"Book full" is an ambiguous statement these days, for it can mean that a stallion has been booked to anywhere from 40 to 200 mares.
For the Darley-owned stallion Essence of Dubai, who stands at Hartley/DeRenzo Thoroughbreds in Ocala, a full book is about 80 mares, according to Dean DeRenzo of Hartley/DeRenzo.
Essence of Dubai has reached that point.
"As the season goes along, and assuming that everything goes right and the horse is not busy, we could breed him to an additional mare or two, but we're not soliciting mares," DeRenzo said.