----

----

----

----

| x | QUARTERLY REPORT PURSUANT TO SECTION 13 or 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 |
|---|------------------------------------------------------------------------------------------------------------------|

| o | TRANSITION REPORT PURSUANT TO SECTION 13 or 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 |
|---|------------------------------------------------------------------------------------------|

----

----

| Delaware                                                   |   | 02-0620757                              |
|------------------------------------------------------------|--------|-----------------------------------------|
| (State of Incorporation)                                   |   | (I.R.S. Employer Identification Number) |
|                                                       |   |                                    |
| 3041 W. Pasadena Dr.                                       |   |                                    |
| Boise, ID                                                  |   | 83705                                   |
| (Address of principal executive offices)                   |   | (Zip Code)                              |
|                                                       |   |                                    |
| (208) 955-8930                                             |
| (Registrant’s telephone number, including area code) |

----

| Large accelerated filer | o                  |                                   | Accelerated filer   | x |
|-------------------------|------------------------------------------------------------|----------------------------------------|-------------------------------|---|
| Non-accelerated filer   | o  (Do not check if a smaller reporting company) | Smaller reporting company    | o                             |

----

----

----

MWI

| PART I.  |   | FINANCIAL INFORMATION                                                                                  |   |
|----------|--------|--------------------------------------------------------------------------------------------------------|--------|
|     |   |                                                                                                   |   |
| Item 1.  |   | Financial Statements (Unaudited)                                                                       |   |
|     |   | Condensed Consolidated Statements of Income for the three and six months ended March 31, 2011 and 2010 | 3      |
|     |   |                                                                                                   |   |
|     |   | Condensed Consolidated Balance Sheets as of March 31, 2011 and September 30, 2010                      | 4      |
|     |   |                                                                                                   |   |
|     |   | Condensed Consolidated Statements of Cash Flows for the six months ended March 31, 2011 and 2010       | 5      |
|     |   |                                                                                                   |   |
|     |   | Notes to Condensed Consolidated Financial Statements                                                   | 6      |
|     |   |                                                                                                   |   |
|     |   | Report of Independent Registered Public Accounting Firm                                                | 15     |
|     |   |                                                                                                   |   |
| Item 2.  |   | Management’s Discussion and Analysis of Financial Condition and Results of Operations            | 16     |
|     |   |                                                                                                   |   |
| Item 3.  |   | Quantitative and Qualitative Disclosures About Market Risk                                             | 22     |
|     |   |                                                                                                   |   |
| Item 4.  |   | Controls and Procedures                                                                                | 23     |
|     |   |                                                                                                   |   |
| PART II. |   | OTHER INFORMATION                                                                                      |   |
|     |   |                                                                                                   |   |
|     |   | Cautionary Statement                                                                                   | 23     |
|     |   |                                                                                                   |   |
| Item 1.  |   | Legal Proceedings                                                                                      | 24     |
|     |   |                                                                                                   |   |
| Item 1A. |   | Risk Factors                                                                                           | 24     |
|     |   |                                                                                                   |   |
| Item 2.  |   | Unregistered Sales of Equity Securities and Use of Proceeds                                            | 24     |
|     |   |                                                                                                   |   |
| Item 3.  |   | Defaults Upon Senior Securities                                                                        | 25     |
|     |   |                                                                                                   |   |
| Item 4.  |   | Removed and Reserved                                                                                   | 25     |
|     |   |                                                                                                   |   |
| Item 5.  |   | Other Information                                                                                      | 25     |
|     |   |                                                                                                   |   |
| Item 6.  |   | Exhibits                                                                                               | 25     |

