Elisabeth Kommisrud

• Bremer, Joanna; Narud, Birgitte; Maj, Michał; Johansen, Karina Hauge; Zeremichael, Teklu Tewoldebrhan & Kommisrud, Elisabeth (2026). Swimming against time: Temporal dynamics of sperm motility in Arctic Charr (Salvelinus alpinus). Theriogenology. ISSN 0093-691X. s. 118190–118190. doi: 10.1016/j.theriogenology.2026.118190. Fulltekst i vitenarkiv
• Kaththriarachchi, Sonali Nadeeshani; Kommisrud, Elisabeth; Grevle, Inger S.; Santana, João; Eriksen, Anne Lene & Narud, Birgitte [Vis alle 10 forfattere av denne artikkelen] (2026). Combined physicochemical and proteomic profiling identifies biochemical associations of oocyte quality and fertilisation outcome in Atlantic salmon (Salmo salar L.). Aquaculture. ISSN 0044-8486. 623, s. 1–13. doi: 10.1016/j.aquaculture.2026.744171. Fulltekst i vitenarkiv Vis sammendrag

  Atlantic salmon is a commercially important salmonid species facing ongoing challenges in broodstock and gamete management, where oocyte quality represents an important factor influencing reproductive success. In this study, we combined physicochemical analysis of oocytes and ovarian fluid (OF) with proteomic profiling of selected embryonic stages i.e., eyed egg and hatched larvae to identify candidate indicators associated with oocyte quality in commercial aquaculture. Significant associations were observed between OF properties and fertilisation outcome: aspartate aminotransferase (AST) enzyme activity in OF and pH exhibited the strongest correlations with fertilisation and eyed egg success. OF osmolality and relative weight gain during water hardening (RWH) in oocytes were also associated with variation in oocyte performance. Proteomic profiling revealed proteins associated with proteostasis, translation, calcium regulation, lipid metabolism, and immune and inflammatory responses. Notably, 135 proteins were significantly correlated with fertilisation outcome, of which 80 were identified in OF, suggesting that the surrounding biochemical environment may be associated with oocyte viability.

• Shrestha, Asmita; van_Son, Maren; Hashim, Adnan; Rouzbehani, Soudabeh; Gilfillan, Gregor & Berge, Urszula [Vis alle 8 forfattere av denne artikkelen] (2026). Sperm RNA landscape during sexual maturation in Duroc boars. BMC Genomics. 27(1). doi: 10.1186/s12864-025-12490-0. Fulltekst i vitenarkiv Vis sammendrag

  Background Sexual maturation in boars impacts reproductive efficiency in swine production, yet the molecular mechanisms underlying this developmental transition remain poorly understood. This study aimed to investigate the transcriptomic changes in sperm from Duroc boars during sexual maturation, conducting a longitudinal analysis. The total RNA and miRNA profiles from the same individuals (n = 6) at puberty (7.24 ± 0.39 months) and sexual maturity (10 ± 0.40 months) were compared, identifying molecular signatures associated with reproductive development. Total RNA sequencing (Illumina NovaSeq-6000) and miRNA sequencing (Illumina NextSeq-500) were performed on all 12 paired samples (6 boars at 2 time points), followed by differential expression analysis using a paired statistical model in DESeq2 to account for repeated measures. Results Differential expression analysis identified 60 differentially expressed genes using stringent criteria (adj P < 0.05, |log2FC| ≥ 0.5), with 65% upregulated in sperm of boars 10-months versus 7-months of age. Key upregulated genes included NCLN, RGS12, CIB2, FOXP4, PHC1, CDC25B and AKAP1, while HSP90AA1, EVI5, FSIP2, VDAC3, and ALMS1 were key downregulated genes. Furthermore, Gene ontology analysis revealed significant enrichment of 11 biological processes, mostly related to reproductive development, and four molecular functions (transferase activity, transferring phosphorus-containing groups, protein serine/threonine kinase activity, protein kinase activity and signal sequence binding). Additionally, our miRNA analysis identified six differentially abundant miRNAs (adj P < 0.05 & |log2FC| ≥ 0.5); ssc-miR-193a-5p, ssc-miR-574-3p, ssc-miR-126-3p, ssc-miR-196a, ssc-miR-210 were upregulated, and ssc-miR-338 showed downregulation in 10-months age. Integrated analysis of differentially expressed mRNA and predicted miRNA targets identified 18 miRNA-mRNA regulatory pairs, enriched in pathways related to cell cycle processes and chromatin binding, suggesting coordinated regulation across RNA biotypes in sperm during sexual maturation. Conclusions Our study reveals coordinated transcriptomic shifts in boar sperm during sexual maturation. Most genes show increased RNA abundance at 10 months of age, with enrichment in terms of reproductive development. Several miRNAs appear to regulate these changes through targeted mRNA interactions. These findings expand our understanding of the biological processes underlying sexual maturation in pigs.

• Fosslie, Madeleine Lystad; Ilaslan, Erkut; Skuland, Trine; Choudalakis, Michel; Søegaard, Mirra Louise Cicilie & Halliwell, Jason Alexander [Vis alle 23 forfattere av denne artikkelen] (2025). Major waves of H2A.Z incorporation during mouse oogenesis and preimplantation embryo development. Nature Communications. 17(1). doi: 10.1038/s41467-025-66919-x. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Epigenomes of mammalian oocytes and embryos undergo major transitions essential for successful development. Here, we provide genome-wide maps of histone variant H2A.Z during twelve stages of mouse oogenesis and preimplantation embryo development and relate it to histone marks and genomic features. This revealed that major waves of H2A.Z incorporation occur early in growing oocytes, forming distinct patterns of maternal, embryonic, and persistent H2A.Z enrichment. Late maternal enrichment is inherited by the zygote and precedes reduced formation of lamina associated domains and early replication in the maternal genome of 2-cell embryos. Persistent H2A.Z enrichment is strongly associated with CpG islands and H3K4me3 near transcription start sites of active genes, but thousands of maternal and embryonic H2A.Z incorporation sites exist elsewhere, frequently at transposable elements. The persisting H2A.Z enrichments across related developmental stages enable preservation of epigenetic information despite major concurrent changes in H3K4me3, H3K27me3, and DNA methylation. Altogether, this advances our understanding of how histone variants contribute to epigenetic reprogramming during mammalian oogenesis and early development.

• Jochems, Reina; Kristiansen, Camilla O.; Kommisrud, Elisabeth & Morrell, Jane (2025). Preliminary study of pregnancy rates and litter sizes following artificial insemination of boar spermatozoa prepared by colloid centrifugation and hypothermic storage. Scientific Reports. 15. doi: 10.1038/s41598-025-24586-4. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Stringent efforts are being made to restrict the development of antimicrobial resistance by good antibiotic stewardship in medical, veterinary and environmental health. In the pig industry, considerable volumes of antibiotic-containing extender are utilised in artificial insemination. Separating spermatozoa from bacteria by colloid centrifugation followed by cold storage could provide an alternative to antibiotics in semen extenders, provided that sperm fertility is not affected by this combination of techniques. The objective of this proof-of-concept study was to compare reproductive outcomes in sows inseminated with control sperm samples or with samples prepared by Single Layer Centrifugation (SLC) through a low density colloid and cooled to 4 °C. A further aim was to compare the SLC sperm preparations with and without antibiotics. Sows were divided into three groups for insemination as follows: control semen prepared and stored conventionally ( n  = 16), SLC samples prepared with antibiotics and cold stored ( n  = 18), SLC samples prepared without antibiotics and cold stored ( n  = 18). The yield of spermatozoa was 84–93%, respectively. Farrowing rates were 88% for controls and 89% for SLC samples. Mean litter size was 16.6, 17.5 and 17 for controls, SLC with antibiotics and SLC without antibiotics, respectively. Stillborn piglets per litter were also similar between groups (0.7, 1.4 and 1.4 respectively). In conclusion, the combination of techniques did not adversely affect sperm fertility or reproductive outcomes of inseminated sows, regardless of whether antibiotics were included in the resuspended sperm pellets after SLC.

• Sinani, Valentina Krivenjeva; Wilson, Robert Charles; Nome, Torfinn; Acharya, Ujjwal; Kommisrud, Elisabeth & Wetten, Marte [Vis alle 7 forfattere av denne artikkelen] (2025). Development and validation of a 70K SNP genotyping array for Atlantic halibut (Hippoglossus hippoglossus). BMC Genomics. 26(1). doi: 10.1186/s12864-025-12128-1. Fulltekst i vitenarkiv Vis sammendrag

  Background The analysis of single nucleotide polymorphism (SNP) genotypes which capture genome-wide polymorphic variation can be used to improve the accuracy of selection in breeding programs and reveal the genetic architecture of quantitative traits. Mid-density SNP genotyping arrays containing > 60 K SNP markers have been developed for numerous production species and have been used to enable enhanced breeding progress. Despite recent genomic advances, Atlantic halibut lacks mid-density genotyping tools, limiting the application of genomic selection and high-resolution association studies in this species. The evolving Atlantic halibut (Hippoglossus hippoglossus) industry is also interested in genetically informed selection of breeding candidates to facilitate genetic improvement. The present study reports the development of the first mid-density SNP-array for use in Atlantic halibut and describes its performance in samples from different breeding populations. Results Variant discovery was performed using whole genome sequencing (WGS) data from 40 individuals and resulted in the detection of more than 8 million small genetic variants including 6,224,375 SNPs and 2,131,436 insertion-deletion variants (INDELS). An Affymetrix Axiom custom array containing 70,824 assays (including 697 for determining genetic gender) was created and used to genotype 1152 Atlantic halibut samples. Assays for 59,491 SNP loci (84% of the array total) performed well and generated reliable genotypes, with an average SNP call rate of 99.64% and genotype concordance of 99.0% with whole-genome sequencing data. Of the gender-specific loci, 133 SNP assays could be used to assign genetic gender. Conclusions This article describes the first mid-density SNP genotyping array for Atlantic halibut. It contains nearly 60 K robust assays for genome-wide dispersed SNP loci, along with those suitable for determining genetic gender. The array is amenable for use as a platform for high-resolution genetics research into traits of evolutionary and economic importance and the results have practical relevance for genomic selection in Atlantic halibut.

