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                                                                     EXHIBIT 4.1
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                         CERTIFICATE OF DETERMINATION

                                      of

                 SERIES A JUNIOR PARTICIPATING PREFERRED STOCK

                                      of

                            SYNBIOTICS CORPORATION


                      __________________________________


          Kenneth M. Cohen and Michael K. Green hereby certify that:

          A.   They are the duly elected and acting President and Secretary,
respectively, of Synbiotics Corporation, a corporation organized and existing
under the General Corporation Law of the State of California (hereinafter called
the "Corporation").

          B.   Pursuant to the authority given by said Corporation's Restated
Articles of Incorporation, as amended to date, the Board of Directors of said
Corporation has duly adopted the following resolution:

          RESOLVED, the Board of Directors hereby creates a series of Preferred
Stock (the "Preferred Stock") of the Corporation consisting of Two Hundred
Thousand (200,000) shares designated as "Series A Junior Participating Preferred
Stock," and hereby fixes the rights, preferences, privileges and restrictions
and other matters relating to said Series A Junior Participating Preferred Stock
as follows:

          Series A Junior Participating Preferred Stock:

          Section 1.  Designation and Amount.  The shares of such series shall
                      ----------------------                                  
be designated as "Series A Junior Participating Preferred Stock" (the "Series A
Preferred Stock") and the number of shares constituting the Series A Preferred
Stock shall be Two Hundred Thousand (200,000).  Such number of shares may be
increased or decreased by resolution of the Board of Directors; provided, that
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no decrease shall reduce the number of shares of Series A Preferred Stock to a
number less than the number of shares then outstanding plus the number of shares
reserved for issuance upon the exercise of outstanding options, rights or
warrants or upon the

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conversion of any outstanding securities issued by the Corporation convertible
into Series A Preferred Stock.

          Section 2.  Dividends and Distributions.
                      --------------------------- 

          (A) Subject to the rights of the holders of any shares of any series
     of Preferred Stock (or any similar stock) ranking prior and superior to the
     Series A Preferred Stock with respect to dividends, each holder of a share
     of Series A Preferred Stock, in preference to the holders of shares of
     Common Stock (the "Common Stock"), of the Corporation, and of any other
     junior stock, shall be entitled to receive, when declared by the Board of
     Directors out of funds legally available for the purpose, quarterly
     dividends payable in cash on the last day of March, June, September and
     December in each year (each such date being referred to herein as a
     "Quarterly Dividend Payment Date"), commencing on the first Quarterly
     Dividend Payment Date after the first issuance of a share or fraction of a
     share Series A Preferred Stock, in an amount per share (rounded to the
     nearest cent) equal to, subject to the provision for adjustment hereinafter
     set forth, One Thousand (1,000) times the aggregate per share amount of all
     cash dividends, and One Thousand (1,000) times the aggregate per share
     amount (payable in kind) of all non-cash dividends or other distributions,
     other than a dividend payable in shares of Common Stock or a subdivision of
     the outstanding shares of Common Stock (by reclassification or otherwise),
     declared on the Common Stock since the immediately preceding Quarterly
     Dividend Payment Date or, with respect to the first Quarterly Dividend
     Payment Date, since the first issuance of a share or fraction of Series A
     Preferred Stock.  In the event the Corporation shall at any time declare or
     pay any dividend on the Common Stock payable in shares of Common Stock, or
     effect a subdivision or combination or consolidation of the outstanding
     shares of Common Stock (by reclassification or otherwise than by payment of
     a dividend in shares of Common Stock) into a greater or lesser number of
     shares of Common Stock, then in each such case the amount to which holders
     of shares of Series A Preferred Stock were entitled immediately prior to
     such event under clause (b) of the preceding sentence shall be adjusted by
     multiplying such amount by a fraction, the numerator of which is the number
     of shares of Common Stock outstanding immediately after such event and the
     denominator of which is the number of shares of Common Stock that were
     outstanding immediately prior to such event.

