UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                             ----------------------

                                  SCHEDULE 13D
                                 (RULE 13d-101)
                                (AMENDMENT No. 3)*

    INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-1(A)
             AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(A)

                             THE CATTLESALE COMPANY
                      (f/k/a Dynacore Holdings Corporation)
         --------------------------------------------------------------
                                (Name of Issuer)

                     COMMON STOCK, PAR VALUE $.01 PER SHARE
         --------------------------------------------------------------
                         (Title of Class of Securities)

                                   149479 10 7
                             (formerly 26779T 30 8)
         --------------------------------------------------------------
                                 (CUSIP Number)


                                  Tom F. Perles
                             Chief Financial Officer
                             AEI Environmental, Inc.
                               710 North York Road
                            Hinsdale, Illinois 60521
                             (630) 325-4232 ext. 222
--------------------------------------------------------------------------------
   (Name, Address and Telephone Number of Person Authorized to Receive Notices
                               and Communications)

                                February 11, 2004
         --------------------------------------------------------------
             (Date of Event which Requires Filing of this Statement)

      If the filing person has previously filed a statement on Schedule 13G
   to report the acquisition that is the subject of this Schedule 13D, and is
filing this schedule because of Rule 13d-1(e), 13(d)-1(f) or 13(d)- 1(g), check
                             the following box [ ].

 Note. Schedules filed in paper format shall include a signed original and five
   copies of the schedule, including all exhibits. See Rule 13d-7(b) for other
                     parties to whom copies are to be sent.

 *The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
   for any subsequent amendment containing information which would alter the
                  disclosures provided in a prior cover page.
The information required in the remainder of this cover page shall not be deemed
 to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
   but shall be subject to all other provisions of the Act (however, see the
                                    Notes).







                                  SCHEDULE 13D
------------------------
CUSIP NO. 149479 10 7
------------------------

--------------------------------------------------------------------------------
1. NAME OF REPORTING PERSONS

   AEI ENVIRONMENTAL, INC.

   S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (Intentionally
   Omitted)
--------------------------------------------------------------------------------
2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                     (A) [ ]
                                     (B) [ ]
--------------------------------------------------------------------------------
3. SEC USE ONLY

--------------------------------------------------------------------------------
4. SOURCE OF FUNDS

   NOT APPLICABLE
--------------------------------------------------------------------------------
5.       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEMS 2(d) OR 2(e)

                                                              [x]
--------------------------------------------------------------------------------
6. CITIZENSHIP OR PLACE OF ORGANIZATION

   COLORADO
--------------------------------------------------------------------------------

   NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH

7. SOLE VOTING POWER 6,490,680

--------------------------------------------------------------------------------
8. SHARED VOTING POWER 0

--------------------------------------------------------------------------------
9. SOLE DISPOSITIVE POWER 6,490,680





--------------------------------------------------------------------------------
10. SHARED DISPOSITIVE POWER 0

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

11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

                                    6,490,680
--------------------------------------------------------------------------------
12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES.

                                                              [   ]
--------------------------------------------------------------------------------
13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11).

         16.6%
--------------------------------------------------------------------------------
14. TYPE OF REPORTING PERSON.

         CO
--------------------------------------------------------------------------------




                                       2




                            STATEMENT ON SCHEDULE 13D
                             PURSUANT TO RULE 13D-1
                                    UNDER THE
                   SECURITIES EXCHANGE ACT OF 1934, AS AMENDED

ITEM 1. SECURITY AND ISSUER.

         This amended Statement on Schedule 13D (this "Statement") relates to
the beneficial ownership of common stock, par value $0.01 per share (the "Common
Stock") of The CattleSale Company (f/k/a Dynacore Holdings Corporation), a
Delaware corporation (the "Company"). The principal executive offices of the
Company are located at 9901 IH-10 West, Suite 800, San Antonio, Texas 78230.


ITEM 2. IDENTITY AND BACKGROUND.

         Item 2 of the Schedule 13D is hereby supplemented as follows:

        (a) - (f) This Statement is being filed by AEI Environmental, Inc., a
Colorado corporation (the "Reporting Person"). There is no change to report for
Item 2 as of the date of this Amendment No. 3.


ITEM 3. SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.

         Not applicable.

ITEM 4. PURPOSE OF TRANSACTION.

        (a) The response to Item 6 is incorporated by reference.

        (b) - (c) Not applicable.

