Standard & Poor's Announces Change to U.S. Index

NEW YORK, Sept. 30  /PRNewswire/ -- MWI Veterinary Supply Inc. (NASDAQ: MWIV) will replace Photon Dynamics Inc. (NASDAQ:PHTN) in the S&P SmallCap 600 after the close of trading on Thursday, October 2. Photon Dynamics is being acquired by Orbotech Ltd. in a deal expected to be completed on or about that date.

Standard & Poor's will monitor this transaction, and post any relevant updates on its website: http://www.standardandpoors.com/.

MWI Veterinary Supply distributes animal health products to veterinarians. Headquartered in Meridian, ID, the company will be added to the S&P SmallCap 600 GICS (Global Industry Classification Standard) Health Care Distributors Sub-Industry index.

  Following is a summary of the change:



                 S&P SMALLCAP 600 INDEX   - October 2, 2008

              COMPANY       GICS ECONOMIC SECTOR         GICS SUB-INDUSTRY

  ADDED    MWI Veterinary         Health Care                Health Care
              Supply                                         Distributors

  DELETED  Photon Dynamics        Information                Electronic
                                  Technology                 Equipment &
                                                             Instruments



Additions to and deletions from an S&P equity index do not in any way reflect an opinion on the investment merits of the companies concerned.

About Standard & Poor's Index Services

Standard & Poor's Index Services, the world's leading index provider, maintains a wide variety of investable and benchmark indices to meet an array of investor needs. Its family of indices includes the S&P 500, an index with $1.5 trillion invested and $4.85 trillion benchmarked, and the S&P Global 1200, a composite index comprised of seven regional and country headline indices. For more information, please visit http://www.standardandpoors.com/indices.

About Standard & Poor's

Standard & Poor's, a division of The McGraw-Hill Companies (NYSE:MHP), is the world's foremost provider of financial market intelligence, including independent credit ratings, indices, risk evaluation, investment research and data. With approximately 8,500 employees, including wholly owned affiliates, located in 21 countries. Standard & Poor's is an essential part of the world's financial infrastructure and has played a leading role for more than 140 years in providing investors with the independent benchmarks they need to feel more confident about their investment and financial decisions. For more information, visit http://www.standardandpoors.com/. 

DATASOURCE: Standard & Poor's



CONTACT:  David M. Blitzer, Ph.D., Managing Director & Chairman of the

Index Committee, [phone]



Web Site:  http://www.standardandpoors.com/ 

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