          (B) The Corporation shall declare a dividend or distribution on the
     shares of Series A Preferred Stock as provided in paragraph (A) of this
     Section immediately after it declares a dividend or distribution on the
     Common Stock (other than a dividend payable in shares of Common Stock);
     provided, however, that, in the event no dividend or distribution shall
     have been declared on the Common Stock during the period between any
     Quarterly Distribution Date and the next subsequent Quarterly Dividend
     Payment Date, a dividend of $.001 per share of Series A Preferred Stock
     shall nevertheless be payable on such subsequent Quarterly Dividend Payment
     Date.

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          (C) Dividends shall begin to accrue and be cumulative on each
     outstanding share of Series A Preferred Stock from the Quarterly Dividend
     Payment Date next preceding the date of issue of such share of Series A
     Preferred Stock, unless the date of issue of such share is prior to the
     record date for the first Quarterly Dividend Payment Date, in which case
     dividends on such share shall begin to accrue from the date of issue of
     such share, or unless the date of issue is a Quarterly Dividend Payment
     Date or is a date after the record date for the determination of holders of
     shares of Series A Preferred Stock entitled to receive a quarterly dividend
     and before such Quarterly Dividend Payment Date, in either of which events
     such dividends shall begin to accrue and be cumulative from such Quarterly
     Dividend Payment Date.  Accrued but unpaid dividends shall not bear
     interest.  Dividends paid on the shares of Series A Preferred Stock in an
     amount less than the total amount of such dividends at the time accrued and
     payable on such shares shall be allocated pro rata on a share-by-share
     basis among all such shares at the time outstanding.  The Board of
     Directors may fix a record date for the determination of holders of shares
     of Series A Preferred Stock entitled to receive payment of a dividend or
     distribution declared thereon, which record date shall be not more than 60
     days prior to the date fixed for the payment thereof.

          Section 3.  Voting Rights.  The holders of shares of Series A
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Preferred Stock shall have the following voting rights:

          (A) Subject to the provision for adjustment hereinafter set forth,
     each share of Series A Preferred Stock shall entitle the holder thereof to
     One Thousand (1,000) votes on all matters submitted to a vote of the
     shareholders of the Corporation.  In the event the Corporation shall at any
     time declare or pay any dividend on the Common Stock payable in shares of
     Common Stock, or effect a subdivision or combination or consolidation of
     the outstanding shares of Common Stock (by reclassification or otherwise
     than by payment of a dividend in shares of Common Stock) into a greater or
     lesser number of shares of Common Stock, then in each such case the number
     of votes per share to which holders of shares of Series A Preferred Stock
     were entitled immediately prior to such event shall be adjusted by
     multiplying such number by a fraction, the numerator of which is the number
     of shares of Common Stock outstanding immediately after such event and the
     denominator of which is the number of shares of Common Stock that were
     outstanding immediately prior to such event.

          (B) Except as otherwise provided herein, in any other Certificate of
     Determination creating a series of Preferred Stock or any similar stock, or
     by law, the holders of shares of Series A Preferred Stock and the holders
     of shares of Common Stock and any other capital stock of the Corporation
     having general voting rights shall vote together as one class on all
     matters submitted to a vote of shareholders of the Corporation.

          (C) Except as set forth herein, or as otherwise provided by law,
     holders of Series A Preferred Stock shall have no special voting rights and
     their consent shall not

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     be required (except to the extent they are entitled to vote with holders of
     Common Stock as set forth herein) for taking any corporate action.

