SYNBIOTICS CORPORATION                Exhibit 10.50
                                                                  -------------
                     1995 STOCK OPTION/STOCK ISSUANCE PLAN
                     -------------------------------------


                                  ARTICLE ONE
                              GENERAL PROVISIONS
                              ------------------


I.    PURPOSE OF THE PLAN

This 1995 Stock Option/Stock Issuance Plan (the "Plan") is intended to promote
the interests of Synbiotics Corporation, a California corporation, by providing
eligible persons with the opportunity to acquire a proprietary interest, or
otherwise increase their proprietary interest, in the Corporation as an
incentive for them to remain in the service of the Corporation.

Capitalized terms not otherwise defined shall have the meanings assigned to such
terms in the attached Appendix.


II.   STRUCTURE OF THE PLAN

      A.     The Plan shall be divided into three separate equity programs:

             (i)    the Discretionary Option Grant Program under which eligible
                    persons may, at the discretion of the Plan Administrator, be
                    granted options to purchase shares of common stock of the
                    Corporation,

             (ii)   the Stock Issuance Program under which eligible persons may,
                    at the discretion of the Plan Administrator, be issued
                    shares of common stock of the Corporation directly, either
                    through the immediate purchase of such shares or as a bonus
                    for services rendered the Corporation (or any Parent or
                    Subsidiary), and

            (iii)   the Automatic Option Grant Program under which non-employee
                    directors shall automatically receive option grants at
                    periodic intervals to purchase shares of common stock of the
                    Corporation.

      B.    The provisions of Articles One and Five shall apply to all equity
            programs under the Plan and shall accordingly govern the interests
            of all persons under the Plan.


III.  ADMINISTRATION OF THE PLAN

      A.    This Plan shall be administered by the Board or by a committee
            ("Committee") consisting of two (2) or more Board members who assume
            full responsibility for the administration of the Plan (the "Plan
            Administrator"). Members of any Committee shall serve for such
            period of time as the Board may determine and shall be subject to
            removal by the Board at any time.

      B.    The Plan Administrator shall have full power and authority (subject
            to the express provisions of the Plan) to establish such rules and
            regulations as it may deem appropriate for the proper administration
            of the Plan and to make such determinations under, and issue such
            interpretations of, the Plan and any outstanding option grants or
            stock issuances as it may deem necessary or

                                      -1-

 
            advisable. Decisions of the Plan Administrator shall be final and
            binding on all parties who have an interest in the Plan or any
            outstanding option or stock issuance.

      C.    Notwithstanding the above, the administration of the Automatic
            Option Grant Program under Article Three shall be self executing in
            accordance with the terms and conditions thereof and the Plan
            Administrator shall not exercise any discretionary functions in
            respect to matters governed by Article Three.

     D.     The Plan Administrator shall, within the scope of its administrative
            jurisdiction under the Plan, have full authority to determine, (i)
            with respect to the option grants under the Discretionary Option
            Grant Program, which eligible persons are to receive option grants,
            the time or times when such option grants are to be made, the number
            of shares to be covered by each such grant, the status of the
            granted option as either an Incentive Option or a Non-Statutory
            Option, the time or times at which each option is to become
            exercisable, the vesting schedule (if any) applicable to the option
            shares and the maximum term for which the option is to remain
            outstanding and (ii) with respect to stock issuances under the Stock
            Issuance Program, which eligible persons are to receive stock
            issuances, the time or times when such issuances are to be made, the
            number of shares to be issued to each Participant, the vesting
            schedule (if any) applicable to the issued shares and the
            consideration to be paid by the Participant for such shares.

      E.    The Plan Administrator shall have the absolute discretion either to
            grant options in accordance with the Discretionary Option Grant
            Program or to effect stock issuances in accordance with the Stock
            Issuance Program.


IV.   OPTION GRANTS AND STOCK ISSUANCES

      A.    Subject to Section V.B below, the persons eligible to receive stock
            issuances under the Stock Issuance Program ("Participant") and/or
            option grants pursuant to the Discretionary Option Grant Program
            ("Optionee") are as follows:

            (i)     officers and other employees of the Corporation (or its
                    parent or subsidiary corporations) who render services which
                    contribute to the management, growth and financial success
                    of the Corporation (or its parent or subsidiary
                    corporations);

            (ii)    those consultants or other independent contractors who
                    provide valuable services to the Corporation (or its parent
                    or subsidiary corporations);

            provided that, notwithstanding any other provision of this Plan, no
            option grants under the Discretionary Option Grant Program or stock
            issuances under the Stock Issuance Program shall be made to any
            director hereunder unless, at the time of such option or issuance,
            the Plan Administrator is a Committee composed entirely of non-
            employee Board members none of whom have received an option grant or
            stock issuance under this Plan or any other stock plan of the
            Corporation (or any parent or subsidiary corporation) other than
            under the Automatic Option Grant Program during the one year prior
            to service on the Committee or during such service.

     B.     The individuals eligible to receive option grants under the
            Automatic Option Grant Program shall be those individuals who serve
            as non-employee Board members during the term of the Plan.

                                      -2-

 
V.    STOCK SUBJECT TO THE PLAN

      A.    The stock issuable under the Plan shall be shares of authorized but
            unissued or reacquired common stock of the Corporation ("Common
            Stock"), including shares repurchased by the Corporation on the open
            market. The maximum number of shares of Common Stock which may be
            issued over the term of the Plan shall not exceed 1,300,000 shares.
            Such authorized share reserve is comprised of (i) the number of
            shares available for issuance under the Predecessor Plan as last
            approved by the Corporation's stockholders prior to such date,
            including the shares subject to the outstanding options incorporated
            into the Plan and any other shares which would have been available
            for future option grants under the Predecessor Plan, plus (ii) an
            additional increase of 282,055 shares authorized by the Board under
            the Plan, subject to stockholder approval.

      B.    No one person participating in the Plan may receive options and
            direct stock issuances for more than 800,000 shares of Common Stock
            in the aggregate over the term of the Plan.

