The Colts began their season at Reliant Stadium in an AFC South duel against the Houston Texans.  Indianapolis started the season going 3-and-out on their first offensive possession of the new year.  The Texans got good field position with a big punt return from Jacoby Jones to set up a 30-yard field goal to give them a 3-0 lead. The offense continued to struggle throughout the first half, getting two first downs on the next drive, however, eventually having to punt.  The Texans continued to show energy on both offense and defense by scoring two more time, a field goal and a touchdown, giving the Texans a 13-0 lead halfway through the second quarter.  The Colts eventually got the offense going late in the second quarter by scoring on a touchdown reception by Reggie Wayne, which broke the lead down to one possession. Adam Vinatieri made a 20-yard field goal at the end of the first half and the Colts went into the half trailing 13-10. The momentum was seemingly shifting to Indianapolis, until Houston took almost eight minutes off the third quarter clock on a 15-play drive, 13 rushes, that resulted in one of Arian Foster's rushing touchdowns on the day to give Houston a 20-10 lead. Peyton Manning and the offense struggled throughout the third quarter with missed opportunities and continued to shoot themselves in the foot with penalties.  With the start of the fourth quarter Houston scored another touchdown and broke the game open.  The Colts would eventually score two touchdowns late in the game, only when there was no chance of a comeback. With the final score 34-24, the Colts were 0-1 to start a season for the first time since 2008, when they lost to the Chicago Bears.

Answer this question based on the article: How many touchdowns were scored during the first half?
2