisms +4641 (I2/I3) and +4601 (A/G) was observed in the region of exon 7. The I2-I3 variation is characterized by a repeat sequence of 10 bp, varying in two and three times, and it being possible to identify by electrophoresis. The I3 variation was often very low, and there was no association between this polymorphism and any production trait. Polymorphism +4601 (G/A) was identified by enzyme SacII digestion. Alleles were identified frequencies close to those reported by other authors and were associated with the percentage of fat in milk goats, and the animals with the S1S2 genotype had higher fat percentage than S1S1 animals and S2S2. The increased production of lipid content may be related to the characteristic of transporting fatty acids ?-lactoglob / A qualidade proteica do leite de cabras e a digestibilidade da fra??o lip?dica s?o importantes fatores que o destacam, quando comparado ao leite de vacas. A ?-Lactoglobulina ? a prote?na de maior abundancia no soro do leite em ruminantes sendo produzida na gl?ndula mam?ria durante o per?odo de lacta??o. Ela pode representar at? 12% do total proteico. Buscamos com o presente trabalho, avaliar o gene da ?-Lactoglobulina (BLG) com seus polimorfismos gen?ticos nas regi?es promotoras 5? e 3? UTR e associ?-los as caracter?sticas de produ??o de leite no rebanho caprino experimental. Para isso foram utilizadas 150 cabras (Capra hircus) das ra?as Saanen e Alpinas, genotipadas para os polimorfismos do gene BLG. Para a genotipagem foram coletados 10 mL de sangue por animal. O sangue foi utilizado para a extra??o de DNA e amplifica??o de 2 fragmentos do gene BLG por interm?dio da rea??o em cadeia da polimerase (PCR). Os fragmentos amplificados foram ent?o submetidos ? eletroforese em gel de poliacrilamida e avaliados pelo polimorfismo no tamanho do fragmento por restri??o (PCR-RFLP). Foram utilizadas as enzimas SmaI e SacII, para a regi?o promotora (regi?o promotora + ?xon 1) e para a regi?o do ?xon 7 (?xon 7 + regi?o 3?), respectivamente. As diferen?as nos padr?es de corte foram visualizadas em gel de poliacrilamida. Na regi?o promotora o polimorfismo de base ?nica (SNP) na posi??o -60 (C/T) foi identificado e apresentou associa??o com a percentagem de prote?nas no leite. Esse resultado sugere uma rela??o entre os gen?tipos da regi?o promotora do gene BLG e o n?vel proteico do leite. Foi observado na regi?o do ?xon 7 a presen?a de dois polimorfismos +4641 (I2/I3) e +4601 (A/G). A varia??o I2-I3 ? caracterizada pela repeti??o de uma sequ?ncia de 10 pb, variando em duas e tr?s vezes, e sendo poss?vel identifica-la por eletroforese. A varia??o I3 teve frequ?ncia muito baixa, e n?o houve associa??o entre esse polimorfismo e nenhuma caracter?stica de produ??o. O polimorfismo +4601 (A/G) foi identificado por meio da digest?o da enzima SacII. Os alelos identificados tiveram frequ?ncias pr?ximas ?s relatadas por outros autores e apresentaram associa??o com a percentagem de gordura no leite cabras, sendo que os animais com o gen?tipo S1S2 apresentaram maior percentagem de gordura que animais S1S1 e S2S2. A maior produ??o de conte?do lip?dico pode estar relacionada com a caracter?stica de transporte de ?cidos graxos da ?-Lactoglobulina

The exposure to heat can adversely affect animal performance and productivity, particularly when associated with pregnancy. The comprehension of the physiological and cellular responses during heat stress assists the decisions to improve the productivity of goats in a tropical environment. In this context, this study evaluated the physiological and cellular responses of Saanen goats in acute and chronic stress conditions. Healthy Saanen goats were randomly assigned to heat stress treatment, short-term, under solar radiation and in the long-term, in climatic chamber. Data were analyzed using the Statistical Analysis System (SAS). The normality was confirmed using the Shapiro-Wilk test. In acute heat stress, solar radiation caused the increase of cortisol release, respiratory rate and reduced T3 and T4 to restore homeothermia. The expression of p53 (pro-apoptotic protein), Bcl-2 (anti-apoptotic protein), HSP60, HSP70 and HSP90 was higher in leukocyte cells for heat stressed goats. In chronic heat stress at the end of gestation, goats significantly mobilized the increase of respiratory rate to lose heat, with cortisol elevation on the 15 days previous to parturition (P < 0.05), which was even greater at day 15 postparturition. At the cellular level, HSP70 was the most expressed during and after heat challenge, with more transcripts at day 15 postparturition for the heat stressed goats. In mammary epithelial cells, there were an increase in apoptosis-related transcripts, p53 and Bax, for the group undergoing heat stress before parturition. The expression of HSP27 was higher before and after parturition for the same group when compared to the animals in thermal neutrality. During lactation, the stressed goats presented lower milk yield. The heat challenge increased the percentage of fat and decreased lactose. The somatic cell count was higher for stressed goats during all lactation. During lactation, the gene expression of prolactin receptor (PRLr) was lower for heat stress goats, which may explain the reduction in milk production at subsequent lactation. In conclusion, our findings suggest that respiratory rate and HSP70 are reliable biomarkers for assessing the thermal comfort and thermotolerance of Saanen goats under acute and chronic heat stress. In addition, chronic thermal stress at final gestation impaired milk production and milk composition from subsequent lactation. / A exposição ao calor pode afetar negativamente o desempenho e a produtividade dos animais, particularmente quando associados à gestação. Compreender as relações entre as respostas fisiológicas e celulares, quando em estresse por calor, auxilia na tomada de decisões para melhorar a produtividade de caprinos em ambiente tropical. Neste contexto, este estudo avaliou as respostas fisiológicas e celulares de cabras Saanen em condição de estresse agudo e crônico. Cabras da raça Saanen saudáveis foram aleatoriamente expostas ao estresse por calor, de curto prazo sob radiação solar e a longo prazo em câmara climática. Os dados foram analizados utilizando o software estatístico \"Statistical Analysis System\" (SAS, 2008). A normalidade foi confirmada com o teste de Shapiro-Wilk. Em estresse agudo, a radiação solar promoveu o aumento da liberação de cortisol, elevou a frequência respiratória e reduziu T3 e T4, para reestabelecer a homeotermia. Observou-se nas células leucocitárias das cabras sob estresse, aumento da expressão da p53 (proteína pró-apoptótica), Bcl-2 (proteína anti-apoptótica), HSP60, HSP70 e HSP90. Sob estresse crônico no final da gestação, as cabras aumentaram a frequência respiratória para perder calor, com elevação do cortisol no dia 15 pré-parto (P <0,05), que foi ainda maior no dia 15 pós-parto. A nível celular, a HSP70 foi a mais expressa durante e após o desafio com calor, com mais transcritos no dia 15 pós-parto para as cabras sob estresse. Nas células epiteliais mamárias, houve aumento dos transcritos relacionados à apoptose, p53 e Bax, para o grupo sob estresse por calor antes do parto. A expressão da HSP27 foi maior antes e após o parto para o mesmo grupo quando comparado aos animais em termoneutralidade. Durante a lactação, as cabras sob estresse apresentaram menor produção de leite. O desafio de calor aumentou o percentual de gordura e diminuiu a lactose. A contagem de células somáticas foi maior para as cabras sob estresse durante toda a lactação. A expressão gênica do receptor de prolactina (PRLr) foi menor para as cabras sob estresse, 15 dias após o parto, o que pode explicar a redução na produção de leite na lactação subsequente. Em conclusão, nossos achados sugerem que a frequência respiratória e a HSP70 são biomarcadores confiáveis para avaliar o conforto térmico e a termotolerância de cabras Saanen sob estresse por calor agudo e crônico. Além disso, o estresse por calor crônico pré-parto prejudicou a produção e a composição do leite da lactação subsequente.