      C.    Shares of Common Stock subject to outstanding options shall be
            available for subsequent issuance under the Plan to the extent (i)
            the options (including any options incorporated from the Predecessor
            Plan) expire or terminate for any reason prior to exercise in full
            or (ii) the options are cancelled in accordance with the
            cancellation-regrant provisions of Article Two. All shares issued
            under the Plan (including shares issued upon exercise of options
            incorporated from the Predecessor Plan), whether or not those shares
            are subsequently repurchased by the Corporation pursuant to its
            repurchase rights under the Plan, shall reduce on a share-for-share
            basis the number of shares of Common Stock available for subsequent
            issuance under the Plan. In addition, should the exercise price of
            an option under the Plan (including any option incorporated from the
            Predecessor Plan) be paid with shares of Common Stock or should
            shares of Common Stock otherwise issuable under the Plan be withheld
            by the Corporation in satisfaction of the withholding taxes incurred
            in connection with the exercise of an option or the vesting of a
            stock issuance under the Plan, then the number of shares of Common
            Stock available for issuance under the Plan shall be reduced by the
            gross number of shares for which the option is exercised or which
            vest under the stock issuance, and not by the net number of shares
            of Common Stock issued to the holder of such option or stock
            issuance.

      D.    Should any change be made to the Common Stock by reason of any stock
            split, stock dividend, recapitalization, combination of shares,
            exchange of shares or other change affecting the outstanding Common
            Stock as a class without the Corporation's receipt of consideration,
            appropriate adjustments shall be made to (i) the maximum number
            and/or class of securities issuable under the Plan, (ii) the maximum
            number and/or class of securities for which the share reserve is to
            increase automatically each year, (iii) the number and/or class of
            securities for which any one person may be granted options and
            direct stock issuances over the term of the Plan, (iv) the number
            and/or class of securities for which automatic option grants are to
            be subsequently made under the Automatic Option Grant Program and
            (v) the number and/or class of securities and the exercise price per
            share in effect under each outstanding option (including any option
            incorporated from the Predecessor Plan) in order to prevent the
            dilution or enlargement of benefits thereunder. The adjustments
            determined by the Plan Administrator shall be final, binding and
            conclusive.

                                      -3-

 
                                  ARTICLE TWO
                      DISCRETIONARY OPTION GRANT PROGRAM
                      ----------------------------------


I.   OPTION TERMS

Each option shall be evidenced by one or more documents in the form approved by
the Plan Administrator; provided, however, that each such document shall comply
                        --------                                               
with the terms specified below.  Each document evidencing an Incentive Option
shall, in addition, be subject to the provisions of the Plan applicable to such
options.

     A.     Exercise Price.
            -------------- 

            1.    The exercise price per share shall be fixed by the Plan
                  Administrator but shall not be less than eighty-five percent
                  (85%) of the Fair Market Value per share of Common Stock on
                  the option grant date.

            2.    The exercise price shall become immediately due upon exercise
                  of the option and shall, subject to the provisions of Section
                  I of Article Five and the documents evidencing the option, be
                  payable in one or more of the forms specified below:

                  (i)      cash or check made payable to the Corporation,

                  (ii)     shares of Common Stock held for the requisite period
                           necessary to avoid a charge to the Corporation's
                           earnings for financial reporting purposes and valued
                           at Fair Market Value on the exercise date, or

                  (iii)    to the extent the option is exercised for vested
                           shares, through a special sale and remittance
                           procedure pursuant to which the Optionee shall
                           concurrently provide irrevocable written instructions
                           to (a) a Corporation-designated brokerage firm to
                           effect the immediate sale of the purchased shares and
                           remit to the Corporation, out of the sale proceeds
                           available on the settlement date, sufficient funds to
                           cover the aggregate exercise price payable for the
                           purchased shares plus all applicable Federal, state
                           and local income and employment taxes required to be
                           withheld by the Corporation by reason of such
                           exercise and (b) the Corporation to deliver the
                           certificates for the purchased shares directly to
                           such brokerage firm in order to complete the sale
                           transaction.

                  Except to the extent such sale and remittance procedure is
                  utilized, payment of the exercise price for the purchased
                  shares must be made on the exercise date.

      B.    Exercise and Term of Options.  Each option shall be exercisable at
            ----------------------------                                      
            such time or times, during such period and for such number of shares
            as shall be determined by the Plan Administrator and set forth in
            the documents evidencing the option. However, no option shall have a
            term in excess of ten (10) years measured from the option grant
            date.

      C.    Effect of Termination of Service.
            -------------------------------- 

            1.    The following provisions shall govern the exercise of any
                  options held by the Optionee at the time of cessation of
                  Service or death:

                                      -4-

 
                  (i)     Any option outstanding at the time of the Optionee's
                          cessation of Service for any reason shall remain
                          exercisable for such period of time thereafter as
                          shall be determined by the Plan Administrator and set
                          forth in the documents evidencing the option, but no
                          such option shall be exercisable after the expiration
                          of the option term.

                  (ii)    Any option exercisable in whole or in part by the
                          Optionee at the time of death may be subsequently
                          exercised by the personal representative of the
                          Optionee's estate or by the person or persons to whom
                          the option is transferred pursuant to the Optionee's
                          will or in accordance with the laws of descent and
                          distribution.

                  (iii)   During the applicable post-Service exercise period,
                          the option may not be exercised in the aggregate for
                          more than the number of vested shares for which the
                          option is exercisable on the date of the Optionee's
                          cessation of Service. Upon the expiration of the
                          applicable exercise period or (if earlier) upon the
                          expiration of the option term, the option shall
                          terminate and cease to be outstanding for any vested
                          shares for which the option has not been exercised.
                          However, the option shall, immediately upon the
                          Optionee's cessation of Service, terminate and cease
                          to be outstanding to the extent it is not exercisable
                          for vested shares on the date of such cessation of
                          Service.

                  (iv)    In the event of a Corporate Transaction,the provisions
                          of Section III of this Article Two shall govern the
                          period for which the outstanding options are to remain
                          exercisable following the Optionee's cessation of
                          Service and shall supersede any provisions to the
                          contrary in this section.

