sure
Dairy products , eggs, poultry, maple syrup i believe pork and likely some others are produced according to quotas
Pros: as mentioned a steady supply of quality products is available, ensures family farms remain economically viable
Cons: Canadian pay way more for these food items than Americans do ex exchange rate impacts,
over production is disposed of or diverted to some other low margin use (down the drain or into dog food I am guessing, storage for the maple syrup ) .
It is a barrier to US competitors - not free trade
The Quebec dairy farms sway a really disproportion amount of political influence on this issue
I do not know for sure, however I suspect there are some exceptionally rich Quebec framers .
Thus far they have managed to keep supply management intact in trade agreements
It is always a contentious issue , I believe the UK walked away from a trade deal for a while because of supply management
Quebec will fight tooth and nail against any changes to supply management
I know the Dairy framers in Wisconsin have called out Canada's supply management system and have Trumps ear, maple syrup producers in Vermont are none too happy about it either
It is likely a tiny fraction of rounding error wrt to US GDP , however it is not at all free trade and is an irritant for the US trade negotiators
I suspect Trump will want a win on this issue.