This study is an extension of the author's previous thesis (Theorell 2013) and focus on the analysed tibia, the humerus and the proximal and distal part of the radius of sheep bones from Gotland and goat bones from City of Falun. Methods for bone elements assessed in this study are compiled and evaluated by Zeder and Lapham (2010). The bones were then geneticallyspecies identified and the results were compared. Seven of thirteen criteria for both sheep and goat reached 100% of correct identification.Best performing criteria were on humerus and distal radius for both sheep and goats. The results for the complete bone assessments divided for the species showed best performance ongoats. Worst performing bone is the tibia. High performing criteria were found on all thetypes of bones used in this study which can be used to distinguish between sheep and goats. / Föreliggande studie är en utökning av författarens tidigare magisteruppsats (Theorell 2013) och fokuserar på att analysera skenben, överarmsben samt proximal och distal del av strålbenet från fårben från Gotland och getben från Falun. Metoder för benslagen som används i denna studie har samlats och utvärderats av Zeder och Lapham (2010). Efter osteologisk analys har benen genetiskt artidentifierats och resultaten från bägge analyser har jämförts. Sju av tretton kriterier för både får och getter visade 100% korrekt bedömning. Kriterier med bäst resultat fanns på överarmsben och distalt på strålben. Sett till bedömning av komplett benslag skilt mellan får och getter visade att metoderna presterade bäst på getter. Sämst resultat uppvisades på skenbenet. Generellt uppvisade samtliga benslag kriterier som är möjliga att använda för att särskilja mellan får och getter.

Evalúa la diversidad y estructura genética de 269 cabras criollas, Capra hircus, de los departamentos de Lima (187) y Piura (82) en Perú, mediante el uso de 21 marcadores tipo microsatélite, de los cuales diecisiete fueron altamente informativos (PIC>0.5) y se recomiendan para el análisis de la diversidad genética en estas poblaciones. La población de Lima presentó una He y número medio de alelos por locus de 0.67 y 8.19, respectivamente; mientras que para Piura estos fueron 0.71 y 7.86, respectivamente. La diversidad genética de las poblaciones fue alta, siendo la de Piura ligeramente mayor que la de Lima. Además, se observó una ausencia de endogamia en ambas poblaciones (FIS=0.036). Los estadísticos de AMOVA, FST y RST mostraron valores de 3% de variación interpoblacional, 0.030 y 0.045, respectivamente, lo que indica una baja estructuración genética. El análisis de estructura genética por métodos bayesianos, el análisis factorial de correspondencias y los análisis de distancia corroboraron la baja estructura genética entre las poblaciones de Lima y Piura, así como entre cada una de sus subpoblaciones. Este resultado puede deberse al significativo flujo génico entre las poblaciones, a pesar de su lejanía geográfica, la predominancia de apareamientos no dirigidos debido al sistema de producción mayormente extensivo, diversidad de criterios de selección, así como el gran tamaño poblacional en estos departamentos, lo cual tiende a disminuir el efecto de la deriva génica. / Tesis

(1) Reliable measures of population abundance are essential for managing wildlife effectively. Aerial surveys provide a rapid and efficient means of surveying large mammals and many techniques have been developed to adjust for the inability to count all animals within transects. The probability of detection varies according to a range of factors which are important to consider when estimating density. Standardised survey methods developed in flat country are not readily transferable to steep terrain due to safety, access and difficulties delineating transect widths. Other methods have logistic constraints and must adhere to various other assumptions. (2) Density estimators are seldom examined using actual population size, hence their ability to correct for true bias is unknown. Studies that compare techniques are difficult to interpret because of the uncertainty of adherence to their respective assumptions. Factors influencing detection probability, estimators that correct for bias, the validity of their assumptions and how these relate to true density are important considerations for selecting suitable methods. The aim of this study was to obtain accurate and reliable methods for estimating the density of feral goats by improving predictions of detection probability, investigating the