Sexed semen is proving to be a useful tool for dairy farmers in the business of breeding replacement heifers.
While it is a useful management tool in reducing the numbers of lower-value dairyXdairy male calves, using sexed semen correctly is of the utmost importance as there can be lower conception rates when using it and correct female selection is priority when allocating straws.
Before deciding on the use of sexed semen, it should be discussed with the herds’ breeding advisor if the herd is suitable and if suitable, what cows/heifers would be most eligible.
In some cases, the fertility performance of the herd may not be high enough to justify the use of sexed semen.
According to the Irish Cattle Breeding Federation (ICBF), sexed semen should be preferentially used on heifers.
Breeding future replacement heifers from your heifers will naturally result in the quickest rates of genetic gain.
Heifers also have ‘a clean slate’ in terms of health and calving related issues, are the most fertile and can have the best conception rates when sexed semen is used correctly.
Where cows are being selected for sexed semen use, farmers should ensure they are:
- Calved 60+ days by the start of breeding;
- Clean bill of health – no health issues in the past number of years;
- Always in calf after one serve;
- A calving interval (close to 365 days);
- High genetic merit.
Once the heifers/cows have been identified for breeding replacements, the ICBF are advising farmers to use high Dairy-Beef Index (DBI) beef bulls on their remaining dairy cows and heifers.
As well as selecting a bull with a high DBI, it is also important to use beef bulls with high carcass merit. ICBF recommends that beef sires used have a minimum beef sub index of €90+.
Farmers should first identify the level of calving difficulty they are comfortable with, and from there choose the highest beef sub index available to them.