        (d) Item 4(d) of the Schedule 13D is supplemented as follows:

            On June 5, 2003, Mr. David S. Geiman was elected President and Chief
Executive Officer of the Company effective June 15, 2003, and, on December 11,
2003, Mr. Geiman was elected to the Company's Board of Directors and to serve as
Chairman of the Executive Committee.

            On December 9, 2003, Mr. Joshua J. Angel resigned from the Company's
Board of Directors, and, on December 10, 2003, Asher B. Edelman resigned from
the Company's Board of Directors and as Vice Chairman of the Board and Chairman
of the Executive Committee. The Company is in the process of filling its
remaining two Board of Director vacancies.

        (e) Item 4(e) of the Schedule 13D is supplemented as follows:


                                       3


         Based on information publicly disseminated by the Company as of the
date of this Statement, the Reporting Person is not aware of any change in the
capitalization or dividend policy of the issuer.

         (f) Item 4(f) of the Schedule 13D is supplemented as follows:

         Based on information publicly disseminated by the Company as of the
date of this Statement, the Reporting Person is not aware of any other material
changes in the issuer's business or corporate structure.

         (g) - (j) Not applicable.


ITEM 5. INTEREST IN SECURITIES OF THE ISSUER.

         There is no change to report for Item 5 except for the addition of the
following:

         (a) The Reporting Person is the beneficial owner of 6,490,680 shares,
or 16.6%, of the Company's outstanding Common Stock (on a fully converted basis)
as of the date of this Statement (based upon 39,152,894 shares of Common Stock
[on a fully converted basis] outstanding as of September 30, 2003, as reported
in the issuer's Quarterly Report on Form 10-Q for the quarter ended September
30, 2003). See Item 5(c) regarding the number of shares and percentage ownership
for other persons required to be disclosed in response to Item 2 and Instruction
C to Schedule 13-D.

         (b) See Item 5(c) regarding the number of shares as to which there is
sole power to vote or direct the vote, shared power to vote or to direct the
vote, sole power to dispose or to direct the disposition or shared power to
dispose or to direct the disposition for persons required to be disclosed in
response to Item 2 and Instruction C to Schedule 13-D.

         (c) The Reporting Person has not effected any transaction in the Common
Stock of the Company during the past 60 days, except for the following:

         Between September 15, 2003 and February 11, 2004, the Reporting Person
disposed of in private transactions a total of 391,003 shares of the Company's
Series B Preferred Stock and 1,162,144 shares of the Company's Common Stock, all
of which shares were originally acquired in the transaction previously disclosed
in Item 3. The aforementioned Series B Preferred Stock is convertible into
2,834,772 shares of the Company's Common Stock. All of the aforementioned shares
of Series B Preferred Stock and Common Stock were distributed either to (i)
holders of the Reporting Person's Senior Secured Convertible Promissory Notes,
(ii) holders of other debt upon the respective note holder's election to
exercise to convert the debt, (iii) to creditors of the Reporting Person in
settlement of the respective liabilities, or (iv), to a lesser extent,
represented contracted amounts or grants approved by the Reporting Person's
board of directors for services rendered to the Reporting Person. Following is a
summary of those individuals and organizations who received in excess of 1% of
the Company's outstanding Common Stock, on a fully converted basis, during the
aforementioned period from September 15, 2003 to February 11, 2004, and from the
date of the transaction previously disclosed in Item 3 (February 25, 2003) to
February 11, 2004:

                                       4






                                                   Period 9/15/03 to 2/11/04  Period 2/25/03 to 2/11/04
                                                                 Percent of                Percent of
                                                     Common        Total        Common       Total
                                                      Stock     Outstanding     Stock     Outstanding
                                                                              

MPI Venture Management. LLC * ...................    801,750       2.05%      2,203,677      5.63%
Horace H. Work ..................................    336,941        .86       1,546,446      3.95
Thomas F. Taft, Sr ..............................  1,221,860       3.12       1,221,860      3.12
Douglas A. Dyer ** ..............................      --           --        1,093,221      2.79
John T. Zick ....................................      --           --          676,907      1.73
William J. Ritger ...............................      --           --          646,676      1.65
Bruce A. Brown ..................................      --           --          575,548      1.47
Broadstreet Investment
         Management, LLC *** ...................       --           --          498,732      1.27
Others (individually less than 1%)                 1,636,365       4.18       4,231,171     10.81
                                                   ---------   ---------    -------------   -----
                                                   3,996,916     10.21%      12,694,238     32.42%
                                                   ==========   =========    ===========    ======



