Shavuot is the second of the three habits and falls on the day after the end of the counting of the Omer. It is identified in Judaism with the giving of the Torah and is also called the "holiday of giving the Torah" The holiday was also known as the "harvest festival", since near it was the wheat harvest that was brought as an offering to God.
There is a general prohibition against "eating an animal organ" (part of an animal that has not died)