What are teaser rams?

A teaser ram is an entire ram that has had a surgery to make him infertile. This means he still has testicles, testosterone, and ram behaviour, but can’t get ewes pregnant.
This is done by removing a section of the vas deferens, so sperm cannot travel from the epididymis (where it is made) to urethra/penis, essentially making him infertile. The ram still produces testosterone and so still wants to mate, and is still producing the pheromones to bring ewes into heat. This is called the ram effect and we can use this to our advantage.
Rams should be vasectomised at least 2 months before being needed so they can recover from the surgery. Selected rams should be healthy, with good teeth, legs, feet and a high libido. Ram lambs are not preferred.

Why use teaser rams?

Since sheep often have a short or silent heat at the beginning of the breeding season, using a teaser ram can increase their chances of conception when the ram is introduced. Around half the flock will start their breeding season by having a normal 17-day estrous cycle, with the second cycle making them fertile. The other 40- 50% will have two cycles (one short five-day cycle and a normal cycle) before becoming fertile on the third cycle.
Using a teaser also synchronise the ewes, so that more will be on heat and on a fertile cycle when the ram goes in.
While weight is most important for getting hoggets to reach puberty, the ram effect is also thought to help them reach puberty/start cycling.
Also, hoggets can be shy breeders, so introducing them to an infertile ram first may increase their conception rates when the time comes.
An increased conception rate will compress (shorten) the lambing period, so more lambs are born earlier, and reduces the workload on the fertile rams (since they aren’t working through silent and infertile heats). It will also make the start of lambing more predictable.

When should we use teaser rams?

Recommendations are to put the teaser rams in 14-17 days before the planned start of tupping, at a rate of 1:200 at most.
Ideally, for the best effect, ewes should be separated from the sight and smell of rams for at least a month before putting in the teaser. Any questions? Give your local vet a call to discuss using teaser rams in your own farm system.