| 1. |
- Abraham, Maria Celina
(författare)
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Reproductive biotechnologies in Swedish male alpacas
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Alpacas have become more popular during the last decades. The herds have been built up by importing live animals since reproductive biotechnologies, for example artificial insemination and semen preservation, are not well-developed in this species. A major problem is the viscosity of the seminal plasma which hinders processing or evaluation of the semen. Enzymes have been used to deal with the viscous seminal plasma but they may damage spermatozoa or render them incapable of fertilization. The use of reproductive biotechnologies would permit the introduction of new genetics without the need to import live animals, thus improving animal welfare and reducing the risk of spreading diseases. Therefore, our aim was to improve reproductive biotechnologies to help develop the Swedish alpaca breeding industry. Laboratory techniques were performed to select the best spermatozoa with Single Layer Centrifugation (SLC), in order to improve cryopreservation. These techniques were developed first using bull semen. There was an improvement in sperm quality in the SLC-selected samples, particularly from poor quality semen. In addition, the SLC technique could be modified to process small volumes. Alpaca epididymides were obtained after routine castration for husbandry purposes, with the intention of comparing semen extenders using extracted epididymal spermatozoa. Most of the organs came from pre-pubertal animals and therefore did not contain spermatozoa. Nevertheless, a decision-making tool for alpaca husbandry under Swedish conditions was developed. We suggest a combination of testicular size and body condition score as a tool for decision-making in the selection of potential sires for animal husbandry under Swedish conditions. A phantom was designed and built to collect semen samples in Sweden, and semen collection trials were also performed in Perú. The advantages and disadvantages of different semen collection techniques were evaluated. However, the problem with semen viscosity still has to be solved. Therefore a semen collection method should be established so that semen handling methods can be developed. We conclude that a phantom could be the best method to use for semen collection in Sweden, since it is a fairly simple technique and, as far as we are aware, there are no animal welfare concerns.
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| 2. |
- Ahlbäck Widenfalk, Lina
(författare)
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Traits or species – space or environment : how to understand the spatial structure of springtail community composition
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- How communities are structured and the processes shaping species composition are among the basic questions in ecology. Knowledge about these processes is essential to predict changes in community composition in response to changes in for example climate or land use practices. Soil communities are considered to be both remarkably species-rich and to have many generalist species with seemingly similar niche requirements. Soil fauna composition shows a large variation even at small spatial scales and both local environment and spatial configuration of habitats are regarded as important forces shaping the community composition. In this thesis, I examine the factors influencing small-scale community composition of springtails (Collembola) in two habitats, a variable and dynamic salt marsh and a more stable mature pine forest. The functional traits of species determine both their responses to the environment and their effects on ecosystem processes. The current knowledge on environment - species - traits relationship is limited in spite of its potential importance for ecosystem function. I show that by combining perspectives from two closely linked theoretical frameworks – metacommunity ecology and community assembly theory – we get a better understanding of the important ecological factors operating in this system. I found that the factors influencing community composition was context dependent, but in a predictable way. In the environmentally variable habitat, salt marsh, with spatial and temporal heterogeneity, there was evidence of strong environmental filtering. Small-scale topography was the strongest predictor of community composition, likely due to disturbances restricting where habitat-generalists can persist. In contrast, in the more stable habitat, mature pine forest, environmental filtering appeared weaker and biotic interactions seemed to have a stronger impact. Coexisting species were more similar in traits related to resource utilisation and sensory ability than expected, and variation in species composition was explained mainly by spatial factors like the distance between samples, i.e. each local community seemed to depend on the composition of the surrounding communities.