• Shrestha, Asmita; Gaustad, Ann Helen; Øiaas, Janne Beate; Nordborg, Anna; Kommisrud, Elisabeth & van_Son, Maren [Vis alle 8 forfattere av denne artikkelen] (2025). Untargeted metabolomics reveals changes in boar sperm and seminal plasma metabolites associated with sexual maturity. Journal of Animal Science and Biotechnology. ISSN 1674-9782. 16. doi: 10.1186/s40104-025-01258-x. Fulltekst i vitenarkiv Vis sammendrag

  Background: Boars undergo physiological and biochemical changes in semen composition as they grow from puberty to sexual maturity. However, comprehensive metabolomic profiles of boar semen remain uncharacterised. Understanding metabolic alterations in semen during this period is important for optimising reproductive performance in breeding programs. The aim of this study was to characterise the semen metabolome as boars mature, utilising an untargeted metabolomic approach. Semen samples were collected from 15 Duroc boars at three developmental ages: ~ 7 months, 8.5 months, and 10 months. Sperm and seminal plasma were separated and analysed by hydrophilic interaction and reversed-phase liquid chromatography coupled with mass spectrometry to capture a wide range of metabolites. Results: We identified a total of 4,491 features in boar semen, annotating 92 distinct metabolites. Amino acids, peptides and analogues constituted the most abundant components, followed by fatty acid esters. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) showed a clear separation between metabolomic profiles by age groups. PERMANOVA analysis of PCA scores confirmed statistically significant differences ( P  < 0.05) between younger (7 months) and more mature boars (8.5 months and 10 months). Pathway analysis identified porphyrin metabolism, taurine and hypotaurine metabolism, and glycerolipid metabolism as significantly enriched pathways in sperm, while glutathione and nitrogen metabolism were prominently enriched in seminal plasma. Using linear modelling, partial Spearman correlation and random forest analyses, we identified homoisovanillic acid as a key metabolite discriminating age groups in both sperm and seminal plasma. Additionally, L-glutamic acid, decanoyl-L-carnitine and N-(1,3-Thiazol-2-yl)benzenesulfonamide emerged as important sperm metabolites, while glyceric acid, myo-inositol, glycerophosphocholine, and several other compounds were identified as critical seminal plasma metabolites. Conclusion: This study provides a detailed characterisation of metabolic changes in Duroc boar semen during the transition from puberty to sexual maturity. Our findings enhance the understanding of reproductive development and could inform strategies to assess sexual maturity in breeding programs.

• Shrestha, Asmita; Gaustad, Ann Helen; Øiaas, Janne Beate; Kommisrud, Elisabeth; Son, Maren van & Nordborg, Anna [Vis alle 7 forfattere av denne artikkelen] (2025). A metabolomic study uncovering key amino acids and amines in Duroc boar semen as biomarkers of sexual maturity. Animal Reproduction Science. ISSN 0378-4320. 275, s. 1–14. doi: 10.1016/j.anireprosci.2025.107800. Fulltekst i vitenarkiv Vis sammendrag

  Metabolomic analysis of boar semen associated with sexual maturation is essential for improving fertility management and breeding, with amino acids and amines playing key roles in the reproductive process. This study aimed to explore changes in amino acids and amines in boar spermatozoa and seminal plasma during puberty to sexual maturity and identify potential biomarkers of sexual maturity. Semen was collected from the same 15 Duroc boars over time at approximately 7 months (Age 1), 8.5 months (Age 2), and 10 months (Age 3). Liquid chromatography-mass spectrometry was used to analyse amino acids and amines in spermatozoa and seminal plasma separately. Multivariate analysis (PLS-DA) revealed pronounced age- dependent changes in amino acids and amines in spermatozoa between Age 1 and Age 3, and more subtle shifts in seminal plasma. Univariate analysis (Repeated measure ANOVA/Friedman) revealed that glutamate and taurine had significant pairwise differences in seminal plasma (P < 0.05). In sperm, 15 amino acids (glutamate, alanine, aspartate, choline, taurine, histidine, methionine, tryptophan, leucine, cystine, tyrosine, arginine, lysine, valine and glycine) exhibited significant pairwise differences (P < 0.05). VIP scoring (>1.5) prioritised glutamate, alanine, aspartate, and choline as key contributors to the variations and pathway analysis implicated alanine, aspartate and glutamate metabolism, and histidine metabolism linked to sexual maturity. Our study highlights metabolic changes during sexual maturation, identifying potential biomarkers for assessing reproductive maturity. These findings are initial steps toward optimising younger boars’ usage in breeding, enhancing genetic gain, and reducing costs associated with their non-productive days at AI centres.

• Mikkola, Marja; Desmet, Karolien; Kommisrud, Elisabeth & Riegler, Michael (2024). Recent advancements to increase success in assisted reproductive technologies in cattle. Animal Reproduction. ISSN 1806-9614. 21(3), s. 1–31. doi: 10.1590/1984-3143-AR2024-0031. Fulltekst i vitenarkiv Vis sammendrag

  Assisted reproductive technologies (ART) are fundamental for cattle breeding and sustainable food production. Together with genomic selection, these technologies contribute to reducing the generation interval and accelerating genetic progress. In this paper, we discuss advancements in technologies used in the fertility evaluation of breeding animals, and the collection, processing, and preservation of the gametes. It is of utmost importance for the breeding industry to select dams and sires of the next generation as young as possible, as is the efficient and timely collection of gametes. There is a need for reliable and easily applicable methods to evaluate sexual maturity and fertility. Although gametes processing and preservation have been improved in recent decades, challenges are still encountered. The targeted use of sexed semen and beef semen has obliterated the production of surplus replacement heifers and bull calves from dairy breeds, markedly improving animal welfare and ethical considerations in production practices. Parallel with new technologies, many well-established technologies remain relevant, although with evolving applications. In vitro production (IVP) has become the predominant method of embryo production. Although fundamental improvements in IVP procedures have been established, the quality of IVP embryos remains inferior to their in vivo counterparts. Improvements to facilitate oocyte maturation and development of new culture systems, e.g. microfluidics, are presented in this paper. New non-invasive and objective tools are needed to select embryos for transfer. Cryopreservation of semen and embryos plays a pivotal role in the distribution of genetics, and we discuss the challenges and opportunities in this field. Finally, machine learning (ML) is gaining ground in agriculture and ART. This paper delves into the utilization of emerging technologies in ART, along with the current status, key challenges, and future prospects of ML in both research and practical applications within ART.

• Kaththriarachchi, Sonali Nadeeshani; Kommisrud, Elisabeth; Myromslien, Frøydis Deinboll; Zeremichael, Teklu Tewoldebrhan; Grevle, Inger Synnøve & Santana, João [Vis alle 10 forfattere av denne artikkelen] (2024). Lipid droplet distribution in Atlantic salmon (Salmo salar L.) oocytes is related to the fertilisation and developmental outcome. Aquaculture. ISSN 0044-8486. 596. doi: 10.1016/j.aquaculture.2024.741759. Fulltekst i vitenarkiv Vis sammendrag

  At present, there is no simple and practical applicable method to determine the quality of Atlantic salmon oocytes upon collection at the fish farm. Investigating oocyte lipid droplet patterns might be a tool for the aquaculture industry to predict oocyte quality in Atlantic salmon. While examining the lipid distribution in oocyte batches from 16 females of Atlantic salmon with a range in fertilisation rate (6–97 %), five categories of lipid droplet patterns were distinguished. In category 1, the lipid droplets were evenly distributed whereas in the remaining categories lipid droplets showed varying degree of coalescence. Categories 2, 3, 4 and 5 were distinguished based on the area of coalesced lipid droplets. The fertilisation rate was observed to be high (≥ 90 %), in females that had more oocytes from category 1, 2 and 3 whereas females with more oocytes from category 4 and 5 showed a low fertilisation rate (<90 %). A similar pattern was revealed between lipid droplet categories and eyed embryo and hatching success. Staining of salmon oocytes further confirmed the observed lipid droplet patterns, and different sizes of lipid droplets were present in almost all oocytes. The study revealed a significant association between lipid droplet category and fertilisation outcome in oocytes of Atlantic salmon that can be a practical tool for predicting oocyte quality.

• Haug, Linda Marijke Dekker; Jochems, Reina; Gaustad, Ann Helen; Kommisrud, Elisabeth; Myromslien, Frøydis Deinboll & Grindflek, Eli [Vis alle 7 forfattere av denne artikkelen] (2023). Liquid storage of porcine in vitro -produced blastocysts; a practical approach for short storage. Zygote (Cambridge. Print). ISSN 0967-1994. 31(5), s. 441–450. doi: 10.1017/S0967199423000308. Fulltekst i vitenarkiv
• Narud, Birgitte; Khezri, Abdolrahman; Zeremichael, Teklu Tewoldebrhan; Eriksen, Anne-Lene; Grevle, Inger Synnøve & Nordborg, Anna [Vis alle 9 forfattere av denne artikkelen] (2023). Sperm quality parameters, fertilizing potential, metabolites, and DNA methylation in cold-stored and cryopreserved milt from Atlantic salmon (Salmo salar L.). Frontiers in Genetics. 14. doi: 10.3389/fgene.2023.1199681. Fulltekst i vitenarkiv Vis sammendrag

  Cold storage and freezing/thawing of milt may affect sperm functionality and the subsequent fertilization ability of milt. This study aimed to investigate sperm quality parameters and fertilization potential of Atlantic salmon milt, stored cold and subsequently cryopreserved, using different storage conditions. The objective was also to assess if analysis of milt metabolites and sperm DNA methylation signatures could be applicable to further elucidate sperm quality and fertilization following preservation. Milt samples were collected from eight mature Atlantic salmon males and stored for 4 days at 2°C and 8°C. Samples were taken on day one of storage at 2°C and on day four of storage at 2°C and 8°C. Storage for 4 days at 8°C is expected to be detrimental to sperm quality, and was included to create contrasts. Correspondingly, aliquots of cold-stored milt were prepared for cryopreservation, resulting in a total of six experimental conditions. Samples from all six experimental conditions were used in fertilization trials and analyzed for sperm viability, motility, ATP content, DNA fragmentation index, and High DNA stainability. In addition, milt samples from four of the males were analyzed for targeted metabolites and DNA methylation signatures by reduced representation bisulfite sequencing. The fertilization trials were performed using sperm:egg ratios of 75 × 103 and 500 × 103, respectively. Storage duration, temperature, and cryopreservation of cold-stored milt influenced several sperm quality parameters, metabolites, and DNA methylation signatures. The total motility, progressive motility, ATP, and velocity parameters were the sperm parameters with the strongest correlation to fertilization rates (p < 0.01). Several metabolites were correlated with fertility rates in both cold-stored and cryopreserved samples (p < 0.05). The fertilizing capacity of cold-stored milt was significantly reduced after 4 days of storage at 8°C, while corresponding cryopreserved milt showed reduced fertilization at both storage temperatures (2°C and 8°C) (p < 0.05). The results indicate that cryopreservation of milt stored for 1 day does not compromise either fertilization ability or DNA methylation signatures.

