ABSTRACTThe aim of this study was to give an overview of the evidence for Genomic Imprinting in livestock and other mammals as well as outline the potential use of gene imprinting in livestock breeding. Epigenetics is the mitotical and meiotical partial hereditary variation in genomic activity without any alterations of the DNA sequence. An example of epigenetic regulation is Genomic Imprinting where one allele?s expression differs depending on which parent it was inherited from. These parent-of-origin effects are currently overlooked in livestock production.

During the last decade a new technique in animal breeding has developed called genomic selection. It is based on estimations of the effect from genetic markers on traits that are calculated in a reference population. By genotyping individuals, genomic breeding values can then be estimated without phenotypic observations. The aim of this essay is to investigate the response of genomic selection on breeding schemes for dairy cattle. The accuracy of the genomic breeding values is affected by the proportion of observations included in the validation set and how often the equation for estimating breeding values is reevaluated.

Genomic selection (GS) is used for selection of breeding animals of dairy cattle. GS is though not as extensively used within the beef industry. One reason for that is the low accuracy (rTI) of the breeding value that is of great importance for the final genetic gain. Causes to the low accuracy are high effective population size, a small reference population and a genetically differentiated population. There is however a market for genomic selection with High Density (HD) tests for beef cattle.

This study was conducted at the University of Bath, UK, from September to December 2014 as part of an ongoing research project aimed at elucidating how the Grb10 gene might act as a mediator of long-term health effects (such as predisposition to obesity, diabetes, coronary heart disease and hypertension) caused by environmental factors during development. This phenomenon is known as developmental programming. The purpose of this thesis was not primarily to answer any of the broader questions posed by this research project at large since this would require much more data than is reasonable to acquire over the course of a few months, but rather to evaluate the methods used in this project and reveal whether they are working the way they are presumed to. In the research project, which employs mice with the Grb10 gene knocked out as well as wild-type control mice, a dietary restriction model is utilized during gestation, which is supposed to generate offspring with lower birth weight and subsequent detrimental health effects in adulthood. This is supposed to be achieved by restricting the protein content of the pregnant mothers? diet to 9 % (as opposed to the control diet of 20 %) throughout gestation.

In the year of 1935 Sweden started to apply the practice of their first sterilizing laws. In this thesis 2 sterilizing laws are considered. The laws regulated those individuals who were not considered appropriate for reproduction. The sterilizing laws themselves are based on several large investigative studies on how to evaluate and categorize different individuals.  The purpose of my thesis is to examine through a literature study how these individuals considered for sterilization were valued and how social problems were created to fit the character features of these people. I also look at how sterilization became an acceptable method to deal with these constructed social problems. The materials I have studied include 3 pre-studies and the 2 laws about sterilization which were the result of these pre-studies.  I found that the motives behind the sterilizations were social, economical and genomic hygienical.

After a workshop in Kuopio held in June 2006, Interbull decided to go forward with the development of a system for beef international genetic evaluation and a three year project called Interbeef was launched in June 2007. The participating countries are so far limited to Europe and the only trait evaluated at present is adjusted weaning weight (weight at 200 days). The results from a first international genetic evaluation have been shared with the countries but are not yet official. The evaluation is based on data from purebred Charolais and Limousin. To achieve good estimates of proofs in an international context it is important that methods for data validation and model selection are implemented.

Cassava (Manihot esculenta Crantz) is a root crop that plays an important role in many households in Africa. It is sometimes called ?Africa´s food insurance?. The advantages with the crop are that cassava is drought-resistant and it can grow in a semi-dry land. It is a perennial crop and does not require much labor.

Bovine viral diarrhoea virus (BVDV) is the causative agent of a complex of disease syndromes in cattle with high economical and welfare impacts. BVDV occurs as two biotypes; cytopathic (BVDVcp) and noncytopathic (BVDVncp) determined by differential effects on cultured cells and can also be divided into two genotypes (BVDV1 and BVDV2) on the basis of genomic diversity. The interaction between BVDV and the host?s immune system is regarded a key aspect in the sequel of BVDV infection. Infection with BVDV normally causes an acute transient infection, with mild to subclinical signs, but occasionally results in severe and even fatal disease.

Porcine circovirus type 2 (PCV2) is a common virus present in most parts of the world. PCV2 has been pointed out as the major causative agent to post weaning multisystemic wasting syndrome (PMWS) that affects pigs after weaning. The clinical symptoms of PMWS are impaired growth, diarrhoea, respiratory problems and increased mortality. At autopsy enlarged lymph nodes with depletion of lymphocytes are commonly found. Since 1991 PMWS has spread all over the world and was first described among Swedish pigs in 2003. Although PCV2 is widespread, only some pigs develop PCV2-related diseases. Why this is and what other factors that are required in order for the disease to develop is yet unknown. The main theories involve other infections, for example PRRS, and management issues but also genetic differences between pigs and/or virus strains have been suggested.