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| 3. |
- Amentae, Tadesse Kenea
(författare)
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Evaluation of supply chains and post-harvest losses of selected food commodities in Ethiopia
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Supply chain management practices and losses in food value chains of three major food commodities in Ethiopia (milk, teff and warqe or enset) were evaluated in this thesis. Teff is a cereal, while warqe is a perennial plant from which the food products kocho and bulla are extracted. Teff, kocho and bulla are staple foods for many Ethiopians. In the three case studies, value chain analysis, questionnaire-based loss estimations and Likert scale-based loss factor evaluation were applied. Qualitative and quantitative primary data were collected using a semi-structured survey questionnaire and key informant interviews. The data were analysed using descriptive statistics, Tobit and Probit models in SPSS and Microsoft Excel software. The study identified major chain actors and losses at each stage of the food supply chains. In the milk chain, estimated losses were 3.35%, 5.46%, 2.45%, 0.95%, 1.23% and 0.88% at producers, cooperatives/union, wholesalers, retailers, processors and catering institutions, respectively. In the teff chain, estimated losses were 8.18%, 1.67%, 2.85% and 3.58% at producers, wholesalers, retailers and catering institutions/consumer stage, respectively, while the corresponding values in the kocho chain were 5.8%, 15.2%, 24% and 5.8%, respectively. In the bulla chain, 1.4%, 3.1%, 12.6%, 28.8% and 4.5% losses were estimated to occur at producers, wholesalers, retailers, processors and catering institutions/consumer stage, respectively. The loss hotspots identified were cooperatives, farmers, retailers and processors for milk, teff, kocho and bulla, respectively. Poor handling at collection points, the threshing process and poor packaging and processing facilities were among the major problems causing losses. Tobit model analysis identified distance to the nearest market as the most important factor for farmers’ post-harvest losses, while Probit analysis identified attendance in formal education as most determining for value addition decisions in the teff chain. Relationships among the chain actors were mostly based on spot transactions, lacking long-term market orientation and adequate mutuality and trust. However, application of supply chain management (SCM) practices could potentially improve the overall supply chains and reduce food losses.
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| 4. |
- Amiri, Saeid
(författare)
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On variance estimation and a goodness-of-fit test using the bootstrap method
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with the study of variance estimation using the bootstrap method, including the problem of choosing between nonparametric and parametric bootstrap methods. Paper I compares the two approaches, determines which method is preferable and analyses the accuracy of the approximations. The underlying concept of parametric bootstrap is based on the assumption of correct choice of parametric distribution. Paper II therefore considers goodness-of-fit tests and presents a new test based on the bootstrap method.
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| 5. |
- Andersson, Emma
(författare)
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Impact of litter size on sow health and welfare
- 2018
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Genetic improvement of litter size has been the main breeding goal in piglet production during the last decades, resulting in a steady increase in total number of born piglets in each litter both in Sweden and in other European countries. It has been suggested that large litters pose a major welfare problem for sows and piglets. However, there is a lack of recent studies investigating the impact of litter size on the health and welfare of sows. Therefore the objective of this thesis was to investigate the association between litter sizes and sow health and welfare. The two studies included in this thesis were performed as observational studies and investigated by retrospective analysis of available pig production data. The first study investigated the association between litter sizes and sow stayability, and the second study the association between litter size and medical treatment of sows during farrowing and lactation. The final dataset used in the first study included a study population of 38 878 sows in 24 herds and the final dataset in the second study included observations from 1 947 litters from 655 sows. Associations between litter size and sow health and welfare was found. There was an association between litter size and stayability of the sow, as well as association between litter size and medical treatment of the sow. The results from both studies imply that sows with medium sized litters have a better lifetime production than sows with very small or large litters. Piglet producers should therefore pay even more attention to prophylactic management of sows during gestation and lactation. In planning of breeding strategies and annual removal of sows, piglet producers should also aim for keeping sows giving birth to a medium-sized litter, with approximately 12 to 14 piglets born in total in their breeding program, as this seems to improve sows’ stayability and decreasing the risk of unplanned removal which would favour health and welfare of both sow and piglets.
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| 6. |
- Anerud, Erik
(författare)
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Stump as a fuel : the influence of harvesting technique and storage method on fuel quality of Norway spruce
- 2010
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Uncertain long-term availability of fossil fuels and the negative environmental impact of using it have created an urgent need for reliable renewable energy sources. Wood fuel, particularly forest residues is one of these sources which are in high demand in Sweden today. Stumps can be used as a complement to these, since they contain high concentrations of energy-rich lignin and extractives. However, stump removal can have negative environmental effects such as reduction of biodiversity and disturbance of nutrient balance in the soil. As to the fuel quality of stump biomass, there are some concerns connected with the utilisation of stumps since presence of excessive contaminants leads to high ash contents which reduce its value as fuel and causes operating problems. To ensure the supply of fuel of acceptable quality, an optimal system for harvesting, handling, and storage must be devised for stump procurement. The main aim of this work was to evaluate various stump harvesting techniques, storage methods (windrow or heaps), and different storage durations at two geographical locations and examine their effect on the fuel quality of Norway spruce stump biomass. Fuel quality parameters moisture content, ash content and calorific value were evaluated on five occasions during May 2008 - September 2009. Stump harvesting techniques that split the stumps allowed better drying during 13 months of storage. Storage method had no clear effect on these stumps. The ash content decreased considerably, particularly when transport and crushing took place at temperatures exceeding 0°C. In general, fuel quality was improved in all treatments after storage. However, as the storage time progressed, the net energy increment became continuously smaller due to the increased substance losses.
