The following piece of correspondence can be found in the book, Letters of Note: Dogs.

President Bush & Ranger in 1991. Photo: Presidential Library & Museum.

Since 1800, when John Adams first moved into the newly-built White House with his admirably-named dogs, Juno and Satan, the majority of US Presidents have brought their canine friends to live at 1600 Pennsylvania Avenue. In fact, Donald Trump was the first US President in over a century, since poochless William McKinley took the reins in 1897, to not own a dog. In 1989, when Ronald Reagan’s Cavalier King Charles Spaniel, Rex, left the presidential kennel, his place was immediately filled by Millie, the English Springer Spaniel belonging to George H W Bush, and within months she gave birth to a litter of puppies, one of whom, Ranger, became Bush’s favourite. In 1992, panicked by Ranger’s ballooning weight, President sent this urgent missive to all White House personnel. (Scroll down for a transcript.)

February 6, 1992
IMPORTANT ANNOUNCEMENT
THIS IS AN ALL-POINTS BULLETIN FROM THE PRESIDENT
SUBJECT: MY DOG “RANGER”
Recently Ranger was put on a weight-reduction program. Either that program succeeds or we enter Ranger in the Houston Fat Stock Show as Prime Hereford.
All offices should take a formal “pledge” that reads as follows: “WE AGREE NOT TO FEED RANGER. WE WILL NOT GIVE HIM BISCUITS. WE WILL NOT GIVE HIM FOOD OF ANY KIND.”
In addition, Ranger’s 'access' is hereby restricted. He has been told not to wander the corridors without an escort. This applies to the East and West Wings, to the Residence from the 3rd floor to the very, very bottom basement.
Although Ranger will still be permitted to roam at Camp David, the Camp David staff including the Marines, Naval personnel, All Civilians and Kids are specifically instructed to “rat” on anyone seen feeding Ranger.
Ranger has been asked to wear a 'Do not feed me' badge in addition to his ID.
I will, of course, report on Ranger’s fight against obesity. Right now, he looks like a blimp, a nice friendly appealing blimp, but a blimp.
We Need Your Help—All hands, please help.
FROM THE PRESIDENT

He looks like a blimp