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Steps to improve the likelihood of success with sexed semen

Steps to improve the likelihood of success with sexed semen

Sexed semen provides many potential advantages to dairy farmers. The most obvious reason to use sexed semen is the sex bias induced in the calf crop, with 90% of the pregnancies resulting in a heifer birth and only 10% male dairy calves.

Producing more heifers through sexed semen usage means that more high Dairy Beef Index sires can be used, thus providing long term sustainability for the Irish dairy industry.

Some of the key factors that affect the likelihood of pregnancy establishment when using sexed semen have been identified. These are included below.

Guidelines for sexed semen usage

Bull team

  • Pick the highest EBI bulls available;
  • Use a team of ≥5 bulls.

Suitable dams


  • Target liveweight and BCS ≥3.25;
  • Cycling regularly.


  • Parity 1 to 4;
  • >50 days in milk on day of AI;
  • BCS ≥3.00;
  • Cycling regularly;
  • Free of postpartum disorders and uterine disease.

When to use?

  • During the first three weeks of the breeding season, and within first 10 days if possible;
  • 14 to 20 hour after heat onset (first standing mount). Practice AM/PM rule if possible. If using once a day AI, use conventional semen if time of AI is <14 h after heat onset.

Timing of AI

Fixed time AI

  • Costly, but mitigates risk;
  • Facilitates targeted usage of sexed semen on mating start date.

Straw handling on day of AI

  • Organise sexed straws into one goblet;
  • Thaw two sexed semen straws at a time MAX;
  • Thaw straws at 35 to 37°C for 45 seconds;
  • Load straws into pre-warmed AI guns, keep warm;
  • Deposit semen in uterine body;
  • Complete inseminations within five minutes.

Dr Stephen Butler offers key advice on the use of sexed semen in the below video:

Also read: How many sexed semen straws do I need to use?

Also read: Weigh heifers before opting for sexed semen