• Bremer, Joanna; Maj, Michal; Nordbø, Øyvind & Kommisrud, Elisabeth (2023). Deep learning–based automated measurements of the scrotal circumference of Norwegian Red bulls from 3D images. Smart Agricultural Technology. 3. doi: 10.1016/j.atech.2022.100133. Fulltekst i vitenarkiv Vis sammendrag

  The main aim of this study was to create an automated method for the measurement of the scrotal circumference (SC) of Norwegian Red bulls using 3D images of the scrotum based on convolutional neural networks. The study population was bull calves recruited for performance testing before the selection of bulls for semen production in the breeding program. Bulls were measured at four different time points: upon arrival in quarantine (Q) and thereafter at approximately 6, 9 and 12 months of age. Both 3D images and manual SC measurements were performed at all time points. In our approach, SC could be calculated without direct contact with the bull, using only 3D images and a simple, user–friendly application into which mentioned images are uploaded. The results show that SC measurements obtained using semantic segmentation are comparable with manual measurements. The mean prediction error was significantly different between age groups Q, 6, 9 and 12, and it was -3.07 cm, -3.02 cm, -1.79 cm and -1.11 cm, respectively. The results show a significant difference in the measurement error of the SC based on the quality of the images. Images were categorised into three quality groups. For good prediction accuracy, we recommend capturing 3D images of quality 2 – full circle from individuals older than 6 months.

• Munthe-Kaas, Maien; Sveberg, Guro; Holmøy, Ingrid Hunter; Kommisrud, Elisabeth; Haadem, Caroline Sorknes & Martin, Adam Dunstan (2023). Pilot study investigating estrus length and estrus behavior in Norwegian Red cattle on a commercial dairy farm. Frontiers in Veterinary Science. 10. doi: 10.3389/fvets.2023.1219001. Fulltekst i vitenarkiv Vis sammendrag

  Introduction: Norwegian Red has been shown to have high levels of estrus behavior under experimental conditions. However, the estrus behaviors of Norwegian Red cows have not been studied under commercial conditions. Methods: A herd of 89 Norwegian Red cows housed in free stalls on concrete, slatted floors, were continuously video monitored for 21 days. Ovarian cyclicity was confirmed in a final study sample group (n = 18) using milk progesterone concentrations. All mounting and standing activities were recorded, and the duration of mount estrus, standing estrus and the differences between these; prestand and poststand, were determined. The cycle stages metestrus, diestrus and proestrus were estimated based on the starting time and ending time of mount estrus. Results: All cows in the final study sample group exhibited the primary estrus sign, ‘standing to be mounted’ during estrus. Two (11%), eleven (61%) and six (33%) cows exhibited the behavior ‘standing to be mounted’ during metestrus, diestrus and proestrus, respectively. The number of mounts initiated by individual cows was higher during mount and stand estrus than during the rest of the estrous cycle. This study reports a median duration of mount estrus and stand estrus of 21.0  h (interquartile range (IQR) 15.0 to 27.3) and 14.3  h (IQR 12.0 to 18.8), respectively. The median counts per hour of all mount behaviors were 8.6 (IQR 5.6 to 11.3), 1.51 (IQR 0.3 to 3.8) and 1.7 (IQR 0.8 to 6.0) for standing estrus, prestand and poststand, respectively. Discussion: This study shows that under commercial conditions the Norwegian Red cow displays a high level of mount and stand activity associated with estrus.

• Bremer, Joanna; Heringstad, Bjørg; Morrell, Jane & Kommisrud, Elisabeth (2023). Associations between insulin-like factor 3, scrotal circumference and semen characteristics in young Norwegian Red bulls. Animal. ISSN 1751-7311. 17(3), s. 1–7. doi: 10.1016/j.animal.2023.100713. Fulltekst i vitenarkiv Vis sammendrag

  With the integration of genomic selection in the cattle artificial insemination (AI) industry, bulls are selected for their semen production capacity and fertility at a younger age than previously. Norwegian Red bull calves selected as candidates to become future AI bulls based on their genomic breeding value are kept in a performance testing station from around the age of 3–12 months, allowing for sample collection and analysis of different parameters during their pre- and peripubertal period. Insulin-like factor 3 (INSL3) is a small peptide hormone specifically secreted by the mature Leydig cells of the testes. In the foetus, it induces the first phase of testicular descent and is considered to reflect Leydig cell development during puberty; it could therefore be an interesting early indicator of future semen production capacity. The main objective of our study was to evaluate the relationship between INSL3, scrotal circumference (SC), and semen characteristics. This is the first time INSL3 was measured in the Norwegian Red population. We collected blood samples for analysis of INSL3 from 142 Norwegian Red bulls at the performance testing station and measured their SC on the same day. Altogether, measurements were made at four time points: upon arrival at the performance testing station (quarantine (Q): 2–5 months) and later at approximately 6, 9 and 12 months of age. Information on season and place of birth were made available from the database of the breeding company Geno, together with data on semen characteristics from the test station and the AI station. The median SCs for age groups Q, 6, 9, and 12 were 15, 21.5, 29, and 34 cm, respectively. INSL3 was shown to be positively correlated with SC (R = 0.4) but not with any of the semen characteristics. Similarly, we found no correlation between SC and sperm characteristics from data on ejaculates analysed at the performance testing station and AI station. The mean sperm volume for the 31 selected bulls with at least 10 ejaculates produced in the AI station increased from 2.3 ml at the performance testing station to 6.4 ml at the AI station. The corresponding increase in mean sperm concentration was from 497 million/ml to 1 049 million/ml. We conclude that INSL3 exhibits high inter-individual variability in the Norwegian Red bull population, which cannot be explained by the parameters measured in this study. At present, INSL3 cannot be used as a biomarker of sperm production in this breed.

• Bremer, Joanna; Heringstad, Bjørg; Morrell, Jane & Kommisrud, Elisabeth (2023). Novel interpretation of sperm stress test and morphology for maturity assessment of young Norwegian Red bulls. Animal Reproduction Science. ISSN 0378-4320. 253. doi: 10.1016/j.anireprosci.2023.107261. Fulltekst i vitenarkiv Vis sammendrag

  The use of genomic selection significantly reduces the age of dairy bulls entering semen production compared to progeny testing. The study aimed to identify early indicators that could be used for screening bulls during their performance testing period and could give us insight into their future semen production performance, acceptance for the AI station, and prediction of their future fertility. The study population consisted of 142 young Norwegian Red bulls enrolled at the performance test station, followed until we received semen production data, semen doses, and, subsequently, non-return rates (NR56) from the AI station. A range of semen quality parameters were measured with computer-assisted sperm analysis and flow cytometry from ejaculates collected from 65 bulls (9–13 months). The population morphometry of normal spermatozoa was examined, showing that Norwegian Red bulls at 10 months of age have homogenous sperm morphometry. Norwegian Red bulls could be separated into 3 clusters according to their sperm's reaction patterns to stress test and cryopreservation. Results of semi-automated morphology assessment of young Norwegian Red bulls showed that 42% of bulls rejected for the AI station and 18% of bulls accepted had ejaculates with abnormal morphology scores. For the youngest age group at 10 months, the mean (SD) proportion of spermatozoa with normal morphology was 77.5% (10.6). Using novel interpretation of sperm stress test combined with sperm morphology analysis and consecutive cryopreservation at a young age allowed identification of the candidate's sperm quality status. This could help breeding companies introduce young bulls earlier to the AI stations.

• Haug, Linda Marijke Dekker; Wilson, Robert Charles; Gaustad, Ann Helen; Jochems, Reina; Kommisrud, Elisabeth & Grindflek, Eli [Vis alle 7 forfattere av denne artikkelen] (2023). Cumulus Cell and Oocyte Gene Expression in Prepubertal Gilts and Sows Identifies Cumulus Cells as a Prime Informative Parameter of Oocyte Quality. Biology (Basel). 12(12). doi: 10.3390/biology12121484. Fulltekst i vitenarkiv Vis sammendrag

  Cumulus cells (CCs) are pivotal during oocyte development. This study aimed to identify novel marker genes for porcine oocyte quality by examining the expression of selected genes in CCs and oocytes, employing the model of oocytes from prepubertal animals being of reduced quality compared to those from adult animals. Total RNA was extracted either directly after follicle aspiration or after in vitro maturation, followed by RT-qPCR. Immature gilt CCs accumulated BBOX1 transcripts, involved in L-carnitine biosynthesis, to a 14.8-fold higher level (p < 0.05) relative to sows, while for CPT2, participating in fatty acid oxidation, the level was 0.48 (p < 0.05). While showing no differences between gilt and sow CCs after maturation, CPT2 and BBOX1 levels in oocytes were higher in gilts at both time points. The apparent delayed lipid metabolism and reduced accumulation of ALDOA and G6PD transcripts in gilt CCs after maturation, implying downregulation of glycolysis and the pentose phosphate pathway, suggest gilt cumulus–oocyte complexes have inadequate ATP stores and oxidative stress balance compared to sows at the end of maturation. Reduced expression of BBOX1 and higher expression of CPT2 in CCs before maturation and higher expression of G6PD and ALDOA after maturation are new potential markers of oocyte quality.

