Ranahan (or Ranny)

“Ranahan” (or “ranny”) is another name for a cowboy or top ranch hand. The origin of the name is uncertain.
 
 
Google Books
Cowboy Lingo
by Ramon F. Adams
New York: Houghton Mifflin
2000
1936 (original copyright)
Pg. 22:
The cowboy was known, too, by such slang names as “ranahan” (which really referred to a top hand), “saddle-warmer,” “saddle-slicer,” “saddle-stiff,” “leather-pounder,” “cow-poke,” “cow-prod,” or “waddie,” but the most common term used in the cattle country was the simple title of “cow-hand” or “hand.”
     
(Dictionary of American Regional English)
ranahan n [Perh ranny + hand] West CF ranny
An experienced cowhand.
1936 Adams Cowboy Lingo 22, The cowboy was known, too, by such slang names as “ranahan” (which really referred to a top hand).
1936 McCarthy Lang. Mosshorn np West [range terms], Ranahan,,,An experienced “hand” or cowboy.
(...)
ranny n
also rannycavoo: A cowboy. sometimes derog Cf ranahan
1907 Sinclair Lure Dim Trails 159 NW, There’s going to be roundups like these old Panhandle rannies tell about, when the green grass comes.
1924 James Cowboys N. & S. 25, Then it was about time for the “rannies” to pull up their ponies and figger where to go next. They remembered how they left Texas and how every State from there north was feeling the pinch of the fences.
1934 (1940) Weseen Dict. Amer. Slang 104 Ranny—A cowboy on the open range.
1942 Henry High Border 165 nRocky Mts. Catfish Joe, Hell-roaring Jones, Theodore Roosevelt, et al., were in the vernacular of the High Bender “cowpokes,” “rannies,” “rannycavoos,” “hombres,” or in a more refined manner, simply “cowboys.”
 
11 January 1941, Charleston (WV) Daily Mail,“Fugitive on a Dude Ranch” by Stephen Payne, pg. 12, col. 4:
Ike introduced him as “Slim,” and continued, “Two more rannies, Shorty and Gabby, are trailin’ a bunch o’ cows to Eagle butte pasture.”
 
10 July 1968, New Mexican (Santa Fe, NM), “Spanish, French, Indian, English—All in Cowboy Lingo,” pg. 4:
Ranahan
A top hand, a cowboy who is efficient.
Ranny
Short for ranahan.