Read the following:

yaSvaD taj vInob

I give the knife to the officer

yaSvaD taj vIqem

I give the knife to the officer by bringing it to him

You might give the knife to the officer, but you don't say so in this sentence. This sentence just says you bring the knife to the officer. Whether the officer picks it up after you bring it is another sentence.

yaSvaD taj vIngeH

I give the knife to the officer by sending it to him

So when giving something to someone we use the {-vaD} regardless whether we bring it to him, or send it to him.

No. We use -vaD when we want to specify the recipient or beneficiary of the verb. When you're specifying a recipient, this role is called the indirect object.

But would we use the {-vaD} too even if we threw the knife to him?

Ha'DIbaHvaD chuvmey vIvo'

I give the leftovers to the animal by throwing them to it

You propel he leftovers, intending them to be received by the animal. That's a perfectly good use of the indirect object.

Would this sentence be correct, or does the {vo'} change something, thus making the choice of {-vaD} wrong?

I don't see any reason for the choice between {-Daq} and {-vaD} to be influenced by the way something is given, but I'd like to verify this.

If you said Ha'DIbaHDaq chuvmey vIvo' I throw the leftovers at the animal, then grammatically the animal is a target, not a recipient. You might intend this lobbing of leftovers as an act of giving, and this might come across in context, but it's not expressed in the sentence.

-Daq means a location. -vaD means a recipient or other beneficiary. It's not about what verb you use.

-- 
SuStel
http://trimboli.name