שולחן ערוך אורח חיים · סימן תס״ט

English

It is prohibited to say over any cattle, whether living or slaughtered, "this meat is for Passover" due to the fact that one appears to be consecrating his animal as his Paschal lamb, and he thereby eats consecrated items outside the permitted area. Rather, one may say "this meat is for the Festival". Note: and it is prohibited to roast a kid whole (—with its head, its legs and its entrails at its side) even when one does not specify "this meat is for Passover". However, [with regard to wheat] one may say "this wheat is for Passover".