assumptions of aerial surveys, and examining the accuracy of 15 density estimators by comparing with total counts of feral goats. (3) Group size, vegetation and observer were the most important factors influencing the probability of observing a group of goats during aerial surveys. However, different approaches to analysing these data influenced the significance of variables and the predicted probabilities. Goat colour, type of helicopter, site and rear observer experience in hours were also found to be significant (P<0.05) when using likelihood equations based on all animals in the population rather than only those in the sample. The slope of the terrain was also shown to significantly (P=0.014) affect the probability of detection. (4) Indices are commonly used in wildlife management for their simplicity and practicality, but their validity has been questioned because of variable probability of detection. Results of this study suggest aerial survey indices are useful in monitoring a range of medium-sized mammal species across space and time if differences in detection probability between species, group size, vegetation and observer are considered and their effects are standardised. (5) An assumption of most sampling regimes that is fundamental but rarely examined is that animals are not counted more than once. In this study the behavioural responses of feral goats to helicopters were investigated as a basis for estimating the probability that goats were recounted. No long-term consequences were evident in feral goat behaviour of responses to helicopters. However, helicopter surveys were found to alter the structure of 42% of groups observed, with 28% of groups merging with others and 14% splitting into separate groups. Therefore, group size estimated from the air should not be considered as biologically important, and when estimating density, researchers should also avoid using group sizes determined from independent ground observations to correct group sizes determined from aerial surveys. Goats were also more likely to flush further when helicopters were within 150 m, which is close to or within standard helicopter strip widths. Substantial movement occurred between transects and 21% of goats were estimated to be available for recounting in adjacent transects. (6) Different detection probabilities between groups of goats may be particularly relevant when using double-counting, where multiple observers are �capturing� and �recapturing� animals in the same instant. Many analyses test and adjust for this �unequal catchability� assumption in different ways, with the approaches of Huggins and Alho allowing prediction of unique probability values for a range of co-variates. The approach of Chao attempts to correct for skewed distributions in small samples. The Horvitz-Thompson approach provides a useful basis for estimating abundance (or density) when detection probability can be estimated and is known to vary between observations according to a range of independent variables, and also avoids errors associated with averaging group size. (7) After correcting for recounting, the Alho estimator applied to helicopter surveys was the most accurate (Bias = 0.02) and reliable of all techniques, which suggests that estimates were improved by taking into account unconditional detection probability and correcting individual observations according to their characteristics. The positive bias evident in the Chao (Bias = 0.28) and Petersen (Bias = 0.15) aerial survey estimators may have been a result of averaging detection probability across all observations. The inconsistency and inaccuracy of the ground-based area-count technique emphasises the importance of other assumptions in density estimation, such as representative sampling and availability bias. The accuracy of index-manipulation-index techniques was dependent on the indices used. Capture-recapture estimates using mustering showed slight negative bias (Bias = -0.08), which was likely a result of increased probability of re-capture (i.e. trap happy). Ground-based capture-resight estimates were labour intensive and positively biased (Bias = 0.13), likely due to underestimating the area sampled, or overestimating the number of unmarked individuals with each sample. (8) Helicopter survey using double-counting is recommended for estimating the density of feral goats in steep terrain. However, consideration of recounting under intensive sampling regimes and adjustments for the factors that influence unconditional detection probability is required.

