Exhibit 10.2

[***]     – 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.

TENTH AMENDMENT TO SECOND AMENDED AND RESTATED
CREDIT AND SECURITY AGREEMENT

                This Amendment, dated as of July 26, 2005, is made by and
between Heska Corporation, a Delaware corporation (“Heska”), Diamond Animal
Health, Inc., an Iowa corporation (“Diamond”) (each of Heska and Diamond may be
referred to herein individually as a “Borrower” and collectively as the
“Borrowers”), and Wells Fargo Business Credit, Inc., a Minnesota corporation
(the “Lender”).

Recitals

                The Borrowers and the Lender are parties to a Second Amended and
Restated Credit and Security Agreement dated as of June 14, 2000 (as amended to
date and as the same may be hereafter amended from time to time, the “Credit
Agreement”). Capitalized terms used in these recitals have the meanings given to
them in the Credit Agreement unless otherwise specified.

                The Borrowers have requested that certain amendments be made to
the Credit Agreement, which the Lender is willing to make pursuant to the terms
and conditions set forth herein.

                NOW, THEREFORE, in consideration of the premises and of the
mutual covenants and agreements herein contained, it is agreed as follows:

               1.       Defined Terms.  Capitalized terms used in this Amendment
which are defined in the Credit Agreement shall have the same meanings as
defined therein, unless otherwise defined herein. In addition, Section 1.1 of
the Credit Agreement is amended by adding or amending, as the case may be, the
following definitions:

         “Additional Capital” means any of the following received by a Borrower
on or after June 30, 2005: (a) net cash proceeds from issuance of Heska common
stock, including common stock issued under an employee stock purchase plan or as
a result of the exercise of options or warrants, (b) net cash proceeds from
issuance of Heska preferred stock, subject to approval by Wells Fargo with
respect to payment terms of such preferred stock, (c) net cash proceeds from a
Borrower’s issuance of debt instruments subject to a subordination agreement
acceptable to Wells Fargo in its sole discretion, and (d) net cash proceeds from
the licensing or sale of Non-Core IP.  

         “Advance” means a Revolving Advance, an Equipment Advance, or a Term
Loan B Advance.  

         “Book Net Worth” of a Borrower means the aggregate of the common and
preferred stockholders’ equity in such Borrower, determined in accordance with
GAAP, but excluding (a) the non-cash impact of expensing options, restricted
stock or other stock-based compensation under APB 25, SFAS 123, SFAS 123R and/or
SFAS 148, and  

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  (b) the non-cash impact of income or expense relating to deferred tax assets
and liabilities caused by the use of net loss carry-forwards for Heska AG, in
each case after December 31, 2004.  

         “Borrowing Base” for a Borrower means, at any time the lesser of:  

(a)       the Maximum Line; or  

(b)       subject to change from time to time in the Lender's sole discretion:  

            (i)     85% of Eligible Accounts of such Borrower, plus  

            (ii)     the lesser of (A) the sum of (1) Eligible Inventory of such
Borrower consisting of raw materials multiplied by the Raw Materials Advance
Rate plus (2) 55% of Eligible Inventory of such Borrower consisting of finished
goods, or (B) the difference of (1) $4,000,000 less (2) the aggregate amount of
Advances made to all Borrowers other than such Borrower in reliance on Eligible
Inventory.  

         “Borrower” means Heska or Diamond, and “Borrowers” means Heska and
Diamond.  

         “Capital Expenditures” for any Borrower for a period means the sum of
(a) any expenditure of money for the purchase or construction of assets, or for
improvements or additions thereto during such period, which are capitalized on
such Borrower’s balance sheet, whether financed or unfinanced, but excluding
expenditures to purchase [***].  

         “Diamond Equipment Note” means the promissory note payable to the order
of the Lender in substantially the form of Exhibit B to the Tenth Amendment, and
any note or notes issued in substitution therefor, as the same may hereafter be
amended, supplemented or restated from time to time.  

         “Eligible Equipment” of a Borrower means Equipment owned by such
Borrower and designated by the Lender as eligible from time to time in its sole
discretion but excluding any Equipment having any of the following
characteristics:  

            (i)     Equipment that is subject to any Lien other than in favor of
the Lender;  

            (ii)     Equipment that has not been delivered to the Premises;  

            (iii)     Equipment in which the Lender does not hold a first
priority security interest;  

            (iv)     Equipment that is obsolete or not currently saleable;  

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            (v)     Equipment that is not covered by standard “all risk”
insurance for an amount equal to its forced liquidation value;  

            (vi)     Equipment that requires proprietary software in order to
operate in the manner in which it is intended when such software is not freely
assignable to the Lender or any potential purchaser of such Equipment;  

            (vii)     Equipment consisting of computer hardware, software,
tooling, or molds;  

            (viii)     Equipment consisting of [***]; and  

            (ix)     Equipment otherwise deemed unacceptable to Lender in its
sole discretion.  

