Document:

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                                 FIRST AMENDMENT
                                       TO
                      SECURED SUBORDINATED PROMISSORY NOTE
                            DATED AS OF JUNE 3, 2004

      This First Amendment is made as of the 24th day of March, 2005, by and
among Virbac Corporation, a Delaware corporation, PM Resources, Inc., a Missouri
corporation, St. Jon Laboratories, Inc., a California corporation, Francodex
Laboratories, Inc., a Kansas corporation, Delmarva Laboratories, Inc., a
Virginia corporation and Virbac AH, Inc., Delaware corporation (collectively,
the "Borrowers"), and Virbac S.A., a company organized under the laws of the
Republic of France (the "Holder") (capitalized terms used but not defined herein
shall have the meanings ascribed to such terms in that certain Secured
Subordinated Promissory Note, dated June 3, 2004, in the original principal
amount of $2,000,000.00 by and between the Borrowers and the Holder (the
"Note")).

      WHEREAS, the parties hereto desire to amend the Note as set forth herein;
and

      NOW, THEREFORE, for and in consideration of the premises and the mutual
covenants and agreements set forth herein and other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged by
each of the parties hereto, the parties hereto hereby agree as follows:

            1. The Note is hereby amended in all respects necessary such that
      Maturity Date shall be automatically extended for up to four (4) periods
      of three months.

            2. Except as provided for in this First Amendment, the Note, as
      amended, shall remain in full force and effect and is hereby reaffirmed.

            3. This Amendment shall be interpreted, construed and enforced in
      accordance with the laws of the State of Delaware.

                   REMAINDER OF PAGE INTENTIONALLY LEFT BLANK.
                             SIGNATURE PAGE FOLLOWS.

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      IN WITNESS WHEREOF, the undersigned have executed this Amendment effective
as of the date first written above.

                                     BORROWERS:

                                     VIRBAC CORPORATION
                                     A DELAWARE CORPORATION

                                     By: /s/ Jean M. Nelson
                                        ________________________________________
                                     Name: Jean M. Nelson
                                     Title: Executive Vice President & C.F.O.PM
                                     RESOURCES, INC.
                                     A MISSOURI CORPORATION

                                     By: /s/ Jean M. Nelson
                                        ________________________________________
                                     Name: Jean M. Nelson
                                     Title: Executive Vice President & C.F.O.

                                     ST. JON LABORATORIES, INC.
                                     A CALIFORNIA CORPORATION

                                     By: /s/ Jean M. Nelson
                                        ________________________________________
                                     Name: Jean M. Nelson
                                     Title: Executive Vice President & C.F.O.

                                     FRANCODEX LABORATORIES, INC.
                                     A KANSAS CORPORATION

                                     By: /s/ Jean M. Nelson
                                        ________________________________________
                                     Name: Jean M. Nelson
                                     Title: Executive Vice President & C.F.O.

                                     DELMARVA LABORATORIES, INC.
                                     A VIRGINIA CORPORATION

                                     By: /s/ Jean M. Nelson
                                        ________________________________________
                                     Name: Jean M. Nelson
                                     Title: Executive Vice President & C.F.O.

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                                     VIRBAC AH, INC.
                                     A DELAWARE CORPORATION

                                     By: /s/ Jean M. Nelson
                                         ------------------------------------
                                     Name: Jean M. Nelson
                                     Title: Executive Vice President & C.F.O.

                                     HOLDER:

                                     VIRBAC S.A.
                                     A COMPANY ORGANIZED UNDER THE LAWS OF THE
                                     REPUBLIC OF FRANCE

                                     By: /s/ Eric Maree
                                         ------------------------------------
                                     Name: Eric Maree
                                     Title: President of the Management Board<PAGE>

                                  April 1, 2005

Virbac Corporation and Subsidiaries
3200 Meacham Boulevard
Fort Worth, Texas 76137
Attention: Jean M. Nelson, Executive Vice
           President and Chief Financial Officer

Re: Amendment re Delivery of Audited Financial Statements

Dear Ms. Nelson:

      You have requested an amendment to the Forbearance Agreement dated as of
April 9, 2004 made by and among Virbac Corporation, PM Resources, Inc., St. Jon
Laboratories, Inc., Francodex Laboratories, Inc., Virbac AH, Inc. and Delmarva
Laboratories, Inc. (collectively, the "Borrowers"), and First Bank ("Bank"), as
the same has been from time to time amended (the "Forbearance Agreement") to
permit the delivery of the audited financial statements for Borrowers' fiscal
years ending December 31, 2003, December 31, 2002, December 31, 2001 and
December 31, 2000 on or before April 18, 2005 instead of on or before April 1,
2005 as set forth in Section 1(b)(iii)(C) of the Forbearance Agreement.

