Why use ‘Teasers’?
A ‘teaser’ is a ram that has been vasectomised (rendering him unable to impregnate ewes), but maintains his testosterone levels, driving his libido and physical mating ability. As a result the ‘ram effect’ naturally synchronises the ewes ready for your entire, fertile rams to be introduced.
Teaser rams are used to advance the breeding season by two to three weeks, and to tighten your lambing window.
Ewes need to be kept away from any males (sight and sound) for a minimum of 28 days prior to introducing the teasers (6 weeks+ is ideal).
Timing
A vasectomy should be performed 6 – 8 weeks prior to the intended introduction of the teaser ram. In this period the teaser ram should not run with any breeding ewes as he may still be partially fertile. Vasectomies can be carried out on your farm, or at any of the practices involved in Midlands Advanced Breeding Services.
Teaser selection
Whilst there is no hard and fast rule about which rams you can vasectomise, the following criteria are preferable:
• High libido; teasers will have to work hard and do lots of chasing
• Fit and healthy; teasers will work harder than your normal rams
• Legs; sound on their legs, with no current or historical issues with lameness
• Good teeth; an indicator of health and longevity
• Disease status: vaccinated (as per your flock vaccine protocol) and screened for Maedi Visna (or other diseases your flock is screened for)
If you intend to vasectomise a ram lamb, you should use him on experienced ewes.
If you purchase a vasectomised ram, or a ram to vasectomise, ensure he goes through your quarantine and vaccination protocols.
Breeds such as Dorsets and Suffolks are ideal as they are early breeders, but any breed can be used if their natural breeding season is taken into account.
Annual examination
Very rarely vasectomised tups can recanalise and, therefore, semen collection and evaluation prior to introduction in future years is recommended to ensure fertile rams are not being used as teasers.