Livy and the Gladius vs Macedonians

[Nathan Ross]

Philip decided to parade the bodies of those killed in the skirmish with Roman cavalry

That's interesting - I've often seen this same quote (or what I think is this same quote) used to counter Vegetius's suggestion that Roman soldiers were trained to thrust with the sword and not cut. But the Romans here are cavalry, so even if they're using the same or a similar weapon to that carried by the infantry ('gladius hispaniensis'), their use of it would surely be different when fighting from horseback. Is that right, or is there another Livy quote more specifically about infantry?