Just and FYI... there are 2 collegiate equestrian programs. The NCEA (National Collegiate Equestrian Association) is the program that Texas A&M competes in. It was formed to equalize the competative nature of showing, where riders compete heads up on one horse. This format also invites only "Open" level riders for the most part. In the Big 12 that includes Baylor, Kansas State and Oklahoma State. In the SEC, you have Georgia, Auburn and South Carolina. This was the competition format that Texas A&M elected to follow. TCU also competes in the NCEA format, so there will still be 4 teams in the Big 12, when A&M moves to the SEC.
There are over 370 universities that compete in IHSA (Intercollegiate Horse Show Association). This format has its downfall, but adds a nice feature that NCEA does not promote. In the IHSA format, each rider competes on a horse, which is not competed on by another rider in that level of competition. If you draw a bad horse, then there is no heads up for another rider to have that same bad horse. This does not allow for the judges to completely judge the rider's abilities. The nice thing about the IHSA format, is that there are levels of competition. Back when my wife was on the team, there was a Beginner, Intermediate I, Intermediate II, Novice, Advanced and Open level. This allowed different skill level of riders to compete. Some other SEC schools that compete in IHSA are LSU, Vanderbilt, Mississippi State, Florida and Kentucky.
With Texas A&M moving to the SEC, this will most likely open up the SEC to holding an SEC Championship match comparatively to what they do in the Big 12 a few weeks before the National Championships. It really needs to have 4 schools to hold a good Conference Championship.
The hope is that many more of the IHSA schools will move to the NCEA format and clear the way for a more defined national presence in collegiate athletics.