            2.    The Plan Administrator shall have the discretion, exercisable
                  either at the time an option is granted or at any time while
                  the option remains outstanding, to:

                  (i)    extend the period of time for which the option is to
                         remain exercisable following the Optionee's cessation
                         of Service from the period otherwise in effect for that
                         option to such greater period of time as the Plan
                         Administrator shall deem appropriate, but in no event
                         beyond the expiration of the option term, and/or

                  (ii)   permit the option to be exercised, during the
                         applicable post-Service exercise period, not only with
                         respect to the number of vested shares of Common Stock
                         for which such option is exercisable at the time of the
                         Optionee's cessation of Service but also with respect
                         to one or more additional installments in which the
                         Optionee would have vested under the option had the
                         Optionee continued in Service.

      D.    Stockholder Rights.  The holder of an option shall have no
            ------------------
            stockholder rights with respect to the shares subject to the option
            until such person shall have exercised the option, paid the exercise
            price and become a holder of record of the purchased shares.

      E.    Repurchase Rights.  The Plan Administrator shall have the discretion
            -----------------                                                   
            to grant options which are exercisable for unvested shares of Common
            Stock. Should the Optionee cease Service while holding such unvested
            shares, the Corporation shall have the right to repurchase, at the
            exercise price paid per share, any or all of those unvested shares.
            The terms upon which such repurchase right shall be exercisable
            (including the period and procedure for exercise and the appropriate

                                      -5-

 
            vesting schedule for the purchased shares) shall be established by
            the Plan Administrator and set forth in the document evidencing such
            repurchase right.

      F.    Limited Transferability of Options.  During the lifetime of the
            ----------------------------------                             
            Optionee, the option shall be exercisable only by the Optionee and
            shall not be assignable or transferable other than by will or by the
            laws of descent and distribution following the Optionee's death.
            However, a Non-Statutory Option may be assigned in accordance with
            the terms of a Qualified Domestic Relations Order within the meaning
            of Internal Revenue Code Section 414(p). The assigned option may
            only be exercised by the person or persons who acquire a proprietary
            interest in the option pursuant to such Qualified Domestic Relations
            Order. The terms applicable to the assigned option (or portion
            thereof) shall be the same as those in effect for the option
            immediately prior to such assignment and shall be set forth in such
            documents issued to the assignee as the Plan Administrator may deem
            appropriate


II.   INCENTIVE OPTIONS

The terms specified below shall be applicable to all Incentive Options.  Except
as modified by the provisions of this Section II, all the provisions of Articles
One, Two and Five shall be applicable to Incentive Options. Options which are
specifically designated as Non-Statutory Options when issued under the Plan
shall not be subject to the terms of this Section II.
      ---                                            

      A.    Eligibility.  Incentive Options may only be granted to Employees.
            -----------                                                      

      B.    Exercise Price.  The exercise price per share shall not be less than
            --------------                                                      
            one hundred percent (100%) of the Fair Market Value per share of
            Common Stock on the option grant date.

      C.    Dollar Limitation.  The aggregate Fair Market Value of the shares of
            -----------------                                                   
            Common Stock (determined as of the respective date or dates of
            grant) for which one or more options granted to any Employee under
            the Plan (or any other option plan of the Corporation or any Parent
            or Subsidiary) may for the first time become exercisable as
            Incentive Options during any one (1) calendar year shall not exceed
            the sum of One Hundred Thousand Dollars ($100,000). To the extent
            the Employee holds two (2) or more such options which become
            exercisable for the first time in the same calendar year, the
            foregoing limitation on the exercisability of such options as
            Incentive Options shall be applied on the basis of the order in
            which such options are granted.

      D.    10% Stockholder.  If any Employee to whom an Incentive Option is
            ---------------                                                 
            granted is a 10% stockholder (within the meaning of Internal Revenue
            Code Section 424(d)), then the exercise price per share shall not be
            less than one hundred ten percent (110%) of the Fair Market Value
            per share of Common Stock on the option grant date, and the option
            term shall not exceed five (5) years measured from the option grant
            date.


III.  CORPORATE TRANSACTION

      A.    In the event of any Corporate Transaction, each outstanding option
            shall automatically accelerate so that each such option shall,
            immediately prior to the effective date of the Corporate
            Transaction, become fully exercisable for all of the shares of
            Common Stock at the time subject to such option and may be exercised
            for any or all of those shares as fully-vested shares of Common
            Stock. However, an outstanding option shall NOT so accelerate if and
            to the extent: (i) such option is, in connection with the Corporate
            Transaction, either to be assumed by the successor corporation (or

                                      -6-

 
            parent thereof) or to be replaced with a comparable option to
            purchase shares of the capital stock of the successor corporation
            (or parent thereof), (ii) such option is to be replaced with a cash
            incentive program of the successor corporation which preserves the
            spread existing on the unvested option shares at the time of the
            Corporate Transaction and provides for subsequent payout in
            accordance with the same vesting schedule applicable to such option
            or (iii) the acceleration of such option is subject to other
            limitations imposed by the Plan Administrator at the time of the
            option grant. The determination of option comparability under clause
            (i) above shall be made by the Plan Administrator, and its
            determination shall be final, binding and conclusive.

     B.     All outstanding repurchase rights shall also terminate
            automatically, and the shares of Common Stock subject to those
            terminated rights shall immediately vest in full, in the event of
            any Corporate Transaction, except to the extent: (i) those
            repurchase rights are to be assigned to the successor corporation
            (or parent thereof) in connection with such Corporate Transaction or
            (ii) such accelerated vesting is precluded by other limitations
            imposed by the Plan Administrator at the time the repurchase right
            is issued.

     C.     Immediately following the consummation of the Corporate Transaction,
            all outstanding options shall terminate and cease to be outstanding,
            except to the extent assumed by the successor corporation (or parent
            thereof).

     D.     Each option which is assumed in connection with a Corporate
            Transaction shall be appropriately adjusted, immediately after such
            Corporate Transaction, to apply to the number and class of
            securities which would have been issuable to the Optionee in
            consummation of such Corporate Transaction had the option been
            exercised immediately prior to such Corporate Transaction.
            Appropriate adjustments shall also be made to (i) the number and
            class of securities available for issuance under the Plan on both an
            aggregate and per Optionee basis following the consummation of such
            Corporate Transaction and (ii) the exercise price payable per share
            under each outstanding option, provided the aggregate exercise price
                                           --------
            payable for such securities shall remain the same.

