Many sheep farmers aim for a compact lambing period, but achieving it can be challenging in some cases.
One effective method to tighten up the lambing period is by using the ‘ram effect’.
The ‘ram effect’, as suggested by Teagasc, involves inducing ewes or ewe lambs to start cycling, provided they are close to the normal cyclicity time period.
For the ‘ram effect’ to work, ewes must not have any contact with rams (sight, sound, or smell) for at least 28 days.
When exposed to rams again, the pheromones released by the rams cause hormonal changes in the ewes, initiating cyclicity.
Upon introducing adult rams, most ewes not already cycling will experience a ‘silent heat’ within 36 hours, and some may have a second silent heat after six days, which goes undetected by rams.
It is recommended to remove rams after 24-36 hours, and approximately 17 days after the final silent heat, ewes should start cycling.
The first detectable heat by rams will occur 18-23 days after ewes have been exposed to rams.
For effective synchronization of the mating season using the ‘ram effect’, introduce fertile rams to the flock 14 days after the initial ram introduction to pick up any short cycles or ewes that were already cyclic at that time.
It is advisable to have one ram per about 18 ewes to ensure adequate mating.
Additionally, make sure to have sufficient facilities, especially lambing pens (one pen per six ewes), and enough labor to cope with the increased workload during the compact lambing period.
By following these guidelines and using the ‘ram effect’ properly, you can achieve a successful and compact lambing period on your sheep farm.