      Subject to the conditions of this letter, Borrowers and Bank hereby agree
that Section 1(b)(iii)(C) of the Forbearance Agreement shall be amended to read
in its entirety as follows:

            (C) on or before April 18, 2005, the consolidated balance sheet of
      Borrowers and their Consolidated Subsidiaries as of December 31, 2003 and
      the related consolidated statements of income, retained earnings and cash
      flows for the fiscal year ended as of December 31, 2003, all with
      consolidating disclosures and setting forth in each case, in comparative
      form, the figures for the previous fiscal year, together with any and all
      restated financial statements (balance sheets and statements of income,
      retained earnings and cash flows) for the fiscal years (or any periods
      during the fiscal years) ending December 31, 2002, December 31, 2001 and
      December 31, 2000, all such financial statements to be prepared in
      accordance with Generally Accepted Accounting Principles consistently
      applied and audited by and accompanied by the unqualified opinion of
      PriceWaterhouse Coopers;

      Capitalized terms used in this letter and not otherwise defined shall have
their meanings under the Forbearance Agreement.

      The amendments contained herein are expressly conditioned upon the Bank's
receipt of this letter agreement executed by a duly authorized officer of each
of the Borrowers and acknowledged by a duly authorized officer of Bank One, NA,
the Bank's participant in the credit facilities to the Borrowers.

      Please indicate your acknowledgment and agreement to the amendments
contained herein by signing and returning this letter at your earliest
convenience. The amendments set forth herein shall not be effective unless
counterpart originals of this letter, signed on behalf of each of the Borrowers
and by Bank One, NA, are returned to Bank on or before April 5, 2005.

      This notice is provided pursuant to Section 432.047, R.S.Mo. As used
herein, "creditor" means each of the Bank and its participant, Bank One, NA, the
"credit agreement" means the Loan Agreement, as amended by the Forbearance
Agreement, and as each such document has been further amended from

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Virbac Corporation and Subsidiaries
April 1, 2005
Page 2

time to time, and "this writing" means the Loan Agreement, as amended by the
Forbearance Agreement, and as each such document has been further amended from
time to time, the Note, the other Transaction Documents, all guaranties executed
by any other Obligors, and any other agreement executed in connection herewith
or therewith. ORAL AGREEMENTS OR COMMITMENTS TO LOAN MONEY, EXTEND CREDIT OR TO
FORBEAR FROM ENFORCING REPAYMENT OF A DEBT INCLUDING PROMISES TO EXTEND OR RENEW
SUCH DEBT ARE NOT ENFORCEABLE, REGARDLESS OF THE LEGAL THEORY UPON WHICH IT IS
BASED THAT IS IN ANY WAY RELATED TO THE CREDIT AGREEMENT. TO PROTECT YOU
(BORROWER(S)) AND US (CREDITOR) FROM MISUNDERSTANDING OR DISAPPOINTMENT, ANY
AGREEMENTS WE REACH COVERING SUCH MATTERS ARE CONTAINED IN THIS WRITING, WHICH
IS THE COMPLETE AND EXCLUSIVE STATEMENT OF THE AGREEMENT BETWEEN US, EXCEPT AS
WE MAY LATER AGREE IN WRITING TO MODIFY IT. This Agreement embodies the entire
agreement and understanding between the Borrowers and the Bank and supersedes
all prior agreements and understandings (oral or written) relating to the
subject matter hereof.

                                               Very truly yours,

                                               FIRST BANK

                                               By: /s/ Traci Dodson
                                                  -----------------------------

                                                   Traci Dodson, Vice President

ACKNOWLEDGED AND AGREED TO
THIS 1st DAY OF APRIL, 2005

VIRBAC CORPORATION
PM RESOURCES, INC.
ST. JON LABORATORIES, INC.
VIRBAC AH, INC.
FRANCODEX LABORATORIES, INC.
DELMARVA LABORATORIES, INC.

By: /s/ Jean M. Nelson
   -----------------------------------------
    Jean M. Nelson, Executive Vice President
    and Chief Financial Officer

CONSENTED AND AGREED TO THIS 1st
DAY OF APRIL, 2005

BANK ONE, NA

By: /s/ Jennifer Baggs
   -----------------------------------------
Title: Vice President

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