• Jochems, Reina; Gaustad, Ann Helen; Styrishave, Bjarne; Zak, Louisa J.; Oskam, Irma Caroline & Grindflek, Eli [Vis alle 9 forfattere av denne artikkelen] (2022). Follicular fluid steroid hormones and in vitro embryo development in Duroc and Landrace pigs. Theriogenology. ISSN 0093-691X. 190, s. 15–21. doi: 10.1016/j.theriogenology.2022.07.004. Fulltekst i vitenarkiv Vis sammendrag

  The Duroc sire line has a smaller litter size compared to the Landrace dam line and we have previously observed fewer surface follicles on Duroc ovaries one day after weaning. In that same study, a broader cumulus expansion and faster nuclear maturation were observed for Duroc oocytes at 20 h of in vitro maturation (IVM), while Landrace oocytes showed more advanced stages of cortical granule distributions. However, no differences between breeds were observed after the final IVM period. The aim of this study was to assess subsequent in vitro embryo production (IVP) in Duroc and Landrace. Furthermore, follicle diameter and steroid hormone levels in follicular fluid (FF) were measured to study possible relation to oocyte developmental competence. Follicular phase sow ovaries were collected one day after weaning and follicle size of the 10 largest follicles were measured per ovary before aspiration. Cumulusoocyte complexes (COCs) were matured in vitro, and cumulus expansion was analysed by assessing individual COC areas at 0 and 20 h. Fertilization of Duroc and Landrace oocytes was performed with sperm from both a Duroc and a Landrace boar. A larger follicle diameter was observed for Landrace animals (5.7 vs. 4.8 mm, P < 0.0001) and individual COC area was additionally larger at 0 h after aspiration (P < 0.0001) compared to Duroc. Contrary, cumulus expansion from 0 to 20 h of maturation was broader for Duroc oocytes than for Landrace (407 ± 67% vs. 319 ± 31%, P < 0.0001). After fertilization, cleavage rate was higher for Duroc oocytes, and the highest blastocyst yield was obtained for Duroc oocytes fertilized with the Landrace sperm. Steroid hormone analysis of the follicular fluid showed differences in the pathways between breeds with a higher total level of estrogens (P ¼ 0.01) and aromatase products/substrates ratio (P < 0.01) in Landrace compared to Duroc. In conclusion, results suggest that Duroc oocytes have a better in vitro oocyte developmental competence when cultured under the same in vitro conditions and breed differences in steroidogenesis were found in the early follicular phase.

• Jochems, Reina; Gaustad, Ann Helen; Zak, Louisa J.; Grindflek, Eli; Zeremichael, Teklu Tewoldebrhan & Oskam, Irma Caroline [Vis alle 9 forfattere av denne artikkelen] (2022). Effect of two 'progressively motile sperm-oocyte' ratios on porcine in vitro fertilization and embryo development. Zygote (Cambridge. Print). ISSN 0967-1994. 30. doi: 10.1017/S0967199422000053. Fulltekst i vitenarkiv Vis sammendrag

  Sperm motility and viability of cryopreserved semen vary between boars and straws, which influences the outcomes of in vitro embryo production (IVEP). However, progressive motility is usually not considered during IVEP. The aim of this study was to assess fertilization with a 500:1 and 250:1 ‘progressively motile sperm to oocyte’ ratio on IVEP outcomes using semen from three Duroc and three Landrace boars. Frozen–thawed sperm was centrifuged through a 45/90% Percoll® density gradient and sperm quality parameters were assessed. In vitro matured oocytes were fertilized at the two ratios, a portion was stained 10–12 h after start of fertilization to analyze fertilization and polyspermy, while the remaining zygotes were cultured up to day 7. The 500:1 ratio resulted in a higher fertilization and blastocyst yield on day 6 compared with the 250:1 ratio, but no effect of ratio was observed for polyspermy, cleavage rate or blastocyst cell number. Individual differences between boars were observed for fertilization, cleavage and blastocyst rates, but not for the other IVEP outcomes. In conclusion, a higher fertilization and blastocyst yield was obtained with the 500:1 ratio compared with the 250:1 ratio, while polyspermy level was consistent across ratios. Differences in IVEP outcomes were still observed between the individual boars although adjusted for progressive motility. Promising blastocyst yields and high total blastocyst cell counts were obtained with sperm from both breeds.

• Narud, Birgitte; Khezri, Abdolrahman; Nordborg, Anna; Klinkenberg, Geir; Zeremichael, Teklu Tewoldebrhan & Stenseth, Else-Berit [Vis alle 9 forfattere av denne artikkelen] (2022). Semen quality parameters including metabolites, sperm production traits and fertility in young Norwegian Red AI bulls. Livestock Science. ISSN 1871-1413. 255. doi: 10.1016/j.livsci.2021.104803. Fulltekst i vitenarkiv Vis sammendrag

  Genomic selection in cattle breeding has gradually allowed younger bulls to be recruited for semen production. In this study, sperm quality parameters, seminal plasma and sperm metabolites, semen production capacity and fertility in young Norwegian Red bulls were analysed. For in vitro analyses of sperm quality and metabolites, ejaculates were collected from the same 25 bulls at both 14 and 17 months of age. Semen production and fertility data were collected for all Norwegian Red bulls in production from December 2017 throughout 2019. Bull fertility was measured as 56 days non-return rate (NR56), for both age groups. In both fresh and frozen-thawed semen samples, the proportion of hyperactive spermatozoa, average path velocity, curvilinear velocity and amplitude of lateral head displacement were higher in samples collected at 17 months of age compared to 14 months (P

• Narud, Birgitte; Khezri, Abdolrahman; Zeremichael, Teklu Tewoldebrhan; Stenseth, Else-Berit; Heringstad, Bjørg & Johannisson, Anders [Vis alle 10 forfattere av denne artikkelen] (2021). Sperm chromatin integrity and DNA methylation in Norwegian Red bulls of contrasting fertility. Molecular Reproduction and Development. ISSN 1040-452X. 88(3), s. 187–200. doi: 10.1002/mrd.23461. Fulltekst i vitenarkiv Vis sammendrag

  n this study, the complexity of chromatin integrity was investigated in frozen-thawed semen samples from 37 sires with contrasting fertility, expressed as 56-day non-return rates (NR56). Protamine deficiency, thiols, and disulfide bonds were assessed and compared with previously published data for DNA fragmentation index (DFI) and high DNA stainability (HDS). In addition, in vitro embryo development and sperm DNA methylation were assessed using semen samples from 16 of these bulls. The percentages of DFI and HDS were negatively associated with NR56 and cleavage rate and positively associated with sperm protamine deficiency (p < 0.05). Significant differences in cleavage and blastocyst rates were observed between bulls of high and low NR56. However, once fertilization occurred, further development into blastocysts was not associated with NR56. The differential methylation analysis showed that spermatozoa from bulls of low NR56 were hypermethylated compared to bulls of high NR56. Pathway analysis showed that genes annotated to differentially methylated cytosines could participate in different biological pathways and have important biological roles related to bull fertility. In conclusion, sperm cells from Norwegian Red bulls of inferior fertility have less compact chromatin structure, higher levels of DNA damage, and are hypermethylated compared with bulls of superior fertility.

• Jochems, Reina; Gaustad, Ann Helen; Zak, Louisa J.; Grindflek, Eli; Zeremichael, Teklu Tewoldebrhan & Oskam, Irma Caroline [Vis alle 9 forfattere av denne artikkelen] (2021). Ovarian characteristics and in vitro nuclear and cytoplasmic oocyte maturation in Duroc and Landrace pigs. Veterinary Medicine and Science. doi: 10.1002/vms3.498. Fulltekst i vitenarkiv Vis sammendrag

  Differences in total number of piglets born per litter are observed between the Norwegian Duroc (ND) sire and Norwegian Landrace (NL) dam line. The aim of this study was to evaluate ovarian characteristics, and in vitro nuclear and cytoplasmic oocyte maturation in both breeds. One day after weaning, follicular phase ovaries were collected. Ovary length and weight were measured and the number of follicles (< 3 mm and 3–8 mm) was counted. Cumulus-oocyte complexes (COCs) were collected and matured for 48 hr. To assess cumulus expansion, COC area was analysed at 0 and 20 hr. Nuclear maturation and cortical granule (CG) distribution were analysed at 20 and 48 hr, and total glutathione (GSH) was measured at 48 hr to further elucidate cytoplasmic maturation. In first parity sows, a smaller ovary length and fewer 3 to 8 mm follicles were observed in ND compared to NL. For all sows, ND COCs covered a significantly smaller area at 0 hr, but a higher cumulus expansion ratio was observed at 20 hr compared to NL (364 ± 46% versus. 278 ± 27%, p < 0.001). At 20 hr, more ND oocytes exhibited advanced stages of nuclear maturation, while more NL oocytes showed advanced stages of CG distribution. Nuclear maturation to MII stage at 48 hr did not differ between ND and NL oocytes (90.1% and 87.7%, respectively). Moreover, no significant differences were observed for GSH content or CG distribution after maturation. In conclusion, differences with regard to ovarian characteristics as well as to cumulus expansion, and nuclear and cytoplasmic oocyte maturation at 20 hr were observed between the breeds. Further studies are required to determine if this subsequently affects in vitro fertilization and embryo development.

• Berg, Halldor Felde; Heringstad, Bjørg; Alm-Kristiansen, Anne Hege; Kvale, Vilde Granne; Dragset, Knut Ingolf & Waldmann, Andres [Vis alle 8 forfattere av denne artikkelen] (2020). Ovarian Follicular Response to Oestrous Synchronisation and Induction of Ovulation in Norwegian Red Cattle. Acta Veterinaria Scandinavica (AVS). ISSN 0044-605X. 62. doi: 10.1186/s13028-020-00514-6. Fulltekst i vitenarkiv Vis sammendrag

  Oestrous synchronisation of cattle has been widely applied to accomplish simultaneous ovulation in animals and facilitate timed artificial insemination. The main aim of this study was to investigate the ovarian follicular growth and ovulatory response to oestrus and ovulation synchronisation in Norwegian Red heifers and cows. Oestrous cycles in 34 heifers and 10 cows from 4 herds were synchronised with two PGF2α analogue treatments 11 days apart, followed by GnRH analogue treatment for induction of ovulation. Thereafter, the ovaries were examined by ultrasonography at 3 h intervals until ovulation. Results The luteolytic effect of the PGF2α analogue was verified in 9 of 10 cows by progesterone contents in milk. Maximum physical activity of the cows occurred on average 69 h after PGF2α analogue treatment. An ovulatory response was recorded in 95.5% (42/44) of the animals. A significant difference in follicle size at ovulation was found between 2 of the herds. Animals with medium sized and large follicles and heifers aged > 16 months ovulated earlier than other animals. Conclusions The applied sequence of treatments in the study was shown to be effective in synchronizing and inducing ovulation within a relatively narrow time interval in the Norwegian Red heifers and cows, consistent with findings in other cattle breeds.