      E.    Any options which are assumed or replaced in the Corporate
            Transaction and do not otherwise accelerate at that time, shall
            automatically accelerate (and any of the Corporation's outstanding
            repurchase rights which do not otherwise terminate at the time of
            the Corporate Transaction shall automatically terminate and the
            shares of Common Stock subject to those terminated rights shall
            immediately vest in full) in the event the Optionee's Service should
            subsequently terminate by reason of an Involuntary Termination
            within eighteen (18) months following the effective date of such
            Corporate Transaction. Any options so accelerated shall remain
            exercisable for fully-vested shares until the earlier of (i) the
                                                          -------
            expiration of the option term or (ii) the expiration of the one (1)-
            year period measured from the effective date of the Involuntary
            Termination.

      F.    The portion of any Incentive Option accelerated in connection with a
            Corporate Transaction or Change in Control shall remain exercisable
            as an Incentive Option only to the extent the applicable One Hundred
            Thousand Dollar limitation is not exceeded. To the extent such
            dollar limitation is exceeded, the accelerated portion of such
            option shall be exercisable as a Non-Statutory Option under the
            Federal tax laws.

      G.    The grant of options under the Discretionary Option Grant Program
            shall in no way affect the right of the Corporation to adjust,
            reclassify, reorganize or otherwise change its capital or business
            structure or to merge, consolidate, dissolve, liquidate or sell or
            transfer all or any part of its business or assets.

                                      -7-

 
IV.   CANCELLATION AND REGRANT OF OPTIONS

The Plan Administrator shall have the authority to effect, at any time and from
time to time, with the consent of the affected option holders, the cancellation
of any or all outstanding options under the Discretionary Option Grant Program
(including outstanding options incorporated from the Predecessor Plan) and to
grant in substitution new options covering the same or different number of
shares of Common Stock but with an exercise price per share based on the Fair
Market Value per share of Common Stock on the new option grant date.


                                 ARTICLE THREE
                            STOCK ISSUANCE PROGRAM
                            ----------------------


I.    STOCK ISSUANCE TERMS

Shares of Common Stock may be issued under the Stock Issuance Program through
direct and immediate issuances without any intervening option grants.  Each such
stock issuance shall be evidenced by a Stock Issuance Agreement which complies
with the terms specified below.

      A.    Purchase Price
            --------------

            1.    The purchase price per share shall be fixed by the Plan
                  Administrator, but shall not be less than eighty-five percent
                  (85%) of the Fair Market Value per share of Common Stock on
                  the stock issuance date.

            2.    Subject to the provisions of Section I of Article Five, shares
                  of Common Stock may be issued under the Stock Issuance Program
                  for one or both of the following items of consideration which
                  the Plan Administrator may deem appropriate in each individual
                  instance:

                  (i)     cash or check made payable to the Corporation, or

                  (ii)    past services rendered to the Corporation (or any
                          Parent or Subsidiary).

      B.    Vesting Provisions
            ------------------

            1.    Shares of Common Stock issued under the Stock Issuance Program
                  may, in the discretion of the Plan Administrator, be fully and
                  immediately vested upon issuance or may vest in one or more
                  installments over the Participant's period of Service or upon
                  attainment of specified performance objectives. The elements
                  of the vesting schedule applicable to any unvested shares of
                  Common Stock issued under the Stock Issuance Program, namely:

                  (i)     the Service period to be completed by the Participant
                          or the performance objectives to be attained,

                  (ii)    the number of installments in which the shares are to
                          vest,

                  (iii)   the interval or intervals (if any) which are to lapse
                          between installments, and

                                      -8-

 
                  (iv)    the effect which death, Permanent Disability or other
                          event designated by the Plan Administrator is to have
                          upon the vesting schedule,

                  shall be determined by the Plan Administrator and incorporated
                  into the stock issuance agreement.

            2.    Any new, substituted or additional securities or other
                  property (including money paid other than as a regular cash
                  dividend) which the Participant may have the right to receive
                  with respect to the Participant's unvested shares of Common
                  Stock by reason of any stock dividend, stock split,
                  recapitalization, combination of shares, exchange of shares or
                  other change affecting the outstanding Common Stock as a class
                  without the Corporation's receipt of consideration shall be
                  issued subject to (i) the same vesting requirements applicable
                  to the Participant's unvested shares of Common Stock and (ii)
                  such escrow arrangements as the Plan Administrator shall deem
                  appropriate.

            3.    The Participant shall have full stockholder rights with
                  respect to any shares of Common Stock issued to the
                  Participant under the Stock Issuance Program, whether or not
                  the Participant's interest in those shares is vested.
                  Accordingly, the Participant shall have the right to vote such
                  shares and to receive any regular cash dividends paid on such
                  shares.

            4.    Should the Participant cease to remain in Service while
                  holding one or more unvested shares of Common Stock issued
                  under the Stock Issuance Program or should the performance
                  objectives not be attained with respect to one or more such
                  unvested shares of Common Stock, then those shares shall be
                  immediately surrendered to the Corporation for cancellation,
                  and the Participant shall have no further stockholder rights
                  with respect to those shares. To the extent the surrendered
                  shares were previously issued to the Participant for
                  consideration paid in cash or cash equivalent (including the
                  Participant's purchase-money indebtedness), the Corporation
                  shall repay to the Participant the cash consideration paid for
                  the surrendered shares and shall cancel the unpaid principal
                  balance of any outstanding purchase-money note of the
                  Participant attributable to such surrendered shares.

            5.    The Plan Administrator may in its discretion waive the
                  surrender and cancellation of one or more unvested shares of
                  Common Stock (or other assets attributable thereto) which
                  would otherwise occur upon the non-completion of the vesting
                  schedule applicable to such shares. Such waiver shall result
                  in the immediate vesting of the Participant's interest in the
                  shares of Common Stock as to which the waiver applies. Such
                  waiver may be effected at any time, whether before or after
                  the Participant's cessation of Service or the attainment or
                  non-attainment of the applicable performance objectives.


