It is not clear if a foreign investor may set up a 100% foreign owned company in veterinary services. This is because:

In the commitments to the WTO, Vietnam only undertakes to allow “foreign natural persons” exclusively for the conduct of private professional veterinary practice and under the authorization by the veterinary authorities. This means that Vietnam has the right to reject an application for setting up 100% foreign owned company in veterinary services.
In Official Letter 5972 dated 26 August 2015 implementing the Investment Law 2014, the Ministry of Planning and Investment contemplates that foreign investors are not allowed to invest in ‘veterinary services” (dịch vụ thú y). Also in this Official Letter, the Ministry of Planning and Investment (MPI) has indicated that there have been foreign investors which are licensed to provide “consultancy veterinary services” (dịch vụ tư vấn thú y);
However, in a subsequent Official Letter dated 3 September 2015 providing correction to Official Letter 5972, the MPI has removed all references to veterinary services; and
Under the Law on Veterinary which has just been passed in June 2015 and took effect from 1 July 2016, the Government is authorised to issue conditions for setting companies to provide veterinary services.

So until, the Government issues its guidance to allow a foreign investor to set up 100% foreign owned company in veterinary services, it remains unclear that a foreign investor could set up 100% foreign owned company in veterinary services. When the Government will issue the implementing Decree is not known. In practice, the Government may do so around the effective date of the new law being July 2016.

Vietnam Business Law