As we learned on yesterday’s daf, according to Rabbi Yehuda, beyond cutting the esophagus and trachea, sheḥita – ritual slaughter – also requires severing the veins in the neck. On today’s daf, Rav Ḥisda limits Rabbi Yehuda’s teaching to sheḥita performed on a bird, since a bird is often roasted whole. Larger animals, however, that are invariably cut into pieces, do not need to have their veins severed.
The Gemara concludes from this that Rabbi Yehuda’s ruling is not connected with sheḥita per se, so much as it is a response to a potential problem with blood becoming congealed in the body of the animal. Therefore, it is not essential that the veins be cut during the act of ritual slaughter, in fact it is sufficient if they are punctured after slaughter, as well. Furthermore, the rishonim point out that if the veins were not cut during slaughter or punctured after slaughter, nevertheless the bird would still be kosher; it would just have to be cut up, rather than roasted whole, so that the blood would have an opportunity to drain out of the meat.
The term used by Rabbi Yehuda for veins is veridim – a word that does not appear in biblical Hebrew at all – that refers to the major blood vessels in the neck. The distinction that is made today between veins – the vessels that carry deoxygenated blood from the rest of the body to the heart – and arteries that carry oxygenated blood from the heart to the rest of the body, is a modern concept that was unknown in the time of the Gemara. The Arukh haShulḥan rules that Rabbi Yehuda requires that the large veins in the neck near the skin be cut, but most of the poskim, following the Rambam in his Commentary to the Mishna, argue that the reference is to the two arteries that are deeper in the neck, behind the esophagus and the trachea.