I don’t want to nurse this wolf from my breasts
But — gods! – the shepherd makes me.
The wolf will grow — because of me —
To become a fierce beast who will tear me apart:
Grace does not change nature.

From the Loeb Greek Anthology, Book IX, number 47, there entitled, “On a goat that suckled a wolf”.

Greek text and notes for this translation:

Τὸν λύκον ἐξ ἰδίων μαζῶν τρέφω οὐκ ἐθέλουσα,

ἀλλά μ᾿ ἀναγκάζει ποιμένος ἀφροσύνη.

αὐξηθεὶς δ᾿ ὑπ᾿ ἐμοῦ, κατ᾿ ἐμοῦ πάλι θηρίον ἔσται·

ἡ χάρις ἀλλάξαι τὴν φύσιν οὐ δύναται.

 
Τὸν λύκον ἐξ ἰδίων μαζῶν: the wolf, from my own breasts!

Wolf is accusative as the object of the verb: I feed the wolf.

μαζῶν: 2. esp. a womans breast, μαζὸν ἄνεσχε, of Hecuba mourning over Hector, Ib.; παῒς δέ οἱ ἦν ἐπὶ μαζῷ Od.; πρόσεσχε μαστόν, of the mother, Aesch.; of animals, the udder,

H.G. Liddell, A Lexicon: Abridged from Liddell and Scott’s Greek-English Lexicon (Oak Harbor, WA: Logos Research Systems, Inc., 1996), 489.

τρέφω οὐκ ἐθέλουσα: I am feeding not that I am wishing it were so
The participle explains the manner or the emotion with which the main verbal action (feeding) is carried out. See, Wallace, Beyond the Basics, Adverbial Participles, Manner.

ἀλλά μ᾿ ἀναγκάζει ποιμένος: but the shepherd compels me

The ma makes this a complaint with a suppressed oath, O gods! By Zeus!

μά [ᾰ], a Particle used in strong protestations and oaths, followed by acc. of the deity or thing appealed to; in itself neither affirmative nor negative, but made so by prefixing ναί or οὐ, or by the context:—thus,
I. ναὶ μὰ. . , in affirmation, ναὶ μὰ τόδε σκῆπτρον yea by this sceptre, Il.; ναὶ μὰ Δία, ναὶ μὰ τὸν Δία Ar., Plat.
II. οὐ μὰ. . , in negation, οὐ μὰ Ζῆνα, nay, by. . , Il.; οὔ τοι μὰ τοὺς δώδεκα θεούς Ar.
III. in Att. μά is often used alone, mostly in negat. sense μὰ τὸν Ποσειδῶ Eur.:—in answers, when the negation is expressed in the question, οὐκ αὖ μʼ ἐάσεις; Answ. μὰ Δἴ (sc. οὐκ ἐάσω) Ar.
IV. the name of the deity was often suppressed, ναὶ μὰ τόν, οὐ μὰ τόν Plat.
H.G. Liddell, A Lexicon: Abridged from Liddell and Scott’s Greek-English Lexicon (Oak Harbor, WA: Logos Research Systems, Inc., 1996), 483.
αὐξηθεὶς δ᾿ ὑπ᾿ ἐμοῦ,

but it increases/grows up because of me/by means of my agency

Ὑπό with the Genitive
1. Used of Persons (denoting agency)
Mt 4:1 τότε ὁ Ἰησοῦς ἀνήχθη εἰς τὴν ἔρημονὑπὸ τοῦ πνεύματος πειρασθῆναι ὑπὸ τοῦ διαβόλου
“Then Jesus was led away by the Spirit into the desert to be tempted by the devil.”
Gal 1:11 τὸ εὐαγγέλιον τὸ εὐαγγελισθὲν ὑπʼ ἐμοῦ
“the gospel that I preached”

Murray J. Harris, Prepositions and Theology in the Greek New Testament: An Essential Reference Resource for Exegesis (Grand Rapids, MI: Zondervan, 2012), 220.

κατ᾿ ἐμοῦ πάλι θηρίον ἔσται·

Against me fighting a wild beast it shall be

kata with the genitive: An obvious development from the local meaning “down upon” is where κατά expresses the idea of hostile movement directed against someone or something. The opposition involved ranges from a simple accusation laid against someone to aggressive hostility between irreconcilable adversaries.
Murray J. Harris, Prepositions and Theology in the Greek New Testament: An Essential Reference Resource for Exegesis (Grand Rapids, MI: Zondervan, 2012), 154.
πάλη: is wrestling, fighting against

θηρίον: even though a diminutive form, it does not mean a small beast: e.g.,

Revelation 11:7 (ESV)
7 And when they have finished their testimony, the beast that rises from the bottomless pit will make war on them and conquer them and kill them,
ἡ χάρις ἀλλάξαι τὴν φύσιν οὐ δύναται.

Kindness is not able to transform nature

Charis is an interesting word here: It is used in Christian writing as a tt “grace” typically denoting a divine gift or kindness. Here is used more broadly to denote the good done by the goat or ewe to the wolf. By translating it as “grace”, the parable suggests an application — and irony, because the grace of God does transform nature. It also implies the grace vs. nature question in Christian philosophy. I admit that it is probably over translating the word. Kindness would be a safer, though somewhat less interesting choice.