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| 7. |
- Aradom Messmer, Samuel
(författare)
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Animal transport and welfare with special emphasis on transport time and vibration including logistics chain and abattoir operations
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During transport animals are exposed to a number of stressors such as, separation from familiar and mixing with unfamiliar groups, vibration and transport time. Logistics chain of animals comprises collecting from farms, transport, unloading and slaughter chain operations. The current licentiate thesis deals with transport of pigs and cattle from farms to abattoirs including all logistics chain. Two trucks with natural ventilation and air suspension systems were used for field experiments. Stress hormones such as cortisol, glucose, lactate and creatine kinease, ethological parameters, carcass pH value, temperature and relative humidity were measured to study effect of transport on pigs welfare. Vibration levels on chassi, floor and cattle were studied and the influence of speeds, road types and cattle standing orientations on vibration levels were investigated. Field measurements were also conducted to describe the potential effect of operations planning and route optimization on welfare and meat quality. Highest pH24 value was (5.990.29) at 12 h summer transport time. Concentrations of cortisol was inversely proportional (P<0.001) to transport time, lactate and creatine kinase (P<0.002) positively correlated where as glucose level (P<0.01) was highest at 8 h transport time. Lying, sitting and rooting correlated with transport time (P<0.009). On cattle, highest vibration was 2.27±0.33 m s-2 during transport on gravel road at 70 km h-1. Vibrations in horizontal and lateral directions were lower on animals positioned perpendicular to driving direction. Uneven distributions of arrivals affected handling at the delivery gate. Unloading, including waiting and preparation, varied between 7 and 98, with an average of 23.7 minutes. Queues at washing occurred at 29% of deliveries, with waiting of up to 56 minutes. Potential savings for individual routes was up to 23%, consequently reducing negative impact on animal welfare, meat quality and environment. Based on climatic conditions, behaviours, stress hormones, and final carcases pH values, an increase from 4 to 8 h had higher effect than from 8 to 12 h transport time. To reduce vibration levels animal transporters more have to adapt vehicle's speed to road and animal conditions. Time and distance of transport activity can be reduced through effective planning and route optimisation which also improves animals' welfare and environmental impact.
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| 8. |
- Beier, Ulrika
(författare)
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Habitat selection and indirect interactions in fish communities : mechanisms to explain spatial distribution of perch, roach, and vendace
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- To increase the understanding of freshwater lake ecosystems, I have studied the habitat selection of perch (Perca fluviatilis L.), roach (Rutilus rutilus (L.)), and vendace (Coregonus albula (L.)). These fish species use the pelagic and the littoral-benthic habitats in lakes to different extents. Perch and roach are omnivorous, and perch become piscivorous at larger sizes. Vendace is a pelagic species specialized in eating zooplankton. Vendace was expected to affect biotic interactions and habitat use of roach and perch, both directly and indirectly. I used monitoring data to examine how species distribution patterns, as well as population structures, depended on species composition. In a predation experiment, I studied the relative predation sensitivity as well as evasive behaviours of roach and vendace, with piscivorous perch used as predators. In foraging experiments in aquaria, I studied foraging efficiencies and swimming performances of roach and vendace eating zooplankton in different temperature and light treatments. I then applied metabolic models for roach and vendace, respectively, to compare their net energy gain in different abiotic conditions. Roach used the pelagic habitat less, and the biomass of roach was lower in lakes with vendace. Results did not support the prediction that perch populations would benefit from the presence of vendace. However, results indicated that a release of competition for small perch may be mediated by vendace, through changed habitat use of roach, increasing the possibilities for predation. Roach and vendace were similar in their sensitivity to predation, indicating that energy gain can explain their habitat use. Foraging efficiencies did not explain the habitat use of roach and vendace in the field. However, the net energy gain in different abiotic conditions, could explain observed patterns of their habitat use in lakes. This thesis shows how the trade-off between mortality and net energy gain is manifested in habitat use. Including habitat selection in ecological studies may increase our understanding of biotic interactions. Metabolic costs as well as foraging abilities in different abiotic conditions are important for explaining the habitat use of species. Such knowledge can make it possible to forecast how interacting fish species may be affected by environmental change.
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| 9. |
- Bell, David
(författare)
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Forest restoration guided by an umbrella species : will measures to protect the white-backed woodpecker benefit saproxylic beetles?
