A few, very small, Jewish groups support constructing a Third Temple today, but most Jews oppose this, for a variety of reasons.
Most religious Jews feel that the Temple should only be rebuilt in the messianic era, and that it would be presumptuous of people to force God's hand, as it were.
Until then, the cow will be carefully watched to ensure that nothing occurs to invalidate its status.
According to Biblical law, the cow's ashes are used for purification from certain forms of impurity, and is therefore a prerequisite for the renewal of Holy Temple service.
From: RED HEIFER BORN - OPENS WAY FOR THIRD TEMPLE 3/16/97 - Sunday Telegraph (London) According to London's Sunday Telegraph of March 16, 1997, a team of rabbinical experts have confirmed the birth of a red heifer.
Such an animal is necessary for purification of the temple site according to Numbers 19:2-7.
Standing today in the historical location of the Temple is the Dome of the Rock, a Muslim shrine.
The Al-Aqsa Mosque, the third holiest site in Islam, is located just to its south.
Are there other scriptures which confirm that the abomination of desolation happens in the middle of the end-times 7 year period?
Furthermore, there are many ritual impurity constrictions that are difficult to resolve, making the building's construction a practical impossibility.
Additionally, many Jews are against rebuilding the Temple due to the enormously hostile reaction from Muslims that would likely result even were the building to be complementary to those holy to Islam, there would be high suspicion that such a building project would ultimately end with the destruction of these and the rebuilding of the Temple on its original spot.
It has traditionally been assumed that some sort of animal sacrifices would be reinstituted, in accord with the rules in Leviticus and the Talmud.
However there is another opinion, beginning with Maimonides, that God deliberately has moved Jews away from sacrifices towards prayer, as prayer is a higher form of worship.