Be sure of what you say. Do you mean to say that sale of beef and eating beef is unconstitutional. Where it is written. In North East India, beef is the main source of protein.
Secondy directive principles have no value when it comes to their enforcement. Read this;
The provisions contained in this Part shall not be enforceable by any court, but the principles therein laid down are nevertheless fundamental in the governance of the country and it shall be the duty of the State to apply these principles in making laws.
48. Organisation of agriculture and animal husbandry.—The State shall endeavour to organise agriculture and animal husbandry on modern and scientific lines and shall, in particular, take steps for preserving and improving the breeds, and prohibiting the slaughter, of cows and calves and other milch and draught cattle