Exhibit 10.1

[***] - Certain information in this exhibit have been omitted and filed
separately with the Securities and Exchange Commission. Confidential treatment
has been requested with respect to the omitted portions.

THIRD AMENDMENT
TO
AMENDED AND RESTATED
BOVINE VACCINE DISTRIBUTION AGREEMENT

          This Third Amendment (“Third Amendment”) is entered into as of the
26th day of May, 2006 (“Effective Date”) by and between DIAMOND ANIMAL HEALTH,
INC., an Iowa corporation with offices at 2538 Southeast 43rd Street, Des
Moines, Iowa 50317 (“Diamond”) and AGRI LABORATORIES, LTD., a Delaware
corporation, with offices at 20927 State Route K, St. Joseph, Missouri 64505
(“Distributor”) as an amendment to that certain Amended and Restated Bovine
Vaccine Distribution Agreement dated as of September 30, 2002 between Diamond
and Distributor (the “Original Agreement”), as amended by that certain First
Amendment dated as of September 20, 2004 (the “First Amendment”) and that
certain Second Amendment dated as of December 10, 2004 (the “Second Amendment”)
(collectively, the “Agreement”).

          WHEREAS, Diamond and Distributor are parties to the Agreement
providing for the distribution of certain bovine antigens; and

          WHEREAS, Diamond and Distributor desire to amend the Agreement on the
terms and conditions of this Third Amendment.

          NOW, THEREFORE, the parties agree as follows:

          1.        Definitions. Capitalized terms used herein shall have the
meaning ascribed to them in the Agreement, unless otherwise defined herein.

          2.        Prepayments. Distributor hereby reaffirms its obligation to
make a [***] prepayment on each of June 16, 2006 and September 16, 2006, as
outlined in and subject to the terms and conditions of Section 3.04(iii)(A) of
the Agreement.

          3.        Use of Prepayment Proceeds. The unused balance of any
prepayment made by Distributor on June 16, 2006 and September 16, 2006 shall be
carried over as a credit for purchases in future periods, including Contract
Year 2007 if necessary, and any revenue from such balance shall be included in
Initial Product Qualified Revenues and Qualified Revenues for Contract Year 2006
only, regardless of the actual fulfillment date.

          4.        Take or pay obligations. Diamond hereby waives Distributor’s
obligations under Section 3.04(iii)(D) of the Agreement for the third and fourth
quarter of Contract Year 2006 only.

          5.        Reaffirmation of purchase orders. Distributor reaffirms its
obligations under firm written purchase orders currently outstanding for
delivery in the third and fourth quarter of Contract Year 2006, as outlined on
Exhibit C, and subject to regulatory approval and the terms and conditions of
this Agreement.

          6.        Third quarter [***] orders. Distributor agrees to submit
firm written purchase orders for Products other than [***] Products scheduled
for delivery in the third

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[***] - Certain information on this page have been omitted and filed separately
with the Securities and Exchange Commission. Confidential treatment has been
requested with respect to the omitted portions.

quarter of Contract Year 2006 of at least [***]. If there are less than [***] of
such purchase orders on Exhibit C for Products other than [***] Products,
Distributor shall promptly submit enough of such purchase orders so that there
are [***] of such purchase orders. Distributor shall not be required to pay or
lose prepayment credit on any order unless and until Diamond fulfills such
order. All revenue from these purchase orders shall be included in Initial
Product Qualified Revenues and Qualified Revenues for Contract Year 2006 only,
regardless of the actual fulfillment date.

          7.        Fourth quarter [***] orders. Distributor agrees to submit
firm written purchase orders for Products other than [***] Products scheduled
for delivery in the fourth quarter of Contract Year 2006 of at least [***].
Distributor shall not be required to pay or lose prepayment credit on any order
unless and until Diamond fulfills such order. All revenue from these purchase
orders shall be included in Initial Product Qualified Revenues and Qualified
Revenues for Contract Year 2006 only, regardless of the actual fulfillment date.

