“Why do cows lie when it’s raining?”/“To keep each udder dry.”

A cow riddle is:
 
Q: Why do cows lie down when it’s raining?
A: To keep each udder dry.
 
“Udder” sounds like “other.” The riddle was printed in the book I Know an Old Lady (1992) by Brough Girling and Arthur Robins.
 
         
Google Books
I Know an Old Lady
By Brough Girling and Arthur Robins
Walker
1992
Pg. ?:
Why do cows lie down when it’s raining?
To keep each udder dry!
 
Reddit—Jokes
Posted by u/PARAKEET_FUCKER March 16, 2013
WHY DO COWS LIE DOWN IN THE RAIN?
TO KEEP EACH UDDER DRY.
     
Reddit—Punny
Posted by u/john2496 March 16, 2013
Why do cows lie down in the rain?
TO KEEP EACH UDDER DRY!
credit for this gem goes to /u/PARAKEET_FUCKER
   
Google Books
Christmas Cracker Jokes
By Amanda Li
London, UK: Pan Macmillan
2014
Pg. ?:
Why do cows lie down when it’s raining?
To keep each udder dry.
 
Reddit—Jokes
Posted by u/everydayadrawing December 13, 2015
Why do cows lie down in the rain?
To keep each udder dry.
 
Reddit—Jokes
Posted by u/Ca1ig4 July 21, 2016
Why do cows huddle together when it rains?
To keep each udder dry
Courtesy of my significant other
 
Reddit—Dadjokes
Posted by u/PB_Monk3y December 16, 2018
Why do cows lie on each other in the rain
To keep each udder dry
 
Twitter
Johnny
@JustJohnny1882
When it rains, cows normally lie down. The reason for this is to keep each udder dry.
GIF
6:40 AM · Jun 18, 2021·Twitter for iPad