According to CAFRE, sexed semen technology has been constantly evolving over recent years, and its use in Northern Ireland dairy herds has “increased rapidly” as a result.
Relative conception rates (compared to conventional semen) have been claimed to be around 90%.
Thus, if the conception rate to conventional semen is 40%, the conception rate for sexed would be 36%.
A Teagasc trial previously found that a small number of herds actually achieved better conception rates with sexed semen than conventional.
Some of the main points around achieving better conception rates with sexed semen are as follows:
- Sexed semen should be thawed and handled more carefully;
- One straw of semen should be utilised at a time if there are multiple animals to be served – read, how many sexed semen straws will I need?
- The use of sexed semen on known problem breeders or cows that have had difficult calvings should be avoided;
- Animals to be bred should be restrained before thawing of semen;
- Sexed semen performs better when used around 18 hours after oestrus (peak heat), compared to about 12 hours for conventional semen;
- Heat detection monitors are now installed on many farms, and these can help to better predict the optimal timing of AI with sexed semen;
- The use of sexed semen should be prioritised on maiden heifers as these animals will be the best genetics in the herd and will have higher conception rates when compared to cows.
Sexed semen technology
According to CAFRE, sexed semen has the potential to produce a larger number of heifers in a herd when compared to using conventional semen.
Dairy farmers should have a clear plan for cow numbers on their farm and only produce the number of replacements that they require. This will avoid a large number of unproductive stock on the farm.
Cows not intended for breeding replacements can be bred to beef semen. The use of mixed sire beef semen has, according to the body, the potential to improve conception rates by 6-9% when compared to conventional semen.
This should allow the overall herd conception rate (including sexed and mixed beef) to average out close to the use of conventional semen across the entire herd.
More expensive & lower conception rates
A spokesperson commented: “Sexed semen is generally more expensive than conventional.”
“This, coupled with a lower conception rate, will be an extra cost for the dairy herd.”
“The reduced number of unwanted Holstein bull calves on farm is one of the main benefits for sexed semen – especially when their value is compared to beef calves from the dairy herd.”
“The dairy farm will thus have more beef calves to sell, and this should more than offset the additional costs associated with sexed semen.”
If a large proportion of maiden heifers are bred to sexed, this will also speed up genetic progress in the herd, CAFRE added.
Breeding the best animals in the herd to the best bulls has “always been the route” to the most rapid genetic progress.
And according to CAFRE, sexed semen is now “a more reliable” tool to allow dairy farmers to do this.
In another post, Teagasc looked at three consequences of increased sexed semen use in dairy herds, which you can read via this link.