Merck Animal Health Statement on Zilmax

Animal well-being is a priority for Merck Animal Health.

The facts are clear. The benefits and safety of Zilmax® (zilpaterol) are well documented. Zilmax has a 30+ year history of research and development and rigorous testing. Worldwide regulatory agencies have reviewed extensive data on Zilmax and have concluded that use of Zilmax according to the label is safe in cattle. It is important to understand these data included rigorous animal health safety and well-being studies – conducted by University experts – that found the behavior and movement of cattle fed Zilmax is normal.

We are surprised by Tyson’s letter. We are confident that, based on all of the available data on Zilmax, the experience reported by Tyson is not attributable to Zilmax. Indeed, Tyson itself points to the fact that there are other possible causes and that it does not know the specific cause of the issues it recently experienced. We will continue to work with Tyson to help it identify those other causes. Again, we are confident that the totality of our data does not support Zilmax as being the cause of these experiences, and we remain confident in the safety of the product.

Zilmax has a withdrawal period 3 days prior to harvest. Not for use in animals intended for breeding. Do not allow horses or other equines access to feed containing zilpaterol. Do not use in veal calves. For complete safety information, refer to product label and Zilmax website.

About Merck Animal Health

Today’s Merck is a global healthcare leader working to help the world be well. Merck Animal Health, known as MSD Animal Health outside the United States and Canada, is the global animal health business unit of Merck. Merck Animal Health offers veterinarians, farmers, pet owners and governments one of the widest range of veterinary pharmaceuticals, vaccines and health management solutions and services. Merck Animal Health is dedicated to preserving and improving the health, well-being and performance of animals. It invests extensively in dynamic and comprehensive R&D resources and a modern, global supply chain. Merck Animal Health is present in more than 50 countries, while its products are available in some 150 markets. For more information, visit www.merck-animal-health.com.

Merck Forward-Looking Statement

This news release includes “forward-looking statements” within the meaning of the safe harbor provisions of the United States Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of Merck’s management and are subject to significant risks and uncertainties. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; Merck’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of Merck’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

Merck undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in Merck’s 2012 Annual Report on Form 10-K and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).