Sexed semen: Interest in sexed semen continues to increase. As a farmer said to me during the week, it’s great to be able to get a heifer calf from your best cows.

That and the fact that more beef straws can be used are probably the main benefits of sexed semen.

The downside of it is that conception rate is reduced when sexed semen is used. However, there are ways to reduce the impact. These rules must be followed if using sexed semen, otherwise it could be a very costly exercise:

  • Only use in the first 10 days of breeding (so that cows that don’t hold have a chance of going in calf in the first month).
  • Only use on cows that are in good body condition score, are calved 50 to 60 days and have been cycling.
  • Avoid using on cows above fourth lactation and perhaps avoid using on first lactation cows also, as these cows can often be under pressure.
  • Follow the correct AI procedure to the letter of the law. Sexed semen straws must be treated more sensitively than conventional straws. If the AI technician or DIY operator doesn’t have the time or is not willing to do this, then I would seriously reconsider using sexed semen.
  • Sexed Ultra 4M has twice as many sperm cells per straw than alternative sexed semen.
  • The timing of AI is critical with sexed semen. The cow or heifer should be inseminated 14 to 20 hours after the onset of heat. The onset of heat can be trickier to gauge with heifers than with cows. If using once-a-day AI, sexed semen will only be suitable for a portion of the cows due to be served that day.
  • Reseeding: Grass growth rates are hovering between 50kg and 70kg/day on most farms, which is in or around demand, but there is little or no surplus grass available. Some farmers are wondering if it is too risky to take out paddocks for reseeding.

    It is big decision, because when you spray off a field, it’s gone for at least two months. Whether or not you can afford to do so depends on the stocking rate and prospects for growth. If stocked at greater than 3.5 cows/ha on the milking platform, it’s probably risky, as you need a growth rate of 55kg just to meet demand, even with 2kg of nuts being fed.

    Those that are stocked less than this should be safe enough to take land out for reseeding. Keep watching the forecast and act as soon as conditions improve.

    Fertiliser: From now on, applying somewhere in the region of half to one unit of nitrogen per day to grazing ground is sufficient. Higher stocked farms with no clover will need to apply the higher amount, while lower stocked farms with clover will get away with the lesser amount. Those in the middle can get away at 0.75 units/day.

    In practice, this can mean spreading one unit/day on fields with no clover and less on those with clover.

    To know how much to apply, multiply the rotation length by the daily rate – e.g. 0.75 units/day by 21 days is 16 units/ac. This is a lot less than many farmers will be used to, but if the clover is present, you need to make it work for you.