II.   CORPORATE TRANSACTION

      A.    All of the outstanding repurchase rights under the Stock Issuance
            Program shall terminate automatically, and all the shares of Common
            Stock subject to those terminated rights shall immediately vest in
            full, in the event of any Corporate Transaction, except to the
            extent (i) those repurchase rights are assigned to the successor
            corporation (or parent thereof) in connection with such Corporate
            Transaction or (ii) such accelerated vesting is precluded by other
            limitations imposed in the stock issuance agreement.

                                      -9-

 
    B.    Any repurchase rights that are assigned in the Corporate Transaction
          shall automatically terminate, and all the shares of Common Stock
          subject to those terminated rights shall immediately vest in full, in
          the event the Optionee's Service should subsequently terminate by
          reason of an Involuntary Termination within eighteen (18) months
          following the effective date of such Corporate Transaction.


III.  SHARE ESCROW/LEGENDS

Unvested shares may, in the Plan Administrator's discretion, be held in escrow
by the Corporation until the Participant's interest in such shares vests or may
be issued directly to the Participant with restrictive legends on the
certificates evidencing those unvested shares.


                                 ARTICLE FOUR
                        AUTOMATIC OPTION GRANT PROGRAM
                        ------------------------------


I.    OPTION TERMS

      A.    Grant Dates.  Option grants shall be made on the dates specified
            -----------                                                     
            below:

            1.    Each non-employee director who is who is first elected or
                  appointed as a non-employee Board member after the effective
                  date of the Plan shall automatically be granted, on such
                  initial election or appointment, a Non-Statutory Option to
                  purchase 7,000 shares of Common Stock.

            2.    On the date of each Annual Stockholders Meeting, beginning
                  with the 1995 Annual Meeting, each individual who is to
                  continue to serve as a non-employee director after such
                  meeting, shall automatically be granted, whether or not such
                  individual is standing for re-election as a Board member at
                  that Annual Meeting, a Non-Statutory Option to purchase an
                  additional 7,000 shares of Common Stock, provided such
                  individual has served as a non-employee Board member for at
                  least six (6) months prior to the date of such Annual Meeting.
                  There shall be no limit on the number of such 7,000-share
                  option grants any one non-employee director may receive over
                  his or her period of Board service.

      B.    Exercise Price.
            -------------- 

            1.    The exercise price per share shall be equal to one hundred
                  percent (100%) of the Fair Market Value per share of Common
                  Stock on the option grant date.

            2.    The exercise price shall be payable in one or more of the
                  alternative forms authorized under the Discretionary Option
                  Grant Program. Except to the extent the sale and remittance
                  procedure specified thereunder is utilized, payment of the
                  exercise price for the purchased shares must be made on the
                  exercise date.

      C.    Option Term.  Each option shall have a term of ten (10) years
            ----------- 
            measured from the option grant date.

                                      -10-

 
      D.    Exercise and Vesting of Options.  Each option shall be immediately
            -------------------------------                                   
            exercisable for any or all of the option shares. However, any shares
            purchased under the option shall be subject to repurchase by the
            Corporation, at the exercise price paid per share, upon the
            Optionee's cessation of Board service prior to vesting in those
            shares. Each grant shall vest, and the Corporation's repurchase
            right shall lapse, in a series of four (4) equal and successive
            quarterly installments over the Optionee's period of continued
            service as a Board member, with the first such installment to vest
            upon the Optionee's completion of three (3) months of Board service
            measured from the option grant date.

      E.    Effect of Termination of Board Service.  The following provisions
            --------------------------------------                           
            shall govern the exercise of any options held by the Optionee at the
            time the Optionee ceases to serve as a Board member:

            (i)    The Optionee (or, in the event of Optionee's death, the
                   personal representative of the Optionee's estate or the
                   person or persons to whom the option is transferred pursuant
                   to the Optionee's will or in accordance with the laws of
                   descent and distribution) shall have the balance of the
                   option term in which to exercise each such option.

            (ii)   Following cessation of service on the Board for other than
                   death or disability, the option may not be exercised in the
                   aggregate for more than the number of vested shares of Common
                   Stock for which the option was exercisable at the time of the
                   Optionee's cessation of Board service.

            (iii)  Should the Optionee cease to serve as a Board member by
                   reason of death or Permanent Disability, then all shares at
                   the time subject to the option shall immediately vest so that
                   such option may be exercised for all or any portion of such
                   shares as fully-vested shares of Common Stock.

            (iv)   Upon expiration of the option term, the option shall
                   terminate and cease to be outstanding for any vested shares
                   for which the option has not been exercised. However, the
                   option shall, immediately upon the Optionee's cessation of
                   Board service, terminate and cease to be outstanding to the
                   extent it is not exercisable for vested shares on the date of
                   such cessation of Board service.


II.   CORPORATE TRANSACTION/CHANGE IN CONTROL/HOSTILE TAKE-OVER

      A.    In the event of any Corporate Transaction, the shares of Common
            Stock at the time subject to each outstanding option but not
            otherwise vested shall automatically vest in full so that each such
            option shall, immediately prior to the effective date of the
            Corporate Transaction, become fully exercisable for all of the
            shares of Common Stock at the time subject to such option and may be
            exercised for all or any portion of such shares as fully-vested
            shares of Common Stock. Immediately following the consummation of
            the Corporate Transaction, each automatic option grant shall
            terminate and cease to be outstanding, except to the extent assumed
            by the successor corporation (or parent thereof).

      B.    In connection with any Change in Control, the shares of Common Stock
            at the time subject to each outstanding option but not otherwise
            vested shall automatically vest in full so that each such option
            shall, immediately prior to the effective date of the Change in
            Control, become fully exercisable for all of the shares of Common
            Stock at the time subject to such option and may be exercised for
            all or any portion of such shares as fully-vested shares of Common
            Stock. Each such option shall

                                      -11-

 
            remain exercisable for such fully-vested option shares until the
            expiration or sooner termination of the option term or the surrender
            of the option in connection with a Hostile Take-Over.