          8.        [***] Orders. If necessary to purchase [***], including
amounts from Section 6 and 7 above, from Diamond during the last six months of
Contract Year 2006 if [***] on or before [***], Distributor agrees to issue
purchase orders for [***] Products in addition to those listed on Exhibit C.
Distributor shall not be required to pay or lose prepayment credit on any order
unless and until Diamond fulfills such order. All revenue from these purchase
orders shall be included in Initial Product Qualified Revenues and Qualified
Revenues for Contract Year 2006 only, regardless of the actual fulfillment date.

          9.        [***]. [***] on or before [***], Distributor will commit to
purchase at least [***] from Diamond during the last six months of Contract Year
2006. If at the time [***], Distributor has not submitted firm written purchase
orders for delivery in the last six months of Contract Year 2006 totaling at
least [***], Distributor shall promptly submit enough of such purchase orders so
that there are [***] of such purchase orders. Distributor shall not be required
to pay or lose prepayment credit on any order unless and until Diamond fulfills
such order. All revenue from these purchase orders shall be included in Initial
Product Qualified Revenues and Qualified Revenues for Contract Year 2006 only,
regardless of the actual fulfillment date.

          10.        Amendment of Loan. Pursuant to Section 3 of the Second
Amendment Diamond delivered to Distributor a substitute Note (the “Substitute
Note”) attached as Exhibit A to evidence the Loan. Upon execution and delivery
of this Third Amendment, the parties shall cancel the Substitute Note and
execute and deliver a second substitute note (the “2007 Note”) in the form
attached hereto as Exhibit B.

          11.        [***]. If [***], there shall be no change to Section 3.07
of the Agreement, which is entitled [***]. If [***], the first sentence of
Section 3.07 of the Agreement shall be deleted in its entirety and replaced with
the following sentence:

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[***] - Certain information on this page have been omitted and filed separately
with the Securities and Exchange Commission. Confidential treatment has been
requested with respect to the omitted portions.

                       [***]

          12.        Effect of Amendment. This Third Amendment is hereby
incorporated by reference into the Agreement as if fully set forth therein, the
Agreement as amended by this Third Amendment shall continue in full force and
effect following execution and delivery hereof, and references to the term
“Agreement” shall include this Third Amendment. In the event of any conflict
between the terms and conditions of the Original Agreement, First Amendment or
Second Amendment and this Third Amendment, the terms and conditions of this
Third Amendment shall control.

          IN WITNESS WHEREOF, the parties have caused this Third Amendment be
executed by their duly authorized representatives as of the date first written
above.

                                 DIAMOND ANIMAL HEALTH, INC.

                              By:    /s/  Jason A. Napolitano     
Its:     Chief Financial Officer

                      AGRI LABORATORIES, LTD.

                              By:    /s/  Steve Schram                
Its:     CEO/President

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EXHIBIT A

AMENDED AND RESTATED
PROMISSORY NOTE

$500,000.00 as of April 15, 2002
Des Moines, Iowa

          FOR VALUE RECEIVED, the undersigned DIAMOND ANIMAL HEALTH, INC., an
Iowa corporation (“Maker”), promises to pay to AGRI LABORATORIES, LTD., a
Delaware corporation (“Holder”), or order, at such place as the Holder of this
Note shall designate in writing, the sum of Five Hundred Thousand Dollars
($500,000.00) in lawful money of the United States of America. Beginning from
the date hereof interest shall accrue until the effective date of that certain
Second Amendment to the Distribution Agreement (defined below) on the
outstanding principal balance at the “prime rate” plus one-quarter percent
(1/4%) per annum and thereafter, at the “prime rate” plus one percent (1%) per
annum. Accrued interest shall be paid quarterly on each quarterly anniversary of
the date of this Note, and shall accrue based upon a thirty-day month and a
360-day year. Principal under this Note shall be paid in one annual installment
on May 31, 2006.

All principal and any accrued but unpaid interest shall be due and payable on
the maturity date of this Note.

          Notwithstanding any provision of this Note to the contrary, all
principal and unpaid accrued interest shall be due and payable on the ninetieth
(90th) day following the date that either (i) Holder’s exclusivity rights under
that certain Amended and Restated Bovine Vaccine Distribution Agreement dated as
of September 30, 2002, as amended (the “Distribution Agreement”) are terminated
due to Distributor’s nonpayment of any Additional Payment under the Distribution
Agreement or (ii) in the event of a merger, sale or fifty percent (50%) change
in ownership of Maker.

