A Berkeley man who used his horse's birthday to help select six winning numbers in the Lotto 6/49 game claimed a jackpot worth $17.1 million, California Lottery officials said. Walter Dayton used his birthday and the birthday of his trail horse, Mal Niloj, to come up with the winning combination, lottery spokesman John Schade said. Seeking to preserve his privacy, Dayton declined to disclose more information about himself, including his occupation, Schade said. He turned in his winning ticket at the lottery's San Francisco office. The big prize will be paid out in 20 annual installments of about $686,400 after federal taxes.