The United States Department of Agriculture has implemented the Animal Disease Traceability program. Each state requires that all cattle leaving the state must have an official tag. If you are selling any animals to the livestock market you should tag the animal prior to leaving your dairy.
Which cattle require official ear tags?
Dairy breed cattle (including cows, bulls, steers, and calves)
Beef breed cattle older than 18 months
Cattle of any age used for rodeos, shows, and exhibitions
You may obtain official tags from your veterinarian or your state Department of Agriculture regional office. An official tag must have the US shield symbol.
US shield symbol required on official animal identification tags.
Pennsylvania Department of Agriculture Region 5 veterinarian Dr. Elizabeth Santini, stated that it would be in the best interest of dairies to tag all calves–including bull calves–leaving the farm with either a metal tag or an RFID tag. Be sure that the tag has the US shield. You do not want to be responsible for any animal that did not originate from your dairy.
It is not a legal requirement in all states for producers to identify their cattle if they are not transporting them across state lines. However, it is in your best interest to place an official metal (or RFID) tag and record that tag number including the back tag number placed by the hauler or market at the time of sale. You lose all control of your animals once they leave the farm. You should do all you can to positively identify your livestock, so they won’t be involved in an erroneous disease or drug residue trace back.
If you have any questions regarding the animal traceability program, contact your regional PDA office or Greg Strait at the Fulton County Extension office (717-485-4111)
Source: Pennsylvania State University