In SimpleDVM email templates, you can now use the field "Client Primary Veterinarian".
If you are creating an email template in Sendgrid, you can use the field primaryVeterinarianName when building the template.
Please note that this field should probably only be used for emails that are being sent directly to a client's primary DVM, as not all clients will have this field populated and if you try to populate this in an email where the client does not have a primary DVM, this will be blank.