         “Equipment Advance” has the meaning given in Section 2.3.  

         “Equipment Note” means the Heska Equipment Note or the Diamond
Equipment Note.  

         “Guarantors” shall mean Diamond and any other Person who executes a
guaranty of all or any part of the Obligations for the benefit of the Lender.  

         “Heska Equipment Note” means the promissory note payable to the order
of the Lender in substantially the form of Exhibit A to the Tenth Amendment, and
any note or notes issued in substitution therefor, as the same may hereafter be
amended, supplemented or restated from time to time.  

         “Inventory” of a Borrower means all of such Borrower’s inventory, as
such term is defined in the UCC, whether now owned or hereafter acquired,
whether consisting of whole goods, spare parts or components, supplies or
materials, whether acquired, held or furnished for sale, for lease or under
service contracts or for manufacture or processing, and wherever located, and
including, without limitation, all [***].  

         “Liquidity” means the sum of Cash (excluding Cash located in accounts
outside the United States or owned by any entity not incorporated in the United
States) plus Excess Collateral Base less Past Due Payables.  

         “Maturity Date” means June 30, 2009.  

         “Net Income” for a Borrower means, for any period, after-tax net income
from continuing operations (that is, not including extraordinary items, or gains
or losses from unusual items or discontinued operations), in each case for such
Borrower for such period, as determined in accordance with GAAP, but excluding
(a) the non-cash impact of expensing options, restricted stock or other
stock-based compensation under APB 25, SFAS 123, SFAS 123R and/or SFAS 148, and
(b) the non-cash impact of income or expense relating to deferred tax assets and
liabilities caused by the use of net loss carry-forwards for Heska AG.  

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         “Non-Core IP” means intellectual property (including, without
limitation, any patent, trademark, trade name, or copyrighted material) of any
Borrower that is unrelated to the Borrowers’ veterinary product sales and the
sale of which would not have a material adverse effect on any Borrower.  

         “Note” means a Revolving Note, an Equipment Note, or the Term Loan B
Note, and “Notes” means the Revolving Notes, the Equipment Notes, and the Term
Loan B Note.  

         “Past Due Payables” means accounts payable (other than accounts payable
to Affiliates) that are 60 days or more past due; provided, however, that for
purposes of calculating “Past Due Payables” as of June 30, 2005, accounts
payable to Boule Medical AB shall be excluded from such calculation.  

         “Prepayment Factor” means three percent (3%) at all times unless one of
the following conditions applies: (a) if Heska achieves, on a consolidated
basis, Net Income greater than $0 for its fiscal year ending December 31, 2006,
“Prepayment Factor” shall mean two percent (2%) from July 1, 2006 through and
including June 30, 2007; and (b) if Heska achieves, on a consolidated basis, Net
Income greater than $0 for its fiscal year ending December 31, 2007, “Prepayment
Factor” shall mean two percent (2%) from July 1, 2007 through and including June
30, 2008; and (c) if Heska achieves, on a consolidated basis, Net Income greater
than $0 for its fiscal year ending December 31, 2008, “Prepayment Factor” shall
mean one percent (1%) from July 1, 2008 through and including June 30, 2009.  

         “Real Property Maturity Date” means May 31, 2006; provided, however,
that upon notice to the Borrower that the Lender has received a real property
evaluation with respect to the Farm Property and the Factory Property, and that
such evaluation is acceptable to the Lender in its sole discretion, “Real
Property Maturity Date” shall mean June 30, 2009.  

         “[***]”.  

         “Revolving Note” means the Heska Revolving Note or the Diamond
Revolving Note.  

         “Tenth Amendment” means the Tenth Amendment to Second Amended and
Restated Credit Agreement, dated as of July 26, 2005, by and among the Borrowers
and the Lender.  

         “Term Advances” means the Equipment Advance and the Term Loan B
Advances.  

               2.       Deletion of Obsolete Definitions. Section 1.1 of the
Credit Agreement is further amended by deleting the definitions “Expanded Heska
Borrowing Base,” “Limited

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Diamond Borrowing Base,” “Permanent Capital,” “Term Loan A Advance” and “Term
Loan A Note.”

               3.       Replacement of “Term Loan A Advance” and “Term Loan A
Note” with “Equipment Advance” and “Equipment Note”. Sections 2.12, 2.14, and
6.10(b) are amended by replacing each occurrence of the terms “Term Loan A
Advance” and “Term Loan A Note” with “Equipment Advance” and “Equipment Note”,
respectively.

