Animal Sacrifice:
It is not their flesh, nor their blood, that reaches Allah; it is your righteousness {piety and spiritual volition} that reaches Him….Their flesh will never reach Allah, nor yet their blood, but your devotion will reach Him (Qur'an 22:37).
The main purpose of allowing Muslims to continue with animal sacrifices was to turn this tradition into an institution of charity. All the verses of the Qur'an Majeed which deal with the subject wind up with the proviso that the meat be fed to the poor, the needy, those who are too modest to beg as well as the mendicants - those who beg openly (The Qur'an, 2:196; 22:28; 35-37).
In some cases, the offerers of the sacrifice are allowed to consume a portion of the meat themselves, while in others the whole of the carcass is to be given in charity. Sacrifice is meant to be an act of worship and thanksgiving to solicit the approbation of God neither in the sense of atonement nor in the sense of transposing one's sins onto a scapegoat; but it is meant to be an act of benevolence (Ihsan) to fulfill a social obligation. After reading the Qur'anic version of sacrifice, there remains no doubt in one's mind that any sacrifice that is allowed to go to waste is a sinful as well as a criminal violation of the Islamic law (shariah). Verses 22:36 and 37 make this proviso abundantly clear."
The Qur'anic injunctions are so exacting on the point of not taking the life of an animal without a justifiable cause (Be-ghair-e-haqqin) that wasting meat, even by offering it to deities and gods is called a devilish act.
"During the early period of Islam the traditional offerings of animals made some sense. Meat was then an important ingredient of human diet and not even a scrap of it was wasted. Today we have made their killing an emptyritual and forgotten the intent."
A learned Muslim scholar, Sheikh Farid Wagdi, says in his Wagdi's Encyclopaedia - Article on Sacrifice that there might come a day when Muslims shall have to substitute the rite of animal sacrifice with other methods of giving alms.
[22:36] The animal offerings are among the rites decreed by GOD for your own good.* You shall mention GOD's name on them while they are standing in line. Once they are offered for sacrifice, you shall eat therefrom and feed the poor and the needy. This is why we subdued them for you, that you may show your appreciation.
Islamic method of Slaughtering animals is better?
http://www.themodernreligion.com/misc/an/an_slaughter.htm
Islam regaring Animals :
http://www.themodernreligion.com/index2.html