Avid and Homeagain are the two big brands, although there are others.
The base of the ear is a NONSTANDARD place! The normal place is in the Nu-somethinorother ligament in teh neck on the left side. This is the ligament which holds up the neck and head.
There are some big concerns with microchipping. The two big ones are which frequency (and now where do you put it, if people are putting them in the head), and how can the technology be abused. The previous standard was 125khz. This is standard for small animals, and companion horses. Livestock, and European animals use a different frequency, 132khz. 132 scanners can not read 125 chips, and vica versa. This is very important, since 125 readers were given away to all major officials years ago, so almost everyone has a scanner for these chips. 132 scanners are very rare, most often in the hands of government inspectors since they've mandated that new chips use the 132 frequency. NAIS for some stupid reason decided to use the European technology rather than the type used in the US for decades. ANYWAYS, editorial aside, it is a real problem as far as which do you choose. At the moment, its decided like this:
If you are doing it for NAIS or registration, use a 132khz chip. (I don't know who makes these)
If you are chipping for personal identification, animal recovery, etc, use 125khz. Everyone has a reader, adn they are DIRT cheap to find and purchase. (Homeagain and AVID sell them, I paid $22 for the chip and $25 for lifetime registration)
More info on my website at: http://aztecstables.com/deacon/microchip.htm
or email [email protected]