Slaughter in the Desert

The Torah forbade slaughtering cattle and flock in the desert other than in the Mishkan for the purpose of a korban (Vayikra 17:3-7). The commentators and indeed the Tannaim, centuries before them, disputed the question of how broad and long-lasting this prohibition was (see Chulin 16b). According to Rabbi Yishmael (accepted by the Ramban) there was a special prohibition in the desert not to eat any meat other than in the framework of a korban. Thus, these p’sukim are discussing not only animals consecrated for a korban but also simple animals a person wanted to eat. According to this approach, there was an unusual phenomenon. The Torah (Devarim 12:20-22), on the eve of the entry to Eretz Yisrael, lifted the prohibition and allowed non-sanctified animals to be slaughtered outside the Mikdash. According to Rabbi Akiva (accepted by Rashi), there was no prohibition of the slaughter for normal consumption of non-sanctified animals. Rather, our p’sukim are referring to animals that were sanctified for korbanot, which must be done in the Mikdash.
There are also differences of opinion as to the reason behind the prohibition. The Rambam (Moreh Nevuchim III:46) says that the prohibition was to counter certain ceremonies of idol worship. The Ramban (as understood by Abarbanel) says that it has to do with the fact that the animal’s blood contains its spirit, and thus it should not be spilled in such a manner. Abarbanel says that each of these reasons applies to a different prohibition. Idol worship is behind the prohibition on slaughtering outside the Mishkan; the soul in the blood is the reason for the prohibition on eating blood.
The Ramban, who says that the p’sukim forbid the slaughter of even non-sanctified animals, explains the rationale of this prohibition being specifically in the desert on practical grounds. In the desert, everyone had easy access to the Mishkan, and so it was reasonable to demand that people would bring a Korban Shelamim, in which they ate the main part of the animal. However, as the Torah stresses in Devarim, when the nation was spread out throughout the Land, the Torah did not expect people to travel to the Mikdash to eat meat.
Rav Hirsch has a philosophical approach to the problem of slaughtering and eating animals in the desert specifically, which picks up on the Torah’s mention of both the practice of slaughtering to the se’irim (Vayikra 17:5) and the spilling of blood (ibid. 4). In the wilderness, what was done "in the field" connected a person to an animalistic state. The spilling of the blood the Torah rejects was not that of the animal, but of the person who might connect to the spirit of the animal he ate in the wilderness. Rather, one had to partake in the eating of the meat in a manner that brought him closer to Hashem, through a Korban Shelamim, not in a way that made him closer to an animal.
Until the day (which we pray is soon) that we will once again be able to bring korbanot, let us concentrate on ensuring that our day-to-day activities, including eating meat, are done in a manner that complements our designation as "a holy nation."