I can't say for sure, but it sounds to me like a distinction between two sorts of learning: 'chunks' of study ("feedlot") or constant little intakes of information ("grazing"). The word "graze" is related to "grass"; grazing is how sheep (and many other herbivores) eat.
I've never met the word "feedlot" though; and the more common term for taking in small bits of information is 'browse'. (Interestingly, this word is related to herbivores eating too, but at the level of their brow: a goat sometimes grazes and sometimes browses.) But the metaphorical use of "browse" (information, reading-matter) is more common than the 'animal feeding' meaning. This might be heard in a bookshop: 'Would you like to buy that, or are you just browsing?'
PS In Shakespeare's time, the 'feeding' sense was stronger. When King Lear disowns Cordelia he says 'Browse where you will, you will not house with me.'
Student or Learner