Merino sheep are the most numerous domestic livestock in Australia and feral goats are wide-spread and locally abundant in many of the regions where sheep are grazed. Foot and mouth disease (FMD) is a disease of ungulates that causes severe economic hardship to countries where outbreaks occur or where it has become endemic. In India, Africa, Greece and recently the United Kingdom and Eire, sheep and goats have been implicated in the spread and maintenance of FMD. In Australia, there are contingency plans (AUSVETPLANS) for dealing with an outbreak of FMD. Included in those plans are strategies for control of the disease in feral ungulates including feral pigs and feral goats. Modelling has provided assistance in developing strategies to combat outbreaks in feral pigs and for controlling outbreaks in domestic livestock. No models have been constructed to aid decisions about controlling FMD in feral goats where they co-occur with merino sheep. In Australia, the greatest densities of free-ranging feral goats and domestic livestock occur in the high rainfall zone (> 500 mm mean annual rainfall) along the eastern tablelands and adjacent slopes of the Great Dividing Range. Previous studies of feral goat biology, population dynamics and behaviour in Australia have concentrated on arid and semi-arid zones or on islands. Interactions between free ranging feral goats and merino sheep have not previously been studied in the high rainfall zone. My study investigated the ecological and behavioural characteristics of feral goats and their interactions with sympatric merino sheep at a high rainfall site in central eastern New South Wales. The population dynamics, biological and behavioural parameters of feral goats and sheep were then used to model FMD in such an environment. Deterministic temporal models and a new spatial stochastic model were used. Of particular interest were the rates of contact within and between subgroups of feral goats (termed herds and mobs), within and between subgroups of merino sheep (termed flocks and mobs), and between subgroups of the two species. Feral goats at the study site were found to be numerous (mean density = 34.94 goats km-2, from aerial surveys), in good condition, fecund and had high adult survival and low annual adult mortality (survival= 0.81�1.00) in the absence of harvesting and hunting. They had an observed instantaneous rate of increase of 0.112 per year. Annual rate of increase was similar to other sites in Australia without sustained harvesting pressure. Home ranges were small for both males (3.754 km², s.e. = 0.232, n = 116 goats) and females (2.369 km², s.e. = 0.088, n = 241 goats). From this and other Australasian studies, an inverse power function was found to be an excellent descriptor of the relationship between mean annual rainfall and female home range size. A resource selection function was fitted in a geographic information system to observational data of feral goats. The habitat selection of feral goats included a preference for wooded vegetation on eastern and north eastern aspects at higher elevations. The resource selection function was also used to set the probabilities of occurrence of feral goats in 1 ha areas of the landscape and these probabilities were used to generate heterogeneity in a spatial model of foot and mouth disease virus (FMDV) transmission. Daily per capita contact rates were estimated from observed contacts in the field where a contact between individuals was recognised when one approached within 1 body length ([approx] 1m) of another. The contacts between feral goats within herds were frequent and occurred at a rate of 6.96 (s.e. = 1.27) goat�goat contacts day-1. Sheep to sheep contacts were slightly less frequent (4.22 sheep�sheep contacts day-1, s.e. = 0.65) but both estimates were most likely negatively biased because of observer errors in estimating the number of individual animals coming in contact with observation subject (focal) animals. Contacts between herds of feral goats were not common and those between adjacent populations were fewer than 1 per year. In sheep, flock to flock contact was largely governed by husbandry practices and occurred at a mean daily rate of 0.0014 flock�flock contacts. Contacts between sheep and feral goats were less frequent but nonetheless common (2.82 goat�sheep contacts day-1, s.e. = 0.40). In feral goats the size of the mob in which focal goats were observed was found to be the most important factor in determining contact rates between individuals and a counter-intuitive inverse relationship was identified. Contacts were heterogeneous and density was not an important determinant of contact rates implying that, because of the uniformly high densities at the site, saturation had occurred. The temporal models of FMDV transmission showed that the rate of contact within and between species was such that FMD was predicted to spread rapidly throughout an infected herd or flock. Control strategies of intense culling of feral goats at the population level were predicted to allow the disease to persist at low prevalence, with a small peak corresponding to the annual lambing pulse in sheep. However, the same level of control (>90% reduction) at the herd level was predicted to eliminate FMD and allow the safe reintroduction of sheep. Extreme control that left very small groups (<3 individuals) may be counter productive because such small groups are likely to join the reintroduced sheep in an effort by the goats to meet gregarious urges. The spatial model was more reassuring. It predicted that FMD would die out in a mixed sheep and feral goat population in less than 90 days because of the low rate of herd to herd contact and herd to flock contact. For similar environments, the contingency planning consequences are that an outbreak of FMD introduced into feral goats from sympatric sheep is likely to be containable by removing all the sheep, determining the extent and likely range of the feral goats, then removing a substantial proportion of or eradicating each herd. Feral goats, being relatively sedentary, are unlikely to spread to adjacent populations and the disease will die out through lack of contact between herds and populations. Because feral goat home ranges overlap and are centred on one or two small catchments, a containment ring of feral goat control, set to encompass the home range of a target herd and that of adjacent herds, should be adequate to limit spread of FMD.

