Exhibit 99.1

MWI VETERINARY SUPPLY ANNOUNCES 2012 SECOND QUARTER RESULTS AND UPDATES ITS 2012 BUSINESS OUTLOOK

BOISE, Idaho (May 3, 2012) – MWI Veterinary Supply, Inc. (Nasdaq:  MWIV) (the “Company”) announced financial results today for its second quarter ended March 31, 2012.

Highlights:

§   Total revenues were $507.2 million for the quarter, 38.2% higher than revenues for the same period in the prior fiscal year.  Excluding the impact of the acquisition of the assets of Micro Beef Technologies, Ltd. (“Micro”) which was acquired on October 31, 2011, revenue growth in the United States was 22.9% for the quarter compared to the same period in the prior fiscal year.

§   Selling, general and administrative (“SG&A”) expenses as a percentage of total revenues were 8.5% for the quarter, compared to 8.8% for the same period in the prior fiscal year.

§   Operating income was $21.4 million for the quarter, 26.9% higher than operating income for the same period in the prior fiscal year.

§   Net income was $13.2 million for the quarter, 27.5% higher than net income for the same period in the prior fiscal year.  Diluted earnings per share were $1.04 for the quarter, compared to $0.83 for the same period in the prior fiscal year.

§   Internet sales to independent veterinary practices and producers in the United States grew by approximately 37% for the quarter compared to the same period in the prior fiscal year.

§   Revenues from our veterinary pharmacy programs increased approximately 46% to $46.6 million for the quarter compared to the same period in the prior fiscal year.

“I am very pleased with our sales growth of over 38%,” said Jim Cleary, President and Chief Executive Officer.  “Our leading innovative market approach, including the integration of Micro, is influencing our positive results.  The efforts by our team members have been tremendous as we continue to focus on growth while providing outstanding customer service.”

Quarter ended March 31, 2012 compared to quarter ended March 31, 2011

Total revenues increased 38.2% to $507.2 million for the quarter ended March 31, 2012, compared to $367.1 million for the quarter ended March 31, 2011.  Excluding the impact of the acquisition of the assets of Micro, revenue growth in the United States was 22.9% for the quarter ended March 31, 2012, compared to the same period in the prior fiscal year.  Revenues from the acquisition of Micro were $63.0 million for the quarter ended March 31, 2012.  Revenue growth in the United Kingdom was 11.6% for the quarter ended March 31, 2012 compared to the same period in the prior fiscal year, consisting of 13.7% organic growth and a decline of 2.1% related to foreign currency exchange.  Commissions decreased 21.6% to $4.4 million for the quarter ended March 31, 2012, compared to $5.6 million for the quarter ended March 31, 2011.  Commissions were negatively impacted from the loss of a pet food line that we represented for most of fiscal year 2011 that we are not representing in fiscal year 2012, and a shift in commissions revenues to buy-sell revenues for certain parasiticides.

Gross profit increased by 30.7% to $66.6 million for the quarter ended March 31, 2012, compared to $51.0 million for the quarter ended March 31, 2011.  Gross profit as a percentage of total revenues decreased to 13.1% for the quarter ended March 31, 2012, compared to 13.9% for the quarter ended March 31, 2011 due to lower product margins, a reduction in commissions and lower vendor rebates.  Vendor rebates for the quarter ended March 31, 2012 decreased by $210,000 compared to the quarter ended March 31, 2011.

Operating income increased 26.9% to $21.4 million for the quarter ended March 31, 2012, compared to $16.9 million for the quarter ended March 31, 2011.  SG&A expenses increased 32.3% to $42.9 million for the quarter ended March 31, 2012, compared to $32.5 million for the quarter ended March 31, 2011.  SG&A expenses as a percentage of total revenues were 8.5% for the quarter ended March 31, 2012, compared to 8.8% for the quarter ended March 31, 2011.

Net income increased 27.5% to $13.2 million for the quarter ended March 31, 2012, compared to $10.3 million for the quarter ended March 31, 2011.  Diluted earnings per share were $1.04 and $0.83 for the quarters ended March 31, 2012 and 2011, respectively, an increase of 25.3%.