               4.       [***] Eligibility. The definition of “Eligible
Inventory” found in Section 1.1 of the Credit Agreement is amended by deleting
the word “and” from the end of clause (viii), changing the number on clause (ix)
to “(x)", and inserting a new clause (ix), which shall read in its entirety as
follows:

       “(ix)  all [***] that has been delivered to, or is in transit to, a
customer, and all [***] that is not substantially the same in functionality and
quality as other Inventory carried for sale by the Borrower; and”  

               5.       Revolving Advances. Section 2.2 of the Credit Agreement
is hereby amended by deleting the initial paragraph thereof in its entirety and
replacing such initial paragraph with the following:

       “The Lender agrees, on the terms and subject to the conditions herein set
forth, to make advances (the “Revolving Advances”) to any Borrower from time to
time from the date the Inactive Period ends (the “Funding Date”) to the
Termination Date, on the terms and subject to the conditions herein set forth.
The Lender shall have no obligation to make a Revolving Advance to a Borrower
if, after giving effect to such requested Revolving Advance, (a) the sum of the
outstanding and unpaid Revolving Advances to such Borrower exceed such
Borrower’s Borrowing Base, or (b) the sum of the outstanding and unpaid
Revolving Advances would exceed the Aggregate Borrowing Base. Each Borrower’s
obligation to pay the Revolving Advances shall be evidenced by such Borrower’s
Revolving Note and shall be secured by the Collateral as provided in Article III
and the Mortgaged Property as defined in each of the Factory Mortgage and the
Farm Mortgage. Within the limits set forth in this Section 2.2, each Borrower
may borrow, prepay pursuant to Section 2.12 and reborrow. Each Borrower agrees
to comply with the following procedures in requesting Revolving Advances under
this Section 2.2:”  

               6.       Equipment Advances and Payment. Sections 2.3 and 2.4 of
the Credit Agreement are amended to read in their entireties as follows:

       “Section 2.3 Equipment Advances.  

            (a)     The Lender agrees, subject to the terms and conditions of
this Agreement, on the date all of the conditions precedent to the Tenth
Amendment have been fulfilled, to make an advance to Diamond in the amount of
$2,000,000 and to make an advance to Heska in the amount of $500,000 (each an
“Equipment Advance”). Each Borrower’s obligation to pay the Equipment Advances
shall be evidenced by such Borrower’s Equipment Note and shall be secured by the
 

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       Collateral as provided in Article III and the Mortgaged Property as
defined in each of the Factory Mortgage and the Farm Mortgage.  

       Section 2.4 Payment of Equipment Note. The outstanding principal balance
of each Equipment Note shall be due and payable as follows:  

            (a)     On February 1, 2006, and the first day of each month
thereafter, Diamond shall pay monthly installments of $37,037.04; and  

            (b)     On February 1, 2006, and the first day of each month
thereafter, Heska shall pay monthly installments of $9,259.26; and  

            (c)     On the Maturity Date, the entire unpaid principal balance of
each Equipment Note, and all unpaid interest accrued thereon, shall in any event
be due and payable.”  

               7.       Payment of Term Loan B Note. Section 2.6(b) of the
Credit Agreement is amended to read in its entirety as follows:

            “(b)     On the Real Property Maturity Date, the entire unpaid
principal balance of the Term Loan B Note, and all unpaid interest accrued
thereon, shall in any event be due and payable.”  

               8.       Spread. Section 2.7 of the Credit Agreement is amended
to read in its entirety as follows:

         “Section 2.7 Spread. The spread (the “Spread”) means the percentage set
forth in the table below opposite the applicable prior-fiscal-year Net Income of
the Borrowers, which percentage shall change annually effective as of the first
day of the month following the month in which the Borrower delivers to the
Lender its audited financial statements for the prior fiscal year; provided,
however, that so long as no Default Period then exists, if Heska raises
Additional Capital of not less than [***], the “Spread” shall be decreased by
0.75% below the otherwise-applicable rate, effective as of the first day of the
month following the month in which such Additional Capital is raised; and
provided further that if Heska does not raise at least [***] of Additional
Capital on or before January 1, 2006, the “Spread” shall be increased by 0.25%
above the otherwise-applicable rate, effective as of January 1, 2006; and
provided further that if Heska does not raise at least [***] of Additional
Capital on or before July 1, 2006, the “Spread” shall be increased by 0.75%
(including, and not in addition to, the 0.25% increase described in the proviso
above) above the otherwise-applicable rate, effective as of July 1, 2006; and
provided further that in no case shall any decrease in the Spread occur during a
Default Period:  

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  Prior Fiscal Year Net Income
Less than $0
Greater than or equal to $0
but less than $2,500,000
Greater than or equal to $2,500,000 Spread
2.75%

1.75%
0.75%”

               9.       Spread. Section 2.8(b) of the Credit Agreement is
amended to read in its entirety as follows:

         “(b)        Equipment Note. Except as set forth in Sections 2.8(e),
2.8(f) and 2.8(g), the outstanding principal balance of the Equipment Note shall
bear interest at the Term Floating Rate.”  

               10.       Termination and Prepayment Fees. Section 2.13 is
amended to read in its entirety as follows:

         “Section 2.13 Termination, Line Reduction and Prepayment Fees; Waiver
of Termination, Prepayment and Line Reduction Fees.  

