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Is synchronisation right for my herd?

Friday, April 22, 2022

Synchronisation can be implemented on most farms with simple planning to reduce labour and facilitate an efficient and profitable breeding season.
Sychronisation with fixed-time artificial insemination (FTAI) is a popular, cost effective, and relatively simple reproductive technology that is ideally suited for the compact breeding season in pasture-based systems.

Synchronisation uses precise protocols to mimic the natural oestrous cycle with hormone treatments.  These protocols are designed to achieve timed ovulation and schedule subsequent AI to reach optimal pregnancy rates in the absence of heat detection.  

Synchronisation can be implemented on most farms with simple planning to reduce labour and facilitate an efficient and profitable breeding season.


Synchronisation has numerous benefits for the dairy and suckler farmer (Fig. 1).

Fig. 1:  Benefits of synchronisation with FTAI
  • Eliminates oestrus detection; reduces labour
  • Enables single, scheduled AI technician visit
  • Brings forward service to mating start date
  • Facilitates compact calving
  • Treats noncycling cows
  • Increases profitability
Synchronisation reduces labour on the farm by eliminating heat detection. ¬†In addition to saved labour, the costly risk of a missed heat is also avoided. ¬†Teagasc estimates each missed heat costs ‚ā¨149.50 in a 12-week breeding season.
By following straightforward protocol steps, all heifers and cows can be scheduled for AI on a specific date and time.  Logistical benefits also include a single AI technician visit.  Speak to your veterinarian and AI technician to choose a protocol best for your herd and plan AI based on their availability. 

Instead of waiting for a heat, AI is brought forward for all cows and heifers to the mating start date.  This will shorten the calving interval to better complement pasture growth as well as facilitate compact calving to promote optimal calf management and rearing.

Noncycling cows can be managed with synchronisation protocols to induce follicle growth and ovulation.  Again, it is important to work with your veterinarian to assess nutrition and reproductive health and appropriately address any underlying problems prior to the mating start date. 


The benefits of synchronisation with FTAI are reflected in increased profits to the farmer.  Recent Irish economic modelling research factors numerous variables including hormone costs, land, labour, fertility, genetic gain, calving profile, fertiliser, milk, and calf prices among numerous other outputs for an 80-cow dairy herd (Walsh 2022). 

Compared to conventional AI breeding following heat detection, synchronisation has an increased profit of over ‚ā¨34 per cow per year when used with heifers and cows and over ‚ā¨41 per cow per year when used with sexed semen in cows and heifers (Fig. 2).

Fig. 2: Average increase in profit per cow per year in an 80-cow her using synchronisation (synch) over breeding AI on heat detection (Walsh 2022)
  • Synch Conventional semen: heifers only -¬†‚ā¨3.90
  • Synch Conventional semen: heifers and cows -¬†‚ā¨34.11
  • Synch Sexed semen: heifers only -¬†‚ā¨13.96
  • Synch Sexed semen: heifers and cows -¬†‚ā¨41.52

Heifers must be target body weight, cycling, and in good general health to start FTAI with recommended body condition score (BCS) ‚Č•3.25. Cows also need to be in good general and reproductive health as well as 40 days in milk at AI and BCS ‚Č•3.0. ¬†For sexed semen, cows need to be a minimum in 50 days in milk at AI.

Teagasc research has developed optimal synchronisation protocols.  Protocols are also available for suckler cows and heifers.  Speak to your veterinarian to implement a protocol that is best for your herd.  It is critical to follow each step accurately as skipping a hormone or altering times will negatively influence pregnancy rates.  Anticipated pregnancy rates for dairy cows and heifers are 60% and 70%, respectively (Fig. 3).

Fig. 3:  Anticipated conception rates using synchronisation protocols for dairy cows and heifers (Teagasc)
  • Heifers
    • Conventional semen Synch pregnancy rates: 70%
    • Sexed semen Synch pregnancy rates: 60%
  • Cows
    • Conventional semen Synch pregnancy rates: 60%
    • Sexed semen Synch pregnancy rates: 50%
Both dairy and suckler synchronisation protocols were developed through Teagasc and UCD research using products from the Interchem fertility range.


Progesterone is a key hormone provided through an intravaginal device that controls the growth of the follicle (developing egg) and influences the quality of the oocyte (egg) and embryo.  Research has shown that higher progesterone during follicular development is key to improving the quality and survival and the embryo, which is then crucial to optimising pregnancy rates and limiting early embryonic death.

Speak to your veterinarian about the triangle progesterone device that contains the highest dose of progesterone on the Irish market and is used in Teagasc fertility trials.


Synchronisation complements the use of sexed semen by ideally timing ovulation with insemination to achieve optimal conception rates (Fig. 3). Sexed semen goes through a sorting process that damages the sperm and creates more fragile product.  Therefore, sperm do not survive as long in the female reproductive tract, and a narrow window exists for timing insemination with the fertile period around ovulation. Critical timing of AI with sexed semen can be targeted and scheduled with synchronisation protocols.  In addition, you can ensure all your desired heifers and cows selected for sexed semen can be bred and will not be missed due to the very narrow window for AI following oestrus detection.

Speak to your veterinarian about how synchronisation can help your herd achieve fertility targets and create an efficient and profitable breeding season.

References available upon request.

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