Sales of sexed semen are going to peak this year as the new sexing lab in Moorepark operates at full capacity.

Having this lab in Ireland means that the choice and selection of bulls for sexed semen is now much greater than ever before.

It’s a brilliant technology but it carries some risks that should be mitigated against.

1: Use appropriately

Conception rate with sexed semen is lower than conventional semen. On-farm research experiments have shown that sexed semen has an average conception rate of 50%, while conventional semen has a conception rate of 60%.

This difference is narrowed when sexed semen is used on hand-picked cows with a greater chance of conception (see point two).

This also means that sexed semen should only be used in the numbers needed to deliver sufficient replacements for the herd.

2: Cows going in calf

Only use sexed semen in cows that have a good chance of going in calf. These are generally cows which:

  • Have calved more than 50 days and have been seen cycling.
  • Have had an easy calving and have no uterine infections.
  • Have a body condition score greater than three.
  • Are between their first and fourth lactation.
  • Are in good overall health, such as not lame, not had mastitis this lactation and have no other obvious health issues.
  • 3: Get the timing right

    Delaying the timing of AI is an important step in ensuring higher conception rates.

    The optimum time to inseminate with sexed semen is 14 to 20 hours after the onset of heat.

    This means that if using once-a-day AI or even twice-a-day AI it will not be possible to serve all animals that come into heat with sexed semen, even if all other criteria is met.

    4: Handle the straw carefully

    There are fewer viable sperm cells in a sexed semen straw compared to a conventional semen straw so mishandling the straw can have a more detrimental effect than mishandling a conventional AI straw.

    The following protocol should be adopted when using sexed semen:

  • Organise sexed straws into one goblet.
  • Thaw a maximum of two sexed semen straws at a time.
  • Thaw straws at 35°C to 37°C for 45 seconds.
  • Load straws into pre-warmed AI guns and keep guns warm.
  • Deposit semen in uterine body.
  • Complete inseminations within five minutes.
  • 5: Choose a team of bulls

    There is more variation in bull fertility using sexed semen compared to conventional semen.

    By the time the information on bulls is known, it will be too late so the best policy is to use a team of sexed semen bulls to limit any negative impacts the sexing process may have.

    There are some very young bulls available as sexed now and this brings with it even greater risk.