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Teaser Rams

Influence on Joining


Best Practice Teasing to Optimise Oestrus Synchronisation

The introduction of rams, including vasectomised (infertile) rams or testosterone-treated wethers, stimulates ewes to commence cycling. This practice is known as ‘teasing’ and rams used for this purpose are called ‘teasers’. It is particularly important for out of season breeding i.e. any time before February.

Ram teasing


The number of teasers used should be equal to the number of rams (1-2%) or double for testosterone-treated wethers (2-4%).
A harness may be fitted to the ram to mark the ewes to give an indication of when most of the ewes are cycling (see photo).
The breeding rams can be introduced 14 days after the teasers, once the teasers have been taken out (Diagram 1).

Note that keeping the breeding rams in a paddock adjacent to the ewes for two weeks prior to the start of mating will have a similar effect to teasing.

The pattern of lamb births will give an indication of whether the ewes were ready for joining i.e. if there are only a few lambs in the first ten days of lambing, ewes were not ready. If there is a flush of lambs in the first ten days, ewes were properly prepared for mating.

Best Practice Teaser Timing in Joining Program


Diagram 1 - Time periods of teaser joining
Reproductive Cycle of Ewes
Stage Average Range
Puberty age 5 to 12 Months
Oestrus cycle 17 days 13-19 days
Oestrus duration 30 days 18-48 days
Ovulation release 20-30 hours after start of Oestrus
Gestation 146 days 135-150 days
Table 1 - Variation in Ewe Reproductive Cycle

Further Reading

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