What is the meaning of Othello's expression "goats and monkeys!" in IV. I. 243 of Othello?
It is important to always look at the context of particular phrases if you are attempting to understand them. In this scene the phrase you have identified clearly reflects the way that Othello is becoming overwhelmed with the jealousy that Iago is creating between both Othello and Cassio and Othello and Desdemona. Thus when Lodovico enters, Othello leaves him with this final line which is rather puzzling because of the way that the first half seems to have nothing to do with the second half:
You are welcome, sir, to Cyrpus. Goats and monkeys!
This apparent non sequitur seems to indicate the imagery of bestiality and lust, but also indicate the way that such imagery that Iago has taunted him with still clearly rings in his ears and how he is becoming "unmanned" by his jealousy.