Without good oestrus detection, it does not matter how good an inseminator is; cows just will not conceive.
Cows ovulate approximately 24 to 30 hours after the beginning of oestrus or 12 -14 hours after the end of oestrus. However, semen must be deposited in the female reproductive tract several hours before ovulation to insure high conception rates. Cows remain in oestrus for 8 - 16 hours.
The average life span of an ovum (egg) in the female reproductive tract is about 8-12 hours. The life span of sperm in the reproductive tract is about 30 - 48 hours. Therefore, it is better to inseminate too early rather than too late. However, on time is the best.
Breed 12 hours after you first see the cow in heat.
Follow the old a.m. - p.m. rule - If in heat in the morning before noon, breed the cow that p.m. In heat in the afternoon or evening, breed the next morning.
Cows should be checked at least twice a day at dawn and dusk!
This will catch 80-90 % of the cows that show heat. Additional heat checks will increase the number of cows you find in heat.
TRY NOT to check heat on cows at feeding time. When eating, cows are not interested in expressing oestrus.
Remember that you are losing financially for every day the cow is empty!