I use the Destron Fearing tag system and have found the only two my cattle have lost in the past couple years have been due to the use of one particular round bale hay feed ring.  This particular ring that seems to cause eartag loss has bent Zee shaped neck rails. 

My other types of bale feeders (I have 5 different types) including a similar ring with straight (not Zee) diagonal neck bars do not seem to cause eartag loss like the one with the Zee shaped neck bars.  So my conclusion from this is that eartag retention is more of a function of type of bale feeder than anything else. Probably has a lot to do with how/where the tags are inserted in the ear also.

I am switching to an RFID button system to help me in frequent weighings. I do not see RFID as a government plot,  I am doing it because it seems to make my life easier and any cattle I do sell at various sales should bring a premium for age and source verification. This is because more premium buyers want to know where their cattle are coming from, not a government plot.

I am using a Destron Fearing 2-piece system on retained animals with a yellow preprinted visual tag in the left ear and a matching RFID button in the right ear. Both have the 840 number on them. The right ear is closest to me in my alley/scale/chute system and easiest to read with the wand as they are on the scale.  It seems like it would be unlikely to lose both button and visual tag, especially once I do a better job of installing the buttons deeper in the ear next time.

On animals not likely to be retained they get a Destron Fearing one piece white combination RFID/blank tag where I write the animal's number on it (cow number plus the year letter - 2011 calves are "Y") and the first time through the scale I enter the visual tag number (such as "66Y"), read the rfid tag, press "record" on the scale indicator and the visual and rfid numbers are then associated with each other for the future and saved with the current weight. I'm just getting started with RFID but so far it looks like it will do what I want it to do.

I see a lot of folks use the Z tag system. They must have an rfid version also?  I think RFID makes sense - sort of like going from a pencil and paper system to computerization of records. Just an evolution of technology - not a government plot!  jmho.

Jim at Dawn

edit: I see Z tags do offer an RFID tag also.