“Didn’t do her any good, didn’t do her any harm”

A verse of unknown authorship goes:
 
The cow kicked Nelly in the belly in the barn.
The farmer said it wouldn’t do her any harm.
(or, “Didn’t do her/Nelly any good, didn’t do her/Nelly any harm.”)
 
The verse has been cited in print since at least 1946 and has been used in politics to describe an event that wasn’t either good or bad for the politician. Conservative columnist George Will has used the lines.
     
   
Google Books
I too, Nicodemus
By Curtis Bok
New York, NY: Alfred A. Knopf
1946
Pg. 71:
The old song swelled to its climax:
 
The cow kicked Nelly in the belly in the barn,
The cow kicked Nelly in the belly in the barn.
The farmer said it wouldn’t do her any harm.
 
30 August 1946, Paris (TX) News, “Matter of Fact” by Stewart Alsop, pg. 8, col. 2:
Some conservative southerners assert that the C. I.O. support fora candidate antagonizes as many votes as it attracts. They contend that the total result is about like that so vividly described in the pastoral couplet,
 
The cow kicked Nelly in the belly in the barn,
Didn’t do her any good, didn’t do her any harm.
 
4 March 1969, Alton (IL) Evening Telegraph, “DeGaulle’s Doubts of U.S. Honor Is Disquieting to Us” by Frank Mankiewicz and Tom Braden, pg. A-5, cols. 6-7:
The true value of the presidential trip can be summed up in the ancient and bucolic couplet:

The cow kicked Nelly in the belly in the barn;
Didn’t do her any good, didn’t do her any harm.
 
10 June 1975, Greensboro (NC) Record, “Britain sticks with ‘Community’” by George F. Will, pg. 14, col. 5:
LONDON—Britain’s referendum on Common Market membership was an anti-constitutional distraction, but otherwise no worse than Nelly’s cow:
 
The cow kicked Nelly in the belly in the barn;
It did her no good, and it did her no harm.
 
Twitter
Patrick Strother
‏@PatrickStrother
George Will on tonight: “Cow kicked Nelly in the belly in the barn…didn’t do Nelly any good, didn’t do Nelly any harm.” #SOTU
9:47 PM - 28 Jan 2014
 
Twitter
Peter Anderson
‏@PepeDelAnderson
“The cow kicked Nelly in the belly in the barn, didn’t do her any good, didn’t do her any harm.” -@georgewillf #SOTUresponse
9:48 PM - 28 Jan 2014
 
Twitter
Gabe
‏@Gabriel_M_Ruiz
“By the way, the cow kicked nelly in the belly is also a way republicans use contraception” - Steven Colbert… I’m dead lol @ColbertReport
10:50 PM - 29 Jan 2014 from South Carolina, US