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Management shortcuts in conservation biology, like the umbrella species concept, have been debated worldwide. Umbrella species have been used to identify and delineate protective areas, but habitat requirements of umbrella species can also provide tangible targets in ecological restoration. In Sweden, forest habitats have been restored for the white-backed woodpecker (WBW, Dendrocopos leucotos) under the assumption that it will benefit other habitat-associated (background) species. In this thesis, the umbrella species concept was evaluated based on the response of wood-inhabiting (saproxylic) beetles to forest restoration for the WBW. The WBW is a top-predator in saproxylic food webs associated with broadleaved trees, but it is also critically endangered in Sweden because of commercial forestry practices that disadvantage broadleaved trees and reduce dead wood availability. Spruce trees (Norway spruce, Picea abies) were selectively harvested during forest restoration to make way for broadleaved trees like birch (Betula spp.) and European aspen (Populus tremula). Some broadleaved trees were also killed to create high-stumps (snags) and downed logs. Commercially managed forests were compared with restored forests; either directly in comparative studies, or before and after forest restoration. Two types of flight-intercept traps were used to catch saproxylic beetles: IBL2-traps and trunk-window traps. Results presented in this thesis show that habitat requirements of an umbrella species can be used to guide forest restoration. There were many beneficiary species at the stand-level. Commercially managed and restored forests were inhabited by different communities of saproxylic beetles, and species positively associated with broadleaved trees and sun-exposed substrates were particularly responsive. This was reflected by an increased species richness and abundance. Several near-threatened and vulnerable species were also attracted to substrates created for the WBW. This shows that efforts to bring back the WBW can benefit other resource-limited groups of conservation concern. Saproxylic beetles might even facilitate restoration efforts since many important prey species for the WBW were attracted to restored sites. Umbrella species, like the WBW, will require landscape-level efforts to recover. This is a strength of the umbrella species concept, but also a weakness since landscape-level efforts are time consuming. The WBW is still struggling in Sweden, and failed attempts to re-establish viable populations might undermine conservation incentives. Early signs of progress, however, are sometimes provided by less demanding species, like many saproxylic beetles in this thesis. Background species can also provide much needed examples of restoration success at the stand-level.
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| 10. |
- Bergkvist, Johan
(författare)
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Landskapsarkitektur i järnvägslandskap : platsernas förändring i historiskt perspektiv
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Järnvägens organisation för skötsel av den yttre miljön avvecklades redan i början av 1970-talet. Järnvägsparker och andra planteringar togs bort eller förenklades för att minska skötselbehovet. Banverket bildades1988 med uppgift att förvalta och utveckla statens spåranläggningar. Det nya verket övertog då också en stor mängd tidigare välvårdad park- och trädgårdskultur, med redan då tämligen eftersatt skötsel. Den svenska järnvägssektorn har därefter, liksom många andra europeiska järnvägsorganisationer, genomfört omfattande förändringar för att göra verksamheten effektivare och mer ekonomiskt bärkraftig. Detta har skett genom teknisk utveckling, fortsatta rationaliseringar och avregleringar. Samtidigt som allt detta skett har järnvägens fysiska miljöer, med sin tidigare så förebildliga arkitektur och trädgårdskonst, hamnat i skymundan. Avhandlingen huvudfrågor är hur den pågående fysiska omvandlingen av järnvägsmiljöerna kan beskrivas och kategoriseras och hur värden i arkitektur och trädgårdskonst kan tillvaratas. En stor mängd av järnvägens stationer och andra järnvägsmiljöer har besökts och dokumenterats under denna tid. Ett snävare urval har sedan legat till grund för en flerfallstudie där de fysiska förändringsprocesserna studerats på ett systematiskt sätt. Förändringen av de undersökta miljöerna följer med små variationer samma mönster överallt. De karakteriseras av förskjutningar i olika riktningar, även vertikala när spårens höjdläge förändras. Tillkommande eller utbytta funktioner och strukturer överlagrar ofta de gamla. Samtliga studerade järnvägsmiljöer har också reducerats i förhållande till sin ursprungliga utbredning. Spår och fragment från olika generationers anläggningar är ofta synliga i den omgivande miljön; igenväxande och ibland i rent förfall. Olika teoretiska perspektiv har använts för att diskutera hur järnvägsmiljöernas förändring kan beskrivas och tolkas. Slutligen diskuteras vilket värde järnvägens kulturarv har i den förnyelse- och omvandlingsprocess som pågår och om det är möjligt att se den historiska järnvägens materiella och immateriella kulturarv inte bara som en kostnad och ett problem utan också som resurs i ett hållbarhetsperspektiv. Avhandlingen vill fästa uppmärksamheten på dessa materiella och immateriella värden och de argument som finns för att integrera och återbruka dem i den pågående fysiska omvandlingen av järnvägssystemet.
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