Big Thicket Veterinary Clinic. Associate Veterinarian. Welcome to Big Thicket Veterinary Clinic in Cleveland Texas. We are a well established and highly respected Veterinary Practice in Liberty County Texas ( greater Houston area) and we are seeking a mixed animal veterinarian for our growing hospital. We have been in business for almost 40 years. We will assist with sign-on/relocation for the right candidate. . IF you are a new graduate- we are ...