During the Second Temple period, the Sages saw that goats and sheep sent out to pasture were causing widespread damage to trees and fields, threatening Jewish farmers’ ability to make a living and continue settling the Land. To protect both agriculture and the settlement of the Land, they enacted that small livestock may not be raised west of the Jordan River. “Small livestock” refers to sheep and goats. Because they are nimble, they can reach almost anywhere and graze from nearly any tree or plant, making them the main cause of damage to vegetation. Later history showed the importance of this enactment. After the Arab conquest of the Land, the conquerors were not careful to preserve its vegetation, and their herds destroyed the plant life, turning the Land that had flowed with milk and honey into desolation.
Large livestock, namely oxen and cows, can also damage trees. Nevertheless, the Sages did not prohibit raising them, because they do not impose a decree on the public unless most people can abide by it. Since oxen and cows are needed for plowing, milk, and meat, are difficult to bring from outside the Land over long distances, and cause less damage, the Sages permitted raising them in the Land. Their owners must still guard them carefully, and if the animals damage fields, the owners must pay for the damage.
Small livestock, by contrast, can be brought from outside the Land, since sheep and goats are capable of walking long distances. The Sages therefore decreed that they may not be raised in the settled areas of the Land. They may be raised only in the deserts and forests of Eretz Yisrael, east of the Jordan River, and in countries near Eretz Yisrael. One who wishes to buy small livestock for meat for a festival or wedding may buy it and keep it for up to thirty days, provided that it is not taken out to graze; rather, he must bring it its food. Meat sellers may likewise bring in small livestock for sale, provided they do not keep them for more than thirty days and do not let them graze in fields or gardens (Bava Kama 79b–80a; MT, Laws of Damage to Property 5:2, 7). [12]
[12]. The Gemara relates (Bava Kama 80a) the story of a pious man who was ill and groaning from heart pain. When the doctors were consulted, they said that there was no remedy for him unless he drank warm milk directly from an animal’s udder each morning. They brought him a goat and tied it to the legs of his bed so that it could not go out and cause damage, and each morning he would drink its milk. Some time later, his colleagues, the Sages of Israel, came to visit him. When they saw the goat tied to his bedposts, they immediately turned back and said: “An armed robber is in this man’s house, and we should enter?” According to most commentators, this pious man was suffering from a non-life-threatening illness; had his illness been dangerous, he would have been permitted to keep the goat. Ben Ish Ḥai explains in Ben Yehoyada that even an ordinary sick person would have been permitted to keep a goat tied to his bed, since the Sages permitted one who is ill to violate a rabbinic prohibition. However, because this pious man was known as a great person, he should have been especially careful so that others would not learn from him to be lenient. That is why the Sages were strict with him. Indeed, at the time of his death, this pious man himself acknowledged this and said: “I know that I have only the sin of that goat, for I violated the words of my colleagues.”
The main reason for the enactment is the settlement of the Land (Rashi). Therefore, the concern is not only that small livestock might damage other people’s property, but also that they might damage their owners’ own fields (Tosafot Yom Tov and Tiferet Yisrael, Bava Kama 7:7). Kaftor Va-feraḥ 10 adds that the prohibition applies even when there are no Jewish-owned fields at all, due to the damage these animals cause to wild vegetation. SA ḤM 409:1, however, rules that the prohibition applies only where there is Jewish settlement. Although the enactment was primarily for the sake of settling the Land, after Rav moved to Babylonia he instituted the same rule in the Jewish communities there: small livestock may not be raised near settled areas (Bava Kama 80a; MT, Laws of Damage to Property 5:8).
