<PAGE>   1
                   FIRST AMENDMENT TO AMENDED AND RESTATED
                   REVOLVING CREDIT AND TERM LOAN AGREEMENT

        THIS FIRST AMENDMENT TO AMENDED AND RESTATED REVOLVING CREDIT AND TERM
LOAN AGREEMENT (the "First Amendment"), made and entered into as of the 28th
day of June, 1996, by and between DOANE PRODUCTS COMPANY, a Delaware
corporation ("Borrower"), MERCANTILE BANK OF ST. LOUIS NATIONAL ASSOCIATION, a
national banking association, SOUTHTRUST BANK OF ALABAMA, NATIONAL ASSOCIATION,
a national banking association, HARRIS TRUST AND SAVINGS BANK, an Illinois state
banking corporation, HIBERNIA NATIONAL BANK, a national bank, NBD BANK, a
Michigan banking corporation, and BANK OF OKLAHOMA, N.A., a national banking
association (collectively referred to herein as the "Banks"), and MERCANTILE
BANK OF ST. LOUIS NATIONAL ASSOCIATION, a national banking association, as
agent for the Banks (in such capacity, the "Agent").

                                 WITNESSETH:

        WHEREAS, Borrower, Agent and Banks entered into an Amended and Restated
Revolving Credit and Term Loan Agreement dated February 28, 1996 (as amended,
the "Credit Agreement"); and

        WHEREAS, Borrower has requested that the Credit Agreement be amended
and modified as hereinafter set forth, to which said amendments and
modifications Agent and Banks are willing to agree;

        NOW, THEREFORE, in consideration of the premises and the mutual
provisions and agreements hereinafter set forth, the parties hereto do hereby
mutually promise and agree as follows:

        1.      Section 10.1(m)(i) of the Credit Agreement shall be deleted in
its entirety and in its place shall be substituted the following:

                (i)     Minimum Consolidated EBITDA. Borrower will have and
        maintain a Consolidated EBITDA, determined for the four-quarter period
        ending on the date of each such calculation hereunder, of at least:


<TABLE>
<CAPTION>
         For Fiscal Quarters
         Ended On Or Between                    Minimum Consolidated EBITDA
         -------------------                    ---------------------------
<S>                                                     <C>
June 30, 1996                                           $37,500,000.00
September 30, 1996                                       32,500,000.00
December 31, 1996                                        32,500,000.00
March 31, 1997                                           34,000,000.00
June 30, 1997                                            37,000,000.00
September 30, 1997                                       41,500,000.00
October 1, 1997 through September 30, 1998               45,200,000.00
October 1, 1998 through September 30, 1999               47,000,000.00

</TABLE>

<PAGE>   2

<TABLE>
<S>                                                     <C>
October 1, 1999 through September 30, 2000               48,500,000.00

</TABLE>

        2.      Section 10.1(m)(ii) of the Credit Agreement shall be deleted in
its entirety and in its place shall be substituted the following:

                (ii)    Minimum Consolidated Cash Flow Coverage Ratio.
        Borrower will have and maintain a Consolidated Cash Flow Coverage Ratio
        of at least (i) 0.85 to 1.0 at all times up to and including June 30,
        1996, (ii) 0.70 to 1.0 at all times during the period commencing
        July 1, 1996 and ending June 30, 1997, (iii) 0.85 to 1.0 at all times
        during the period commencing July 1, 1997 and ending September 30,
        1997, (iv) 0.90 to 1.0 at all times during the period commencing
        October 1, 1997 and ending September 30, 1998, (v) 1.05 to 1.0 at all
        time during the period commencing October 1, 1998 and ending September
        30, 1999, and (vi) 1.10 to 1.0 at all times from and after October 1,
        1999.

