hiho,
first of all i support schlachtrind. Shootarush is very strong on bloodriver. There aren't a lot of oppotunitys to survie it 
I played quiet a few matches against Schlachtrind in this matchup. I was only able to defend my base when i knew that he will rush without building a generator.
2 worker build the aspect portal. When the asprect portal ist 2/3 ready order the second worker to start the generator. So you have enough energy to build farseer first an develop "floot of feet" after yor second guardian.
with Farseer, 2 guardiansqauds(1 full reinforced, 1 constantly reinforced to 5 members), 1 dark reaper sqaud with excarch.
This is what you need. To reach this you will need, good guard micro, and effectiv use of the farseer's spells.
But it remains a very hard competition. Mabye is saved the replays defending this rush.
greetz, gOOn
p.s.: If schlachtrind gets an advantage, try to fear him with sensless sentences like "i know where you are" or "you'll neverwin with your luck-only-tactic"
it works perfectly