          The “prime rate” shall be the annual rate of interest announced from
time to time by Wells Fargo Business Credit, Inc. (“Wells Fargo”) as its prime
rate. The interest accruing on the principal balance of this Note shall
fluctuate from time to time concurrently with changes in the prime rate,
effective as of the date any change in the prime rate is publicly announced. If
Wells Fargo ceases to announce the prime rate, the prime rate as published in
the Wall Street Journal in its “Money Rates” section or a similar financial
publication shall be used, as reasonably determined by Maker.

          Maker shall have the right at any time or from time to time to prepay
all or a portion of the principal or interest without premium or penalty, and
such prepayments shall be applied first to accrued interest and then to
principal.

          If default be made in the payment of any of the installments of
principal, interest, or other amounts when due under this Note, the entire
principal sum and accrued interest and all other amounts due hereunder shall
become due at the option of Holder if not paid within ten (10) days of written
notice to Maker.

          In the event garnishment, attachment, levy or execution is issued
against any substantial or material portion of the property or assets of Maker,
or any of them if more than one, or upon the happening of any event which
constitutes a default pursuant to the terms of any agreement or other instrument
entered into or given in connection herewith, or upon the adjudication of Maker,
or any of them if more than one, a bankrupt, such event shall be deemed a
default hereunder and Holder may declare this Note immediately due and payable
without notice to Maker or exercise any of its remedies hereunder or at law or
equity. Should suit be brought to recover on this Note, or should the same be
placed in the hands of an attorney for collection, Maker promises to pay all
reasonable attorneys’ fees and costs incurred in connection therewith.

PAGE 1 OF PROMISSORY NOTE DATED APRIL 15, 2002

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          Failure of Holder to exercise any option hereunder shall not
constitute a waiver of the right to exercise the same in the event of any
subsequent default, or in the event of continuance of any existing default.

          Maker waives demand, diligence, presentment for payment, protest and
notice of demand, protest, nonpayment and exercise of any option hereunder.
Maker agrees that the granting without notice of any extension or extensions of
time for payment of any sum or sums due hereunder, or for the performance of any
covenant, condition or agreement hereof shall in no way release or discharge the
liability of Maker hereof.

          This Note shall be governed by the laws of the State of Iowa.

          Time is of the essence of this Note and each and every term and
provision hereof.

          This Note is secured by that certain Security Agreement, dated as of
even date herewith, by and between Maker and Holder. Debtor and its affiliates
are parties to that certain Second Amended and Restated Credit and Security
Agreement by and between Debtor and Wells Fargo Business Credit, Inc., fka
Norwest Business Credit, Inc., a Minnesota corporation (“Wells Fargo”),
originally dated June 4, 2000, as amended, that certain Loan Agreement dated as
of April 4, 1994 and related Promissory Note between the City of Des Moines,
Iowa and Debtor, as amended, and that certain CEBA Loan Agreement dated January
20, 1994 and related Promissory Notes between Iowa Department of Economic
Development and Debtor, as amended (collectively, the “Senior Loan Agreements”
and the lender parties thereto collectively, the “Senior Lenders”). This Note
and Maker’s obligations hereunder shall be junior and subordinated to all any
and all indebtedness and obligations for borrowed money (including, without
limitation, principal, premium (if any), interest, fees, charges, expenses,
costs, professional fees and expenses, and reimbursement obligations)
(“Indebtedness”) at any time owing by Debtor to the Senior Lenders, their
successors and assigns under the Senior Loan Agreements or otherwise, and the
extension, renewal or refinancing (including without limitation any additional
advances made in connection therewith) of all or any portion of such
Indebtedness by any of the Senior Lenders or any successor lender and any and
all security interests securing any portion of such Indebtedness and additional
advances from time to time (such Indebtedness, additional advances and security
interests, the “Senior Indebtedness”). Holder hereby agrees to take such
actions, and to execute and deliver such documents and instruments, as shall be
requested from time to time by any holder of Senior Indebtedness to confirm and
further implement such subordination. In addition, this Note is subject to the
terms and conditions of that certain Subordination Agreement dated as of even
date herewith by and among Maker, Holder and Wells Fargo.

