Glanbia has ordered all its stores to put a temporary hold on selling some batches of its bagged cattle feed. The temporary suspension is linked to an ongoing investigation into the presence of an unapproved feed substance detected in its equine feed.Last Friday, GAIN Equine Nutrition, owned by Glanbia, confirmed that it found Zilpaterol, a growth hormone licensed for use in the United States but banned in the EU, in some of its horse feeds.