      C.    Upon the occurrence of a Hostile Take-Over, the Optionee shall have
            a thirty (30)-day period in which to surrender to the Corporation
            each automatic option held by him or her for a period of at least
            six (6) months. The Optionee shall in return be entitled to a cash
            distribution from the Corporation in an amount equal to the excess
            of (i) the Take-Over Price of the shares of Common Stock at the time
            subject to the surrendered option (whether or not the Optionee is
            otherwise at the time vested in those shares) over (ii) the
            aggregate exercise price payable for such shares. Such cash
            distribution shall be paid within five (5) days following the
            surrender of the option to the Corporation. No approval or consent
            of the Board shall be required in connection with such option
            surrender and cash distribution.

D.    The grant of options under the Automatic Option Grant Program shall in no
      way affect the right of the Corporation to adjust, reclassify, reorganize
      or otherwise change its capital or business structure or to merge,
      consolidate, dissolve, liquidate or sell or transfer all or any part of
      its business or assets.


III.  AMENDMENT OF THE AUTOMATIC OPTION GRANT PROGRAM

The provisions of this Automatic Option Grant Program, together with the option
grants outstanding thereunder, may not be amended at intervals more frequently
than once every six (6) months, other than to the extent necessary to comply
with applicable Federal income tax laws and regulations.


IV.   REMAINING TERMS

The remaining terms of each option granted under the Automatic Option Grant
Program shall be the same as the terms in effect for option grants made under
the Discretionary Option Grant Program.


                                 ARTICLE FIVE
                                 MISCELLANEOUS
                                 -------------


I.    ACCELERATION

      A.    The Plan Administrator shall have the discretion, exercisable either
            at the time an option is granted under the Discretionary Stock
            Option Program, at the time that stock is issued under the Stock
            Issuance Program or at any time while the option or stock remains
            outstanding, to provide for the acceleration of one or more
            outstanding options and the termination of repurchase rights on one
            or more outstanding shares upon the occurrence of such events as the
            Plan Administrator may determine, including upon a Corporate
            Transaction regardless or whether or not such options are to be
            assumed or replaced or the repurchase rights are to be assigned in
            the Corporate Transaction.

      B.    The Plan Administrator shall not have the discretion to provide for
            the acceleration of any options granted under the Automatic Option
            Grant Program.
            

                                      -12-

 
II.   FINANCING

      A.    The Plan Administrator may permit any Optionee or Participant to pay
            the option exercise price under the Discretionary Option Grant
            Program or the purchase price for shares issued under the Stock
            Issuance Program by delivering a promissory note payable in one or
            more installments. The terms of any such promissory note (including
            the interest rate and the terms of repayment) shall be established
            by the Plan Administrator in its sole discretion. Promissory notes
            may be authorized with or without security or collateral. In all
            events, the maximum credit available to the Optionee or Participant
            may not exceed the sum of (i) the aggregate option exercise price or
            purchase price payable for the purchased shares plus (ii) any
            Federal, state and local income and employment tax liability
            incurred by the Optionee or the Participant in connection with the
            option exercise or share purchase.

      B.    The Plan Administrator may, in its discretion, determine that one or
            more such promissory notes shall be subject to forgiveness by the
            Corporation in whole or in part upon such terms as the Plan
            Administrator may deem appropriate.


III.  TAX WITHHOLDING

      A.    The Corporation's obligation to deliver shares of Common Stock upon
            the exercise of options or upon the issuance or vesting of such
            shares under the Plan shall be subject to the satisfaction of all
            applicable Federal, state and local income and employment tax
            withholding requirements.

      B.    The Plan Administrator may, in its discretion, provide any or all
            holders of Non-Statutory Options or unvested shares of Common Stock
            under the Plan (other than the options granted or the shares issued
            under the Automatic Option Grant Program) with the right to use
            shares of Common Stock in satisfaction of all or part of the
            federal, state and local income or employment taxes incurred by such
            holders in connection with the exercise of their options or the
            vesting of their shares. Such right may be provided to any such
            holder in either or both of the following formats:

            (i)    Stock Withholding:  The election to have the Corporation
                   -----------------                                       
                   withhold, from the shares of Common Stock otherwise issuable
                   upon the exercise of such Non-Statutory Option or the vesting
                   of such shares, a portion of those shares with an aggregate
                   Fair Market Value equal to the percentage of such taxes (not
                   to exceed one hundred percent (100%)) designated by the
                   holder.

            (ii)   Stock Delivery:  The election to deliver to the Corporation,
                   -------------- 
                   at the time the Non-Statutory Option is exercised or the
                   shares vest, one or more shares of Common Stock previously
                   acquired by such holder (other than in connection with the
                   option exercise or share vesting triggering the taxes) with
                   an aggregate Fair Market Value equal to the percentage of
                   such taxes (not to exceed one hundred percent (100%))
                   designated by the holder.


IV.   EFFECTIVE DATE AND TERM OF THE PLAN

      A.    The Plan shall become effective on the date the Plan is adopted by
            the Board, and options may be granted under the Discretionary Option
            Grant Program from and after the effective date. However, no options
            granted under the Plan may be exercised, and no shares shall be
            issued under the Plan, until the Plan is approved by the
            Corporation's stockholders. If such stockholder approval is not
            obtained within twelve (12) months after such effective date, then
            all options previously granted

                                      -13-

 
            under this Plan shall terminate and cease to be outstanding, and no
            further options shall be granted and no shares shall be issued under
            the Plan.

      B.    The Plan shall serve as the successor to the Predecessor Plan, and
            no further option grants shall be made under the Predecessor Plan
            after the effective date of the Plan. All options outstanding under
            the Predecessor Plan as of such date shall, immediately upon
            approval of the Plan by the Corporations's stockholders, be
            incorporated into the Plan and treated as outstanding options under
            the Plan. However, each outstanding option so incorporated shall
            continue to be governed solely by the terms of the documents
            evidencing such option. No provision of the Plan shall be deemed to
            adversely affect or otherwise diminish the rights or obligations of
            the holders of such incorporated options with respect to their
            acquisition of shares of Common Stock which may exist under the
            terms of the Predecessor Plan under which such incorporated option
            was issued. Subject to the rights of the optionee under the
            incorporated option documents and Predecessor Plan, the discretion
            delegated to the Plan Administrator hereunder may be exercised with
            respect to incorporated options to the same extent as it is
            exercisable with respect to options originally granted under this
            Plan.

