As breeding season approaches, more and more sheep producers across the UK are turning to synchronising as a practical way to take control of lambing and improve overall flock performance. Ewe synchronisation is the management practice of achieving a compact mating period and thereby compact lambing period—making everything from feeding to marketing that bit easier. An additional benefit is that you are able to manipulate out of season breeding if you are wanting to lamb earlier/ later in the year. Sheep are seasonal breeders, most breeds only exhibit oestrus from September onwards in response to increasing night time/darkness which stimulates the secretion of the hormone melatonin with peak fecundity in October or November. Some farms use this method for the whole flock, while others target first-time lambers, pedigree ewes, or groups scheduled for early lambing.
Why Synchronise?
There are several key benefits to synchronising your flock:
1. Tighter Lambing Periods
One of the most significant advantages of synchronisation is the ability to achieve a compact lambing season. By using progesterone-based devices like CIDR Ovis or sponges, ewes can be induced to ovulate within a 48-hour window
. This results in:
- More predictable lambing dates
- Reduced need for prolonged supervision
- Easier planning for veterinary care and vaccinations
2. Improved Labour Efficiency
With lambing concentrated into a shorter period, farmers can better allocate their time and resources. This reduces the physical and mental strain of extended lambing seasons and allows for:
- Streamlined feeding and care routines
- Efficient use of lambing pens and equipment
- Better scheduling of staff or family help
3. Enhanced Use of Rams
Synchronisation reduces the strain on rams by ensuring that ewes are ready to breed at the same time as long as the ewe to ram ratio is correct! You need more rams as the ewes are all ready at the same time. This allows for:
- Lower ewe-to-ram ratios
- More effective use of high-quality rams
- Improved conception rates
4. Uniform Lamb Crop
A synchronised lambing season results in lambs of similar age and size, which simplifies:
- Creep feeding and weaning
- Health management (e.g., vaccinations)
- Marketing and sale of lambs as a uniform group
5. Better Planning for Market Timing
By controlling when lambs are born, farmers can target specific market windows, such as:
- Early lamb markets
- Holiday demand
- Optimised finishing times for grass or feedlot systems
6. Support for Advanced Breeding Techniques
Synchronisation is essential for the successful implementation of artificial insemination (AI) and embryo transfer (ET), which require precise timing of ovulation
7. Potential for Higher Twinning Rates
Some farmers report improved twinning percentages when using CIDR Ovis compared to traditional sponges which can increase the number of lambs born per ewe and improve flock profitability.
The key is all in the timing, and if you are looking at synchronising now is the time to start planning ahead. Synchronisation protocols should begin several weeks ahead of your planned mating date, so now is a good time to speak to your vet about:
- Whether your flock is suitable for synchronisation
- Selecting the right protocol for your system
- Sourcing sponges, PMSG, and other necessary materials
- Ensuring ewes are in ideal condition for successful conception
THINGS TO CONSIDER:
If you are looking at synchronising ewes there are a number of factors to consider to ensure that it it successful:
- A higher ram to ewe ratio (e.g., 1:8 or 1:10) is often recommended for synchronized matings, especially with natural service.
- Breed of ewes- the ovulation rate of certain breeds such as the Finnish Landrace and Blueface Leicester are higher than those of other breeds.
- Ewe Age- The ovulation rate of gimmers is generally lower than that of adult ewes.
- Barren Rates- a higher barren rate than the normal 2 per cent is to be expected, however such barren ewes could be returned to the main flock lambing in the normal season
PRODUCT CHOICE:
There are a number of products on the market, and the right product will depend on breed, needs and budget. All have slightly varied protocols, so please ensure you have spoken to your vet.
CIDR OVIS:
CIDR Ovis is a progesterone-releasing device used in sheep to synchronize oestrus (heat) and ovulation, allowing for controlled breeding. It’s a “T” shaped device inserted vaginally, releasing progesterone to suppress the natural cycle, and then removed to induce synchronized oestrus.
CPD WEBINAR: CONTROLLED SHEEP BREEDING WITH CIDR® OVIS
A webinar providing refresher on the ewe’s reproductive cycle alongside reasoning and methods for advancement and synchronisation of sheep breeding. The practical use of CIDR® Ovis is described with advice on timings for natural service and AI breeding. Differences between CIDR® Ovis and sponges are discussed.
SPONGES:
Sponges are similar to CIDRS and are a progesterone-releasing device. It’s a device inserted vaginally, releasing progesterone to suppress the natural cycle, and then removed usually 14 days later. Often after removal a jab of PMSG Pregnant Mare Serum Gonadotropin is used in conjunction to increase the number of eggs ovulated, potentially leading to larger litter sizes.
REGULIN:
Unique melatonin implant to improve the reproductive performance of pure bred and cross bred sheep. Available in 50 dose packs, and is an implant for subcutaneous administration (at base of ear). Used for sheep which are to be mated early in the season before the usual peak of reproductive activity. Stimulates the early onset of natural reproductive activity.