          Section 4.  Certain Restrictions.
                      -------------------- 

          (A) Whenever quarterly dividends or other dividends or distributions
     payable on the Series A Preferred Stock as provided in Section 2 are in
     arrears, thereafter and until all accrued and unpaid dividends and
     distributions, whether or not declared, on shares of Series A Preferred
     Stock outstanding shall have been paid in full, the Corporation shall not:

               (i)   declare or pay dividends, or make any other distributions,
          on any shares of stock ranking junior (either as to dividends or upon
          liquidation, dissolution or winding up) to the Series A Preferred
          Stock;

               (ii)  declare or pay dividends, or make any other distributions,
          on any shares of stock ranking on a parity (either as to dividends or
          upon liquidation, dissolution or winding up) with the Series A
          Preferred Stock, except dividends paid ratably on the shares of Series
          A Preferred Stock and all such parity stock on which dividends are
          payable or in arrears in proportion to the total amounts to which the
          holders of all such shares are then entitled;

               (iii) redeem or purchase or otherwise acquire for consideration
          shares of any stock ranking junior (either as to dividends or upon
          liquidation, dissolution or winding up) to the Series A Preferred
          Stock, provided that the Corporation may at any time redeem, purchase
          or otherwise acquire shares of any such junior stock in exchange for
          shares of any stock of the Corporation ranking junior (either as to
          dividends or upon dissolution, liquidation or winding up) to the
          Series A Preferred Stock; or

               (iv)  redeem or purchase or otherwise acquire for consideration
          any shares of Series A Preferred Stock, or any shares of stock ranking
          on a parity with the Series A Preferred Stock, except in accordance
          with a purchase offer made in writing or by publication (as determined
          by the Board of Directors) to all holders of such shares upon such
          terms as the Board of Directors, after consideration of the respective
          annual dividend rates and other relative rights and preferences of the
          respective series and classes, shall determine in good faith will
          result in fair and equitable treatment among the respective series or
          classes.

          (B) The Corporation shall not permit any subsidiary of the Corporation
     to purchase or otherwise acquire for consideration any shares of stock of
     the Corporation unless the Corporation could, under paragraph (A) of this
     Section 4, purchase or otherwise acquire such shares at such time and in
     such manner.

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          Section 5.  Reacquired Shares.  Any shares of Series A Preferred Stock
                      -----------------                                         
purchased or otherwise acquired by the Corporation in any manner whatsoever
shall become authorized but unissued shares of Preferred Stock and may not be
reissued as shares of Series A Preferred Stock, but and may be reissued as part
of a new series of Preferred Stock subject to the conditions and restrictions on
issuance set forth herein, in the Articles of Incorporation, or in any other
Certifi cate of Determination creating a series of Preferred Stock or any
similar stock or as otherwise required by law.

          Section 6.  Liquidation, Dissolution or Winding Up.
                      -------------------------------------- 

          (A) Upon any liquidation, dissolution or winding up of the
Corporation, no distribution shall be made (1) to the holders of shares of stock
ranking junior (either as to divi dends or upon liquidation, dissolution or
winding up) to the Series A Preferred Stock unless, prior thereto, the holders
of shares of Series A Preferred Stock shall have received One Thousand Dollars
($1,000) per share, plus an amount equal to accrued and unpaid dividends and
distributions thereon, whether or not declared, to the date of such payment,
provided that the holders of shares of Series A Preferred Stock shall be
entitled to receive an aggregate amount per share, subject to the provision for
adjustment hereinafter set forth, equal to 10,000 times the aggregate amount to
be distributed per share to holders of shares of Common Stock, or (2) to the
holders of shares of stock ranking on a parity (either as to dividends or upon
liquidation, dissolution or winding up) with the Series A Preferred Stock,
except distributions made ratably on the Series A Preferred Stock and all such
parity stock in proportion to the total amounts to which the holders of all such
shares are entitled upon such liquidation, dissolution or winding up.  In the
event the Corporation shall at any time declare or pay any dividend on the
Common Stock payable in shares of Common Stock, or effect a subdivision or
combination or consolidation of the outstanding shares of Common Stock (by
reclassification or otherwise than by payment of a dividend in shares of Common
Stock) into a greater or lesser number of shares of Common Stock, then in each
such case the aggregate amount to which holders of shares of Series A Preferred
Stock were entitled immediately prior to such event under the proviso in clause
(1) of the preceding sentence shall be adjusted by multiplying such amount by a
fraction the numerator of which is the number of shares of Common Stock
outstanding immediately after such event and the denominator of which is the
number of shares of Common Stock that were outstanding immediately prior to such
event.

