Question:

When placing a bull with a cow into a breeding pen, how many times should the bull be allowed to service the cow?

 How many services can 1 bull do in a day?

 Answer:

 The research shows no difference in conception rates between 1 or 3 services.  However, 2 services showed improved rates. So let the bull breed each cow twice. 

Semen evaluated bulls with an above average scrotal circumference can perform 5-6 services in a 24 hour period.