        3.      Section 10.1(m)(iii) of the Credit Agreement shall be deleted
in its entirety and in its place shall be substituted the following:

                (iii)   Maximum Consolidated Total Debt to Consolidated EBITDA.
        Borrower will at all times have and maintain a ratio of Consolidated
        Total Debt to Consolidated EBITDA which is less than or equal to the
        following:


<TABLE>
<CAPTION>
        For Fiscal Quarters                     Maximum Consolidated Total
        Ended On Or Between                     Debt to Consolidated EBITDA
        -------------------                     ---------------------------
<S>                                                     <C>
June 30, 1996                                           6.00 to 1.00
September 30, 1996                                      6.75 to 1.00
December 31, 1996                                       6.60 to 1.00
March 31, 1997                                          6.25 to 1.00
June 30, 1997                                           5.50 to 1.00
September 30, 1997                                      5.00 to 1.00
October 1, 1997 through September 30, 1998              4.65 to 1.00
October 1, 1998 through September 30, 1999              4.25 to 1.00
October 1, 1999 through September 30, 2000              3.90 to 1.00

</TABLE>

        4.      Borrower hereby represents and warrants to Agent and Banks
that:

                (a)  The execution, delivery and performance by Borrower of
this First Amendment are within the corporate powers of Borrower, have been
duly authorized by all necessary corporate action and require no action by or
in respect of, or filing with, any governmental or regulatory body, agency or
official. The execution, delivery and performance by Borrower of this First
Amendment do not conflict with, or result in a breach of the terms, conditions
or provisions of, or constitute a default under or result in any violation of,
and Borrower is not now in default under or in violation of, the terms of the
Articles of Incorporation or Bylaws of Borrower, any applicable law, any rule,
regulation, order, writ, judgment or decree of any court or governmental or
regulatory agency or instrumentality, or any



                                     -2-
<PAGE>   3
agreement or instrument to which Borrower is a party or by which it is bound
or to which it is subject;

            (b) This First Amendment has been duly executed and delivered and
constitutes the legal, valid and binding obligation of Borrower enforceable in
accordance with its terms; and

            (c) As of the date hereof, all of the covenants, representations and
warranties of Borrower set forth in the Credit Agreement are true and correct
and no "Event of Default" (as defined therein) under or within the meaning of
the Credit Agreement has occurred and is continuing.

        5. All references in the Credit Agreement to "this Credit Agreement"
and any other references of similar import shall henceforth mean the Credit
Agreement as amended by this First Amendment.

        6. This First Amendment shall be binding upon and inure to the benefit
of the parties thereto and their respective successors and assigns, except that
Borrower may not assign, transfer or delegate any of its rights or obligations
hereunder or thereunder.

        7. This First Amendment shall be governed by and construed in
accordance with the internal laws of the State of Missouri.

        8. In the event of any inconsistency or conflict between this First
Amendment and the Credit Agreement, the terms, provisions and conditions of this
First Amendment shall govern and control.

        9. The Credit Agreement, as hereby amended and modified, is and shall
remain the binding obligation of Borrower and all of the provisions, terms,
stipulations, conditions, covenants and powers contained therein shall stand
and remain in full force and effect, except only as the same are herein and
hereby specifically varied or amended, and the same are hereby ratified and
confirmed. This First Amendment amends the Credit Agreement and is not a
novation thereof. If any installment of principal or interest on any of the
Notes (as defined in the Credit Agreement) shall not be paid when due as
provided in the Notes, the holders of the Notes shall be entitled to and may
exercise all rights and remedies under the Notes and the Credit Agreement and
any of the other Transaction Documents (as defined in the Credit Agreement).

