Sökning: "egg production"

Visar resultat 16 - 20 av 60 avhandlingar innehållade orden egg production.

  1. 16. Characterisation of social behaviour in red junglefowl and White leghorn laying hens : phenotypic and genetic studies

    Författare :Johanna Väisänen; Harry Blokhuis; Linköpings universitet; []
    Nyckelord :Red junglefowl; social behaviour; behaviour tests; NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : The objective of this thesis was, by using two model strains of chicken, red junglefowl and White Leghorn layer, to study differences in social behaviour of the species that could be derived from domestication and production related selection processes. The social phenotype characterisation was done to be able to further study the association of the social differences to specific production related traits as well as to certain genome areas in intercross and backcross lines generated from these two parental populations. LÄS MER

  3. 17. Copepods in Skeletonema-dominated food webs : Toxicity and nutritional quality as factors controlling copepod-diatom interactions

    Författare :Roswati Md Amin; Ulf Båmstedt; Sigrun Jónasdóttir; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Copepod-diatom interaction; toxicity; nutritional quality; Skeletonema;

    Sammanfattning : My thesis focuses on copepod-diatom interactions, specifically on the effects of food quality and toxicity on copepod feeding, reproductive success and behavior but as a frame, also includes a quantitative evaluation of copepod carbon requirements compared to other trophic plankton groups. My aim was to evaluate the function of copepods in diatom-dominated spring blooms. LÄS MER

  4. 18. Nesting and migration in the introduced Canada goose in Sweden

    Författare :Göran Sjöberg; Catherine M. Lessells; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Species introductions; DNA fingerprinting; natal dispersal; breeding dispersal; bird migration; wintering areas; clutch size; laying date; body reserves; nest defence; waterfowl; Canada goose; Anatidae; Branta canadensis;

    Sammanfattning : The aim of the thesis was to document patterns in breeding and migration in Swedish Canada geese Branta canadensis, to explain these against the genetic and historical background of the population, and to test predictions of hypotheses pertaining to parental investment.The Canada goose population in Sweden was founded by the introduction of a few individuals in the 1930's. LÄS MER

  5. 19. Trophic complexity of zooplankton–cyanobacteria interactions in the Baltic Sea : Insights from molecular diet analysis

    Författare :Nisha H. Motwani; Elena Gorokhova; Jakob Walve; Catherine Legrand; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; bloom-forming filamentous cyanobacteria; diazotrophs; picocyanobacteria; zooplankton; grazing; molecular diet analysis; stable isotopes; biochemical indices; Marine Ecology; marin ekologi;

    Sammanfattning : Blooms of nitrogen fixing cyanobacteria (NFC) occur in many freshwater and marine systems, including the Baltic Sea. By fixing dissolved nitrogen, they circumvent general summer nitrogen limitation, while also generating a supply of novel bioavailable nitrogen for non-diazotrophic primary producers and ultimately supporting secondary production. LÄS MER

  7. 20. Effects of domestication related genes on behaviour, physiology and gene expression in chickens

    Författare :Anna-Carin Karlsson; Per Jensen; Randi Oppermann Moe; Linköpings universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Domestication, the process when animals adapt to captivity, tends to modify a whole array of traits towards what has been termed “the domesticated phenotype”, where the domesticated animal differs from its wild ancestor in morphology, physiology, development and behaviour. Physiological traits and behaviours are controlled by genes. LÄS MER