----

|                                                      |                                | PART I. FINANCIAL INFORMATION                          |                         |                |                       |                |                |                |                |                |                |                |                |
|-----------------------------------------------------------|-------------------------------------|--------------------------------------------------------|------------------------------|---------------------|----------------------------|---------------------|---------------------|---------------------|---------------------|---------------------|---------------------|---------------------|---------------------|
|                                                      |                                |                                                   |                         |                |                       |                |                |                |                |                |                |                |                |
|                                                      |                                | Item 1. Financial Statements                           |                         |                |                       |                |                |                |                |                |                |                |                |
|                                                      |                                |                                                   |                         |                |                       |                |                |                |                |                |                |                |                |
|                                                      |                                | MWI VETERINARY SUPPLY, INC.                            |
|                                                      |                                | CONDENSED CONSOLIDATED STATEMENTS OF INCOME            |
|                                                      |                                | Dollars and shares in thousands, except per share data |
|                                                      |                                | (unaudited)                                            |
|                                                      |                                |                                                   |                         |                |                       |                |                |                |                |                |                |                |                |
|                                                      |                                |                                                   | Three months ended March 31, |                | Six months ended March 31, |
|                                                      |                                |                                                   | 2011                    |                | 2010                  |                | 2011           |                | 2010           |
| Revenues:                                                 |                                |                                                   |                         |                |                       |                |                |                |                |                |                |
|                                                      | Product sales                       | $                                                      |  348,387           |                | $                          |  271,893  |                | $                   |  696,124  |                | $                   |  493,372  |
|                                                      | Product sales to related party      |                                                   |  13,118            |                |                       |  10,516   |                |                |  27,841   |                |                |  21,574   |
|                                                      | Commissions                         |                                                   |  5,607             |                |                       |  4,188    |                |                |  9,321    |                |                |  7,762    |
|                                                      |                                | Total revenues                                         |                         |  367,112  |                       |                |  286,597  |                |                |  733,286  |                |                |  522,708  |
| Cost of product sales                                     |                                |  316,126                                     |                         |                |  247,075         |                |                |  632,228  |                |                |  447,177  |
| Gross profit                                              |                                |  50,986                                      |                         |                |  39,522          |                |                |  101,058  |                |                |  75,531   |
|                                                      |                                |                                                   |                         |                |                       |                |                |                |                |                |                |                |                |
| Selling, general and administrative expenses              |                                |  32,450                                      |                         |                |  25,592          |                |                |  63,497   |                |                |  48,013   |
| Depreciation and amortization                             |                                |  1,667                                       |                         |                |  1,266           |                |                |  3,156    |                |                |  2,121    |
| Operating income                                          |                                |  16,869                                      |                         |                |  12,664          |                |                |  34,405   |                |                |  25,397   |
|                                                      |                                |                                                   |                         |                |                       |                |                |                |                |                |                |                |                |
| Other income (expense):                                   |                                |                                                   |                         |                |                       |                |                |                |                |                |                |
|                                                      | Interest expense                    |                                                   |  (252)                  |                |                       |  (178)         |                |                |  (434)         |                |                |  (218)         |
|                                                      | Earnings of equity method investees |                                                   |  63                |                |                       |  53       |                |                |  136      |                |                |  110      |
|                                                      | Other                               |                                                   |  143               |                |                       |  135      |                |                |  278      |                |                |  242      |
|                                                      |                                | Total other income (expense), net                      |                         |  (46)          |                       |                |  10       |                |                |  (20)          |                |                |  134      |
|                                                      |                                |                                                   |                         |                |                       |                |                |                |                |                |                |                |                |
| Income before taxes                                       |                                |  16,823                                      |                         |                |  12,674          |                |                |  34,385   |                |                |  25,531   |
| Income tax expense                                        |                                |  (6,491)                                          |                         |                |  (5,003)              |                |                |  (13,225)      |                |                |  (10,026)      |
| Net income                                                | $                                   |  10,332                                      |                         | $                   |  7,671           |                | $                   |  21,160   |                | $                   |  15,505   |
|                                                      |                                |                                                   |                         |                |                       |                |                |                |                |                |                |                |                |
| Earnings per common share:                                |                                |                                                   |                         |                |                       |                |                |                |                |                |                |
|                                                      | Basic                               | $                                                      |  0.83              |                | $                          |  0.63     |                | $                   |  1.70     |                | $                   |  1.27     |
|                                                      | Diluted                             | $                                                      |  0.83              |                | $                          |  0.62     |                | $                   |  1.69     |                | $                   |  1.25     |
|                                                      |                                |                                                   |                         |                |                       |                |                |                |                |                |                |                |                |
| Weighted average common shares outstanding:               |                                |                                                   |                         |                |                       |                |                |                |                |                |
|                                                      | Basic                               |                                                   |  12,462            |                |                       |  12,207   |                |                |  12,438   |                |                |  12,190   |
|                                                      | Diluted                             |                                                   |  12,511            |                |                       |  12,376   |                |                |  12,496   |                |                |  12,366   |
|                                                      |                                |                                                   |                         |                |                       |                |                |                |                |                |                |                |                |
|                                                      |                                |                                                   |                         |                |                       |                |                |                |                |                |                |                |                |
| See Notes to Condensed Consolidated Financial Statements. |                                |                                                   |                         |                |                       |                |                |                |                |

