A very nice question PeeWee!! It seems with all the "shorthand" cattleman use, many that are breed specific, we need to remember to either spell it out, or have a glossery of terms!!
OCV = official calfhood vaccinate = female was vaccinated for Bang's (brucellosis) - you can look in her ear and the tattoo will tell you what vaccine was used and the year she was vaccinated, ie RV8 means the RB51 vaccine was used in 2008. The other vaccine is strain 19 and I don't think it is used much any more. Each state can determine when the female can be vaccinated - in MI it is btwn 4 and 8 months. Federal law states they can't be vaccinated older than 12 months without permission. Some states require vaccination and a legible tattoo for importation - the orange metal USDA tag is also used to signify the female has been vaccinated