Utilizing spectroscopy and CASA to predict in vivo fertilization in cattle and pigs

Most fertilizations in pig and dairy production in Norway are carried out through artificial insemination. The aim of this project is to increase knowledge about the properties of semen that are important for the fertilization capacity of boars and bulls. The project has focus on both sperm cells and seminal plasma and use CASA (Computer Assisted Semen Analysis) and spectroscopy to gather characteristics from various semen samples from bulls and boars. Three different spectrometers have been used to analyze seminal plasma samples from 156 boars and 167 bulls. This is a new method, and a dedicated protocol for the analysis of the seminal plasma samples has been developed. The results from the spectrometers show differences in the content (proteins, lipids, etc.) of the seminal plasma samples across species, breeds, and age groups. The CASA technologies collect large amounts of information, and the goal is for this data to provide insights into the fertilization potential of semen samples. For both cattle and pigs, large volumes of detailed data have now been collected and organized in separate cloud databases. This data is at the single sperm cell level, including information on cell motility patterns and morphology, and is prepared for advanced data analysis. One analytical method tested is principal component analysis (PCA), which simplifies large datasets with many variables and identifies the most significant principal components that explain most of the variation. This allows us to calculate relationships between cell-level properties, semen quality, and the fertilization capacity of bulls and boars.

In this project we will use spectroscopic tools and computer assisted semen analysis (CASA) to characterize semen plasma and assess sperm quality. Today there is a lack of objective assessments of seminal plasma, sperm quality, and sperm quantity to describe the fertilization ability and robustness of the semen. Semen from boars and bulls will be evaluated for their ability to capture chemical fingerprints from spectroscopy of seminal plasma. Detailed CASA data will be used in advanced data analysis to estimate associations between sperm quality traits and field fertility, which is the final target of the sperm quality evaluation. This entails a link between these field data, the detailed CASA information for individual AI males on ejaculate level, and potentially novel parameters from semen plasma (spectroscopy). Robustness of the sperm quality, measured from stored and frozen semen, and also identification of bottlenecks in relation to the age of the males for approved semen production is also an activity in the project. Establishing access and storage of the large datasets from the spectroscopy and CASA such that they can easily be combined with data from other data sourches is an important task that will ensure the best possible use of the data. CASA data combined with field fertility data from mates, pedigree information etc will be used to predict genomic breeding values and provide knowledge of the genetic trends for male fertility. The large majority (>98%) of dairy cows and sows in Norway are bred through artificial insemination. Success in this research project will reduce costs in production, increase the quantity of semen doses sold, reduce waste of semen produced, and improve genetic gain as a result of less involuntary culling of males and ejaculates of high genetic value in the breeding companies Geno SA and Norsvin SA.