The player can either enter a Cow in the competition or just watch (pregnant or sick cows cannot enter the competition). Winning the competition depends on the cow's level of affection. A cow will win the competition with an affection level of close to 9 hearts or greater. A cow that wins the competition will start to produce Gold milk on a daily basis.
Talking to villagers will raise their affection. Speak to Barley to begin the judging.