1) Alternative spellings of ‘slate’, that is to set a dog at an animal, especially at sheep and cattle.
1555 No man shall chase or sleit their neighbours shepe or cattell with dogges, Lepton
1665 wee lay in paine that noe ... person ... shall sleat any shepe belounging to the common, Cartworth
1680 tyed his horse to a gorse bush and slett his dogg at the sheep, Dinnington
1785 the sheep was slet off by Meltham people, Lingards.