          This Note replaces that certain Amended and Restated Promissory Note
dated as of April 15, 2004 given by Maker to Holder.

          THE PARTIES WAIVE ANY RIGHT TO TRIAL BY JURY IN ANY ACTION OR
PROCEEDING BASED ON OR PERTAINING TO THIS NOTE.

                                                  DIAMOND ANIMAL HEALTH, INC.,
an Iowa
     corporation, Maker

                              By:    /s/  Jason A. Napolitano     
Its:     Chief Financial Officer     

THIS INSTRUMENT IS SUBJECT TO THE TERMS OF A SUBORDINATION AGREEMENT BY AGRI
LABORATORIES, LTD. IN FAVOR OF WELLS FARGO BUSINESS CREDIT, INC. DATED AS OF
APRIL 15, 2002.

PAGE 2 OF PROMISSORY NOTE DATED APRIL 15, 2002

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EXHIBIT B

2007 Note

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AMENDED AND RESTATED
PROMISSORY NOTE

$500,000.00 as of April 15, 2002
Des Moines, Iowa

          FOR VALUE RECEIVED, the undersigned DIAMOND ANIMAL HEALTH, INC., an
Iowa corporation (“Maker” or (“Debtor”), promises to pay to AGRI LABORATORIES,
LTD., a Delaware corporation (“Holder”), or order, at such place as the Holder
of this Note shall designate in writing, the sum of Five Hundred Thousand
Dollars ($500,000.00) in lawful money of the United States of America. Beginning
from the date hereof interest shall accrue until the effective date of that
certain Second Amendment to the Distribution Agreement (defined below) on the
outstanding principal balance at the “prime rate” plus one-quarter percent
(1/4%) per annum and thereafter, at the “prime rate” plus one percent (1%) per
annum. Accrued interest shall be paid quarterly on each quarterly anniversary of
the date of this Note, and shall accrue based upon a thirty-day month and a
360-day year. Principal under this Note shall be paid in one annual installment
on May 31, 2007.

All principal and any accrued but unpaid interest shall be due and payable on
the maturity date of this Note.

          Notwithstanding any provision of this Note to the contrary, all
principal and unpaid accrued interest shall be due and payable on the ninetieth
(90th) day following the date that either (i) Holder’s exclusivity rights under
that certain Amended and Restated Bovine Vaccine Distribution Agreement dated as
of September 30, 2002, as amended (the “Distribution Agreement”) are terminated
due to Distributor’s nonpayment of any Additional Payment under the Distribution
Agreement or (ii) in the event of a merger, sale or fifty percent (50%) change
in ownership of Maker.

          The “prime rate” shall be the annual rate of interest announced from
time to time by Wells Fargo Bank, National Association (“Wells Fargo”) as its
prime rate. The interest accruing on the principal balance of this Note shall
fluctuate from time to time concurrently with changes in the prime rate,
effective as of the date any change in the prime rate is publicly announced. If
Wells Fargo ceases to announce the prime rate, the prime rate as published in
the Wall Street Journal in its “Money Rates” section or a similar financial
publication shall be used, as reasonably determined by Maker.

          Maker shall have the right at any time or from time to time to prepay
all or a portion of the principal or interest without premium or penalty, and
such prepayments shall be applied first to accrued interest and then to
principal.

          If default be made in the payment of any of the installments of
principal, interest, or other amounts when due under this Note, the entire
principal sum and accrued interest and all other amounts due hereunder shall
become due at the option of Holder if not paid within ten (10) days of written
notice to Maker.

          In the event garnishment, attachment, levy or execution is issued
against any substantial or material portion of the property or assets of Maker,
or any of them if more than one, or upon the happening of any event which
constitutes a default pursuant to the terms of any agreement or other instrument
entered into or given in connection herewith, or upon the adjudication of Maker,
or any of them if more than one, a bankrupt, such event shall be deemed a
default hereunder and Holder may declare this Note immediately due and payable
without notice to Maker or exercise any of its remedies hereunder or at law or
equity. Should suit be brought to recover on this Note, or should the same be
placed in the hands of an attorney for collection, Maker promises to pay all
reasonable attorneys’ fees and costs incurred in connection therewith.