The ability of feral herbivores to reduce the amount of food available to domestic livestock has rarely been quantified. This thesis seeks to examine the degree to which feral goats (Capra hircus) reduce the availability of pasture and shrub biomass for other herbivores. The interaction between feral goat populations and their food supply will be explored using a modelling approach. In addition to this it will also examine the cost of controlling goats and attempt to identify the cost efficient target densities for control operations. The implications of this information for management will be discussed. There are two ways an animal population can interact with its food supply, through: (1) intrinsic food shortages, and (2) extrinsic food shortages. Intrinsic food shortages occur when a negative feed-back loop exists between the animal population and their food supply. This means the animals affect the availability of their food and their food supply affects the dynamics of the animal population. Since the animals are affecting their own food supply it could be said that they will also affect the availability of that food to other herbivores if they consume the same species. Extrinsic food shortages occur when there is no feed-back from the animals to their food supply. Food availability is determined by extrinsic factors such as rainfall and is unaffected by the animal population. To determine how feral goats interact with their food supply several models will be examined, and these include: (1) single species models which use data from the animal population only. These have historically been used to identify density dependence which is commonly caused by the animal population being regulated through their food supply in the case of large herbivores, and (2) trophic models which incorporate data from at least two trophic levels in an ecosystem, in this case those being the animal population and the vegetation they are thought to consume. These models allow a more direct examination of the relationship between the feral goat population and their food supply. The various models were fitted to data collected on the field sites and the following results were obtained: (1) the dynamics of the feral goat populations could not be represented by single-species models. This was most probably due to the stochastic environment in which they lived causing the level of density dependence experienced by the goats to vary greatly masking its presence. (2) the rate of increase of the goat population could be predicted by the numerical response of rate of increase to pasture biomass. This demonstrated that food availability influenced the dynamics of the goat population. (3) goat density affected the availability of some species of shrub biomass. There was, however, no response seen in the availability of pasture species to changes in goat density. Since the study was conducted during a drought this is in agreement with other studies which indicated that goats will primarily browse during dry spells but switch to pasture species when conditions improve following rainfall. These results indicate that a negative feed-back loop does exist between feral goat populations and their food supply since the goats affected the availability of some shrub species and so they suffer intrinsic food shortages. This means goats have the ability to reduce the availability of food to other herbivores providing both are eating the same species. Cost-efficiency analysis showed that the cost of removing individual feral goats increases exponentially as density decreases because the search time per animal becomes greater. This relationship was used to construct a model that predicted the cost of achieving a target density. The model describing cost of control over density was also combined with a productivity model based on the numerical response of feral goats to pasture biomass to predict the cost of maintaining target densities under different environmental conditions. Using these models the most cost-efficient density identified was 11 goats/km2. From this study we can make the following conclusions: (1) feral goats have the ability to reduce the amount of shrub biomass available to other herbivores during dry conditions (2) their ability to influence the availability of pasture species remains unknown (3) given the cost of initial and ongoing control and the minimal benefits that result it would be difficult to justify controlling goats during a drought on the field sites.

M.Tech. / Capra hircus (boer goats) are well known for their hardy adaptability to arid regions and their ability to survive and thrive in areas where grazing is low in nutrition. They are an irreplaceable source of protein for the lower income groups of arid regions in South Africa. Boer goats are prone to helminthiasis (infestation of intestinal parasitic worms), which can result in poor health (Kumba, 2002). This can have a significant effect on the long term productivity of the animal (Alexandre and Mandonnet, 2005), resulting in economic and nutritional strain in poor farming communities who depend on goats as a primary source of protein and income (Kumba, 2002). Conventional treatments worldwide show a trend of resistance of helminths to treatment and carry the risk of inducing side effects when administered (Kumba, 2002; Scarfe, 2004; Schnyder et al., 2005). Homoeopathic research has shown promising results in the treatment of helminthiasis in animals (Zacherias et al., 2008; Jeannes et al, 2001), but no research currently exists of homoeopathy on helminthiasis in Boer goats.