----

Table of Contents

| MWI VETERINARY SUPPLY, INC.                               |
|-----------------------------------------------------------|
| CONDENSED CONSOLIDATED BALANCE SHEETS                     |
| Dollars and shares in thousands, except per share data    |
| (unaudited)                                               |
|                                                      |   |   |   |   |   |   |   |
|                                                      |   |   | March 31, |   | September 30, |
|                                                      |   |   | 2011  |   | 2010  |
| Assets                                                    |   |   |   |   |   |
|                                                      |   |   |   |   |   |   |   |
| Current Assets:                                           |   |   |   |   |   |
|                                                      | Cash and cash equivalents | $ |  974  |   | $ |  911  |
|                                                      | Receivables, net |   |  208,256  |   |   |  189,428  |
|                                                      | Inventories |   |  183,764  |   |   |  175,292  |
|                                                      | Prepaid expenses and other current assets |   |  5,500  |   |   |  8,729  |
|                                                      | Deferred income taxes |   |  1,718  |   |   |  1,556  |
|                                                      |   | Total current assets |   |  400,212  |   |   |  375,916  |
|                                                      |   |   |   |   |   |   |   |
| Property and equipment, net                               |   |  24,105  |   |   |  15,238  |
| Goodwill                                                  |   |  49,245  |   |   |  47,330  |
| Intangibles, net                                          |   |  26,276  |   |   |  26,710  |
| Other assets, net                                         |   |  2,729  |   |   |  2,738  |
| Total assets                                              | $ |  502,567  |   | $ |  467,932  |
|                                                      |   |   |   |   |   |   |   |
| Liabilities And Stockholders’ Equity                |   |   |   |   |   |
|                                                      |   |   |   |   |   |   |   |
| Current Liabilities:                                      |   |   |   |   |   |
|                                                      | Credit facilities | $ |  28,326  |   | $ |  10,140  |
|                                                      | Accounts payable |   |  176,138  |   |   |  183,604  |
|                                                      | Accrued expenses |   |  16,444  |   |   |  15,118  |
|                                                      | Note payable |   |  -  |   |   |  2,000  |
|                                                      | Current portion of long-term debt and capital lease obligations |   |  929  |   |   |  1,631  |
|                                                      |   | Total current liabilities |   |  221,837  |   |   |  212,493  |
|                                                      |   |   |   |   |   |   |   |
| Deferred income taxes                                     |   |  5,964  |   |   |  5,310  |
|                                                      |   |   |   |   |   |   |   |
| Long-term debt and capital lease obligations              |   |  782  |   |   |  953  |
|                                                      |   |   |   |   |   |   |   |
| Other long-term liabilities                               |   |  2,386  |   |   |  2,389  |
|                                                      |   |   |   |   |   |   |   |
| Commitments and contingencies (see Note 14)               |   |   |   |   |   |
|                                                      |   |   |   |   |   |   |   |
| Stockholders’ Equity                                |   |   |   |   |   |
|                                                      | Common stock $0.01 par value, 40,000 authorized; 12,546 and |   |   |   |   |   |
|                                                      |   | 12,457 shares issued and outstanding, respectively |   |  126  |   |   |  125  |
|                                                      | Additional paid in capital |   |  132,505  |   |   |  129,675  |
|                                                      | Retained earnings |   |  138,068  |   |   |  116,908  |
|                                                      | Accumulated other comprehensive income |   |  899  |   |   |  79  |
|                                                      |   | Total stockholders’ equity |   |  271,598  |   |   |  246,787  |
| Total liabilities and stockholders’ equity          | $ |  502,567  |   | $ |  467,932  |
|                                                      |   |   |   |   |   |   |   |
| See Notes to Condensed Consolidated Financial Statements. |   |   |   |   |   |

----

Table of Contents

| MWI VETERINARY SUPPLY, INC.                               |
|-----------------------------------------------------------|
| CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS           |
| Dollars in thousands (unaudited)                          |
|                                                      |   |   |   |   |   |   |   |   |   |
|                                                      |   |   |   |   | Six months ended March 31, |
|                                                      |   |   |   |   | 2011  |   | 2010  |
| Cash Flows From Operating Activities:                     |   |   |   |   |   |
|                                                      | Net income | $ |  21,160  |   | $ |  15,505  |
|                                                      | Adjustments to reconcile net income to net cash (used in)/provided by operating activities: |   |   |   |
|                                                      |   | Depreciation and amortization |   |  3,162  |   |   |  2,127  |
|                                                      |   | Amortization of debt issuance costs |   |  33  |   |   |  25  |
|                                                      |   | Stock-based compensation |   |  651  |   |   |  396  |
|                                                      |   | Deferred income taxes |   |  443  |   |   |  (272) |
|                                                      |   | Earnings of equity method investees |   |  (136) |   |   |  (110) |
|                                                      |   | Excess tax benefit of exercise of common stock options |   |  (1,900) |   |   |  (973) |
|                                                      |   | Pension payment |   |  -  |   |   |  (2,047) |
|                                                      |   | Other |   |  96  |   |   |  4  |
|                                                      |   | Changes in operating assets and liabilities (net of effects of business acquisitions): |   |   |   |   |   |
|                                                      |   |   | Receivables |   |  (13,663) |   |   |  (4,971) |
|                                                      |   |   | Inventories |   |  (4,591) |   |   |  (11,113) |
|                                                      |   |   | Prepaid expenses and other current assets |   |  5,183  |   |   |  181  |
|                                                      |   |   | Accounts payable |   |  (12,332) |   |   |  7,424  |
|                                                      |   |   | Accrued expenses |   |  505  |   |   |  (966) |
|                                                      |   |   |   | Net cash (used in)/provided by operating activities |   |  (1,389) |   |   |  5,210  |
|                                                      |   |   |   |   |   |   |   |   |   |
| Cash Flows From Investing Activities:                     |   |   |   |   |   |
|                                                      |   | Business acquisitions, net of cash acquired |   |  (7,000) |   |   |  (41,379) |
|                                                      |   | Purchases of property and equipment |   |  (9,130) |   |   |  (845) |
|                                                      |   | Other |   |  79  |   |   |  (210) |
|                                                      |   |   |   | Net cash used in investing activities |   |  (16,051) |   |   |  (42,434) |
|                                                      |   |   |   |   |   |   |   |   |   |
| Cash Flows From Financing Activities:                     |   |   |   |   |   |
|                                                      |   | Borrowings on credit facilities |   |  172,129  |   |   |  62,442  |
|                                                      |   | Payments on credit facilities |   |  (153,997) |   |   |  (39,300) |
|                                                      |   | Proceeds from issuance of common stock |   |  189  |   |   |  112  |
|                                                      |   | Proceeds from exercise of stock options |   |  69  |   |   |  96  |
|                                                      |   | Excess tax benefit of exercise of common stock options |   |  1,900  |   |   |  973  |
|                                                      |   | Debt issuance costs |   |  -  |   |   |  (116) |
|                                                      |   | Payment on long-term debt and capital lease obligations |   |  (2,902) |   |   |  (396) |
|                                                      |   |   |   | Net cash provided by financing activities |   |  17,388  |   |   |  23,811  |
|                                                      |   |   |   |   |   |   |   |   |   |
| Effect of Exchange Rate on Cash and Cash Equivalents      |   |  115  |   |   |  (23) |
|                                                      |   |   |   |   |   |   |   |   |   |
| Increase/(Decrease) in Cash and Cash Equivalents          |   |  63  |   |   |  (13,436) |
|                                                      |   |   |   |   |   |   |   |   |   |
| Cash and Cash Equivalents at Beginning of Period          |   |  911  |   |   |  14,302  |
|                                                      |   |   |   |   |   |   |   |   |   |
| Cash and Cash Equivalents at End of Period                | $ |  974  |   | $ |  866  |
|                                                      |   |   |   |   |   |   |   |   |   |
| See Notes to Condensed Consolidated Financial Statements. |   |   |   |   |   |

