For months, Novartis has struggled to resolve numerous quality control problems at various manufacturing plants that have caused shortages of many popular over-the-counter medicines, such as Excedrin and Bufferin (back story). But an equally vexing issue continues to plague its Animal Health division, since one of the troubled plants makes several widely used treatments that veterinarians purchase to market to pet owners. The drugmaker has become so worried, however, that a letter was sent earlier this to week vets in hopes of convincing them that Novartis is “working diligently” to resume production, according to VIN News Service. In his letter, sales vp Andy Ferrigno pleads with vets to resume purchases once distribution is restored, although he did not disclose specific dates for when this may occur.