Browsing by Author "Sainio, Mette"

Cattle breeding has become much more effective in recent decades thanks to the development of reproductive biotechnologies and genetic testing. In 1970s it was discovered that embryo transfer techniques make it possible to produce plenty of offspring from top quality females which intensified dairy cattle breeding. Nowadays, there is two embryo transfer techniques in use, MOET and OPU-IVP. A genomic selection has also made genetic improvement of cattle populations more intense than before. Genomic selection is a method that utilizes single nucleotide polymorphisms that appear in individual genome. Today both the embryo transfer techniques and genomic selection are essential elements of cattle breeding all over the world. Genomic selection has typically been carried out on newborn calves. During the recent years, selection has been increasingly carried out and studied on embryo level. Embryo genomic selection always starts with a biopsy taking. After this, sample needs to be genotyped and the results needs to be analysed. Biopsy size has effect on quality of the genotyping outcomes. When the biopsy size grows, quality and reliability of the results will get higher. The aim of this study was to determine if there was any difference in genotyping success between embryos and newborn calves and is it possible to predict embryo-calf genotype similarities via embryo call rate. Material included SNP-genotyping results from a total of 214 embryo and 13 corresponding calves. R programming language was used to statistically analyse the results. Embryo call rates, SNP call rates and embryo-calf genotype similarities were determined from the data. Embryos and their corresponding calves had high similarity with their genotypes, 91,7 % on average. This supports the hypothesis that embryo and their corresponding calves will not have major differences in their genotyping results. Embryo call rates were also in high levels (on average 90,3 %) as was found also in the previous studies. Hence, results from this study confirmed the hypothesis that genotyping of the embryos is a reliable and successful method. There was no clear relationship between embryo call rates and embryo-calf genotype similarities; embryo-calf pair with weakest genotype similarity results, had good embryo and calf call rates. On the other hand, embryo call rates of the two following pairs that got the second and third worst results were clearly below average. In the cases with overall weakest embryo-calf genotype similarities, it was not possible to improve it by eliminating the worst embryo genotypes. Reliable genotyping of embryos enables prediction of genomic breeding values for embryos. Instead of making decision on embryo purchase according to breeding values of the parents of the embryo, purchaser can select embryos according to their own breeding value. Thereby, in the future, embryo genomic selection is likely to become more common than today.