      C.    The option/vesting acceleration provisions of Article Two relating
            to Corporate Transactions and Changes in Control may, in the Plan
            Administrator's discretion, be extended to one or more options
            incorporated from the Predecessor Plan which do not otherwise
            provide for such acceleration.

      D.    The Plan shall terminate upon the earliest of (i) April 27, 2005,
            (ii) the date on which all shares available for issuance under the
            Plan shall have been issued pursuant to the exercise of the options
            or the issuance of shares (whether vested or unvested) under the
            Plan or (iii) the termination of all outstanding options in
            connection with a Corporate Transaction. Upon such Plan termination,
            all options and unvested stock issuances outstanding on such date
            shall thereafter continue to have force and effect in accordance
            with the provisions of the documents evidencing such options or
            issuances.


V.    AMENDMENT OF THE PLAN

      A.    The Board shall have complete and exclusive power and authority to
            amend or modify the Plan in any or all respects. However, (i) no
            such amendment or modification shall adversely affect the rights and
            obligations with respect to options or unvested stock issuances at
            the time outstanding under the Plan unless the Optionee or the
            Participant consents to such amendment or modification, and (ii) any
            amendment made to the Automatic Option Grant Program (or any options
            outstanding thereunder) shall be in compliance with the limitations
            of that program. In addition, the Board shall not, without the
            approval of the Corporation's stockholders, (i) materially increase
            the maximum number of shares issuable under the Plan, the number of
            shares for which options may be granted under the Automatic Option
            Grant Program or the maximum number of shares for which any one
            person may be granted options and direct stock issuances in the
            aggregate over the term of the Plan, except for permissible
            adjustments in the event of certain changes in the Corporation's
            capitalization, (ii) materially modify the eligibility requirements
            for Plan participation or (iii) materially increase the benefits
            accruing to Plan participants.

      B.    Options to purchase shares of Common Stock may be granted under the
            Discretionary Option Grant Program and shares of Common Stock may be
            issued under the Stock Issuance Program that are in each instance in
            excess of the number of shares then available for issuance under the
            Plan, provided any excess shares actually issued under those
            programs are held in escrow until there is obtained stockholder
            approval of an amendment sufficiently increasing the number of
            shares of

                                      -14-

 
            Common Stock available for issuance under the Plan. If such
            stockholder approval is not obtained within twelve (12) months after
            the date the first such excess issuances are made, then (i) any
            unexercised options granted on the basis of such excess shares shall
            terminate and cease to be outstanding and (ii) the Corporation shall
            promptly refund to the Optionees and the Participants the exercise
            or purchase price paid for any excess shares issued under the Plan
            and held in escrow, together with interest (at the applicable Short
            Term Federal Rate) for the period the shares were held in escrow,
            and such shares shall thereupon be automatically cancelled and cease
            to be outstanding.


VI.   USE OF PROCEEDS

Any cash proceeds received by the Corporation from the sale of shares of Common
Stock under the Plan shall be used for general corporate purposes.


VII.  REGULATORY APPROVALS

      A.    The implementation of the Plan, the granting of any option under the
            Plan and the issuance of any shares of Common Stock (i) upon the
            exercise of any option or (ii) under the Stock Issuance Program
            shall be subject to the Corporation's procurement of all approvals
            and permits required by regulatory authorities having jurisdiction
            over the Plan, the options granted under it and the shares of Common
            Stock issued pursuant to it.

      B.    No shares of Common Stock or other assets shall be issued or
            delivered under the Plan unless and until there shall have been
            compliance with all applicable requirements of Federal and state
            securities laws, including the filing and effectiveness of the Form
            S-8 registration statement for the shares of Common Stock issuable
            under the Plan, and all applicable listing requirements of any stock
            exchange (or the Nasdaq National Market, if applicable) on which
            Common Stock is then listed for trading.


VIII. NO EMPLOYMENT/SERVICE RIGHTS

Nothing in the Plan shall confer upon the Optionee or the Participant any right
to continue in Service for any period of specific duration or interfere with or
otherwise restrict in any way the rights of the Corporation (or any Parent or
Subsidiary employing or retaining such person) or of the Optionee or the
Participant, which rights are hereby expressly reserved by each, to terminate
such person's Service at any time for any reason, with or without cause.

                                      -15-

 
                                   APPENDIX
                                   --------


The following definitions shall be in effect under the Plan:

A.    BOARD shall mean the Corporation's Board of Directors.
      -----                                                 

B.    CHANGE IN CONTROL shall mean a change in ownership or control of the
      -----------------                                                   
      Corporation effected through either of the following transactions:

      (i)    the acquisition, directly or indirectly, by any person or related
             group of persons (other than the Corporation or a person that
             directly or indirectly controls, is controlled by, or is under
             common control with, the Corporation), of beneficial ownership
             (within the meaning of Rule 13d-3 of the Securities Exchange Act of
             1934) of securities possessing more than fifty percent (50%) of the
             total combined voting power of the Corporation's outstanding
             securities pursuant to a tender or exchange offer made directly to
             the Corporation's stockholders which the Board does not recommend
             such stockholders to accept, or

      (ii)   a change in the composition of the Board over a period of thirty-
             six (36) consecutive months or less such that a majority of the
             Board members ceases, by reason of one or more contested elections
             for Board membership, to be comprised of individuals who either (A)
             have been Board members continuously since the beginning of such
             period or (B) have been elected or nominated for election as Board
             members during such period by at least a majority of the Board
             members described in clause (A) who were still in office at the
             time the Board approved such election or nomination.

C.    CORPORATE TRANSACTION shall mean either of the following stockholder-
      ---------------------                                               
      approved transactions to which the Corporation is a party:

      (i)    a merger or consolidation in which the Company is not the surviving
             entity, except for a transaction the principal purpose of which is
             to change the State of the Company's incorporation,

      (ii)   the sale, transfer or other disposition of all or substantially all
             of the assets of the Company in liquidation or dissolution of the
             Company, or

      (iii)  any reverse merger in which the Company is the surviving entity but
             in which securities possessing more than fifty percent (50%) of the
             total combined voting power of the Company's outstanding securities
             are transferred to holders different from those who held such
             securities immediately prior to such merger.

