Well, to shear means to cut the hair or wool off, it is not talking about killing the animal. I believe this is telling how Jesus would be silent before his accusers.
Matt 26:62 And the high priest arose, and said unto him,
Answerest thou nothing? what is it which these witness against thee?
63 But Jesus held his peace. And the high priest answered and said unto him, I adjure thee by the living God, that thou tell us whether thou be the Christ, the Son of God.
Matt 27:12 And when he was accused of the chief priests and elders,
he answered nothing.
13 Then said Pilate unto him, Hearest thou not how many things they witness against thee?
14 And he answered him to never a word; insomuch that the governor marvelled greatly.
Mark 14:60 And the high priest stood up in the midst, and asked Jesus, saying,
Answerest thou nothing? what is it which these witness against thee?
61 But he held his peace, and answered nothing. Again the high priest asked him, and said unto him, Art thou the Christ, the Son of the Blessed?
Mark 15:4 And Pilate asked him again, saying,
Answerest thou nothing? behold how many things they witness against thee.
5 But Jesus yet answered nothing; so that Pilate marvelled.
Luke 23:8 And when Herod saw Jesus, he was exceeding glad: for he was desirous to see him of a long season, because he had heard many things of him; and he hoped to have seen some miracle done by him.
9 Then he questioned with him in many words;
but he answered him nothing.
John 19:7 The Jews answered him, We have a law, and by our law he ought to die, because he made himself the Son of God.
8 When Pilate therefore heard that saying, he was the more afraid;
9 And went again into the judgment hall, and saith unto Jesus, Whence art thou?
But Jesus gave him no answer.
10 Then saith Pilate unto him, Speakest thou not unto me? knowest thou not that I have power to crucify thee, and have power to release thee?
I think the emphasis here is on embarrassment and humiliation. After all, when a sheep has it's wool sheared off, it is naked afterward.
Here is a video of sheep shearing.
http://www.youtube.com/watch?v=yCXl39fgmKg