This post comes from Poco, but I am cross-posting here for the benefit
of all treating chronic renal failure kitties with lactated Ringers as a
subcutaneous fluid as something to be alert to:

http://www.cababstractsplus.org/abstracts/Abstract.aspx?AcNo=19822215090

Title: Toxicity associated with lactated Ringer's solution containing preservatives.
Personal Authors: Ryan, C. P.
Author Affiliation: 16600 Bircher St, Granada Hills, California 91344, USA.
Editors: No editors
Document Title: Feline Practice

Abstract:
Three cats developed hyperkinesia and died after being treated with lactated Ringer's solution (two or three s/c injections of 150 ml), as did a fourth cat given the product experimentally. The product was stated to contain benzyl alcohol (0.25%), methylparaben (0.025%), propylparaben (0.006%) and ethylparaben (0.002%), and to be for use in cattle, horses, sheep and swine.

Original post by Poco:
http://itchmoforums.com/feline-chronic-renal-failure/elvis-and-davey-t5907.0.html;msg117762#msg117762

I don't know the reason for the preservatives in the Ringer's for livestock, but I don't think you will find that the vets are using that for cats and dogs.  They use the same fluids used for humans in vet practices.  Good to ask to make sure, but probably no worry there.