NEWMARKET, UK—Whether in situ or online, breeders from all over the world ensured that the Tattersalls December Mares' Sale got off to a promising start, with a 90% clearance rate helped by plenty of action from internet bidders. The dispersal of Lady Rothschild's Waddesdon Stud had led to a buoyant session on this day last year, so markers were down 12 months on, but there was still a healthy level of activity, with 12,292,200gns traded for 243 fillies and mares. The median dipped by 14% at 30,000gns and the average...