Sexed semen was initially designed for use on maiden heifers but over the past few years it has proven extremely successful when used on cows. It is essential when selecting cows to serve to sexed semen that she is good condition and has good fertility history. Cows that have had mastitis, held cleansings, are lameness or bad health should not be served with sexed semen.
Sexed semen is not recommended for use with synchronisation programmes where heifers or cows are bred using fixed time insemination.
From at least a month before the service period the aim is to get heifers & cows settled and in a stress free condition.
Cows milking heavily and losing condition are less likely to get in calf. Settle the animals onto a consistent diet, nutritionally balanced for energy, protein and minerals preferably on a rising plane of nutrition.
Do not make diet changes for one month before or after the service period.
Heifers should be moved into easily handled groups. Large groups can be difficult to handle and can cause stress. This also makes it easier to spot heats. Observing heats is very important and we suggest the it is done 3 times a day for 15 minutes. Results have shown for best conception rates serving 12 hours after the onset of a standing heat. Insemination should be as stress free as possible for the animal.
Handling Sexed Semen
1. Attention to detail is essential when handling sexed semen.
2. Use tweezers, never fingers to handle straws.
3. Never take out an individual straw to look at and then put back. It will almost certainly damage the sperm.
4. Check the temperature of the water in your thawing device with a thermometer.
5. Flick the straw to remove any trapped nitrogen.
6. Thaw the straw straight away at 37°C for 40 seconds.
7. Thoroughly dry the straw, water kills sperm.
8. Use clean straw cutters, or sharp scissors to cut off the sealed end.
9. Once thawed don't let the straw cool down again.
10. Pre-warm the AI equipment and keep it insulated until the insemination (especially in cold weather).
11. Animals should be inseminated within 5 minutes of removing from the tank.
12. Once thawed, straws cannot be re-frozen.
13. Do not split straws.