If you know what you need to harvest you can set up a macro to get more of what you need.
Name: Harvest
/loot
/pause .25
/harvest (whatever1)
/pause .25
/harvest (whatever2)
/pause .25
/harvest (whatever3)
Whatever? = bone, hide, or meat
Set them in an order and you will harvest what you can off of them. Not all creatures have all three so you can designate what your priorities are with this macro.