Horse
Depending on breed, management and environment, the modern domestic horse has a life expectancy of 25 to 30 years. Uncommonly, a few animals live into their 40s and, occasionally, beyond. The oldest verifiable record was "Old Billy", a 19th-century horse that lived to the age of 62. In modern times, Sugar Puff, who had been listed in "Guinness World Records" as the world's oldest living pony, died in 2007 at age 56.
Mustang
Since 1978, captured horses have been offered for adoption to individuals or groups willing and able to provide humane, long-term care after payment of an adoption fee; the base fee is $125. Adopted horses are still protected under the Act, for one year after adoption, at which point the adopter can obtain title to the horse. Horses that could not be adopted were to be humanely euthanized.Instead of euthanizing excess horses, the BLM began keeping them in "long term holding," an expensive alternative that can cost taxpayers up to $50,000 per horse over its lifetime. On December 8, 2004, a rider amending the Wild and Free Roaming Horse and Burro Act was attached to an appropriation bill before the United States Congress by former Senator Conrad Burns. This modified the adoption program to also allow the unlimited sale of captured horses that are "more than 10 years of age", or that were "offered unsuccessfully for adoption at least three times." Since 1978, there had been specific language in the Act forbidding the BLM from selling the horses to those would take them to slaughter, but the Burns Amendment removed that language. In order to prevent horses being sold to slaughter, the BLM has implemented policies limiting sales and requiring buyers to certify they will not take the horses to slaughter.In 2017, the Trump administration began pushing Congress to remove barriers to implementing both the option to euthanize and sell excess horses.