Yoreh Deah Siman 23 Seif 4

 

ד הַשּׁוֹחֵט בְּהֵמָה בְּסַכִּין שֶׁאֵינוֹ חַד, וְנִתְעַכֵּב כְּשִׁעוּר שְׁהִיָּה בִּשְׁחִיטַת מִעוּט אַחֲרוֹן שֶׁל סִימָן רִאשׁוֹן, הֲרֵי זוֹ פְּסוּלָה.

 

Seif 4

If one slaughters cattle with a knife that is not sharp and delays in the measure of “shehiyah” in his slaughter a little after [cutting] the first sign, it is not acceptable.