BOTSWANA on Saturday followed the example of neighbours Namibia and Zimbabwe by holding an auction of ivory for Japanese buyers who paid thousands of dollars per kilo for the protected material, organisers said.The government is expected to reveal on Monday the proceeds of the auction, which was held under an agreement to permit restricted ivory trading. Convention on International Trade in Endangered Species (Cites) secretary Jimmy Armstrong said the proceeds from the Botswana sale surpassed those from sales in Namibia and Zimbabwe. Twenty tons were sold at the Zimbabwean sale on April 13, while Namibia sold 12,4 tons on April 9.