The number in the right ear is the dog's birthday. This says that Baley was born September of 1994. The first number is the month (9=Sep. 12=Dec, ect...). The second is the last digit of the year (4=1994, 1=1991 or 2001). The letter is used with in a litter (A is the fist dog in a litter, D would be the fourth).
This is Baley's racing number. This number is diffrent for every Greyhound and must be registered by the time the dog is 3 months old with the American Greyhound Association if the dog is going to be allowed to race.