• Kommisrud, Elisabeth; Myromslien, Frøydis Deinboll; Stenseth, Else-Berit; Zeremichael, Teklu Tewoldebrhan; Hofman, Nadine & Grevle, Inger Synnøve [Vis alle 7 forfattere av denne artikkelen] (2020). Viability, motility, ATP content and fertilizing potential of sperm from Atlantic salmon (Salmo salar L.) in milt stored before cryopreservation. Theriogenology. ISSN 0093-691X. 151, s. 58–65. doi: 10.1016/j.theriogenology.2020.04.008. Fulltekst i vitenarkiv Vis sammendrag

  Artificial fertilization is increasingly used in aquaculture, mostly applying short-term cold stored milt. Large scale cryopreservation of milt could be valuable for increased flexibility and acceleration of breeding progress. The aim of this study was to assess viability, motility and ATP content of sperm from Atlantic salmon as a function of storage time, before and after cryopreservation. The objective was also to investigate whether in vitro parameters were associated with sperm fertilizing ability after cryopreservation. Milt from six mature Atlantic salmon males were collected twice, one week apart. The milt was stored undiluted at 5 °C in cell culture flasks for six days. Samples were taken on days 1, 3 and 6 of storage for cryopreservation. In total, 36 batches were diluted to a standardized sperm concentration of 2 × 109 spermatozoa/mL, filled into 0.5 mL French medium straws and cryopreserved. In vitro analyses were assessed on the same sample for the 72 combinations of male, collection week, days of storage and cold stored or frozen-thawed. Fertilization trials with cryopreserved milt were carried out for all 36 batches in triplicate for each combination of male, collection week, storage time and sperm:egg ratios of either 2 or 4 × 106 sperm per egg, respectively, totally 218 experimental units, including two egg controls. There was a significant influence of storage and collection week on sperm quality parameters, both cold stored and cryopreserved, and cryopreservation had a significant effect on all tested sperm quality parameters. High correlations for cold stored vs cryopreserved samples was demonstrated for ATP content (p < 0.00001), motility and velocity parameters (p < 0.001), but not for viability, straightness and linearity. The overall percentage of fertilization achieved was 73.9 ± 1.7%. Sperm collected in week 2 showed significantly lower fertility when cryopreserved after six days of storage than after 1 or 3 days for sperm to egg ratios of 2 × 106 (p < 0.005), while there was no such effect for milt collected in week 1. Several post-thaw sperm parameters were correlated to fertilization rates, while curvilinear velocity best explained variations in fertilization by modelling. Our results suggest that cryopreservation of Atlantic salmon milt should be performed soon after milt collection to maximize the cryopreserved sperm quality. Fertilization results seems not to be compromised by storage for three days before cryopreservation.

• Narud, Birgitte; Klinkenberg, Geir; Khezri, Abdolrahman; Zeremichael, Teklu Tewoldebrhan; Stenseth, Else-Berit & Nordborg, Anna [Vis alle 11 forfattere av denne artikkelen] (2020). Differences in sperm functionality and intracellular metabolites in Norwegian Red bulls of contrasting fertility. Theriogenology. ISSN 0093-691X. 157, s. 24–32. doi: 10.1016/j.theriogenology.2020.07.005. Fulltekst i vitenarkiv Vis sammendrag

  In the dairy breeding industry, prediction of bull fertility in artificial insemination (AI) is important for efficient and economically sustainable production. However, it is challenging to identify bulls with superior fertility applying conventional in vitro sperm assays. In the present study, sperm functionality was investigated to identify a multivariate model that could predict fertility. Two groups of young Norwegian Red bulls were selected, one with inferior fertility (18 bulls) and one with superior fertility (19 bulls) based on non-return rate after 56 days (NR56). Frozen-thawed semen doses were analysed for sperm chromatin integrity, viability, acrosome integrity, motility, and ATP content. A targeted approach was used to study intracellular concentrations of amino acids and trace elements in viable sperm cells. Significant differences between the two groups of bulls were observed, both for sperm functional attributes and intracellular concentrations of metabolites. Pearson correlation analyses indicated a negative relationship between NR56 and chromatin integrity parameters, DNA fragmentation index (DFI) and high DNA stainability (HDS). Several motility parameters correlated positively with NR56. The concentrations of cysteine and glutamic acid in sperm cells correlated negatively with NR56, while the concentrations of aspartic acid, leucine and serine showed a positive NR56-correlation. The sperm intracellular concentrations of the trace elements Fe, Al and Zn, correlated negatively with NR56. Correlations were observed between several sperm parameters and metabolites. Stepwise multiple regression analysis indicated that the best predictor of NR56 was a model containing %DFI, together with the intracellular sperm concentration of aspartic acid, Fe and Zn. This model explained 59% of the variability in NR56.

• Khezri, Abdolrahman; Narud, Birgitte; Stenseth, Else-Berit; Zeremichael, Teklu Tewoldebrhan; Myromslien, Frøydis Deinboll & Wilson, Robert Charles [Vis alle 8 forfattere av denne artikkelen] (2020). Sperm DNA Hypomethylation Proximal to Reproduction Pathway Genes in Maturing Elite Norwegian Red Bulls. Frontiers in Genetics. 11. doi: 10.3389/fgene.2020.00922. Fulltekst i vitenarkiv Vis sammendrag

  Genomic selection in modern farming demands sufficient semen production in young bulls. Factors affecting semen quality and production capacity in young bulls are not well understood; DNA methylation, a complicated phenomenon in sperm cells, is one such factors. In this study, fresh and frozen-thawed semen samples from the same Norwegian Red (NR) bulls at both 14 and 17 months of age were examined for sperm chromatin integrity parameters, ATP content, viability, and motility. Furthermore, reduced representation bisulfite libraries constructed according to two protocols, the Ovation® RRBS Methyl-Seq System (Ovation method) and a previously optimized gel-free method and were sequenced to study the sperm DNA methylome in frozen-thawed semen samples. Sperm quality analyses indicated that sperm concentration, total motility and progressivity in fresh semen from 17 months old NR bulls were significantly higher compared to individuals at 14 months of age. The percentage of DNA fragmented sperm cells significantly decreased in both fresh and frozen-thawed semen samples in bulls with increasing age. Libraries from the Ovation method exhibited a greater percentage of read loss and shorter read size following trimming. Downstream analyses for reads obtained from the gel-free method revealed similar global sperm DNA methylation but differentially methylated regions (DMRs) between 14- and 17 months old NR bulls. The majority of identified DMRs were hypomethylated in 14 months old bulls. Most of the identified DMRs (69%) exhibited a less than 10% methylation difference while only 1.5% of DMRs exceeded a 25% methylation difference. Pathway analysis showed that genes annotated with DMRs having low methylation differences (less than 10%) and DMRs having between 10 and 25% methylation differences, could be associated with important hormonal signaling and sperm function relevant pathways, respectively. The current research shows that RRBS in parallel with routine sperm quality analyses could be informative in reproductive capacity of young NR bulls. Although global sperm DNA methylation levels in 14 and 17 months old NR bulls were similar, regions with low and varying levels of DNA methylation differences can be identified and linked with important sperm function and hormonal pathways.

• Berg, Halldor Felde; Spång, Heidi Cecilie Larsen; Heringstad, Bjørg; Ropstad, Erik; Alm-Kristiansen, Anne Hege & Kommisrud, Elisabeth (2020). Studies of gel with immobilized semen by intrauterine endoscopy post-artificial insemination. Reproduction in domestic animals (1990). ISSN 0936-6768. 55(3), s. 401–404. doi: 10.1111/rda.13630. Fulltekst i vitenarkiv
• Khezri, Abdolrahman; Narud, Birgitte; Stenseth, Else-Berit; Johannisson, Anders; Myromslien, Frøydis Deinboll & Gaustad, Ann Helen [Vis alle 11 forfattere av denne artikkelen] (2019). DNA methylation patterns vary in boar sperm cells with different levels of DNA fragmentation. BMC Genomics. 20:897, s. 1–15. doi: 10.1186/s12864-019-6307-8. Fulltekst i vitenarkiv Vis sammendrag

  Background: Sperm DNA integrity is considered essential for successful transmission of the paternal genome, fertilization and normal embryo development. DNA fragmentation index (DFI, %) has become a key parameter in the swine artificial insemination industry to assess sperm DNA integrity. Recently, in some elite Norwegian Landrace boars (boars with excellent field fertility records), a higher level of sperm DFI has been observed. In order to obtain a better understanding of this, and to study the complexity of sperm DNA integrity, liquid preserved semen samples from elite boars with contrasting DFI levels were examined for protamine deficiency, thiol profile and disulphide bonds. Additionally, the DNA methylation profiles of the samples were determined by reduced representation bisulphite sequencing (RRBS). Results: In this study, different traits related to sperm DNA integrity were investigated (n = 18 ejaculates). Upon liquid storage, the levels of total thiols and disulphide bonds decreased significantly, while the DFI and protamine deficiency level increased significantly. The RRBS results revealed similar global patterns of low methylation from semen samples with different levels of DFI (low, medium and high). Differential methylation analyses indicated that the number of differentially methylated cytosines (DMCs) increased in the low-high compared to the low-medium and the medium-high DFI groups. Annotating the DMCs with gene and CpG features revealed clear differences between DFI groups. In addition, the number of annotated transcription starting sites (TSS) and associated pathways in the low-high comparison was greater than the other two groups. Pathway analysis showed that genes (based on the closest TSS to DMCs) corresponding to low-high DFI comparison were associated with important processes such as membrane function, metabolic cascade and antioxidant defence system. Conclusion: To our knowledge, this is the first study evaluating DNA methylation in boar sperm cells with different levels of DFI. The present study shows that sperm cells with varying levels of DNA fragmentation exhibit similar global methylation, but different site-specific DNA methylation signatures. Moreover, with increasing DNA fragmentation in spermatozoa, there is an increase in the number of potentially affected downstream genes and their respective regulatory pathways.

