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Norsvin research

Possibilities with embryo technology

Did you know that Norsvin does research on embryos? We introduced embryo technology as a completely new field of research in Norsvin in 2018, with two approved projects from the Research Council of Norway and Innovation Norway and our partners in Norway and abroad.

Reina Jochems was employed as a PhD student in Norsvin that same year. She has developed procedures and protocols, and set up her own embryo lab to get the embryo research started. For Norsvin and business-oriented research in international pig production, this is ground-breaking work. In 2022, Jochems completed her doctoral work on embryo transfer in pigs. Read about this here.

A blastocyst

  The image above shows a colored embryo developed from an egg cell fertilized in vitro, meaning in a lab. At this stage, the embryo consists of several cells, and is called a blastocyst.

Norsvin aspires to...

Research alternative methods for embryo production in the lab. Egg cells are harvested from the sows’ reproductive organs, and fertilized in vitro for further development into an early embryo stadium

Develop methods for harvesting embryos from live sows without surgery.

Develop an effective and successful method for transfer of embryo to receiving sows.

Possibilities with embryo technology 

The goal is to provide for successful and cost efficient embryo transfers on a larger scale, making embryo transfers an integral part of the Norwegian breeding program for pigs in the future.

If able to do so, we will strengthen the breeding programs and provide a better distribution of Norsvin genetics internationally. Embryo transfers will contribute to better animal welfare, higher bio security and a decrease in greenhouse gas emissions. By including embryos in our product portfolio, Norsvin and Topigs Norsvin will be able to offer genetics of the highest quality to new markeds, with a higher health status than by traditional livestock transportation.

By including embryos in our product portfolio, Norsvin and Topigs Norsvin will be able to offer genetics of the highest quality to new markeds, with a higher health status than by traditional livestock transportation.

New Norsvin PhD

Reina Jochems defended her PhD thesis, “In Vitro embryo production in Norwegian Duroc and Landrace pigs” on Junie 17th 2022.

During the doctoral period, Jochems was employed as a business PhD, partly funded by the Norwegian Research Council, and supervised by researchers from Norsvin, NMBU Veterinary College and Inland Norway University of Applied Sciences (INN). She now works as a researcher in Norsvin. 

Read more about the doctoral defense in this article (in Norwegian): Ny PhD i Norsvin

The sow's reproductive organs

Skjermbilde 2021-06-09 kl. 12.14.50
Left: cow. Right: sow.

Unlike primates (humans and monkeys), the animals do not have a simple uterus with right and left fallopian tubes that open directly into the uterus. Domestic animals have two long, tubular parts (right and left uterine horns), which lie between the fallopian tubes and the uterus itself.

In the sow, the uterine horns are very long and they bend in tighter and tighter spiral curls inwards towards the ovaries. It makes room for the fetuses to lie one behind the other like “pearls on a string” during pregnancy. There are also clear differences in the size and structure of the reproductive organs in cows and sows. Source: Senger, P. L. (2003) Pathways to pregnancy and parturition.

How do egg cells mature?

...and is there a difference between Landrace and Duroc? 

As part of Reina Jochem’s PhD research, egg cells were collected from slaughtered sows at the Rudshøgda slaughterhouse. These eggs were further matured in the laboratory, where the maturation of the eggs was monitored and studied. The differences between Norsvin Landrace and Duroc was partly in focus, to see if the maturation/development of the eggs, the number of eggs, and various characteristics of the ovaries can explain some of the difference in litter size between the two breeds.

The research demonstrated differences in the characteristics of the ovaries and in egg maturation between Norsvin Duroc and Norsvin Landsvin.

Larger litter size - more follicles at ovulation

The difference in litter size between Landsvin and Duroc correlates with the difference in the number of follicles.

Litter size, the number of piglets born, for the Duroc and Landrace breeds is 9.2 and 13.8 respectively. With a larger litter size, there are more follicles at ovulation, but these follicles are somewhat smaller.

There are indications that smaller follicles may mean somewhat lower quality. In experiments, it has been found that first-litter Duroc sows have 13.6 and Landrace: 21.6 follicles per ovary. The difference has been 16 follicles per sow between the two breeds.

Follicles: Until ovulation, the egg cells lie in follicles; small fluid-filled cysts carrying each egg cell.

Cumulus cells

Cumulus cells are the cells that lie outside the egg cells, which help and nourish the egg cells. The research shows that the cumulus expansion; the increase in the size of the area with cumulus cells, is greater for the Duroc than for the Landrace. In experiments, variations have been observed in how the egg cells from the Duroc and the Landrace mature in the lab, and therefore Norsvin is now looking further into whether this also results in differences in fertilization and later embryo development.

Eggcellene modnes: På bildet til venstre hentes eggceller ut av en eggstokk. På de to bildene til høyre ser man tydelig cumulus-cellene som omslutter eggcellene. Det midterste bildet viser egg- og cumulusceller ved uttak, mens bildet til høyre viser tilsvarende etter 20 timer. Da har området med cumulusceller rundt eggcellene økt 

The egg cells mature: In the picture on the left, egg cells are being harvested from an ovary. In the two pictures on the right, you can clearly see the cumulus cells that surround the egg cells. The middle picture shows egg and cumulus cells at the time of harvest, while the picture on the right shows the same after 20 hours, at which point the area of cumulus cells around the egg cells has increased.
After fertilization, the cell division begins. Eventually during the cell division, the cluster of cells reaches a stage we call the blastocyst stage, with one visible cavity. During the research we have achieved in vitro fertilization of egg cells in the lab, and are satisfied with the number of fertilized cells that develop further. We are currently uncertain about the quality of these blastocysts, and that is what will now be investigated further. We will for instance genotype embryos to see if there are changes in the chromosomes during embryo development in the lab.

