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Dr Joey Rheinberger

A research project by Joey Rheinberger, University of Melbourne dairy resident at The Vet Group, looked at optimising the use of Ovsynch for fixed time artificial insemination (AI). The size of Australian dairy herds is increasing and a growing number of farmers are relying on fixed time insemination as a management tool for better reproductive performance. This trial was designed in response to an identified reduction in the fertility of the Australian dairy cow, particularly of the Holstein-Friesian breed.

The research project

Ovsynch is a synchronisation program using hormone injections to bring cows into oestrus for fixed time AI. Following speculation that the currently adopted Ovsynch programs are not being used at the optimum time, a research project trial was conducted on a number of local farms using a new Ovsynch program.

The aim of the research project was to ascertain whether or not the new Ovsynch program would improve the conception rate for cattle submitted for AI at the start of the mating period. The project was directed at cattle that were calved for a sufficient amount of time, prior to mating start date and was used as a general program for the herd. Each herd was divided according to ear tag numbers with odd numbers (Group 1) receiving the original Ovsynch program and even numbers (Group 2) receiving the new Ovsynch program.

The results from this research project have been significant and will benefit not only the farmers involved in the trial but will also benefit the industry as a whole.

The Ovsynch programs

The original Ovsynch programs use a single prostaglandin injection on day seven with or without a progesterone device inserted for seven days.

The new Ovsynch program used in the trial includes a second prostaglandin injection on day eight. This second injection of prostaglandin was proposed due to concern that only one injection of prostaglandin may not coincide with atresia of the Corpus Luteum which controls the reproductive cycle and ovulation in the dairy cow.

Ovsynch protocol (progesterone device inserted for 7 d) for Timed-AI in cattle.

The results

The trial was conducted on seasonal and split calving dairy herds, predominantly run on pasture. The conception rate improved by an average of 7% using the modified Ovsynch program in Holstein-Freisian cows. Statistically this was a repeatable result which will have great significance to farmers. In addition the result has generated a great deal of interest with both AI companies and pharmaceutical companies.

The significance of the results

The results of the trial are significant for farmers in the following ways:

  • increased conception rate
  • less programs needed to control reproduction and less straws used per pregnancy
  • farmers involved in the trial have also commented on the management benefits of calving down the herd in a tight pattern

Continued analysis

Joey’s masters project continues until the end of 2017. She will continue to analyse the data to make recommendations to farmers and the industry on how this highly significant modification to the conventional Ovsynch program can be best applied to herds.

Please contact Farm Services for more information on the use of Ovsynch in your herd. Call 1300 838 700