Bechorot 21 - A Goat With Three Daughters
If a young goat gave birth to triplet daughters, and each of her daughters gave birth to three daughters, then we have twelve goats born within a year. For example, the triplet daughter goats may be born on the first of Elul, and after six months each daughter conceived. Five months later, before the next Elul, each of the triplet herself bore triplet, and since the accounting for tithe goes from Elul to Elul, and there were at least ten of them, the whole family goes into the same pen for tithing. Rabbi Shimon says, "I myself saw a progeny of a single goat tithed within her first year."
What is Rabbi Shimon saying differently? There are a few possible explanations. (1) The three sister goats miscarried on the last day of the sixth months, and the argument is whether a goat then refuses to mate for the next thirty days; (2) Again, they miscarried, but the argument is can a goat bear young before five months; (3) They agree that the goat needs five full months, but they argue whether a part of the day is considered as complete day; (4) They argue if a premature animal is tithed.
Art: Jakob Philippe Hackert - Italian Landscape With A Goat And Her Kid