----

Table of Contents

MWI

----

Table of Contents

|   |                      |   | 2011  |               | 2010  |
|--------|---------------------------|--------|------------|--------------------|------------|
|   | Cash                      |   | $          |  -       |       | $ |  674  |
|   | Receivables               |   |       |  4,083   |       |   |  32,371  |
|   | Inventories               |   |       |  3,594   |       |   |  17,830  |
|   | Other current assets      |   |       |  -       |       |   |  480  |
|   | Property and equipment    |   |       |  1,900   |       |   |  5,275  |
|   | Goodwill                  |   |       |  1,781   |       |   |  9,483  |
|   | Intangibles               |   |       |  140     |       |   |  17,658  |
|   | Total assets acquired     |   |       |  11,498  |       |   |  83,771  |
|   |                      |   |       |               |       |   |   |
|   | Accounts payable          |   |       |  4,498   |       |   |  25,811  |
|   | Accrued expenses          |   |       |  -       |       |   |  5,299  |
|   | Other liabilities         |   |       |  -       |       |   |  10,476  |
|   | Total liabilities assumed |   |       |  4,498   |       |   |  41,586  |
|   |                      |   |       |               |       |   |   |
|   | Net assets acquired       |   | $          |  7,000   |       | $ |  42,185  |

----

Table of Contents

|   |       | Centaur's operations included in MWI's results |               |
|--------|------------|------------------------------------------------|--------------------|
|   |       | Three months ended March 31, 2011              |               | Six months ended March 31, 2011 |   |
|   | Revenues   | $                                              |  61,688  |   | $ |  124,222  |   |
|   | Net Income | $                                              |  763     |   | $ |  1,379  |   |

|   |       | Unaudited Pro Forma Consolidated Results |                |
|--------|------------|------------------------------------------|---------------------|
|   |       | Three months ended March 31, 2010        |                | Six months ended March 31, 2010 |   |
|   | Revenues   | $                                        |  310,641  |   | $ |  607,328  |   |
|   | Net Income | $                                        |  8,162    |   | $ |  16,577  |   |

|   |                            | March 31,  |                | September 30, |   |
|--------|---------------------------------|------------|---------------------|---------------|--------|
|   |                            | 2011  |                | 2010     |   |
|   | Trade                           | $          |  193,897  |          | $      |  177,317  |   |
|   | Vendor rebates and programs     |       |  16,723   |          |   |  14,681  |   |
|   |                            |       |  210,620  |          |   |  191,998  |   |
|   | Allowance for doubtful accounts |       |  (2,364)       |          |   |  (2,570) |   |
|   |                            | $          |  208,256  |          | $      |  189,428  |   |