           (a)       Termination and Line Reduction Fees. If the Credit Facility
is terminated for any reason as of a date other than the Maturity Date, or Heska
reduces the Maximum Line, the Borrowers shall pay the Lender a fee in an amount
equal to the Prepayment Factor multiplied by the Maximum Line (or the reduction,
as the case may be).  

           (b)       Prepayment Fees. If the Equipment Note is prepaid for any
reason except in accordance with Section 2.4, the Borrowers shall pay to the
Lender a fee in an amount equal to the Prepayment Factor multiplied by the
amount prepaid. If the Term Loan B Note is prepaid for any reason except in
accordance with Section 2.6, the Borrowers shall pay to the Lender a fee in an
amount equal to one percent (1%) of the amount prepaid.  

           (c)       Waiver of Termination and Line Reduction Fees. The
Borrowers will not be required to pay the termination or line reduction fees
otherwise due under this Section 2.13 if such termination or line reduction is
made (i) because of refinancing of the Borrowers by Wells Fargo Bank, National
Association, (ii) within 60 days after any demand for payment upon any Borrower
in accordance with Section 2.11, or (iii) within 60 days after any Discretionary
Reduction Date.”  

               11.       Minimum Capital. Sections 6.12 through 6.16 of the
Credit Agreement are hereby amended to read in their entireties as follows:

         “Section 6.12 Minimum Capital. Heska will maintain, on a consolidated
basis, as of each date listed below, its Capital at an amount not less than the
amount set forth opposite such date [***]:  

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  Date
June 30, 2005
July 31, 2005
August 31, 2005
September 30, 2005
October 31, 2005
November 30, 2005
December 31, 2005
January 31, 2006 and the last day
of each month thereafter Minimum Capital
[***]
[***]
[***]
[***]
[***]
[***]
[***]

[***]

         Section 6.13 Minimum Net Income. Heska will achieve, on a consolidated
basis, during each period described below. Net Income in an amount not less than
the amount set forth opposite such period (amounts in parentheses denote
negative numbers):  

  Period
Six months ending June 30, 2005
Nine months ending September 30, 2005
Twelve months ending December 31, 2005 Minimum Net Income
[***]
[***]
[***]

         Section 6.14 Minimum Liquidity. Heska will maintain, on a consolidated
basis, as of the last day of each month, its Liquidity at an amount not less
than $1,500,000.  

         Section 6.15 Minimum Individual Book Net Worth. Each Borrower shall at
all times maintain its Book Net Worth, calculated without regard to any
Subsidiary or other Affiliate, as shown on the “Total stockholders’ equity” line
for each Borrower in Exhibit D, at an amount greater than $0.  

         Section 6.16 New Covenants. On or before November 30, 2005, the
Borrowers and the Lender shall agree on new covenant levels for Sections 6.12,
6.13, 6.14, and 7.10 for periods after such date. The new covenant levels will
be based on (i) the Borrowers’ projections for such periods and (ii) the year to
date financial results of Heska, on a consolidated basis, and such new covenant
levels shall be no less stringent than the present levels. An Event of Default
shall occur if the new covenants are not agreed to by the above date.”  

               12.       Contributions. Sections 7.4(a)(iv) and (v) of the
Credit Agreement are amended in their entireties to read as follows:

         “(iv)     unless a Default Period exists or would exist immediately
after or as a result of any such loan, advance or capital contribution, loans,
advances or capital contributions by Heska to any Subsidiary that is also a
Borrower;  

         (v)        unless a Default Period exists or would exist immediately
after or as a result of any such advance or contribution, advances or
contributions during the fiscal year ending December 31, 2005, by Heska to any
Subsidiary that is not a Borrower; provided, however, that (A) both before and
after such advance or contribution Heska’s  

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  Tangible Net Worth must equal or exceed $100,000 and (B) all contributions and
advances made in reliance on this subsection (v) shall not exceed $700,000 in
the aggregate during the fiscal year ending December 31, 2005;”  

               13.       Dividends. Section 7.5 of the Credit Agreement is
hereby amended in its entirety to read as follows:

         “Section 7.5 Dividends. Such Borrower will not declare or pay any
dividends (other than dividends payable solely in stock of such Borrower) on any
class of its stock or make any payment on account of the purchase, redemption or
other retirement of any shares of such stock or make any distribution in respect
thereof, either directly or indirectly; provided, however, that so long as no
Default Period then exists or would occur immediately following or as a result
of such action, (A) any Borrower that is a Subsidiary of Heska may pay dividends
to Heska so long as such Subsidiary’s Tangible Net Worth both before and after
such dividend equals or exceeds $100,000; and (B) Heska may repurchase capital
stock of Heska held by any employee provided Heska is required to do so pursuant
to any employee equity subscription agreement, stock ownership plan or stock
option agreement in effect from time to time; and provided further that the
aggregate price paid for all such repurchased, redeemed, acquired or retired
capital shall not exceed $100,000 during any fiscal year. Notwithstanding the
foregoing, the exercise of stock options for the purchase of Heska’s capital
stock shall not, by means of any deemed repurchase of shares as a result of a
cashless exercise or otherwise, cause a breach of this Section 7.5.”  

