I have used Sentinel for years and have had no problems. It also helps control fleas, hookworms, roundworms and whipworms. Recently I brought a young dog into my household that unbeknownst to me had whipworm. None of my other dogs who were on Sentinel became infected. Once the whipworm was under control on the new dog, she immediately went on Sentinel. I keep my dogs on it year round. It is not cheap but effective. Kay Springer www.showboatgsd.com Home of Multi BISS & Multi Group Winning Ch. Rohan's Reward TC, CGC, HT, CD, RE, CHIC "Strider" - see his pups on my website On Aug 12, 2009, at 6:49:47 AM, Debra <dhnath@xxxxxxx> wrote: Which heartworm preventative is preferred for German Shepherds. I was told that there was a discussion about this before my time with the group. What was the conclusion? Thanks Debra Hnath Claremore OK ============================================================================ POST is Copyrighted 2008. All material remains the property of the original author and of GSD Communication, Inc. NO REPRODUCTIONS or FORWARDS of any kind are permitted without prior permission of the original author AND of the Showgsd-l Management. ALL RIGHTS RESERVED. ALL PERSONS ARE ON NOTICE THAT THE FORWARDING, REPRODUCTION OR USE IN ANY MANNER OF ANY MATERIAL WHICH APPEARS ON SHOWGSD-L WITHOUT THE EXPRESS PERMISSION OF ALL PARTIES TO THE POST AND THE LIST MANAGEMENT IS EXPRESSLY FORBIDDEN, AND IS A VIOLATION OF LAW. VIOLATORS OF THIS PROHIBITION WILL BE PROSECUTED. For assistance, please contact the List Management at admin@xxxxxxxxxxxx VISIT OUR WEBSITE - http://showgsd.org NATIONAL BLOG - http://gsdnational.blogspot.com/ ============================================================================