----

Table of Contents

|   |                                | March 31,  |               | September 30, |   |
|--------|-------------------------------------|------------|--------------------|---------------|--------|
|   |                                | 2011  |               | 2010     |   |
|   | Land                                | $          |  1,730   |          | $      |  261  |   |
|   | Building and leasehold improvements |       |  8,669   |          |   |  5,870  |   |
|   | Machinery, furniture and equipment  |       |  20,509  |          |   |  17,495  |   |
|   | Computer equipment                  |       |  5,080   |          |   |  4,886  |   |
|   | Construction in progress            |       |  5,154   |          |   |  1,626  |   |
|   |                                |       |  41,142  |          |   |  30,138  |   |
|   | Accumulated depreciation            |       |  (17,037)     |          |   |  (14,900) |   |
|   |                                | $          |  24,105  |          | $      |  15,238  |   |

|   | Goodwill as of September 30, 2010 |                         |   |   | $      |  47,330  |              |
|--------|-----------------------------------|------------------------------|--------|--------|--------|--------------------|-------------------|
|   |                              | Acquisition activity         |   |   |   |               |  1,780  |   |
|   |                              | Foreign currency adjustments |   |   |   |               |  135    |   |
|   | Goodwill as of March 31, 2011     |                         |   |   | $      |  49,245  |              |

|   |                     |   |         |   | March 31,  |               | September 30, |   |
|--------|--------------------------|--------|--------------|--------|------------|--------------------|---------------|--------|
|   |                     |   | Useful Lives |   | 2011  |               | 2010     |   |
|   | Amortizing:              |   |         |   |       |               |          |   |   |   |
|   | Customer relationships   |   | 9-20 years   |   | $          |  25,392  |          | $      |  25,027  |   |
|   | Covenants not to compete |   | 1-5 years    |   |       |  815     |          |   |  811  |   |
|   | Other                    |   | 3-7 years    |   |       |  461     |          |   |  458  |   |
|   |                     |   |         |   |       |  26,668  |          |   |  26,296  |   |
|   | Accumulated amortization |   |         |   |       |  (4,187)      |          |   |  (3,361) |   |
|   |                     |   |         |   |       |  22,481  |          |   |  22,935  |   |
|   | Non-Amortizing:          |   |         |   |       |               |          |   |   |   |
|   | Trade names and patents  |   |         |   |       |  3,795   |          |   |  3,775  |   |
|   |                     |   |         |   | $          |  26,276  |          | $      |  26,710  |   |

----

Table of Contents

|   |              | Amount |               |
|--------|-------------------|--------|--------------------|
|   | Remainder of 2011 | $      |  828     |   |
|   | 2012         |   |  1,623   |   |
|   | 2013         |   |  1,538   |   |
|   | 2014         |   |  1,533   |   |
|   | 2015         |   |  1,380   |   |
|   | Thereafter        |   |  15,579  |   |
|   |              | $      |  22,481  |   |

|   |                                                                                                 |                                               |               | March 31,   |   |               | September 30, |   |
|--------|------------------------------------------------------------------------------------------------------|----------------------------------------------------|--------------------|-------------|--------|--------------------|---------------|--------|
|   |                                                                                                 |                                               |               | 2011   |   |               | 2010     |   |
|   | Revolving credit facility, 1.68% as of March 31, 2011                                                | $                                                  |  25,400  |        | $      |  9,600   |          |
|   | Sterling revolving credit facility, 1.72% as of March 31, 2011                                       |                                               |  2,926   |        |   |  540     |          |
|   | Note payable (1)                                                                                     |                                               |  -       |        |   |  2,000   |          |
|   | Capital lease obligations (2)                                                                        |                                               |  1,711   |        |   |  1,811   |          |
|   | Term note                                                                                            |                                               |  -       |        |   |  773     |          |
|   | Total debt and capital lease obligations                                                             |                                               |  30,037  |        |   |  14,724  |          |
|   |                                                                                                 | Less: Long-term debt and capital lease obligations |               |  (782) |   |               |  (953)   |   |
|   | Total debt included in current liabilities                                                           | $                                                  |  29,255  |        | $      |  13,771  |          |
|   |                                                                                                 |                                               |               |        |   |               |          |   |
|   | (1) Note payable was related to the acquisition of Centaur and was paid in full on February 8, 2011. |                                               |
|   | (2) The capital lease obligations have varying maturity dates.                                       |                                               |

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| ·   | Level 1 – observable inputs such as quoted prices in active markets; |
|--------------------|----------------------------------------------------------------------------|

| ·   | Level 2 – inputs, other than quoted prices, that are observable for the asset or liability, either directly or indirectly.  These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active; and |
|--------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| ·   | Level 3 – unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. |
|--------------------|----------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 2002 Stock Plan |
|--------|-----------------|