               14.       Capital Expenditures. Section 7.10 of the Credit
Agreement is hereby amended to read in its entirety as follows:

         “Section 7.10 Capital Expenditures. The Borrowers, together with any
Affiliates, will not incur or contract to incur, in the aggregate, Capital
Expenditures in the aggregate during any period described below in excess of the
amount set forth opposite such period:  

  Period

Six months ending June 30, 2005
Seven months ending July 31, 2005
Eight months ending August 31, 2005
Nine months ending September 30, 2005
Ten months ending October 31, 2005
Eleven months ending November 30, 2005
Twelve months ending December 31, 2005 Maximum Capital
Expenditures
[***]
[***]
[***]
[***]
[***]
[***]
[***]”

               15.       Compliance Certificate. Exhibit G to the Credit
Agreement is replaced in its entirety by Exhibit C to this Amendment.

               16.       Notice Addresses. In accordance with Section 9.5 of the
Credit Agreement, the following shall serve as notice addresses for all purposes
for the Borrowers and Lender:

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  If to the Borrowers:

Heska Corporation
3760 Rocky Mountain Avenue
Loveland, Colorado 80538
Telecopier: [***]
Attention: Chief Financial Officer

Diamond Animal Health, Inc.
c/o Heska Corporation
3760 Rocky Mountain Avenue
Loveland, Colorado 80538
Telecopier: [***]
Attention: Chief Financial Officer

If to the Lender:

Wells Fargo Business Credit, Inc.
MAC C7300-210
1740 Broadway
Denver, Colorado 80202
Telecopier: [***]
Attention: [***]  

               17.       No Other Changes. Except as explicitly amended by this
Amendment, all of the terms and conditions of the Credit Agreement shall remain
in full force and effect and shall apply to any advance or letter of credit
thereunder.

               18.       Waiver of Defaults. The Borrowers are in default of
Section 6.5 of the Credit Agreement as a result of Heska’s failure to timely pay
franchise taxes to the State of Delaware and of Section 5.1 of the Credit
Agreement as a result of Heska’s failure to maintain its corporate good standing
with the State of Delaware (collectively, the “Existing Defaults”). Upon the
terms and subject to the conditions set forth in this Amendment, the Lender
hereby waives the Existing Defaults. This waiver shall be effective only in this
specific instance and for the specific purpose for which it is given, and this
waiver shall not entitle the Borrowers to any other or further waiver in any
similar or other circumstances.

               19.       Consent to Refinancing of Real Property. So long as no
Default Period then exists, the Lender consents to the following:

       (a)     Diamond's grant of a security interest in the Farm Mortgaged
Property to secure existing indebtedness payable to Agri Laboratories, Ltd. or
new indebtedness for borrowed money of not less than $250,000 nor more than
$750,000, in each case on terms acceptable to the Lender in its reasonable
discretion, but in no event on terms less favorable to the Borrowers than the
terms of the Term Loan B Note. Upon funding of  

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such new indebtedness or the grant of such security interest to Agri
Laboratories, Ltd., the Lender will release its security interst in the Farm
Mortgaged Property.  

       (b)     Diamond’s incurrence of indebtedness not less than $1,000,000 nor
more than $3,000,000, and grant of a security interest in the Factory Mortgaged
Property to secure such indebtedness, each in connection with a refinancing of
the Term Loan B Note, provided that (a) the proceeds of such indebtedness are
sufficient to repay, and in fact are used to repay, the Term Loan B Note in its
entirety, with the balance of such proceeds (if any) being deposited in
Diamond’s Collateral Account for repayment of Revolving Advances, and (b) the
terms of such indebtedness are acceptable to the Lender in its reasonable
discretion, but in no event on terms less favorable to the Borrowers than the
terms of the Term Loan B Note. In the case of such a refinancing, the Lender
agrees that it will release its security interest in the Factory Mortgaged
Property upon receipt of the proceeds of such permitted refinancing. This
consent shall be effective only in this specific instance and for the specific
purpose for which it is given, and this consent shall not entitle the Borrowers
to any other or further consent in any similar or other circumstances. All
previous consents with respect to refinancing of the Farm Mortgage or the
Factory Mortgage are withdrawn and replaced with the consents described in this
paragraph 19.  

               20.       Conditions Precedent. This Amendment, including the
waiver set forth in paragraph 18 and the consents set forth in paragraph 19,
shall be effective when the Lender shall have received an executed original
hereof, together with the following, each in form and substance acceptable to
the Lender in its sole discretion:

       (a)     The Equipment Notes in the form set forth in Exhibits A and B to
this Amendment.  

