Translation:Mishnah/Seder Nezikin/Tractate Avodah Zarah/Chapter 1/6

English Translation
 A place in which one is accustomed to selling small cattle to gentiles, one can sell. A place that one is not accustomed to selling, one cannot sell. And in every place it is forbidden to sell large (literal translation: coarse,rough) cattle, calves, and foals, complete, or lame. (Literal translation: broken, fractured) Rabbi Yehuda permits in the case of a lame one. Ben Beterah permits in the case of a horse. 

Explanation
עבודה זרה פרק א משנה ו