|   | 2005 Stock Plan |
|--------|-----------------|

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|   |                                           |                               | Three months ended March 31, |
|--------|------------------------------------------------|------------------------------------|------------------------------|
|   |                                           |                               | 2011                    |   | 2010  |
|   |                                           |                               | Basic                        |   | Diluted |   | Basic |   | Diluted |
|   | Net income                                     | $                                  |  10,332            |   | $ |  10,332  |   | $ |  7,671  |   | $ |  7,671  |
|   |                                           |                               |                         |   |   |   |   |   |   |   |   |   |   |
|   | Weighted average common shares outstanding     |                               |  12,462            |   |   |  12,462  |   |   |  12,207  |   |   |  12,207  |
|   | Effect of diluted securities                   |                               |                         |   |   |   |   |   |   |   |   |   |
|   |                                           | Stock options and restricted stock |                         |   |   |   |  49  |   |   |   |   |   |  169  |
|   |                                           |                               |                         |   |   |   |   |   |   |   |   |   |   |
|   | Weighted average diluted shares outstanding    |                               |                         |   |   |  12,511  |   |   |   |   |   |  12,376  |
|   | Earnings per share                             | $                                  |  0.83              |   | $ |  0.83  |   | $ |  0.63  |   | $ |  0.62  |
|   |                                           |                               |                         |   |   |   |   |   |   |   |   |   |   |
|   | Anti-dilutive shares excluded from calculation |                               |                         |   |   |  -  |   |   |   |   |   |  -  |
|   |                                           |                               |                         |   |   |   |   |   |   |   |   |   |   |
|   |                                           |                               | Six months ended March 31,   |
|   |                                           |                               | 2011                    |   | 2010  |
|   |                                           |                               | Basic                        |   | Diluted |   | Basic |   | Diluted |
|   | Net income                                     | $                                  |  21,160            |   | $ |  21,160  |   | $ |  15,505  |   | $ |  15,505  |
|   |                                           |                               |                         |   |   |   |   |   |   |   |   |   |   |
|   | Weighted average common shares outstanding     |                               |  12,438            |   |   |  12,438  |   |   |  12,190  |   |   |  12,190  |
|   | Effect of diluted securities                   |                               |                         |   |   |   |   |   |   |   |   |   |
|   |                                           | Stock options and restricted stock |                         |   |   |   |  58  |   |   |   |   |   |  176  |
|   |                                           |                               |                         |   |   |   |   |   |   |   |   |   |   |
|   | Weighted average diluted shares outstanding    |                               |                         |   |   |  12,496  |   |   |   |   |   |  12,366  |
|   | Earnings per share                             | $                                  |  1.70              |   | $ |  1.69  |   | $ |  1.27  |   | $ |  1.25  |
|   |                                           |                               |                         |   |   |   |   |   |   |   |   |   |   |
|   | Anti-dilutive shares excluded from calculation |                               |                         |   |   |  -  |   |   |   |   |   |  -  |

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|   |                                                  | Six months ended March 31, |              |
|--------|-------------------------------------------------------|----------------------------|-------------------|
|   |                                                  | 2011                  |              | 2010  |   |
|   | Supplemental Disclosures                              |                       |              |   |   |   |   |
|   | Cash paid for interest                                | $                          |  283    |   | $ |  143  |   |
|   | Cash paid for income taxes                            |                       |  7,644  |   |   |  9,563  |   |
|   | Non-cash Activities                                   |                       |              |   |   |   |   |
|   | Note payable issued related to Centaur acquisition    |                       |  -      |   |   |  2,000  |   |
|   | Equipment acquisitions financed with accounts payable |                       |  122    |   |   |  77  |   |

|                      |                         |                       | Three months ended March 31, |               | Six months ended March 31, |
|---------------------------|------------------------------|----------------------------|------------------------------|--------------------|----------------------------|
|                      |                         |                       | 2011                    |               | 2010                  |   | 2011  |   | 2010  |
| Net income                | $                            |  10,332          |                         | $                  |  7,671           |   | $ |  21,160  |   | $ |  15,505  |
| Other comprehensive loss: |                         |                       |                         |               |                       |   |   |   |   |   |   |
|                      | Foreign currency translation |                       |  1,868             |               |                       |  (1,742) |   |   |  820  |   |   |  (1,742) |
|                      |                         | Total comprehensive income | $                            |  12,200  |                       | $ |  5,929  |   | $ |  21,980  |   | $ |  13,763  |

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|   | REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM |
|--------|---------------------------------------------------------|

