RAMSES - Ram Semen Extender Study (Development of a long-life storage diluent for fresh spermatozoa to facilitate cervical AI)
(March 2006 - June 2008)


To explore the development of products which will enable the more widespread utilisation of fresh ram semen and cervical AI techniques to facilitate the rapid upgrading of the genetic base of the national sheep flock and thereby increasing productivity.

This project was part of a DEFRA LINK project, which aimed to develop a suitable diluent for longer-term semen storage and to validate its effectiveness by extensive field trials.


Sheep breeding in the UK remains largely an extensive natural mating system involving small flocks with little biosecurity and disease control. The limited artificial insemination (AI) that takes place (about 50,000 inseminations pa) is of little impact, even though its exploitation enables farmers to benefit from genetic improvement programmes and to increase their biosecurity. The situation is in part due to technical limitations of the semen preservation methods currently available.

Although semen freezing and laparoscopic AI procedures work well in sheep, the necessary technical expertise and attendant costs militate against its being extensively adopted; the development potential in AI depends on fresh semen inseminated cervically. However, the lack of suitable diluents for sperm storage imposes a major limitation because there is currently no reliable extender for fresh ram semen that provides more than a few hours storage at ambient or chilling temperatures.

This will allow sheep farmers affordable and wider access to disease-free pedigree rams with high genetic merit; increased productivity; reduced on-farm management costs; reduced sheep movements & improved biosecurity.


This project conducted extensive field trials of promising diluent formulae to determine fertility under farm conditions in Wales and aimed to generate statistically significant results. 


The field trials were undertaken at the Institute of Rural Sciences under the direction of Innovis Ltd

The research partners in this project were the Royal Veterinary College, the Institute of Zoology, Sheffield University, Innovis Ltd., Britbreed Ltd. and IMV Technologies

The project was funded by HCC


To view the final report, click here.