Objective
• a cost effective way of making sure the genetics you want are safe
• an excellent insurance policy against loss of or injury to a ram
• profitable if the semen is sold
• easy transport of genetics
• a back-up for AI when the intention is to use a specific ram fresh
Procedure
Rams are best booked into our purpose built centre where they can be trained to jump our specially trained teaser ewes and be collected into an AV (artificial vagina).
This can take various amounts of time depending on the individual ram; wild or nervous rams can take a week or so to learn to jump, some may be comfortable with the process straight away. Once trained, rams do not usually forget how to be collected and future 'refresher training courses' tend to be much shorter.
Some breeds will only jump on ewes of the same breed, for example a BFL ram may only jump a BFL ewe but we have a collection of attractive teasers so there should be a ewe to suit every ram's taste!
Occasionally some rams may just refuse to jump. We are able to electro-ejaculate (slang term is 'spark') these rams to get a sample, with your consent. This sometimes encourages/stimulates the rams to jump naturally. Sparking a ram is not guaranteed to give a sample and samples that are given are sometimes poorer quality than a natural ejaculate. It should not be relied upon as a method of semen collection for example for an AI day.
The length of time the ram needs to stay on centre depends on how many doses of semen you require but a ram which jumps straight away should only take a few days to give say, 50 doses.
The first couple of jumps are usually not suitable to freeze and can be a little slow if rams have not been with any ewes, as the sperm may have been sitting in their tubes (slang, backed-up). Once this has cleared and good quality grade 5 samples are being given, then we can start freezing.
Semen is graded out of 5. 0 is no good and 5 is top quality. Only semen which is 5 out of 5 will be processed for freezing, as on average 50% of sperm die during the freezing process.
Two to three jumps are taken per day on centre. The semen is diluted and each jump is frozen separately as pellets or straws, using dry ice and liquid nitrogen. Once frozen a sample pellet or straw from each batch is thawed and assessed under a microscope and if over 30% of spermatozoa are swimming strongly forward (progressively motile) and no major abnormalities are present, then it has passed. If any less, then the semen is destroyed as it is not of good enough quality to be used.
One jump of very good quality semen (depending on the amount) could give up to 30 to 40 doses but this alters with diferent breeds.
The more jumps you collect the more the volume tends to drop and the less you can dilute. Individuals vary, some rams would produce enough to sire the county and some, little more than one or two. After a while a ram will only give enough for a single ewe as if he was out being used naturally in the field.
Pellets may be of two types known as P2 and P1.
• P2 are pellets containing two doses of semen.
This is how the best quality semen in pellet form is kept.
• P1 are pellets of the same size but contain only one dose of semen – a double dose.
Usually this means that when a sample of the frozen semen has been assessed the semen has fallen only just underneath the 30% motile bracket. It is usually kept at the request of an owner, if we can not get good quality semen. It is only back-up until it can be replaced and should only be used for AI as a last resort. It is not suitable for sale.
Straws may also be of two types but it does not indicate semen quality.
• S1, straws containing one dose of semen
• S2, straws containing two doses of semen (twice the volume of an S1)
At Ovibreed, generally all of our semen is frozen in pellets.
Even where fresh semen is of excellent quality, semen freezing is not always successful. Sometimes a ram's semen will not freeze at all, sometimes it will not freeze just on a specific week or day or part of a season and often some of the jumps on a given day will freeze fine, whilst others will not. Occasionally rams will not give a sample at all.
Where semen freezing is proving unsuccessful a ram will be sent home and returned after a few weeks. You should not feel discouraged as this is perfectly normal.
Rams will not perform well if they have only recently returned from ewes, are stressed or in poor body conditions. Stress or illness can often lead to a temporary infertility which may last up to 6 weeks but fertility usually returns to normal and so again you should not be too concerned.
Freezing semen from your ram lambs is a good policy this is not because the best semen is taken while the ram is a lamb but just simply as a way of 'banking your assets'.Semen is stored free of charge for the first year so if the ram turns out not to be a breeder you can destroy that semen with no storage costs.
Semen can be collected and frozen on farm but is not recommended as a high proportion of this semen fails assessment. If the ram has been cleaned out you stand a better success rate but rams are not guaranteed to jump and contamination of samples is difficult to avoid when working on farm.