• Reiten, Malin Rokseth; Malachin, Giulia; Kommisrud, Elisabeth; Østby, Gunn Charlotte; Waterhouse, Karin Elisabeth & Krogenæs, Anette Kristine [Vis alle 17 forfattere av denne artikkelen] (2018). Stress resilience of spermatozoa and blood mononuclear cells without prion protein. Frontiers in Molecular Biosciences. 5:1, s. 1–15. doi: 10.3389/fmolb.2018.00001. Fulltekst i vitenarkiv Vis sammendrag

  The cellular prion protein PrPC is highly expressed in neurons, but also present in non-neuronal tissues, including the testicles and spermatozoa. Most immune cells and their bone marrow precursors also express PrPC. Clearly, this protein operates in highly diverse cellular contexts. Investigations into putative stress-protective roles for PrPC have resulted in an array of functions, such as inhibition of apoptosis, stimulation of anti-oxidant enzymes, scavenging roles, and a role in nuclear DNA repair. We have studied stress resilience of spermatozoa and peripheral blood mononuclear cells (PBMCs) derived from non-transgenic goats that lack PrPC (PRNPTer/Ter) compared with cells from normal (PRNP+/+) goats. Spermatozoa were analyzed for freeze tolerance, DNA integrity, viability, motility, ATP levels, and acrosome intactness at rest and after acute stress, induced by Cu2+ ions, as well as levels of reactive oxygen species (ROS) after exposure to FeSO4 and H2O2. Surprisingly, PrPC-negative spermatozoa reacted similarly to normal spermatozoa in all read-outs. Moreover, in vitro exposure of PBMCs to Doxorubicin, H2O2 and methyl methanesulfonate (MMS), revealed no effect of PrPC on cellular survival or global accumulation of DNA damage. Similar results were obtained with human neuroblastoma (SH-SY5Y) cell lines stably expressing varying levels of PrPC. RNA sequencing of PBMCs (n = 8 of PRNP+/+ and PRNPTer/Ter) showed that basal level expression of genes encoding DNA repair enzymes, ROS scavenging, and antioxidant enzymes were unaffected by the absence of PrPC. Data presented here questions the in vitro cytoprotective roles previously attributed to PrPC, although not excluding such functions in other cell types or tissues during inflammatory stress.

• Berg, Halldor Felde; Kommisrud, Elisabeth; Bai, Godlove; Gaustad, Eline Rustad; Klinkenberg, Geir & Standerholen, Fride Berg [Vis alle 11 forfattere av denne artikkelen] (2018). Comparison of sperm adenosine triphosphate content, motility and fertility of immobilized and conventionally cryopreserved Norwegian Red bull semen. Theriogenology. ISSN 0093-691X. 121, s. 181–187. doi: 10.1016/j.theriogenology.2018.08.016. Fulltekst i vitenarkiv
• Alm-Kristiansen, Anne Hege; Standerholen, Fride Berg; Bai, Godlove; Waterhouse, Karin Elisabeth & Kommisrud, Elisabeth (2018). Relationship between post-thaw adenosine triphosphate content, motility and viability in cryopreserved bovine semen applying two different preservation methods. Reproduction in domestic animals (1990). ISSN 0936-6768. s. 1–8. doi: 10.1111/rda.13285. Fulltekst i vitenarkiv
• Alm-Kristiansen, Anne Hege; Gaustad, Eline Rustad; Bai, Guoyun; Standerholen, Fride Berg; Klinkenberg, Geir & Kommisrud, Elisabeth [Vis alle 7 forfattere av denne artikkelen] (2018). In vitro studies of Norwegian Red bovine semen immobilized and cryopreserved in alginate solid gel network. Reproduction in domestic animals (1990). ISSN 0936-6768. 53(2), s. 365–370. doi: 10.1111/rda.13115. Fulltekst i vitenarkiv
• Alm-Kristiansen, Anne Hege; Dalen, Gunnar; Klinkenberg, Geir; Bekk, Laila; Thorkildsen, Lill Therese & Waterhouse, Karin Elisabeth [Vis alle 7 forfattere av denne artikkelen] (2017). Reproductive performance of immobilized cryopreserved bovine semen used for timed artificial insemination. Reproduction in domestic animals (1990). ISSN 0936-6768. 52(6), s. 1019–1024. doi: 10.1111/rda.13017. Fulltekst i vitenarkiv
• Cao, Yanran; Stene, Anne; Yndestad, Harald & Kommisrud, Elisabeth (2016). Impact of Brominated Flame Retardants on Embryo Development of Atlantic Cod (Gadus Morhua) during Early Life Stages, OCEANS 2016 Shanghai - MTS/IEEE. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781467397230. s. 1–7. doi: 10.1109/OCEANSAP.2016.7485615. Fulltekst i vitenarkiv
• Standerholen, Fride Berg; Waterhouse, Karin E; Larsgard, Anne Guro; Garmo, Randi Therese; Myromslien, Frøydis Deinboll & Sunde, Jan [Vis alle 9 forfattere av denne artikkelen] (2015). Use of immobilized cryopreserved bovine semen in a blind artifical insemination trial. Theriogenology. ISSN 0093-691X. 84(3), s. 413–420. doi: 10.1016/j.theriogenology.2015.03.028. Fulltekst i vitenarkiv Vis sammendrag

  To make timing of artificial insemination (AI) relative to ovulation less critical, methods for prolonging shelf life of spermatozoa in vivo after AI have been attempted to be developed. Encapsulation of sperm cells is a documented technology, and recently, a technology in which sperm cells are embedded in alginate gel has been introduced and commercialized. In this study, standard processed semen with the Biladyl extender (control) was compared with semen processed by sperm immobilization technology developed by SpermVital AS in a blind field trial. Moreover, in vitro acrosome and plasma membrane integrity was assessed and compared with AI fertility data for possible correlation. Semen from 16 Norwegian Red young bulls with unknown fertility was collected and processed after splitting the semen in two aliquots. These aliquots were processed with the standard Biladyl extender or the SpermVital extender to a final number of 12 × 106 and 25 × 106 spermatozoa/dose, respectively. In total, 2000 semen doses were produced from each bull, divided equally by treatment. Artificial insemination doses were set up to design a blinded AI regime; 5 + 5 straws from each extender within ejaculates in ten-straw goblets were distributed to AI technicians and veterinarians all over Norway. Outcomes of the inseminations were measured as 56-day nonreturn rate (NRR). Postthaw sperm quality was assessed by flow cytometry using propidium iodide and Alexa 488–conjugated peanut agglutinin to assess the proportion of plasma membrane and acrosome-intact sperm cells, respectively. In total, data from 14,125 first inseminations performed over a 12-month period, 7081 with Biladyl and 7044 with SpermVital semen, were used in the statistical analyses. There was no significant difference in 56-day NRR for the two semen categories, overall NRR being 72.5% and 72.7% for Biladyl and SpermVital, respectively. The flow cytometric results revealed a significant higher level of acrosome-intact live spermatozoa in Biladyl-processed semen compared to SpermVital semen. The results indicate that the level of acrosome-intact live spermatozoa in the AI dose did not affect the 56-day NRR for the two semen processing methods. In conclusion, this study has showed that immobilized spermatozoa provide equal fertility results as standard processed semen when AI is performed in a blinded field trial, although the immobilization procedure caused increased sperm damage evaluated in vitro compared to standard semen processing procedure.

• Sveberg, Guro; Rogers, Gary W.; Cooper, Joan; Refsdal, Arne Ola; Erhard, Hans W. & Kommisrud, Elisabeth [Vis alle 9 forfattere av denne artikkelen] (2015). Comparison of Holstein-Friesian and Norwegian Red dairy cattle for estrus length and estrous signs. Journal of Dairy Science (JDS). ISSN 0022-0302. 98(4), s. 2450–2461. doi: 10.3168/jds.2014-8905. Fulltekst i vitenarkiv Vis sammendrag

  This study addressed the effect of breed on estrus length and estrous behavior by observing 20 Holstein-Friesian (HF) and 20 Norwegian Red (NRF) cows on an outdoor wood-chip pad through 1 estrous cycle (22 d). Detailed behavioral data were collected by continuous (24 h) video monitoring of all cows. Accurate estimation of duration of estrous periods, behavioral signs (sum per period and counts per hour), and duration and number of sexually active groups were reported through all stages of mount estrus (prestand, standing estrus, and poststand). These dependent variables were analyzed with a basic statistical model that included fixed effects for breed and lactation group. Other independent variables (milk yield, body condition score, and number of cows in standing estrus) were added to the basic model one by one and included in an expanded model if they had an effect on the respective dependent variables. Estrus duration was considerably shorter in HF compared with NRF cows for all the major periods: mount estrus (11.2 ± 3.0 vs 21.3 ± 2.7 h), standing estrus (7.1 ± 1.4 vs 11.7 ± 1.3 h), mounting period (6.9 ± 2.7 vs 18.2 ± 2.4 h), and mounted period (9.2 ± 2.8 vs 17.5 ± 2.6 h). Additionally, the NRF cows spent more time in sexually active groups (36.1 ± 4.0 vs 17.6 ± 4.8%) during standing estrus compared with HF cows. The NRF cows participated in a greater number of sexually active groups (9.6 ± 1.3 vs 5.5 ± 1.3) with longer average duration (0.42 ± 0.04 vs 0.20 ± 0.04 h) and continued to be more active in these groups through late stages of estrus (poststand) compared with the HF breed. Mounting activity differed between breeds as NRF mounted more times in total (46.3 ± 6.2 vs 18.1 ± 6.3) and per hour (2.6 ± 0.4 vs 1.5 ± 0.5) during mount estrus. In addition, NRF tended to express the primary estrous sign, standing when mounted, more often during standing estrus (32.4 ± 5.0 vs 18.5 ± 5.2). The HF initiated more unsuccessful mounts (1.6 ± 0.3 vs 0.6 ± 0.3) per hour than did NRF during mount estrus. A significant effect of milk yield was demonstrated only on this behavior. For other estrous signs, HF cows initiated chase-up (2.0 ± 0.5 vs 0.5 ± 0.4) and anogenital sniff (3.7 ± 0.6 vs 2.0 ± 0.5) more frequently (counts per hour), whereas NRF expressed more total head butt behavior (32.3 ± 4.7 vs 14.2 ± 4.8) during mount estrus. Body condition score had a significant effect on receptive behavior. Measures of estrus duration, sexually active group activity, and behavior related to estrus should be subjected to larger studies for improved heat detection and possible implementation in breeding programs.

