A few months <a href="http://www.usmilitaryfsbo.com/index.php/endep-10-fhdf">endep uses</a> CHICAGO, Aug 16 (Reuters) - U.S. drugmaker Merck & Co said on Friday it is suspending sales of its Zilmaxanimal feed additive in the United States and Canada followingconcerns about animals showing signs of distress after use ofthe product, which is given to cattle to increase their weightbefore slaughter.