       (b)     Amendments to the Farm Mortgage and the Factory Mortgage to
reflect the Equipment Notes.  

       (c)     Appraisals of the Eligible Equipment.  

       (d)     A Patent and Trademark Security Agreement, properly executed by
Diamond.  

       (e)     Evidence that Heska is in good standing with the State of
Delaware and has paid all corporate taxes and fees.  

       (f)     A landlord disclaimer for the Borrowers’ office in Loveland,
Colorado.  

       (g)     Such other matters as the Lender may require.  

               21.       Representations and Warranties. The Borrowers hereby
represent and warrant to the Lender as follows:

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       (a)     The Borrowers have all requisite power and authority to execute
this Amendment and to perform all of its obligations hereunder, and this
Amendment has been duly executed and delivered by the Borrowers and constitute
the legal, valid and binding obligation of the Borrowers, enforceable in
accordance with their terms.  

       (b)     The execution, delivery and performance by the Borrowers of this
Amendment have been duly authorized by all necessary corporate action and do not
(i) require any authorization, consent or approval by any governmental
department, commission, board, bureau, agency or instrumentality, domestic or
foreign, (ii) violate any provision of any law, rule or regulation or of any
order, writ, injunction or decree presently in effect, having applicability to
the Borrowers, or the articles of incorporation or by-laws of the Borrowers, or
(iii) result in a breach of or constitute a default under any indenture or loan
or credit agreement or any other agreement, lease or instrument to which any
Borrower is a party or by which it or its properties may be bound or affected.  

       (c)     All of the representations and warranties contained in Article V
of the Credit Agreement are correct on and as of the date hereof as though made
on and as of such date, except to the extent that such representations and
warranties relate solely to an earlier date.  

               22.       No Other Waiver. Except as set forth in paragraph 18,
the execution of this Amendment and acceptance of any documents related hereto
shall not be deemed to be a waiver of any Default or Event of Default under the
Credit Agreement or breach, default or event of default under any Security
Document or other document held by the Lender, whether or not known to the
Lender and whether or not existing on the date of this Amendment.

               23.       Release. The Borrowers hereby absolutely and
unconditionally release and forever discharge the Lender, and any and all
participants, parent corporations, subsidiary corporations, affiliated
corporations, insurers, indemnitors, successors and assigns thereof, together
with all of the present and former directors, officers, agents and employees of
any of the foregoing, from any and all claims, demands or causes of action of
any kind, nature or description, whether arising in law or equity or upon
contract or tort or under any state or federal law or otherwise, which any
Borrower has had, now has or has made claim to have against any such person for
or by reason of any act, omission, matter, cause or thing whatsoever arising
from the beginning of time to and including the date of this Amendment, whether
such claims, demands and causes of action are matured or unmatured or known or
unknown.

               24.       Costs and Expenses. The Borrowers hereby reaffirm their
agreement under the Credit Agreement to pay or reimburse the Lender on demand
for all costs and expenses incurred by the Lender in connection with the Loan
Documents, including without limitation all reasonable fees and disbursements of
legal counsel. Without limiting the generality of the foregoing, the Borrowers
specifically agree to pay all fees and disbursements of counsel to the Lender
for the services performed by such counsel in connection with the preparation of
this Amendment and the documents and instruments incidental hereto. The
Borrowers hereby agree that the Lender may, at any time or from time to time in
its sole discretion and without further authorization by the Borrowers, make a
loan to the Borrowers under the Credit Agreement, or

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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.

apply the proceeds of any loan, for the purpose of paying any such fees,
disbursements, costs and expenses.

               25.       Miscellaneous. This Amendment may be executed in any
number of counterparts, each of which when so executed and delivered shall be
deemed an original and all of which counterparts, taken together, shall
constitute one and the same instrument.

                IN WITNESS WHEREOF, the parties hereto have caused this
Amendment to be duly executed as of the date first written above.

HESKA CORPORATION

By    /s/ JASON NAPOLITANO                       
              Jason Napolitano
     Its    Chief Financial Officer                        

WELLS FARGO BUSINESS CREDIT, INC.

By    /s/ [***]                                                     
          [***], Vice President   DIAMOND ANIMAL HEALTH, INC.

