Commentary for Avodah Zarah 44:2

בשלמא מוקצה ונעבד אם איתא דאקצייה ואם איתא דפלחיה לא הוה מזבין ליה אלא רובע ונרבע לחוש אמר רב תחליפא אמר רב שילא בר אבינא משמיה דרב עובד כוכבים חס על בהמתו שלא תעקר

Now it makes sense not to fear that it was designated as an offering to idols or made an object of worship, since if it had been so designated or worshipped, its owner would not have sold it; but we should be concerned lest it engaged in bestiality! R. Tahlifa said in the name of R. Shila b. Avina in the name of Rav: A non-Jew would have regard for his cattle, lest it becomes barren.

Daf Shevui to Avodah Zarah