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|                                                       |                           |                |                         | Three months ended March 31, |                | Six months ended March 31, |
|------------------------------------------------------------|--------------------------------|---------------------|------------------------------|------------------------------|---------------------|----------------------------|
|                                                       |                           |                |                         | 2011                    |                | %                          |   | 2010  |   | % |   | 2011  |   | % |   | 2010  |   | % |
| Revenues:                                                  |                           |                |                         |                         |                |                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                                       | Product sales                  | $                   |  348,387           |                         | 94.9           | %                          |   | $ |  271,893  |   | 94.9  | % |   | $ |  696,124  |   | 94.9  | % |   | $ |  493,372  |   | 94.4  | % |
|                                                       | Product sales to related party |                |  13,118            |                         | 3.6            | %                          |   |   |  10,516  |   | 3.7  | % |   |   |  27,841  |   | 3.8  | % |   |   |  21,574  |   | 4.1  | % |
|                                                       | Commissions                    |                |  5,607             |                         | 1.5            | %                          |   |   |  4,188  |   | 1.4  | % |   |   |  9,321  |   | 1.3  | % |   |   |  7,762  |   | 1.5  | % |
|                                                       |                           |                | Total revenues               |                         |  367,112  |                       | 100.0  | % |   |   |  286,597  |   | 100.0  | % |   |   |  733,286  |   | 100.0  | % |   |   |  522,708  |   | 100.0  | % |
|                                                       |                           |                |                         |                         |                |                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Cost of product sales                                      |                           |  316,126  |                         | 86.1                    | %                   |                       |   |  247,075  |   | 86.2  | % |   |   |  632,228  |   | 86.2  | % |   |   |  447,177  |   | 85.6  | % |
| Gross profit                                               |                           |  50,986   |                         | 13.9                    | %                   |                       |   |  39,522  |   | 13.8  | % |   |   |  101,058  |   | 13.8  | % |   |   |  75,531  |   | 14.4  | % |
|                                                       |                           |                |                         |                         |                |                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| SG&A expenses                                          |                           |  32,450   |                         | 8.8                     | %                   |                       |   |  25,592  |   | 8.9  | % |   |   |  63,497  |   | 8.7  | % |   |   |  48,013  |   | 9.2  | % |
| Depreciation and amortization                              |                           |  1,667    |                         | 0.5                     | %                   |                       |   |  1,266  |   | 0.5  | % |   |   |  3,156  |   | 0.4  | % |   |   |  2,121  |   | 0.4  | % |
| Operating income                                           |                           |  16,869   |                         | 4.6                     | %                   |                       |   |  12,664  |   | 4.4  | % |   |   |  34,405  |   | 4.7  | % |   |   |  25,397  |   | 4.8  | % |
|                                                       |                           |                |                         |                         |                |                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Other income (expense):                                    |                           |                |                         |                         |                |                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                                       | Interest expense               |                |  (252)                  |                         | -              | %                          |   |   |  (178) |   | -  | % |   |   |  (434) |   | -  | % |   |   |  (218) |   | -  | % |
|                                                       | Earnings of equity method      |                |                         |                         |                |                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                                       |                           | investees           |                         |  63                |                | -                     | % |   |   |  53  |   | -  | % |   |   |  136  |   | -  | % |   |   |  110  |   | -  | % |
|                                                       | Other                          |                |  143               |                         | -              | %                          |   |   |  135  |   | -  | % |   |   |  278  |   | -  | % |   |   |  242  |   | 0.1  | % |
|                                                       |                           |                | Total other income (expense) |                         |  (46)          |                       | -  | % |   |   |  10  |   | -  | % |   |   |  (20) |   | -  | % |   |   |  134  |   | 0.1  | % |
|                                                       |                           |                |                         |                         |                |                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Income before taxes                                        |                           |  16,823   |                         | 4.6                     | %                   |                       |   |  12,674  |   | 4.4  | % |   |   |  34,385  |   | 4.7  | % |   |   |  25,531  |   | 4.9  | % |
| Income tax expense                                         |                           |  (6,491)       |                         | (1.8)                        | %                   |                       |   |  (5,003) |   | (1.7) | % |   |   |  (13,225) |   | (1.8) | % |   |   |  (10,026) |   | (1.9) | % |
| Net income                                                 | $                              |  10,332   |                         | 2.8                     | %                   |                       | $ |  7,671  |   | 2.7  | % |   | $ |  21,160  |   | 2.9  | % |   | $ |  15,505  |   | 3.0  | % |
|                                                       |                           |                |                         |                         |                |                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Earnings per common share:                                 |                           |                |                         |                         |                |                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                                       | Basic                          | $                   |  0.83              |                         |                |                       |   | $ |  0.63  |   |   |   |   | $ |  1.70  |   |   |   |   | $ |  1.27  |   |   |   |
|                                                       | Diluted                        | $                   |  0.83              |                         |                |                       |   | $ |  0.62  |   |   |   |   | $ |  1.69  |   |   |   |   | $ |  1.25  |   |   |   |
|                                                       |                           |                |                         |                         |                |                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Weighted average common shares outstanding (in thousands): |                           |                |                         |                         |                |                       |   |   |   |   |   |   |   |   |   |
|                                                       | Basic                          |                |  12,462            |                         |                |                       |   |   |  12,207  |   |   |   |   |   |  12,438  |   |   |   |   |   |  12,190  |   |   |   |
|                                                       | Diluted                        |                |  12,511            |                         |                |                       |   |   |  12,376  |   |   |   |   |   |  12,496  |   |   |   |   |   |  12,366  |   |   |   |

