Which encyclical talks about the Mass as a sacrifice?

Chapter 1 of the 22nd Session of the Council of Trent directly states that the sacrifice of Christ on the Cross, which is re-presented in the Mass, replaces the Levitical priesthood (that is the sacrifices of the Old Testament in the temple) as well as "various types of sacrifices, during the period of nature, and of the law," so not just the Jewish temple sacrifices, but also, e.g. the sacrifice of Melchizedek is a prefigurement of the Sacrifice of Christ in the Mass.

CHAPTER I.

On the institution of the most holy Sacrifice of the Mass.

Forasmuch as, under the former Testament, according to the testimony of the Apostle Paul, there was no perfection, because of the weakness of the Levitical priesthood; there was need, God, the Father of mercies, so ordaining, that another priest should rise, according to the order of Melchisedech, our Lord Jesus Christ, who might consummate, and lead to what is perfect, as many as were to be sanctified. He, therefore, our God and Lord, though He was about to offer Himself once on the altar of the cross unto God the Father, by means of his death, there to operate an eternal redemption; nevertheless, because that His priesthood was not to be extinguished by His death, in the last supper, on the night in which He was betrayed,--that He might leave, to His own beloved Spouse the Church, a visible sacrifice, such as the nature of man requires, whereby that bloody sacrifice, once to be accomplished on the cross, might be represented, and the memory thereof remain even unto the end of the world, and its salutary virtue be applied to the remission of those sins which we daily commit,--declaring Himself constituted a priest for ever, according to the order of Melchisedech, He offered up to God the Father His own body and blood under the species of bread and wine; and, under the symbols of those same things, He delivered (His own body and blood) to be received by His apostles, whom He then constituted priests of the New Testament; and by those words, Do this in commemoration of me, He commanded them and their successors in the priesthood, to offer (them); even as the Catholic Church has always understood and taught.

For, having celebrated the ancient Passover, which the multitude of the children of Israel immolated in memory of their going out of Egypt, He instituted the new Passover, (to wit) Himself to be immolated, under visible signs, by the Church through (the ministry of) priests, in memory of His own passage from this world unto the Father, when by the effusion of His own blood He redeemed us, and delivered us from the power of darkness, and translated us into his kingdom. And this is indeed that clean oblation, which cannot be defiled by any unworthiness, or malice of those that offer (it); which the Lord foretold by Malachias was to be offered in every place, clean to his name, which was to be great amongst the Gentiles; and which the apostle Paul, writing to the Corinthians, has not obscurely indicated, when he says, that they who are defiled by the participation of the table of devils, cannot be partakers of the table of the Lord; by the table, meaning in both places the altar. This, in fine, is that oblation which was prefigured by various types of sacrifices, during the period of nature, and of the law; in as much as it comprises all the good things signified by those sacrifices, as being the consummation and perfection of them all.

You can also refer to the Encylical, Mediator Dei of Pope Pius XII, especially at numbers 16-20 (of which the following is a part):

16. Thus we observe that when God institutes the Old Law, He makes provision besides for sacred rites, and determines in exact detail the rules to be observed by His people in rendering Him the worship He ordains. To this end He established various kinds of sacrifice and designated the ceremonies with which they were to be offered to Him. His enactments on all matters relating to the Ark of the Covenant, the Temple and the holy days are minute and clear. He established a sacerdotal tribe with its high priest, selected and described the vestments with which the sacred ministers were to be clothed, and every function in any way pertaining to divine worship.[11] Yet this was nothing more than a faint foreshadowing[12] of the worship which the High Priest of the New Testament was to render to the Father in heaven.

17. No sooner, in fact, "is the Word made flesh"[13] than he shows Himself to the world vested with a priestly office, making to the Eternal Father an act of submission which will continue uninterruptedly as long as He lives: "When He cometh into the world he saith. . . 'behold I come . . . to do Thy Will."[14] This act He was to consummate admirably in the bloody Sacrifice of the Cross: "It is in this will we are sanctified by the oblation of the Body of Jesus Christ once."[15] He plans His active life among men with no other purpose in view. As a child He is presented to the Lord in the Temple. To the Temple He returns as a grown boy, and often afterwards to instruct the people and to pray. He fasts for forty days before beginning His public ministry. His counsel and example summon all to prayer, daily and at night as well. As Teacher of the truth He "enlighteneth every man"[16] to the end that mortals may duly acknowledge the immortal God, "not withdrawing unto perdition, but faithful to the saving of the soul."[17] As Shepherd He watches over His flock, leads it to life-giving pasture, lays down a law that none shall wander from His side, off the straight path He has pointed out, and that all shall lead holy lives imbued with His spirit and moved by His active aid. At the Last Supper He celebrates a new Pasch with solemn rite and ceremonial, and provides for its continuance through the divine institution of the Eucharist. On the morrow, lifted up between heaven and earth, He offers the saving sacrifice of His life, and pours forth, as it were, from His pierced Heart the sacraments destined to impart the treasures of redemption to the souls of men. All this He does with but a single aim: the glory of His Father and man's ever greater sanctification.

Pope Pius XII draws extensively on the Letter of St. Paul to the Hebrews in discussing the Mass as sacrifice.

I would note that it's somewhat broader than how you put it. Christ doesn't exactly take the place of the animal sacrificed on the altar of the Temple, rather the animal sacrificed on the altar of the temple is a prefigurement of Christ's sacrifice on the Cross (and in the Mass), so His sacrifice is something more.