D.    CORPORATION shall mean Synbiotics Corporation, a California corporation.
      -----------                                                             

E.    EMPLOYEE shall mean an individual who is in the employ of the Corporation
      --------                                                                 
      (or any Parent or Subsidiary), subject to the control and direction of the
      employer entity as to both the work to be performed and the manner and
      method of performance.

F.    FAIR MARKET VALUE per share of Common Stock on any relevant date shall be
      -----------------                                                        
      determined in accordance with the following provisions:

                                     -A-1-


 
      (i)    If the Common Stock is at the time traded on the Nasdaq National
             Market, then the Fair Market Value shall be the closing selling
             price per share of Common Stock on the date in question, as such
             price is reported by the National Association of Securities Dealers
             on the Nasdaq National Market or any successor system. If there is
             no closing selling price for the Common Stock on the date in
             question, then the Fair Market Value shall be the closing selling
             price on the last preceding date for which such quotation exists.

      (ii)   If the Common Stock is at the time listed on any Stock Exchange,
             then the Fair Market Value shall be the closing selling price per
             share of Common Stock on the date in question on the Stock Exchange
             determined by the Plan Administrator to be the primary market for
             the Common Stock, as such price is officially quoted in the
             composite tape of transactions on such exchange. If there is no
             closing selling price for the Common Stock on the date in question,
             then the Fair Market Value shall be the closing selling price on
             the last preceding date for which such quotation exists.

      (iii)  If the Common Stock is at the time not traded on the Nasdaq
             National Market or listed on any Stock Exchange, the Fair Market
             Value shall be determined by the Plan Administrator after taking
             into account such factors as the Plan Administrator shall deem
             appropriate.

G.    HOSTILE TAKE-OVER shall mean a change in ownership of the Corporation
      -----------------                                                    
      effected through acquisition, directly or indirectly, by any person or
      related group of persons (other than the Corporation or a person that
      directly or indirectly controls, is controlled by, or is under common
      control with, the Corporation) of beneficial ownership (within the meaning
      of Rule 13d-3 of the Securities Exchange Act of 1934) of securities
      possessing more than fifty percent (50%) of the total combined voting
      power of the Corporation's outstanding securities pursuant to a tender or
      exchange offer made directly to the Corporation's stockholders which the
      Board does not recommend such stockholders to accept.

H.    INCENTIVE OPTION shall mean an option which satisfies the requirements of
      ----------------                                                         
      Internal Revenue Code Section 422.

I.    INVOLUNTARY TERMINATION shall mean the termination of the Service of any
      -----------------------                                                 
      individual which occurs by reason of:

      (i)    such individual's involuntary dismissal or discharge by the
             Corporation for reasons other than Misconduct, or

      (ii)   such individual's voluntary resignation following (A) a change in
             his or her position with the Corporation which materially reduces
             his or her level of responsibility, (B) a reduction in his or her
             level of compensation (including base salary, fringe benefits and
             any non-discretionary and objective-standard incentive payment or
             bonus award) by more than fifteen percent (15%) or (C) a relocation
             of such individual's place of employment by more than fifty (50)
             miles, provided and only if such change, reduction or relocation is
             effected by the Corporation without the individual's consent.
 
J.    MISCONDUCT shall mean the commission of any act of fraud, embezzlement or
      ----------                                                               
      dishonesty by the Optionee or Participant, any unauthorized use or
      disclosure by such person of confidential information or trade secrets of
      the Corporation (or any Parent or Subsidiary), or any other intentional
      misconduct by such person adversely affecting the business or affairs of
      the Corporation (or any Parent or Subsidiary) in a material manner. The
      foregoing definition shall not be deemed to be inclusive of all the acts
      or omissions which the Corporation (or any Parent or Subsidiary) may
      consider as grounds for the dismissal or discharge of any Optionee,
      Participant or other person in the Service of the Corporation (or any
      Parent or Subsidiary).

                                     -A-2-


 
K.    NON-STATUTORY OPTION shall mean an option which is not an Incentive
      --------------------  
      Option.
      

L.    PARENT shall mean any corporation (other than the Corporation) in an
      ------                                                              
      unbroken chain of corporations ending with the Corporation, provided each
      corporation in the unbroken chain (other than the Corporation) owns, at
      the time of the determination, stock possessing fifty percent (50%) or
      more of the total combined voting power of all classes of stock in one of
      the other corporations in such chain.

M.    PERMANENT DISABILITY OR PERMANENTLY DISABLED shall mean the inability
      --------------------------------------------
      of the Optionee or the Participant to engage in any substantial gainful
      activity by reason of any medically determinable physical or mental
      impairment expected to result in death or to be of continuous duration of
      twelve (12) months or more.

N.    PREDECESSOR PLANS shall mean the Corporation's existing 1986 Stock Option
      -----------------                                                        
      Plan, 1987 Stock Option Plan, 1988 Stock Option Plan, 1991 Stock Option
      Plan, and 1994 Stock Option Plan.

O.    SERVICE shall mean the provision of services to the Corporation (or any
      -------                                                                
      Parent or Subsidiary) by a person in the capacity of an Employee, a non-
      employee member of the board of directors or a consultant or independent
      advisor, except to the extent otherwise specifically provided in the
      documents evidencing the option grant.

P.    SUBSIDIARY shall mean any corporation (other than the Corporation) in an
      ----------                                                              
      unbroken chain of corporations beginning with the Corporation, provided
      each corporation (other than the last corporation) in the unbroken chain
      owns, at the time of the determination, stock possessing fifty percent
      (50%) or more of the total combined voting power of all classes of stock
      in one of the other corporations in such chain.

Q.    TAKE-OVER PRICE shall mean the greater of (i) the Fair Market Value per
      ---------------                -------                                 
      share of Common Stock on the date the option is surrendered to the
      Corporation in connection with a Hostile Take-Over or (ii) the highest
      reported price per share of Common Stock paid by the tender offeror in
      effecting such Hostile Take-Over. However, if the surrendered option is an
      Incentive Option, the Take-Over Price shall not exceed the clause (i)
      price per share.

                                     -A-3-