          (B) In the event, however, that there are not sufficient assets
available to permit payment in full to the Series A Liquidation Preference and
the liquidation preferences of all other series of Preferred Stock, if any,
which rank on a parity with the Series A Preferred Stock, then such remaining
assets shall be distributed ratably to the holders of such parity shares in
proportion to their respective liquidation preferences.  In the event, however,
that there are not sufficient assets available to permit payment in full of the
Common Adjustment, then such remaining assets shall be distributed ratably to
the holders of Common Stock.

          (C) In the event the Corporation shall at any time after the Rights
Declaration Date (i) declare any dividend on Common Stock payable in shares of
Common Stock, (ii)

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subdivide the outstanding Common Stock, or (iii) combine the outstanding Common
Stock into a smaller number of shares, then in each such case the Adjustment
Number in effect immediately prior to such event shall be adjusted by
multiplying such Adjustment Number by a fraction the numerator of which is the
number of shares of Common Stock outstanding immediately after such event and
the denominator of which is the number of shares of Common Stock that were
outstanding immediately prior to such event.

          Section 7.  Consolidation, Merger, etc.  In case the Corporation shall
                      --------------------------                                
enter into any consolidation, merger, combination or other transaction in which
the shares of Common Stock are exchanged for or changed into other stock or
securities, cash and/or any other property, then in any such case each share of
Series A Preferred Stock shall at the same time be similarly exchanged or
changed into an amount per share, subject to the provision for adjustment
hereinafter set forth, equal to One Thousand (1,000) times the aggregate amount
of stock, securities, cash and/or any other property (payable in kind), as the
case may be, into which or for which each share of Common Stock is changed or
exchanged.  In the event the Corporation shall at any time declare or pay any
dividend on the Common Stock payable in shares of Common Stock, or effect a
subdivision or combination or consolidation of the outstanding shares of Common
Stock (by reclassification or otherwise than by payment of a dividend in shares
of Common Stock) into a greater or lesser number of shares of Common Stock, then
in each such case the amount set forth in the preceding sentence with respect to
the exchange or change of shares of Series A Preferred Stock shall be adjusted
by multiplying such amount by a fraction, the numerator of which is the number
of shares of Common Stock outstanding immediately after such event and the
denominator of which is the number of shares of Common Stock that were
outstanding immediately prior to such event.

          Section 8.  No Redemption.  The shares of Series A Preferred Stock
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shall not be redeemable.

          Section 9.  Rank.  The Series A Preferred Stock shall rank, with
                      ----                                                
respect to the payment of dividends and the distribution of assets, junior to
all series of any other class of the Corporation's Preferred Stock.

          Section 10.  Amendment.  The Restated Articles of Incorporation of the
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Corporation shall not be amended in any manner which would materially alter or
change the powers, preferences or special rights of the Series A Preferred Stock
so as to affect them adversely without the affirmative vote of the holders of at
least a majority of the outstanding shares of Series A Preferred Stock, voting
together as a single class.

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          C.   The authorized number of shares of Preferred Stock of said
Corporation is 25,000,000, none of which has been issued.

          We further declare under penalty of perjury under the laws of the
State of California that the matters set forth in this Certificate are true and
correct of our own knowledge.
 
          Executed at San Diego, California, on October 5, 1998.



                              /s/ KENNETH M. COHEN
                              ------------------------
                              Name: Kenneth M. Cohen
                              Title:  President



                              /s/ MICHAEL K. GREEN
                              ------------------------
                              Name: Michael K. Green
                              Title:  Secretary

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