Grains lower for a third day with livestock mixed.  DuWayne Bosse of Bolt Marketing says pressure in grains is coming from a higher dollar, lower crude oil, Trump's political appointments and weather.  Corn is fading another 27.3 million bushels of flash export sale from Mexico and unknown.  Cattle have traded two-sided with bearish seasonals offset by funds defending their longs.   Lean hogs ae seeing profit taking and hedge pressure after new contract highs and with lower cutouts.