Kottaras beat Rangers reliever Robbie Ross on Saturday for the second straight year in Texas. The team recognized the state's dairy farmers before the game.
The event was held in foul territory down the left-field line, and Ross got off to a good start. But then his cow kicked over the bucket and his early lead trickled away.
Ross was crying over the spilt milk.
"I cannot believe that happened," he said. "I was cruising, too."
Kottaras had never milked a cow before last year, when he came through Arlington while with the Kansas City Royals. He said he hadn't done any milking since last year's win.
"It wasn't the way I wanted, but I'll take it," he said after his latest victory.