Loveday, confirmed as Berkshire's all-time leading runscorer after scoring 138 against Herefordshire, carried his bat through a 386 for six total off 129 overs, and partnered Toby Radford (96) to a county second-wicket record of 252.
Wales had to follow on 185 runs behind as Berkshire became one of four sides to claim first innings wins under the new regulations.
Three other partnership milestones were established as the 'grade' game made a record-shattering start. Andy Griffin (128 not out) and Matt Drury (100 not out) shared a fifth wicket stand of 202 for Hertfordshire against Cumberland, for whom Ashley Metcalfe (102) and Simon Dutton (109) put on 164 for the fourth wicket.
Matt Turner (135) and Adam Shimmons (53) added 129 for the eighth wicket for Shropshire in a game marred by an incident involving Oxfordshire paceman Keith Arnold and William Davies, the Shropshire wicketkeeper. A blow was thrown when Arnold was dismissed; disciplinary action is likely.
In the MCC Trophy, Cheshire, the 1996 winners, have lost all three group games, the latest against the Derbyshire Board XI. They were 191 for seven with one over left, needing 204. The first four balls brought nine, Steve Bramhall was then out for 50 and two wides followed. Two were wanted but Charlie Lamb was run out chasing a second, and Derbyshire won for having lost eight wickets to Cheshire's nine.