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PART

Cautionary

| ·   | the impact of vendor consolidation on our business; |
|--------------------|-----------------------------------------------------|

| ·   | changes in or availability of vendor contracts or rebate programs; |
|--------------------|--------------------------------------------------------------------|

| ·   | vendor rebates based upon attaining certain growth goals; |
|--------------------|-----------------------------------------------------------|

| ·   | changes in the way vendors introduce/deliver products to market; |
|--------------------|------------------------------------------------------------------|

| ·   | exclusivity requirements with certain vendors that may prohibit us from distributing competing products manufactured by other vendors; |
|--------------------|----------------------------------------------------------------------------------------------------------------------------------------|

| ·   | risks associated with our international operations; |
|--------------------|-----------------------------------------------------|

| ·   | transitional challenges associated with acquisitions, including the failure to achieve anticipated synergies; |
|--------------------|---------------------------------------------------------------------------------------------------------------|

| ·   | financial risks associated with acquisitions; |
|--------------------|-----------------------------------------------|

| ·   | the impact of general economic trends on our business; |
|--------------------|--------------------------------------------------------|

| ·   | the recall of a significant product by one of our vendors; |
|--------------------|------------------------------------------------------------|

| ·   | extended shortage or backorder of a significant product by one of our vendors; |
|--------------------|--------------------------------------------------------------------------------|

| ·   | seasonality; |
|--------------------|--------------|

| ·   | the timing and effectiveness of marketing programs or price changes offered by our vendors; |
|--------------------|---------------------------------------------------------------------------------------------|

| ·   | the timing of the introduction of new products and services by our vendors; |
|--------------------|-----------------------------------------------------------------------------|

| ·   | the ability to borrow on our revolving credit facility, extend the terms of our revolving credit facility or obtain alternative financing on favorable terms or at all; |
|--------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| ·   | risks from potential increases in variable interest rates; |
|--------------------|------------------------------------------------------------|

| ·   | the impact of tightening credit standards and/or access to credit on behalf of our customers and suppliers; |
|--------------------|-------------------------------------------------------------------------------------------------------------|

| ·   | unforeseen litigation; |
|--------------------|------------------------|

| ·   | a disruption caused by adverse weather or other natural conditions or disasters; |
|--------------------|----------------------------------------------------------------------------------|

| ·   | inability to ship products to the customer as a result of technological or shipping disruptions; and |
|--------------------|------------------------------------------------------------------------------------------------------|

| ·   | competition. |
|--------------------|--------------|

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| Issuer Purchases of Equity Securities                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------|
|                                                                                                                               |   |   |   |   |   |   |   |   |   |
|                                                                                                                               |   |   |   |   |   |   | Total Number of |   | Maximum Number (or |
|                                                                                                                               |   | Total |   |   |   |   |  Shares Purchased |   |  Approximate Dollar |
|                                                                                                                               |   | Number |   | Average |   |  as Part of Publicly |   |  Value) of Shares that May |
|                                                                                                                               |   |  of Shares |   | Price Paid |   |  Announced Plans |   |  Yet Be Purchased Under |
| Period                                                                                                                             |   |  Purchased |   | per Share |   |  or Programs |   | the Plans or Programs |
| January 1 to January 31, 2011                                                                                                      |   | — |   | $ | — |   | — |   | — |
| February 1 to February 28, 2011                                                                                                    |   |  147  |  (1) |   |  68.27  |   | — |   | — |
| March 1 to March 31, 2011                                                                                                          |   |  225  |  (1) |   |  73.06  |   | — |   | — |
| Total                                                                                                                              |   |  372  |   | $ | 71.16  |   | — |   | — |
|                                                                                                                               |   |   |   |   |   |   |   |   |   |
|                                                                                                                               |   |   |   |   |   |   |   |   |   |
| (1) These shares were withheld upon the vesting of employee stock grants in connection with payment of required withholding taxes. |

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| 10.1           |   | 2011 Livestock Products Distribution Agreement between MWI Veterinary Supply, Inc. and Pfizer, Inc. effective as of January 1, 2011 † |
|----------------|--------|------------------------------------------------------------------------------------------------------------------------------------------------------------|
|           |   |                                                                                                                                                       |
| 10.2           |   | 2011 Strategic Brands Distribution Agreement between MWI Veterinary Supply, Inc. and Pfizer, Inc. effective as of January 1, 2011 †   |
|           |   |                                                                                                                                                       |
| 15             |   | Letter re: Unaudited Interim Financial Information                                                                                                         |
|           |   |                                                                                                                                                       |
| 31.1           |   | Certification of CEO Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002                                                                             |
|           |   |                                                                                                                                                       |
| 31.2           |   | Certification of CFO Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002                                                                             |
|           |   |                                                                                                                                                       |
| 32   |   | Certification Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of theSarbanes-Oxley Act of 2002                                 |

|              |   | MWI Veterinary Supply, Inc.                                                  |   |
|-------------------|--------|------------------------------------------------------------------------------|--------|
|              |   | (Registrant)                                                                 |   |
|              |   |                                                                         |   |
|              |   |                                                                         |   |
| Date: May 5, 2011 |   |   /s/ Mary Patricia B. Thompson                                         |   |
|              |   | Mary Patricia B. Thompson                                                    |   |
|              |   | Senior Vice President of Finance and Administration, Chief Financial Officer |   |

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