• Berg, Fride; Myromslien, Frøydis Deinboll; Kommisrud, Elisabeth; Ropstad, Erik & Elisabeth, Waterhouse Karin (2014). Comparison of Electronic Volume and Forward Scatter Principles of Cell Selection Using Flow Cytometry for the Evaluation of Acrosome and Plasma Membrane Integrity of Bull Spermatozoa. Cytometry Part A. ISSN 1552-4922. 85(8), s. 719–728. doi: 10.1002/cyto.a.22474. Fulltekst i vitenarkiv
• Sveberg, Guro; Refsdal, Arne Ola; Erhard, Hans W.; Kommisrud, Elisabeth; Aldrin, Magne & Tvete, Ingunn Fride [Vis alle 9 forfattere av denne artikkelen] (2013). Sexually active groups in cattle - A novel estrus sign. Journal of Dairy Science (JDS). ISSN 0022-0302. 96(7), s. 4375–4386. doi: 10.3168/jds.2012-6407. Fulltekst i vitenarkiv Vis sammendrag

  The current study presents a novel objective measure for characterizing sexually active groups (SAG 3-5) and relates this measure to other behaviors of lactating Holstein-Friesian cows. Cows in SAG 3-5 were required to participate in a minimum of 1 estrus behavior per 5min while staying within 3m (2 cow lengths) of its partner(s) for a minimum of 5min. Twenty Holstein-Friesian cows were video-monitored continuously through 1 complete estrous cycle (22d). Standing behavior, SAG 3-5, secondary estrus signs (SEC), and other social and agonistic behaviors were recorded continuously. The period of mounting estrus (MTE) was divided into the 3 parts: prestand, standing estrus (STE), and poststand. The mean durations of MTE, prestand, STE, and poststand period were 12.9±1.84, 4.0±1.93, 7.1±1.44, and 1.8±0.57h (n=13). The fractions of time spent in SAG 3-5 during MTE, prestand, STE, and poststand period were 13, 8, 19, and 1% (n=11). During MTE, cows participated, on average, in 5.8±1.24 SAG 3-5 and initiated 9.5±2.99 mounts, with mean durations of 0.25±0.03h and 4.00±0.36s, respectively. The novel measure SAG 3-5 was a sign of long duration not confined only to groups of STE cows. On one day when no cows were in estrus and during the periods 4 to 24h before and after MTE, no SAG 3-5 behaviors were observed. Luteal-phase cows participated in SAG 3-5 only when the partner was a single cow in estrus. The time spent in SAG 3-5 increased between 1 and 3h before MTE and the prestand period (3 vs. 8%) and reached a peak level during STE. From STE to poststand, time spent in SAG 3-5 decreased considerably (19 vs. 1%). The observed decrease in nonmutual agonistic behaviors 4 to 24h before MTE is suggested as an early sign of pre-estrus. Changes in SAG 3-5, agonistic behaviors, and SEC are suggested as indicators of the specific stages of MTE. Increased SEC initiated and SAG 3-5 were indicators of late pre-estrus and early estrus (prestand). Peak levels of SAG 3-5, SEC, and social agonistic behaviors were indicators of STE. A sudden decrease in behaviors, preceded by frequent interactions, was indicative of late estrus (poststand). On the basis of the findings reported here, we propose that SAG 3-5, as well as proceptive and receptive patterns of SEC and agonistic behaviors, be included in estrus detection protocols. Updated knowledge of these behavioral interactions may assist when determining the stage of estrus and the optimal time to breed dairy cows.

• Claussen, Ingrid Camilla; Hemmingsen, Anne Karin; Longva, Karianne Eide; Strømmen, Ingvald & Kommisrud, Elisabeth (2011). Characteristics of Bovine Spermatozoa after Immobilization by Dehydration. Drying Technology. ISSN 0737-3937. 29(5), s. 480–487. doi: 10.1080/07373937.2010.509555. Fulltekst i vitenarkiv
• Sveberg, Guro; Refsdal, Arne Ola; Erhard, Hans W.; Kommisrud, Elisabeth; Aldrin, Magne & Tvete, Ingunn Fride [Vis alle 9 forfattere av denne artikkelen] (2011). Behavior of lactating Holstein-Friesian cows during spontaneous cycles of estrus. Journal of Dairy Science (JDS). ISSN 0022-0302. 94(3), s. 1289–1301. doi: 10.3168/jds.2010-3570. Fulltekst i vitenarkiv Vis sammendrag

  The objectives of the present study were to describe, in detail, behavior associated with standing estrus (STE) in lactating dairy cows and behavioral changes during complete estrous cycles. Estrus signs were monitored by continuous video recording of 20 Holstein-Friesian (HF) cows housed on an outdoor wood-chip pad during 1 estrous cycle (22 d). Other social behavior was recorded during STE and, for comparison, during 1 selected day when none of the cows were in estrus. Standing stationary when mounted was defined as the primary estrus sign. Anogenital sniff, chin rest, attempt to mount, and mount were defined as secondary estrus signs. Ovarian cyclicity was confirmed by progesterone measurements. This study reports short mean duration of STE (7.1±1.44h) and estrus (mount period; 12.9±1.84h) of the 13 cows expressing these signs. All mounting activities involved at least one cow in, or within 4h of, STE. The most frequent sign during STE was anogenital sniff initiated, followed by chin rest received, chin rest initiated, chase up initiated, anogenital sniff received, mount initiated, head butt, mount received, attempt to mount initiated, push away received, play rub, attempt to mount received, follow initiated, threat received, flehmen, avoid, bellow, and social lick received. Standing and mounting activity in HF cows was inconsistent during estrus, indicating that other signs could be of greater use. The frequency of secondary estrus signs initiated and received increased gradually during the last 12h before STE, revealing significant differences between periods from 4 to 6 and 1 to 3h before STE. A considerable increase in receptive behavior (secondary estrus signs received) was identified between 1 to 3h prior to STE and STE. Both frequent initiated and received behaviors were associated with STE. A significant decrease in the frequency of secondary estrus signs initiated and received occurred 3h after STE. Cows in STE simultaneously predominantly chose the other standing cow as mate and expressed secondary estrus signs more frequently. Based on the results of this study, we suggest that chase up could be regarded as a reliable indicator of estrus and that the changes in proceptive (initiated) and receptive (received) behavior could be used as predictors of different stages in estrus. Knowledge of these behavioral signs may improve heat detection rates and the ability to predict the optimum breeding time for dairy cows.

• Waterhouse, Karin Elisabeth; Haugan, T.; Kommisrud, Elisabeth; Tverdal, Aage; Flatberg, Gøril & Farstad, Wenche Kristin [Vis alle 8 forfattere av denne artikkelen] (2006). Sperm DNA damage is related to field fertility of semen from young Norwegian Red bulls. Reproduction, Fertility and Development. ISSN 1031-3613. 18(7), s. 781–788. doi: 10.1071/RD06029. Fulltekst i vitenarkiv

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• Kommisrud, Elisabeth (2026). Research based innovations resulting in Innovation award. Fulltekst i vitenarkiv
• Bremer, Joanna; Narud, Birgitte; Maj, Michal; Riegler, Michael; Hansen, Terkel & Harbak, Møyfrid Therese Myhre [Vis alle 12 forfattere av denne artikkelen] (2026). Towards semen collection at younger age: non-invasive monitoring of puberty onset in young beef bulls at performance testing stations. Fulltekst i vitenarkiv Vis sammendrag

  Breeding companies need tools to monitor puberty onset that are fast, safe, and operable by any technician. Methods currently available for assessing reproductive development in young bulls are neither safe nor practical enough for routine use. Manual scrotal circumference (SC) measurement is typically performed once at around 12 months during breeding soundness evaluation, however many companies have discontinued it altogether due to animal handling risks. Blood-based hormone analysis, while informative, is too labour-intensive to perform routinely. Consequently, the peripubertal window, during which testicular development and the onset of steroid hormone production determine future reproductive potential, is rarely monitored systematically. Earlier identification of bulls ready for semen collection would shorten the generation interval and increase genetic gain, but achieving this requires a novel monitoring approach. Performance testing stations provide a unique setting for this: bulls of multiple breeds are present for an extended period, allowing repeated sampling across the peripubertal window. We monitored 80 beef bulls of five breeds (Aberdeen Angus, Charolais, Hereford, Limousin, Simmental) monthly over 8 consecutive months, covering ages 6 to 15 months, in collaboration with TYR, Norway's national beef breeding organisation. Scrotal circumference was measured manually using scrotal tape, while LiDAR depth imaging data were simultaneously captured via iPhone 16 Pro (iOS 26). The depth images form the training dataset for a deep learning model currently under development to detect and measure SC by LiDAR only. The goal is to integrate this model into an easy-to-use mobile application suitable for routine field use, without the need for specialised equipment. In parallel, tail hair samples were collected for LC-MS/MS quantification of six hormones: five spanning the steroidogenesis pathway (DHEA-S, DHEA, androstenedione, testosterone, and estradiol) and cortisol as a marker of stress response. Both whole-hair and segmental analyses are planned to resolve the temporal hormone dynamics that single-timepoint blood sampling cannot capture. Hair segments reflect hormone incorporation during growth, enabling retrospective measurements of their levels from a single sample.Manual SC growth curves have been completed for all 80 bulls, and iPhone LiDAR depth images have been successfully captured across all monitoring visits. An LC-MS/MS method for simultaneous quantification of all six hormones in tail hair has been developed and validated on pilot samples by SINTEF, confirming reliable extraction and detection sensitivity across the full steroid panel. Initial hormone profiling will focus on a selected subset of Limousin and Angus samples, chosen to capture both breed-level contrast in peripubertal hormonal trajectories and the effect of hair colour, as Limousin (brown) and Angus (black) represent the two contrasting coat colours among the five breeds studied. Hair colour has previously been shown to influence testosterone levels measured in hair, making this comparison particularly informative for method validation. Individual tail hair growth rate was measured in two bulls by shaving, yielding a rate of 2–3 cm/month, consistent with values reported in the literature. Full calibration across all animals was not feasible, limiting the temporal precision of segmental hormone assignment at the individual level. This combined approach could provide breeding companies and performance testing stations with practical, non-invasive tools for routine longitudinal monitoring of reproductive development. The result would be earlier and more accurate identification of bulls ready for semen collection, improving both breeding efficiency and animal welfare.