Important findings

Through this research, new methods have been developed for the maturation of egg cells in vitro (in the lab).

Breed differences have been demonstrated during in vitro oocyte maturation, fertilization and embryo culture.

The results suggest that Duroc oocytes have a better development ability during in vitro embryo production.

Further research will focus on optimizing the protocols for each breed, and to determine how differences between the breeds relate to oocyte development ability and embryo quality.

Embryo transfer:

From donor to recipient sows

Further in the project, Norsvin and its partners will work more on the embryo transfer itself, and how donors and recipient sows can be synchronised, as well as looking at different methods for storing embryos.


Harvesting embryos from living sows

Parallel projects are taking place where embryos are flushed out of living sows without the use of surgery. This is demanding work on pigs, because the sow’s reproductive organs are complicated, with, among other things, a long cervix and long, curly uterine horns (see illustration).

Photo: Julie Lunde Lillesæter/Differ-Media

- Jochem's doctoral work represents a very important milestone in Norsvin's goal of developing top international genetics, where we enable a considerably better and more climate-friendly global distribution that at the same time ensures good animal welfare and infection control
- Eli Grindflek, Head of R&D - 

To be continued

Norsvin is very grateful for support from the Research Council of Norway and Innovation Norway in this research. We would also like to thank the participating herds. 

During the doctoral period, Reina Jochems was employed as a business PhD, partly funded by the Norwegian Research Council, and supervised by researchers from Norsvin, NMBU Veterinary College and Inland Norway University College (INN).

Norsvin still has ongoing research into embryo transfer in pigs. Please subscribe to our newsletter “Forskningsnytt” and visit for updates.


Avl for redusert rånesmak

Androstenon og skatol er begge arvelige komponenter, så avl for lavere nivåer av rånesmak i grisene er mulig og er en langsiktig løsning på rånesmaksproblematikken. Rånesmak er nå implementert i avlsmålet til norsk landsvin og duroc.

Grunnene til at dette ikke har blitt gjort tidligere, er usikkerhet rundt hvordan en seleksjon vil påvirke reproduksjonsegenskaper samt mangel på tilfredsstillende målemetoder.


Androstenon er et feromon som produseres i testikkel i samme biokjemiske reaksjonsvei som testosteron og østrogen. Androstenon fraktes med blod til spyttkjertlene der det fungerer som et duftstoff som bidrar til å aktivere stårefleksen hos purka. Det er dog et fettløselig steroid og for høy produksjon og/eller for dårlig nedbryting fører til at androstenon lagres i fettvev. For høye nivåer i fett gir rånesmak. Nivå av androstenon er sterkt påvirket av genetiske faktorer. 


Skatol er et metabolsk produkt av aminosyren tryptofan som absorberes fra tarm og brytes ned i lever. Nivå av skatol er også påvirket av genetikk, men kan til en viss grad reguleres av miljømessige faktorer. Skatol er ett betydelig større problem hos råner enn hos purker fordi androstenon hemmer nedbryting av skatol slik at det lagres i fettvev.  

Innsamling av data

I prosjektet BoarPPM ble det tatt prøver av nedskjærte halvsøsken til avlsrånene, og androstenon og skatol på disse ble analysert ved hormonlaboratoriet på NMBU Adamstuen. Dette gir sikre målinger på rånesmak som kan brukes i beregning av arvegrader og korrelasjoner til andre egenskaper. 

Videre har det vært ett annet prosjekt, finansiert av Innovasjon Norge, der vi testet den sensoriske (lukt-test) metoden «Human Nose Score». Denne er betydelig mindre nøyaktig enn kjemiske analyser og er heller ikke objektiv, men den er billig og kjapp og har gitt verdifulle fenotyper til bruk i avlsarbeidet. 


Både egne analyser og andre publiserte studier konkluderer med at det ikke er noen store negative genetiske korrelasjoner til andre egenskaper ved seleksjon for lavere rånesmak. Med fenotypene innsamlet i prosjektene som grunnlag, har rånesmak derfor blitt implementert i avlsmålene for landsvin og duroc. For øyeblikket tas det kjemiske målinger på et utvalg av slektninger til avlsrånene for å sikre oppdaterte fenotyper. Selv uten direkte registreringer på avlsrånene så forventer vi en reduksjon i nivået av rånesmak framover ved hjelp av genetisk seleksjon. 

Suksess i Nederland

I Nederland har Topigs Norsvin hatt stor suksess med avl for lavere rånesmak og har iløpet av de siste ti årene klart å redusere nivå av rånesmak med over 50 prosent i sine raser. 

Noe av årsaken til denne suksessen ligger i at de har brukt fettbiopsier fra avlsrånene for å sikre målinger til effektiv avl. Dette har imidlertid så langt ikke vært tillatt i Norge.