Exhibit 10.4

          FIRST AMENDMENT TO NET LEASE AGREEMENT
AND DEVELOPMENT AGREEMENT

           THIS FIRST AMENDMENT TO NET LEASE AGREEMENT AND DEVELOPMENT AGREEMENT
(“First Amendment”) is made and entered into by and between CCMRED 40, LLC, a
Colorado Limited Liability Company (“Landlord”), and HESKA CORPORATION, a
Delaware Corporation (“Tenant”).

RECITALS

         1.     The Landlord and the Tenant previously entered into a Net Lease
Agreement dated May 24, 2004 (“Lease”), and a Development Agreement dated May
24, 2004 (“Development Agreement”), both of which relate to the lease by the
Landlord to the Tenant of approximately five and fifty-two one/hundredths (5.52)
acres of real property (“Real Property”) and the construction of an office,
laboratory and warehouse building thereon.

         2.     The Lease and the Development Agreement require the Landlord to
complete the “Base Building Improvements” no later than one hundred forty-six
(146) business days following the issuance of a building permit for the
construction of the Base Building Improvements.

        3.     The Lease further provides for the payment of liquidated damages
in the event the Landlord shall fail to deliver possession of the substantially
completed Base Building Improvements to the Tenant within said one hundred
forty-six (146) business day period.

        4.     The parties desire to extend the date for the completion of the
Base Building Improvements and the imposition of liquidated damages upon the
terms set forth hereinafter.

        5.     The parties further desire to extend the date for the completion
of landscaping on the Real Property upon the terms set forth hereinafter.

        6.     Initially capitalized terms used herein and defined in the Lease
and/or the Development Agreement shall have the meanings contained in the Lease
and/or the Development Agreement, unless otherwise defined herein.

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           NOW, THEREFORE, for good and valuable consideration, the receipt and
adequacy of which are hereby confessed and acknowledged, each of the parties
hereto hereby agrees as follows:

        1.     Extension of Landlord’s Completion Date and Commencement of
Liquidated Damages. The Lease and the Development Agreement are hereby modified
and amended to grant to the Landlord one hundred seventy-five (175) business
days (i.e., until May 19, 2005) (“Extended Landlord’s Completion Date”) rather
than one hundred forty-six (146) business days for the Completion of the Base
Building Improvements and for delivery of possession of the substantially
completed Base Building Improvements to the Tenant, provided that such extension
shall not materially adversely impact the Tenant’s ability to obtain
certificates of occupancy for the Building or utilize the Building for Tenant’s
intended use. All provisions to the contrary set forth in the Lease and the
Development Agreement are hereby modified accordingly.

        2.     Landscaping. The Plans and Specifications for the Project include
the completion of certain landscaping as more fully set forth in the Development
Agreement. As a result of certain work performed by the City of Loveland,
Colorado (“City”), on Rocky Mountain Avenue adjacent to the Real Property, the
installation of landscaping on the Real Property will be delayed to a date
subsequent to the Extended Landlord’s Completion Date. Therefore, the parties
agree that the Landlord may install such landscaping subsequent to the Extended
Landlord’s Completion Date provided that (i) the Landlord shall post a letter of
credit or other acceptable security required by the City to secure the
Landlord’s obligations to complete the remaining landscaping and (ii) the
Landlord will complete all remaining landscaping as soon as commercially
reasonable following completion of the City’s work on Rocky Mountain Avenue and
subject to any delays caused by adverse weather conditions. All provisions to
the contrary set forth in the Lease and the Development Agreement are hereby
modified accordingly.

        3.    Effect of Amendment. Except as amended by this First Amendment,
all of the terms and provisions of the Lease and the Development Agreement shall
remain in full force and effect and the validity of the Lease and the
Development Agreement, as amended hereby, is hereby reaffirmed by the parties
hereto.

        4.     Conflicting Provisions. Whenever the terms and provisions of this
First Amendment and the terms and provisions of either the Lease or the
Development Agreement conflict, the terms and provisions of this First Amendment
shall be deemed to supersede the conflicting terms and provisions of the Lease
and/or the Development Agreement. Each party agrees that it shall continue to be
bound by all of the terms and conditions of the Lease and the Development
Agreement, as amended hereby.

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        5.        Counterparts. This First Amendment shall be deemed to have
been fully executed and delivered when the undersigned have executed at least
one (1) counterpart, but not necessarily the same counterpart.

        6.        Facsimile Signature. Execution of this First Amendment may
occur by facsimile and a facsimile signature of this instrument shall be deemed
effective in the same manner and to the same extent as an original signature
hereon.

          IN WITNESS WHEREOF, the undersigned have executed this First Amendment
to Net Lease Agreement and Development Agreement on the date set opposite their
respective signatures.

Date:    February 11, 2005                       

Date:    February 11, 2005                       

Date:    February 11, 2005                          CCMRED 40, LLC, a Colorado
  Limited Liability Company

By:  McWhinney Real Estate Services,
        Inc., a Colorado Corporation, Manager

       By    /s/ DOUGLAS L. HILL                                
              Douglas L. Hill
              Chief Operating Officer

                 “Landlord”

HESKA CORPORATION,
a Delaware Corporation

By:    /s/   JASON NAPOLITANO                       
Print Name:     Jason Napolitano                         
Print Title:    Executive Vice President, Chief   
                       Financial Officer and Secretary                  
            

ATTEST:

By:    /s/   MICHAEL A. BENT                            
Print Name:     Michael A. Bent                          
Print Title:    Vice President, Principal              
                     Accounting Officer and Controller                  
            

                 “Tenant”