EXHIBIT 5

OPINION AND CONSENT OF HELLER EHRMAN WHITE & MCAULIFFE LLP

October 15, 2004

Synbiotics Corporation

11011 Via Frontera

San Diego, CA 92127

Re: Synbiotics Corporation Registration Statement on Form S-8 for 3,000,000 Shares of Common Stock and Related Stock Options

Ladies and Gentlemen:

We have acted as counsel to Synbiotics Corporation, a California corporation (the “Company”) in connection with the registration on Form S-8 (the “Registration Statement”) under the Securities Act of 1933, as amended, of 3,000,000 shares of common stock (the “Shares”) for issuance under the Company’s 2004 Stock Option/Stock Issuance Plan (the “Plan”).

This opinion is being furnished in accordance with the requirements of Item 8 of Form S-8 and Item 601(b)(5)(i) of Regulation S-K.

In connection with this opinion, we have assumed the authenticity of all records, documents and instruments submitted to us as originals, the genuineness of all signatures, the legal capacity of natural persons and the conformity to the originals of all records, documents and instruments submitted to us as copies.

We have reviewed the Company’s charter documents and the corporate proceedings taken by the Company in connection with the establishment of the Plan. Based on such review, we are of the opinion that, if, as and when the Shares have been issued and sold (and the consideration therefor received) pursuant to (a) the provisions of option agreements duly authorized under the Plan and in accordance with the Registration Statement, or (b) duly authorized direct stock issuances in accordance with the Plan and in accordance with the Registration Statement, such Shares will be duly authorized, legally issued, fully paid and nonassessable.

We consent to the filing of this opinion letter as Exhibit 5 to the Registration Statement. In giving this consent, we do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act of 1933, as amended, or the rules and regulations of the Securities and Exchange Commission promulgated thereunder, or Item 509 of Regulation S-K.

This opinion letter is rendered as of the date first written above and we disclaim any obligation to advise you of facts, circumstances, events or developments which hereafter may be brought to our attention and which may alter, affect or modify the opinion expressed herein. Our opinion is expressly limited to the matters set forth above and we render no opinion, whether by implication or otherwise, as to any other matters relating to the Company, the Plan or the Shares.

Very truly yours,

/s/ Heller Ehrman White & McAuliffe LLP