Six months ended March 31, 2012 compared to six months ended March 31, 2011

Total revenues increased 32.2% to $969.1 million for the six months ended March 31, 2012, compared to $733.3 million for the six months ended March 31, 2011.  Excluding the impact of the acquisition of the assets of Micro, revenue growth in the United States was 18.5% for the six months ended March 31, 2012, compared to the same period in the prior fiscal year.  Revenues from the acquisition of Micro, which was acquired on October 31, 2011, were $109.2 million for the six months ended March 31, 2012.  Revenue growth in the United Kingdom was 11.3% for the six months ended March 31, 2012 compared to the same period in the prior fiscal year, consisting of 12.7% organic growth and a decline of 1.4% related to foreign currency exchange.  Commissions decreased 12.6% to $8.1 million during the six months ended March 31, 2012, compared to $9.3 million during the six months ended March 31, 2011.

Gross profit increased by 27.8% to $129.1 million for the six months ended March 31, 2012, compared to $101.1 million for the six months ended March 31, 2011.  Gross profit as a percentage of total revenues was 13.3% for the six months ended March 31, 2012, compared to 13.8% for the six months ended March 31, 2011.  Vendor rebates for the six months ended March 31, 2012 increased by approximately $327,000 compared to the six months ended March 31, 2011.

Operating income increased 24.5% to $42.8 million for the six months ended March 31, 2012, compared to $34.4 million for the six months ended March 31, 2011.  SG&A expenses increased 28.9% to $81.8 million for the six months ended March 31, 2012, compared to $63.5 million for the six months ended March 31, 2011.  SG&A expenses as a percentage of total revenues were 8.4% for the six months ended March 31, 2012, compared to 8.7% for the six months ended March 31, 2011.

Net income increased 24.6% to $26.4 million for the six months ended March 31, 2012, compared to $21.2 million for the six months ended March 31, 2011.  Diluted earnings per share were $2.09 and $1.69 for the six months ended March 31, 2012 and 2011, respectively, an increase of 23.7%.

As of March 31, 2012, we had $64.5 million outstanding on our credit facilities.  The increase in the outstanding balance on our credit facilities of $61.6 million from September 30, 2011 resulted primarily from the acquisition of Micro and use of our credit facility to fund working capital due to our revenue growth and strategic inventory purchases.

Business Outlook

The Company estimates that for the fiscal year ending September 30, 2012, revenues will be from $2.0 billion to $2.025 billion, which represents growth of 28% to 29% compared to revenues in fiscal year 2011.  The Company estimates that diluted earnings per share will be from $3.96 to $4.06 per share, which represents growth of 16% to 19% compared to diluted earnings per share in fiscal year 2011.  The Company’s previous guidance for the fiscal year ending September 30, 2012 was revenues from $1.90 billion to $1.95 billion and diluted earnings per share of $3.85 to $4.00.

Conference Call

The Company will be hosting a conference call on May 3, 2012 at 11:00 a.m. eastern time to discuss in greater detail these results and its fiscal year 2012 business outlook.  Participants can access the conference call by dialing (877) 638-4561 and international callers can access the conference call by dialing (720) 545-0002.  The conference call will also be carried live on the Company’s web site at www.mwivet.com.  Audio replay will be made available through May 17, 2012 by calling (855) 859-2056 for calls within the United States or (404) 537-3406 for international calls using the passcode 73098779.  The conference call will also be available on the Company’s web site, www.mwivet.com.

MWI is a leading distributor of animal health products across the United States of America and United Kingdom. MWI sells both companion animal and production animal products including pharmaceuticals, vaccines, parasiticides, diagnostics, micro feed ingredients, supplies, pet food, capital equipment and nutritional products. MWI also is a leading innovator and provider of value-added services and technologies used by veterinarians and producers. For more information about MWI, please visit our website at www.mwivet.com. For investor relations information please contact Mary Pat Thompson, Senior Vice President of Finance and Administration, and Chief Financial Officer at (208) 955-8930 or email investorrelations@mwivet.com.

