I was curious as when the International year/letter number system started but I could not find a specific year this system for cattle identification was first introduced. However, the system has been in use for several decades. The letters are assigned in sequential order, except for the letters “I”, “O”, “Q”, and “V”, which are not used. The letters “I”, “O”, “Q”, and “V” are not used in the international year/letter numbering system for cattle identification to avoid confusion with numbers and other letters. For instance, the letter “O” could be mistaken for the number “0”, while the letter “I” could be confused with the number “1”.
An example is the letter “F” was assigned to the year 2018, and the first calf born that year was given an animal identification of 1F. Similarly, the letter “L” was assigned to the year 2024, and the 56th calf born that year would be identified as 56M.
Personally I find the year letters extremely useful as I can keep a mental tally when searching out potential herd sires if he is out of a first calf heifer there is potential of her being an outstanding brood cow. A yearling out of a J female in 2024 would be out of a first class heifer for example! One can also glance and see a bull out of a "W" was out of a 14 year old (2009) which is longevity an extremely bankable trait.