• Holub, Elina; Jochems, Reina; Zeremichael, Teklu Tewoldebrhan; Klungland, Arne & Kommisrud, Elisabeth (2026). Reduced in vitro maturation time of bovine oocytes may increase blastocyst yield. Fulltekst i vitenarkiv
• Mikkola, Marja; Desmet, Karolien; Kommisrud, Elisabeth & Riegler, Michael (2024). Recent advancements and trends in Assisted Reproductive Technologies (ART) to increase success of artificial insemination and embryo transfer programs – the European perspective. Fulltekst i vitenarkiv
• Kommisrud, Elisabeth (2024). Gamete and embryo research at INN. Fulltekst i vitenarkiv
• Shrestha, Asmita; Nordborg, Anna; Gaustad, Ann Helen; Kommisrud, Elisabeth; Son, Maren van & Alm-Kristiansen, Anne Hege (2024). Investigation of Biomarkers of Sexual Maturity in Boars using Targeted Metabolomics. Fulltekst i vitenarkiv
• Kommisrud, Elisabeth & Zimmermann, Barbara (2024). From research idea to a finalized project. Fulltekst i vitenarkiv
• Haug, Linda Marijke Dekker; Wilson, Robert Charles; Gaustad, Ann Helen; Jochems, Reina; Kommisrud, Elisabeth & Grindflek, Eli [Vis alle 7 forfattere av denne artikkelen] (2023). Cumulus cell gene expression identifies key mechanisms influencing porcine oocyte developmental competence. Fulltekst i vitenarkiv
• Haug, Linda Marijke Dekker; Wilson, Robert Charles; Gaustad, Ann Helen; Jochems, Reina; Kommisrud, Elisabeth & Grindflek, Eli [Vis alle 7 forfattere av denne artikkelen] (2023). Cumulus cell gene expression identifies key mechanisms influencing porcine oocyte developmental competence. Fulltekst i vitenarkiv
• Desmet, Karolien & Kommisrud, Elisabeth (2023). Current status of embryo research and application in Norway. Fulltekst i vitenarkiv
• Desmet, Karolien & Kommisrud, Elisabeth (2022). Current status of embryo research and application, Norway. Fulltekst i vitenarkiv
• Munthe-Kaas, Maien; Holmøy, Ingrid Hunter; Sveberg, Guro; Kommisrud, Elisabeth; Haadem, Caroline Sorknes & Martin, Adam Dunstan (2022). Oestrus length and mounting and standing behaviour in Norwegian Red Cattle. Fulltekst i vitenarkiv
• Kommisrud, Elisabeth (2022). Zygote – et hav av muligheter for kapasitetsløft i Innlandet. Fulltekst i vitenarkiv
• Khezri, Abdolrahman; Narud, Birgitte; Stenseth, Else-Berit; Myromslien, Frøydis Deinboll; Gaustad, Ann Helen & Wilson, Robert Charles [Vis alle 8 forfattere av denne artikkelen] (2019). DNA methylation patterns differ in boar sperm cells with high and low DNA fragmentation index. Fulltekst i vitenarkiv
• Narud, Birgitte; Khezri, Abdolrahman; Myromslien, Frøydis Deinboll; Stenseth, Else-Berit; Zeremichael, Teklu Tewoldebrhan & Kommisrud, Elisabeth (2019). In vitro assessment of sperm characteristics in cryopreserved semen from Norwegian Red bulls with high and low fertility. Fulltekst i vitenarkiv
• Narud, Birgitte; Khezri, Abdolrahman; Kvitvang, Hans Fredrik; Klinkenberg, Geir; Zeremichael, Teklu Tewoldebrhan & Stenseth, Else-Berit [Vis alle 8 forfattere av denne artikkelen] (2018). Age effect on semen quality, metabolomics and fertility in young Norwegian Red bulls. Reproduction in domestic animals (1990). ISSN 0936-6768. 53, s. 92–93. doi: 10.1111/rda.13017. Fulltekst i vitenarkiv
• Narud, Birgitte; Khezri, Abdolrahman; Kvitvang, Hans Fredrik; Klinkenberg, Geir; Zeremichael, Teklu Tewoldebrhan & Stenseth, Else-Berit [Vis alle 8 forfattere av denne artikkelen] (2018). Age effect on semen quality, metabolomics and fertility in young Norwegian Red bulls. Fulltekst i vitenarkiv
• Khezri, Abdolrahman; Narud, Birgitte; Mbuma, Janeth Donald; Myromslien, Frøydis Deinboll & Kommisrud, Elisabeth (2018). Sperm motility, semen production efficiency and field fertility in different aged Norwegian Red bulls. Fulltekst i vitenarkiv
• Berg, Halldor Felde; Kvale, Vilde; Heringstad, Bjørg; Alm-Kristiansen, Anne Hege; Ropstad, Erik & Kommisrud, Elisabeth (2018). Ovulatory response to GnRH following luteolysis by PGF2α in Norwegian Red heifers. Fulltekst i vitenarkiv
• Berg, Halldor Felde; Kvale, Vilde; Heringstad, Bjørg; Alm-Kristiansen, Anne Hege; Ropstad, Erik & Kommisrud, Elisabeth (2018). Ovulatory response to GnRH following luteolysis by PGF2α in Norwegian Red heifers. Reproduction in domestic animals (1990). ISSN 0936-6768. 53, s. 110–111. doi: 10.1111/rda.13270. Fulltekst i vitenarkiv
• Kommisrud, Elisabeth (2016). SpermVital immobilization technology – approaches applicable for canine semen? Fulltekst i vitenarkiv
• Kommisrud, Elisabeth (2016). SpermVital immobilization technology – approaches applicable for canine semen? Reproduction in domestic animals (1990). ISSN 0936-6768. Fulltekst i vitenarkiv
• Kommisrud, Elisabeth & Kommisrud, Elisabeth (2016). SpermVital – erfaring nasjonalt og internasjonalt. Fulltekst i vitenarkiv
• Kommisrud, Elisabeth (2016). Fruktbar forskning. [Journal]. Forskerforum, tidsskrift for forskerforbundet. Fulltekst i vitenarkiv
• Kommisrud, Elisabeth (2015). Gjør gode spermier bedre. [Internet]. forskning.no. Fulltekst i vitenarkiv
• Kommisrud, Elisabeth (2015). Skal gjøre norsk oksesæd mer potent. [Internet]. forskning.no. Fulltekst i vitenarkiv
• Berg, Fride; Alm-Kristiansen, Anne Hege; Waterhouse, Karin E; Myromslien, Frøydis Deinboll; Klinkenberg, Geir & Kommisrud, Elisabeth (2015). Prolonging the shelf-life of spermatozoa by immobilizing technology. Fulltekst i vitenarkiv
• Kiiver, Hannelore; Kommisrud, Elisabeth; Soidra, K & Waldmann, Andres (2015). Effects of milk progesterone and activity level on pregnancy rate in dairy cows using the Ovsynch protocol. Reproduction in domestic animals (1990). ISSN 0936-6768. 50, s. 41–41. Fulltekst i vitenarkiv
• Kommisrud, Elisabeth & Kommisrud, Elisabeth (2015). Hjelp på vegen fra forskning til forretningsutvikling. Fulltekst i vitenarkiv
• Kommisrud, Elisabeth (2014). Sperm Vital® - is exact timing of insemination not important any more? Fulltekst i vitenarkiv
• Kommisrud, Elisabeth; Klinkenberg, Geir; Bekk, Laila & Alm-Kristiansen, Anne Hege (2014). Prolonging shelf life of spermatozoa by immobilizing technology. Fulltekst i vitenarkiv
• Berg, Fride; Myromslien, Frøydis Deinboll; Kommisrud, Elisabeth; Ropstad, Erik & Waterhouse, Karin E. (2014). Comparison of flow cytometers for evaluation of sperm viability and acrosome integrity. Fulltekst i vitenarkiv
• Berg, Fride; Myromslien, Frøydis Deinboll; Kommisrud, Elisabeth; Ropstad, Erik & Waterhouse, Karin E. (2014). Comparison of Flow Cytometers with Electronic Volume and Forward Scatter Principles. Fulltekst i vitenarkiv
• Garmo, R.T.; Sunde, J.; Gillund, P.; Kommisrud, Elisabeth & Klinkenberg, Geir (2011). Performance of the spermvital semen processing technology in field trials. Reproduction in domestic animals (1990). ISSN 0936-6768. 46, s. 72–72. Fulltekst i vitenarkiv
• Shrestha, Asmita; Alm-Kristiansen, Anne Hege; Kommisrud, Elisabeth & Son, Maren van (2025). Metabolomics, transcriptomics, and sperm quality analyses to investigate biomarkers in boar semen related to sexual maturity. Universitet i Innlandet / University of Inland Norway. ISSN 9788283805772. Fulltekst i vitenarkiv Vis sammendrag

  Puberty to sexual maturity marks a key transition in boar reproductive development, yet the molecular and functional changes that occur in semen during this transition remain poorly described. In modern pig breeding, artificial insemination is central to breeding and genetic improvement, and the ability to use boars as young as possible can reduce costs and accelerate genetic gains. At present, decisions about when the boars are ready for semen collection rely mainly on age and analysis of ejaculate volume, sperm concentration, motility, and morphology, which do not fully capture the biological processes underlying maturation. This thesis addresses these gaps by following Duroc boars longitudinally from puberty to sexual maturity, with metabolomics, transcriptomics, and sperm quality assessments to uncover the molecular and functional signatures of maturation. Semen samples were collected longitudinally from individual boars through three maturation ages: at approximately 7 months, 6 weeks later, and finally 12 weeks after the initial sample collection. This longitudinal approach eliminated inter-individual genetic variability while capturing the genuine maturational period. Across four studies, complementary approaches were applied to investigate different biological layers, including targeted metabolomics, untargeted metabolomics, sperm functional assessment, and transcriptomic profiling. Targeted metabolomics was used to quantify amino acids and amines in sperm and seminal plasma, identifying glutamate, alanine, aspartate, choline, and taurine in sperm as key metabolites that changed significantly with age and may serve as potential biomarkers of sexual maturity. Untargeted metabolomics expanded this analysis, capturing thousands of features and highlighting pathways such as porphyrin metabolism, taurine and hypotaurine metabolism, and glycerolipid metabolism, which were significantly enriched during sexual maturation. Functional analyses showed that sperm motility, acrosome integrity and viability, DNA integrity, and tolerance to semen storage all improved significantly as boars matured. Several metabolites, including glutamate, cystine, aspartate, taurine, and choline, were linked directly to these functional gains. Transcriptomic profiling of sperm revealed dynamic changes in both coding and non-coding RNAs. A total of 60 genes and six miRNAs were identified as differentially expressed, which are associated with key reproductive processes such as spermatogenesis and germ cell development. This provides insights into the molecular mechanisms that drive functional improvements. Furthermore, an integrated mRNA-miRNA analysis identified regulatory networks that could influence the maturation process. Together, these findings provide the first comprehensive longitudinal characterization of sexual maturation in boars. This thesis contributes both to fundamental knowledge and applied value to the field of animal reproduction. From a practical perspective, it establishes a basis for further research to develop molecular biomarkers that can guide the usage of young boars in semen production and breeding, thereby reducing non-productive days and accelerating genetic gain in breeding programs.

• Ray, Mithlesh Kumar; Kommisrud, Elisabeth & Ahmad, Rafi (2018). Bioinformatics analysis of epigenetic data from bull and boar semen samples. Universitetet i Innlandet. Fulltekst i vitenarkiv

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