Why use Sexed Semen?
With advances in the technology of sexed semen production and the current prices available for dairy bred bull calves, sexed semen is seen as a viable option for many farmers to reduce the number of dairy bred bull calves being born on the farm and target production of replacement heifers from the better performing bloodlines in the herd.
When using sexed semen first of all it is important to consider which bulls to select, choose high genetic merit bulls that fit in with the breeding objectives of the herd, note there may not be as wide a range of sexed bulls available versus conventional. Select a team of bulls to spread the risk of any fertility issues with any one bull.
Secondly consider the females you plan to target sexed semen towards. If your breeding plan is working, then your heifers will have the best genetic merit of all the females in the herd, the greatest improvement can be achieved by using sexed semen on these heifers. Select heifers with the best likelihood for good fertility based on their mother’s performance and EBI figures, they should also have reached their target liveweight for breeding and be cycling regularly
If you plan to use sexed semen on cows the same principles apply, choose the most fertile cows that are in their 1st-4th parity, cows should be cycling and free from uterine infections or other illness and have a BCS ≥3.00
Picking cows that calve early in the season means the resulting heifers will be born early in the following year giving them the best chance to reach target breeding weights down the line, these cows are also typically the most fertile.
Achieving Good Conception Rates
Achieving high conception rates while using sexed semen has traditionally been more difficult than when using conventional semen, but with some attention to detail and by following best practice good conception rates can be achieved.
As mentioned above the first step is only selecting the most fertile females to use sexed semen on.
Timing of AI is crucial when using sexed semen, the sexing process causes some damage to the sperm cells and hence the viability of this sperm in the reproductive tract is reduced to just <12 hours as opposed to <24 hours for conventional sperm. It is advisable to AI 14-20 hours after the onset of standing heat when using sexed semen to give the best chance for fertilisation to take place. Accurate heat detection and identifying the time standing heat is key to avoid inseminating too early or too late
Finally handling of straws is important, the objective is to minimize the time from the removal of the straw from the goblet to the deposition of the straws in the cow's uterus. Thaw straws for 45 seconds at 35-37% and use a preheated gun, avoid delay of insemination once the straw is loaded in the gun < 5mins if possible.
For further advice on any of the above, please contact a member of the Moocall team to speak to some of our breeding specialists on +353 1 96 96 038 or email firstname.lastname@example.org
Learn more about Moocall HEAT here: https://moocall.com/pages/moocall-heat-information