By    /s/ JASON NAPOLITANO                        
              Jason Napolitano
     Its     Chief Financial Officer                        

--------------------------------------------------------------------------------

Exhibit A to Tenth Amendment

EQUIPMENT NOTE
(HESKA)

$500,000 July 26, 2005
Denver, Colorado

          For value received, the undersigned, Heska Corporation, a Delaware
corporation, (the “Borrower”), hereby promises to pay on the Termination Date
under the Credit Agreement (defined below), to the order of Wells Fargo Business
Credit, Inc., a Minnesota corporation (the “Lender”), at its office in Denver,
Colorado, or at any other place designated at any time by the holder hereof, in
lawful money of the United States of America and in immediately available funds,
the principal sum of Five Hundred Thousand Dollars ($500,000) or the aggregate
unpaid principal amount of all Equipment Advances made by the Lender to the
Borrower under the Credit Agreement (defined below) together with interest on
the principal amount hereunder remaining unpaid from time to time, computed on
the basis of the actual number of days elapsed and a 360-day year, from the date
hereof until this Note is fully paid at the rate from time to time in effect
under the Second Amended and Restated Credit and Security Agreement dated as of
June 14, 2000 (as the same may hereafter be amended, supplemented or restated
from time to time, the “Credit Agreement”) by and between the Lender, the
Borrower, and Diamond Animal Health, Inc., an Iowa corporation. The principal
hereof and interest accruing thereon shall be due and payable as provided in the
Credit Agreement. This Note may be prepaid only in accordance with the Credit
Agreement.

          This Note is issued pursuant, and is subject, to the Credit Agreement,
which provides, among other things, for acceleration hereof. This Note is the
Heska Equipment Note referred to in the Credit Agreement. This Note is secured,
among other things, pursuant to the Credit Agreement and the Security Documents
as therein defined, and may now or hereafter be secured by one or more other
security agreements, mortgages, deeds of trust, assignments or other instruments
or agreements.

          The Borrower hereby agrees to pay all costs of collection, including
attorneys’ fees and legal expenses in the event this Note is not paid when due,
whether or not legal proceedings are commenced.

          Presentment or other demand for payment, notice of dishonor and
protest are expressly waived.

  HESKA CORPORATION

By    /s/ JASON NAPOLITANO                        
              Jason Napolitano
     Its     Chief Financial Officer                        

--------------------------------------------------------------------------------

Exhibit B to Tenth Amendment

EQUIPMENT NOTE
(DIAMOND)

$2,000,000 July 26, 2005
Denver, Colorado

          For value received, the undersigned, Diamond Animal Health, Inc., an
Iowa corporation (“Diamond”) and Heska Corporation, a Delaware corporation
(collectively, the “Borrower”), hereby promise, jointly and severally, to pay on
the Termination Date under the Credit Agreement (defined below), to the order of
Wells Fargo Business Credit, Inc., a Minnesota corporation (the “Lender”), at
its office in Denver, Colorado, or at any other place designated at any time by
the holder hereof, in lawful money of the United States of America and in
immediately available funds, the principal sum of Two Million Dollars
($2,000,000) or the aggregate unpaid principal amount of all Equipment Advances
made by the Lender to Diamond under the Credit Agreement (defined below)
together with interest on the principal amount hereunder remaining unpaid from
time to time, computed on the basis of the actual number of days elapsed and a
360-day year, from the date hereof until this Note is fully paid at the rate
from time to time in effect under the Second Amended and Restated Credit and
Security Agreement dated as of June 14, 2000 (as the same may hereafter be
amended, supplemented or restated from time to time, the “Credit Agreement”) by
and between the Lender and the Borrowers. The principal hereof and interest
accruing thereon shall be due and payable as provided in the Credit Agreement.
This Note may be prepaid only in accordance with the Credit Agreement.

          This Note is issued pursuant, and is subject, to the Credit Agreement,
which provides, among other things, for acceleration hereof. This Note is the
Diamond Equipment Note referred to in the Credit Agreement. This Note is
secured, among other things, pursuant to the Credit Agreement and the Security
Documents as therein defined, and may now or hereafter be secured by one or more
other security agreements, mortgages, deeds of trust, assignments or other
instruments or agreements.

          The Borrower hereby agrees to pay all costs of collection, including
attorneys’ fees and legal expenses in the event this Note is not paid when due,
whether or not legal proceedings are commenced.

--------------------------------------------------------------------------------

          Presentment or other demand for payment, notice of dishonor and
protest are expressly waived.

  DIAMOND ANIMAL HEALTH, INC.

By    /s/ JASON NAPOLITANO                        
              Jason Napolitano
     Its     Chief Financial Officer                        

HESKA CORPORATION

By    /s/ JASON NAPOLITANO                        
              Jason Napolitano
     Its     Chief Financial Officer                        

--------------------------------------------------------------------------------

Exhibit C to Tenth Amendment

COMPLIANCE CERTIFICATE

To:                                                                        
                  Wells Fargo Business Credit, Inc.

Date:                                                       , 20      

Subject:     Heska Corporation
                   Financial Statements

In accordance with our Second Amended and Restated Credit and Security Agreement
dated as of June 14, 2000 (the “Credit Agreement”), attached are the financial
statements of Heska Corporation (“Heska”) as of and for __________, 20___ (the
“Reporting Date”) and the year-to-date period then ended (the “Current
Financials”). All terms used in this certificate have the meanings given in the
Credit Agreement.

I certify that, to the best of my knowledge, the Current Financials have been
prepared in accordance with GAAP, subject to year-end audit adjustments, and
fairly present the Borrowers’ financial condition and the results of its
operations as of the date thereof.