     * Messrs.  David W. Pequet and Mark A. Margason each own 50% of MPI Venture
Management, LLC, and both are directors of the Company and the Reporting Person.
Messrs.  Pequet and Margason have shared power to vote or to direct the vote and
shared power to dispose or to direct the  disposition of the shares  reported as
beneficially owned.
     ** Includes  575,045  shares owned in joint  tenancy with James H. Brennan.
Mr. Dyer is a director of the Reporting  Person.  Messrs.  Brennan and Dyer have
shared  power to vote or to direct  the vote and  shared  power to dispose or to
direct the disposition of the jointly-owned shares.
     *** Broadstreet  Investment  Management,  LLC is a venture fund, managed by
Messrs.  Douglas A. Dyer and James H.  Brennan.  Messrs.  Brennan  and Dyer have
shared  power to vote or to direct  the vote and  shared  power to dispose or to
direct the disposition of the shares.

        After giving effect to these transactions, the Reporting Person is the
beneficial owner of 6,490,680 shares, or 16.6%, of the outstanding Common
Stock.

ITEM 6.  CONTRACTS,  ARRANGEMENTS,  UNDERSTANDINGS  OR  RELATIONSHIPS  WITH
RESPECT TO SECURITIES OF THE ISSUER.

         Item 6 of the Schedule 13D is supplemented as follows:

         The shareholders of the Reporting Person and the holders of the Senior
Secured Convertible Promissory Notes of the Reporting Person (the "Promissory
Notes") have approved a Plan of Reorganization of the Reporting Person pursuant
to which all of the Series B Preferred Stock and Common Stock acquired in the
transaction previously disclosed in Item 3 will be (i) distributed to the
holders of the Promissory Notes and other creditors of the Reporting Person,



                                       5


(ii) sold in private transactions to raise working capital to sustain the
Reporting Person's operations during a "wind-down" period, and (iii) any balance
will be distributed on a pro rata basis to the shareholders of the Reporting
Person.

         Other than as described in this Statement, to the knowledge of the
Reporting Person, there are no contracts, arrangements, understandings or
relationships (legal or otherwise) among the persons named in Item 2 and between
such person and any person with respect to any securities of the Company,
including, but not limited to, transfers or voting of any securities, finder's
fees, joint ventures, loan or option arrangements, puts or calls, guarantees of
profits, division of profits or loss, or the giving or withholding of proxies.


ITEM 7. MATERIAL TO BE FILED AS EXHIBITS.

Exhibit           Description
-------           -----------

                  None


                                   SIGNATURES

After reasonable inquiry and to the best knowledge and belief of the
undersigned, the information set forth in this statement is true, complete and
correct.

Dated: February 29, 2004


                             AEI ENVIRONMENTAL, INC.


                              By: /s/ Tom F. Perles
                             -----------------------
                                 Tom F. Perles
                                 President, Chief Financial Officer
                                 and Secretary

                                       6




                                   APPENDIX A

     Executive   Officers   and   Directors   of   AEI    Environmental,    Inc.
            -------------------------------------------------------
     Unless otherwise  indicated below,  each director and executive  officer of
the Reporting  Person is a U.S.  citizen and has his or her business address c/o
AEI Environmental, Inc., 710 North York Road, Hinsdale, Illinois 60521.
-------------------------------------------------------------------------------
NAME                                       PRINCIPAL OCCUPATION OR EMPLOYMENT
-------------------------------------------------------------------------------
David W. Pequet, Director                  President, MPI Investment Management,
                                           Inc., 710 North York Road, Hinsdale,
                                           Illinois 60521.
-------------------------------------------------------------------------------
Mark A. Margason, Director                 Chief Financial Officer,  MPI
                                           Investment  Management,  Inc., 710
                                           North York Road, Hinsdale, Illinois
                                           60521.
-------------------------------------------------------------------------------
Edward L. McMillan, Chairman               Concord Partners, LLC, Mark Twain
                                           Plaza, Suite 325, 101 West Vandalia
                                           Street, Edwardsville, Illinois 62025
------------------------------------------------------------------------------
Douglas Dyer, Director                     Partner, Brennan Dyer & Company, LLC,
                                           735 Broad Street, Suite 218,
                                           Chattanooga, Tennessee 37402
-------------------------------------------------------------------------------
Tom F. Perles, Director, President,        AEI Environmental, Inc., 710 North
   Chief Financial Officer                 York Road, Hinsdale,Illinois 60521
   and Secretary



                                       7