Technical information - Reproduction

AB and Synchronisation

By Alex Ashwood

Synchronisation has been available for more than 20 years but more recently has witnessed increased use due to the mating of groups of heifers and/or embryo transfer programs. In these cases synchronising is used as a convenient tool to allow more effective use of resources (eg. labour) or organise specially designed mating programs.

Whilst beef producers are aware of the benefits of oestrus synchronisation, intensive synchrony programs are more routinely used by dairy farmers.

At Alinta Stud, NSW we were aware why synchrony programs are not extensively used by beef producers (eg. cost, variable results, and suitability of stock).

“Synchronisation was seen as a management tool but does not replace good reproduction programs.”

Possible benefits included:

  • reduced semen costs
  • fewer repeat breeders
  • more commitment to breeding targets
  • better determine reproduction status of cows
  • planned use of time and resources
  • improved heat detection and submission rates
  • better planning of specific matings.

Before starting synchronisation programs the following points were considered:

  • the suitability of females
  • the bulls available
  • records of calving dates and previous reproduction performance
  • condition score of stock
  • plane of nutrition and feed availability
  • possibility of adverse season and heat stress
  • availability of expertise and resource people
  • possible risk factors and cost of failed programs
  • understanding the principles of reproductive behaviour and purpose of synchronisation programs and products
  • Synchronisation programs used involved two key components:
    • 1. Treatment to shorten the cycle using prostaglandins
    • 2. Treatment to extend the cycle using progesterones.

Table 1 – Prostaglandin Programs

Non oestrus detection Reduced oestrus detection
  • Double injection and double AI consists of two prostaglandin injections 11 days apart. followed by 2 inseminations at 72 and 96 hours. The major advantage is reduced time and labour inputs.
  • Double injection and single AI requires two prostaglandin injections but only one AI at 72 hours after last injection.

These programs use the greatest amount of prostaglandins, but do give tighter synchrony.

  • 10 day program requiring:
    • detection of heat and AI of cycling cows for 10 days.
    • one injection of prostaglandin for cows not inseminated.
    • insemination follows heat detection for the next five days.

This reduces injections and only cycling cows are inseminated. The program requires heat detection of treated stock.

Table 2 – Progesterone Implant Programs

CIDR & Oestradiol Benzoate capsule (ODB)** CIDR & oestradiol & (ODB) Prostaglandins (PG)

The CIDR contains progesterone and the ODB capsule has a synthetic oestrogen. Both of these products are produced by the ovary to control the oestrus cycle.

The CIDR and ODB capsules are placed in the cow’s vagina and removed 10-12 days later. Cows are then inseminated once (56 hours) or twice (48 & 72 hours) after the CIDR* is removed.

CIDR and ODB are inserted on first day and PG are administered (injection) on day 6. On day 10 the CIDR is removed. The stock are mated 48-50 hours after the CIDR removal or on detected oestrus.

* CIDR = Controlled Internal Drug Release

** Note: the capsule has now been replaced by CIDROL injections at specific times. CRESTAR ear implants may also be an alternative to consider.


Used to improve reproductive performance involving non oestrus detection and reduced oestrus detection (Table 1).

Except for two occasions at Alinta, progesterone and prostaglandin programs have provided suitable results. One year, high levels of heat stress reduced submission rates and on another occasion 3 day sickness reduced conception rates with heifers.

From our experience it is considered that a modern synchronisation program must include the following points:

  • Reliability to achieve suitable conception rates in a defined time period.
  • Simple programs and schedules to avoid excess stock handling and herd management complic-ations.
  • Able to be used safely with cycling cows.
  • Has flexibility for re-synchrony if necessary.
  • Intensify symptoms of behavioural oestrus without producing false heats.
  • Be cost effective and practical.
  • With planning can easily fit in with other schedules and farm commitments.

Having conducted several programs, some lessons learnt include:

  • With poor management, conception rates can be low, particularly if the program is run in adverse weather conditions
  • Avoid taking shortcuts.
  • Do not mix approaches and modify treatments.
  • Stick to the right procedures.
  • Good stock identification.
  • Thoroughly plan the job in advance.
  • Have a contingency breeding plan.
  • Keep records and evaluate results – ie. quality control.
  • Early identification of problems prevents disappointments.
  • Importantly, synchron-isation programs and products should be based on the advice and recommendations provided by your veterinarian.

Other Programs:

Whilst both the described prostaglandin and progesterone were fairly simple providing good results, there are newer, more complex synchronisation programs available from your veterinarian. eg OvsynchR program.


Information and advice provided by Dan Jillella and Phil Chamberlain, Veterinary Consultants, Brisbane.