The following table indicates the letter on International Yak Association ear tags and the animal's birth year. C tags include animals born before 1993. The ear tags follow this pattern, X### where the Alpha character indicates the birth year and the number are generated sequentially. For example M080 was the 80th yak registered that was born in 2003. (Thanks to Bob Hasse for clarity)
| C | D | E | ||
| 1993 | 1994 | 1995 | ||
| F | G | H | I | J |
| 1996 | 1997 | 1998 | 1999 | 2000 |
| K | L | M | N | O |
| 2001 | 2002 | 2003 | 2004 | 2005 |
| P | Q | R | S | T |
| 2006 | 2007 | 2008 | 2009 | 2010 |
| U | V | W | X | Y |
| 2011 | 2012 | 2013 | 2014 | 2015 |
| Z | ||||
| 2016 |