PAGE 1 OF PROMISSORY NOTE DATED APRIL 15, 2002

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          Failure of Holder to exercise any option hereunder shall not
constitute a waiver of the right to exercise the same in the event of any
subsequent default, or in the event of continuance of any existing default.

          Maker waives demand, diligence, presentment for payment, protest and
notice of demand, protest, nonpayment and exercise of any option hereunder.
Maker agrees that the granting without notice of any extension or extensions of
time for payment of any sum or sums due hereunder, or for the performance of any
covenant, condition or agreement hereof shall in no way release or discharge the
liability of Maker hereof.

          This Note shall be governed by the laws of the State of Iowa.

          Time is of the essence of this Note and each and every term and
provision hereof.

          This Note is secured by that certain Security Agreement, dated as of
even date herewith, by and between Maker and Holder. Debtor and its affiliates
are parties to that certain Third Amended and Restated Credit and Security
Agreement by and between Debtor and Wells Fargo Bank, National Association, as
successor in interest to Wells Fargo Business Credit, Inc. (“Wells Fargo”),
dated December 30, 2005 and Debtor is party to a certain promissory note with
the City of Des Moines, due in monthly installments through June 2006
(collectively, the “Senior Loan Agreements” and the lender parties thereto
collectively, the “Senior Lenders”). This Note and Maker’s obligations hereunder
shall be junior and subordinated to all any and all indebtedness and obligations
for borrowed money (including, without limitation, principal, premium (if any),
interest, fees, charges, expenses, costs, professional fees and expenses, and
reimbursement obligations) (“Indebtedness”) at any time owing by Debtor to the
Senior Lenders, their successors and assigns under the Senior Loan Agreements or
otherwise, and the extension, renewal or refinancing (including without
limitation any additional advances made in connection therewith) of all or any
portion of such Indebtedness by any of the Senior Lenders or any successor
lender and any and all security interests securing any portion of such
Indebtedness and additional advances from time to time (such Indebtedness,
additional advances and security interests, the “Senior Indebtedness”). Holder
hereby agrees to take such actions, and to execute and deliver such documents
and instruments, as shall be requested from time to time by any holder of Senior
Indebtedness to confirm and further implement such subordination. In addition,
this Note is subject to the terms and conditions of that certain Subordination
Agreement dated as of even date herewith by and among Maker, Holder and Wells
Fargo.

          This Note replaces that certain Amended and Restated Promissory Note
dated as of April 15, 2004 given by Maker to Holder.

          THE PARTIES WAIVE ANY RIGHT TO TRIAL BY JURY IN ANY ACTION OR
PROCEEDING BASED ON OR PERTAINING TO THIS NOTE.

                                                  DIAMOND ANIMAL HEALTH, INC.,
an Iowa
     corporation, Maker

                              By:    /s/  Jason A. Napolitano     
Its:     Chief Financial Officer     

THIS INSTRUMENT IS SUBJECT TO THE TERMS OF A SUBORDINATION AGREEMENT BY AGRI
LABORATORIES, LTD. IN FAVOR OF WELLS FARGO BUSINESS CREDIT, INC. DATED AS OF
APRIL 15, 2002.

PAGE 2 OF PROMISSORY NOTE DATED APRIL 15, 2002

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[***] - Certain information on this page have been omitted and filed separately
with the Securities and Exchange Commission. Confidential treatment has been
requested with respect to the omitted portions.

EXHIBIT C

AgriLabs 3rd Quarter Purchase Orders and 4th Quarter Purchase Orders
and Forecast as of 5/25/06

                         [***]

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[***] - Certain information on this page have been omitted and filed separately
with the Securities and Exchange Commission. Confidential treatment has been
requested with respect to the omitted portions.

EXHIBIT C
(CONT.)

AgriLabs 3rd Quarter Purchase Orders and 4th Quarter Purchase Orders
and Forecast as of 5/25/06
(Cont.)

                         [***]