Certain statements contained herein that are not descriptions of historical facts are "forward-looking" statements (as such term is defined in the Private Securities Litigation Reform Act of 1995). Because such statements include risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Factors that could cause results to differ materially from those expressed or implied by such forward-looking statements include, but are not limited to, those discussed in filings made by the Company with the Securities and Exchange Commission. Many of the factors that will determine the Company's future results are beyond the ability of management to control or predict. Readers should not place undue reliance on forward-looking statements, which reflect management's views only as of the date hereof. The Company undertakes no obligation to revise or update any forward-looking statements, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise. Important assumptions and other important factors that could cause actual results to differ materially from those set forth in the forward-looking information include the impact of vendor consolidation on our business; changes in or availability of vendor rebate programs; transitional challenges associated with acquisitions, including the failure to achieve anticipated synergies; vendor rebates based upon attaining certain growth goals;  changes in the way vendors introduce products to market; exclusivity requirements with certain vendors that may prohibit us from distributing competing products manufactured by other vendors; seasonality; unforeseen litigation; risks associated with our international operations; 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; the timing and effectiveness of marketing programs offered by our vendors; the timing of the introduction of new products and services by our vendors; the ability to borrow on our credit line, extend the terms of our credit line 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; a disruption caused by adverse weather or other natural conditions; inability to ship products to the customer as a result of technological or shipping disruptions; and competition. Other factors include changes in the rate of inflation; changes in state or federal legislation or regulation; the continued safety of the products the Company sells; and changes in the general economy. Investors should also be aware that while we do, from time to time, communicate with securities analysts, it is against our policy to disclose any material non-public information or other confidential commercial information. Accordingly, stockholders should not assume that we agree with any statement or report issued by any analyst irrespective of the content of the statement or report. Furthermore, we have a policy against issuing or confirming financial forecasts or projections issued by others. Thus, to the extent that reports issued by securities analysts contain any projections, forecasts or opinions, such reports are not the responsibility of MWI Veterinary Supply, Inc.

MWI Veterinary Supply, Inc.
(Unaudited - Dollars and shares in thousands, except per share amounts)
Condensed Consolidated			Three Months Ended March 31,					Six Months Ended March 31,
Statements of Income					2012		2011		2012		2011
Revenues				$	507,170	$	367,112	$	969,071	$	733,286
Cost of product sales					440,552		316,126		839,939		632,228
Gross profit					66,618		50,986		129,132		101,058
Selling, general and administrative expenses					42,933		32,450		81,840		63,497
Depreciation and amortization					2,274		1,667		4,466		3,156
Operating income					21,411		16,869		42,826		34,405
Interest expense					(252)		(252)		(435)		(434)
Other income					265		206		530		414
Income before taxes					21,424		16,823		42,921		34,385
Income tax expense					(8,246)		(6,491)		(16,547)		(13,225)
Net income				$	13,178	$	10,332	$	26,374	$	21,160
Net income per share - diluted				$	1.04	$	0.83	$	2.09	$	1.69
Weighted average common
	shares outstanding - diluted				12,648		12,511		12,626		12,496
								March 31,		September 30,
Condensed Consolidated Balance Sheets									2012		2011
Assets
	Cash							$	512	$	606
	Receivables, net								267,886		215,861
	Inventories								238,884		170,065
	Prepaid expenses and other current assets								6,767		10,079
	Deferred income taxes								2,352		1,672
		Total current assets							516,401		398,283
	Property and equipment, net								34,615		25,209
	Goodwill								60,907		49,041
	Intangibles, net								39,930		24,894
	Other assets, net								7,216		6,792
		Total Assets						$	659,069	$	504,219
Liabilities
	Credit facilities							$	64,484	$	2,907
	Accounts payable								234,935		182,594
	Accrued expenses and other current liabilities								19,470		16,385
	Current portion of capital lease obligations								764		909
		Total current liabilities							319,653		202,795
	Deferred income taxes								6,896		5,989
	Long-term debt and capital lease obligations								275		354
	Other long-term liabilities								3,262		2,271
Stockholders' Equity									328,983		292,810
	Total Liabilities and Stockholders' Equity							$	659,069	$	504,219