       10. ORAL AGREEMENTS OR COMMITMENTS TO LOAN MONEY, EXTEND CREDIT OR
TO FOREBEAR FROM ENFORCING REPAYMENT OF A DEBT, INCLUDING PROMISES TO EXTEND OR
RENEW SUCH DEBT, ARE NOT ENFORCEABLE. TO PROTECT BORROWER, AGENT AND BANKS FROM
ANY MISUNDERSTANDING OR DISAPPOINTMENT, ANY AGREEMENTS REACHED BY BORROWER,
AGENT AND BANKS COVERING SUCH MATTERS ARE CONTAINED IN THE CREDIT AGREEMENT, AS
AMENDED BY THIS FIRST AMENDMENT, WHICH CONSTITUTES A COMPLETE AND EXCLUSIVE
STATEMENT OF THE



                                     -3-
<PAGE>   4
AGREEMENTS BETWEEN BORROWER, AGENT AND BANKS EXCEPT AS BORROWER, AGENT AND
BANKS MAY LATER AGREE IN WRITING TO MODIFY. THE CREDIT AGREEMENT, AS AMENDED BY
THIS FIRST AMENDMENT, EMBODIES THE ENTIRE AGREEMENT AND UNDERSTANDING BETWEEN
THE PARTIES HERETO AND SUPERSEDE ALL PRIOR AGREEMENTS AND UNDERSTANDINGS (ORAL
OR WRITTEN) RELATING TO THE SUBJECT MATTER HEREOF.

        IN WITNESS WHEREOF, the parties hereto have executed this instrument as
of the date first written above on this 28th day of June, 1996.

                                DOANE PRODUCTS COMPANY


                                By: /s/ GEORGE B. KELLY
                                    --------------------------------------
                                    George B. Kelly, Chairman of the Board
                                West 20th & State Line Road
                                Joplin, Missouri 64804
                                Telecopy number: (417) 624-6788



                                MERCANTILE BANK OF ST. LOUIS
                                NATIONAL ASSOCIATION


                                By: /s/ JOHN C. BILLINGS
                                    --------------------------------------
                                    John C. Billings, Vice President
                                721 Locust Street
                                St. Louis, Missouri 63101
                                Telecopy number: (314) 425-2162



                                SOUTHTRUST BANK OF ALABAMA,
                                NATIONAL ASSOCIATION


                                By: /s/ STEPHEN F. VICKERY
                                    --------------------------------------
                                    Stephen F. Vickery, Vice President
                                Metropolitan Lending
                                420 North 20th Street
                                Birmingham, Alabama 35203
                                Telecopy number: (205) 254-5911





                                      -4-
<PAGE>   5

                                       HARRIS TRUST AND SAVINGS BANK



                                       By:  /s/ STEPHEN J. GRAY
                                           --------------------------------
                                           Stephen J. Gray, Vice President
                                           111 West Monroe Street
                                           P.O. Box 755
                                           Chicago, Illinois 60690-0755
                                           Telecopy number: (312) 461-2591



                                       HIBERNIA NATIONAL BANK



                                       By:  /s/ WILLIAM P. HARRINGTON
                                           -------------------------------------
                                           William P. Harrington, Vice President
                                           313 Carondelet Street, 6th Floor
                                           New Orleans, Louisiana 70130
                                           Telecopy number: (504) 533-2060



                                       NBD BANK



                                       By:  /s/ PAUL R. DEMELO
                                           ---------------------------------
                                           Paul R. DeMelo, Vice President
                                           Midwest Banking Division
                                           611 Woodward Avenue
                                           Detroit, Michigan 48226
                                           Telecopy number: (313) 225-2649




                                       BANK OF OKLAHOMA, N.A.



                                       By:  /s/ JANE P. FAULKENBERRY
                                           ------------------------------------
                                           Jane P. Faulkenberry, Vice President
                                           One Williams Center
                                           Tulsa, Oklahoma 74172
                                           Telecopy number: (918) 588-6880





                                      -5-
<PAGE>   6




                                       MERCANTILE BANK OF ST. LOUIS
                                       NATIONAL ASSOCIATION, as Agent



                                       By:  /s/ JOHN C. BILLINGS
                                           --------------------------------
                                           John C. Billings, Vice President
                                           721 Locust Street
                                           St. Louis, Missouri 63101
                                           Telecopy number: (314) 425-2162




                                      -6-