Let me clarify whether the Jallikattu ordinance promulgated by the Governor of Tamil Nadu, on behalf of the State Government of Tamil Nadu is a permanent relief.
Since the subject matter of the issue “Prevention of cruelty to animals” falls within the concurrent list (i.e.) Entry 17 of the List III to the VIIth Schedule of the Constitution of India, both the Parliament and the State Legislature are empowered to make law in relation to this subject.
So what if any part of the law made by the Legislature of a State is incompatible to any part of a law made by Parliament? 
Whether the law by the Parliament is passed before or after the law made by the Legislature of such State, the law made by Parliament prevails. The law made by the Legislature of the State, to the extent of the repugnancy, is void. This is the Doctrine of Repugnancy.
But to protect the State Legislature, Constitution of India in Article 254 Clause 2, provides that, 
Where a law made by the Legislature of a State [in this case the Jallikattu ordinance promulgated] with respect to one of the matters enumerated in the concurrent List contains any provision repugnant to the provisions of an earlier law made by Parliament or an existing law with respect to that matter [in this case The Prevention of Cruelty to Animals Act, 1960 (Act 59 Of 1960)], then, the law so made by the Legislature of such State shall, 
  • If it has been reserved for the consideration of the President and has received his assent, prevail in that State.
  • And nothing in this clause shall prevent Parliament from enacting at any time any law with respect to the same matter including a law adding to, amending, varying or repealing the law so made by the Legislature of the State.
Since the President has given accent to the Ordinance, it can override the provisions of ‘The Prevention of Cruelty to Animals Act, 1960’ which prohibits the use of Bulls for Jallikattu.
But does an Ordinance have the same effect as a law passed by the State Legislative Assembly? 
Article 213 of Constitution of India, affirms that “An Ordinance promulgated under this article shall have the same force and effect as an Act of the Legislature of the State assented to by the Governor”.
The provided clause to Article 213 of Constitution of India, Provides that,
for the purposes of the provisions of this Constitution relating to the effect of an Act of the Legislature of a State [in this case the Jallikattu ordinance promulgated] which is repugnant to an Act of Parliament or an existing law with respect to a matter enumerated in the Concurrent List [in this case The Prevention of Cruelty to Animals Act, 1960 (Act 59 of 1960)], an Ordinance promulgated under this article in pursuance of instructions from the President shall be deemed to be an Act of the Legislature of the State which has been reserved for the consideration of the President and assented to by him.
In simple words, an Ordinance, in pursuance of instructions from the President, has the same effect as an Act of the Legislature of the State, if it has been given assent by the President of India.
Is The Ordinance Permanent?
But Article 213 further provides that, every such Ordinance:
  • Shall be laid before the Legislative Assembly of the State, within a period of six weeks, 
  • The ordinance shall cease to operate at the expiration of six weeks from the reassembly of the Legislature, or if before the expiration of that period a resolution disapproving it is passed by the Legislative Assembly.
So, the Ordinance makes Jallikattu legal for only 6 weeks, after which the State Assembly of Tamil Nadu must pass a law to approve it.
What is required to make Jallikattu permanently legal?
a law made by the State Legislature on a subject covered by the Concurrent List is inconsistent with and repugnant to a previous law made by Parliament, then such a law can be protected by obtaining the assent of the President under Article 254(2) of the Constitution. The result of obtaining the assent of the President would be that so far as the State Act is concerned, it will prevail in the State and overrule the provisions of the Central Act in their applicability to the State only. Such a state of affairs will exist only until Parliament may at any time make a law adding to, or amending, varying or repealing the law made by the State Legislature under the proviso to Article 254."
The ordinance promulgated by the Governor of Tamil Nadu, is perfectly valid, and has all the characteristics equivalent to that of the Legislation enacted by the Tamil Nadu State Legislature. But it is only an immediate relief. The only drawback is the 6 weeks validity period. So the ordinance can be regarded as incomplete remedy in a long run. 
If the Tamil Nadu State Legislature passes a legislation, then it would qualify as a relief without expiry date, which the Chief Minister has promised. Then again, nothing shall ever prevent Parliament from enacting at any time, any law with respect to the same matter including a law adding to, amending, varying or repealing the law so made by the Legislature of the State.
Thus, in my legal opinion, there is no such thing as permanent relief. Only if the Tamil Nadu State Government enacts this ordinance as a Legislation and the Central Government accepts it, can provide Jallikattu be permanently legal.