                    Events of Default. (Check one):

  [   ]    The undersigned does not have knowledge of the occurrence of a
Default or Event of Default under the Credit
   Agreement.

  [   ]    The undersigned has knowledge of the occurrence of a Default or Event
of Default under the Credit Agreement
   and attached hereto is a statement of the facts with respect to thereto.

                   I hereby certify to the Lender as follows:

  [   ]    The Reporting Date does not mark the end of one of the Borrowers’
fiscal quarters, hence I am completing all
   paragraphs below except paragraph 4.

  [   ]    The Reporting Date marks the end of one of the Borrowers' fiscal
quarters, hence I am completing all paragraphs
   below.

                         Financial Covenants. I further hereby certify as
follows:

           1.        Accounts Payable.  Pursuant to Section 6.5 of the Credit
Agreement, as of the Reporting Date, Past Due Payables on a consolidated basis
was $_________________, which [   ] satisfies [   ] does not satisfy the
requirement that the Borrowers have no more than $750,000 in Past Due Payables
during the period from May 31, 2005 through September 30, 2005, and no Past Due
Payables at all other times.

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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.

           2.        Spread.  Pursuant to Section 2.7 of the Credit Agreement,
as of the Reporting Date, Heska’s prior-fiscal-year Net Income was, on a
consolidated basis, $_________________, which determines a base Spread of _____%
pursuant to the table below. Heska [   ] has [   ] has not raised at least [***]
in Additional Capital as of the Reporting Date, leading to an [   ] increase
[   ] decrease from the base Spread of _____%, so that the applicable Spread is
equal to _____%.

  Prior Fiscal Year Net Income
Less than $0
Greater than or equal to $0
but less than $2,500,000
Greater than or equal to $2,500,000 Spread
2.75%

1.75%
0.75%

           3.        Minimum Capital. Pursuant to Section 6.12 of the Credit
Agreement, as of the Reporting Date, Heska’s Capital was, on a consolidated
basis, $_____________, which [   ] satisfies [   ] does not satisfy the
requirement that such amount be not less than $________________on the Reporting
Date, as set forth in the table below:

  Date
June 30, 2005
July 31, 2005
August 31, 2005
September 30, 2005
October 31, 2005
November 30, 2005
December 31, 2005
January 31, 2006 and the last day
of each month thereafter Minimum Capital
[***]
[***]
[***]
[***]
[***]
[***]
[***]

[***]

           4.        Minimum Net Income. Pursuant to Section 6.13 of the Credit
Agreement, as of the Reporting Date, Heska’s Net Income was, on a consolidated
basis, $______________, which [   ] satisfies [   ] does not satisfy the
requirement that such amount be no less than $_________________on the Reporting
Date, as set forth in the table below:

  Period
Six months ending June 30, 2005
Nine months ending September 30, 2005
Twelve months ending December 31, 2005 Minimum Net Income
[***]
[***]
[***]

           5.        Minimum Liquidity. Pursuant to Section 6.14 of the Credit
Agreement, as of the Reporting Date, Heska’s Liquidity was, on a consolidated
basis, $________________, which [   ] satisfies [   ] does not satisfy the
requirement that such amount be no less than $1,500,000 on the Reporting Date.

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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.

           6.        Minimum Individual Book Net Worth. Pursuant to Section 6.15
of the Credit Agreement, as of the Reporting Date, Heska’s Book Net Worth was
$________________ and Diamond’s Book Net Worth was $________________, which
[   ] satisfies [   ] does not satisfy the requirement that such amounts be no
less than zero on the Reporting Date.

           7.        Maximum Contributions. Pursuant to Section 7.4(a)(v) of the
Credit Agreement, as of the Reporting Date, Heska’s fiscal year-to-date
aggregate contributions to non-Borrower Subsidiaries was $_______________, which
[   ] satisfies [   ] does not satisfy the requirement that such amounts be no
more than $700,000 during any fiscal year.

           8.        Capital Expenditures. Pursuant to Section 7.10 of the
Credit Agreement, as of the Reporting Date, Heska’s Capital Expenditures were,
in the aggregate and on a consolidated basis, $______________ which [   ]
satisfies [   ] does not satisfy the requirement that such amount be not more
than $________________during the period ending on the Reporting Date, as set
forth in the table below:

  Period

Six months ending June 30, 2005
Seven months ending July 31, 2005
Eight months ending August 31, 2005
Nine months ending September 30, 2005
Ten months ending October 31, 2005
Eleven months ending November 30, 2005
Twelve months ending December 31, 2005 Maximum Capital
Expenditures
[***]
[***]
[***]
[***]
[***]
[***]
[***]

Attached hereto are all relevant facts in reasonable detail to evidence, and the
computations of the financial covenants referred to above. These computations
were made in accordance with GAAP.

  HESKA CORPORATION

By                                            
              
     Its