Learn how to use this product Newborn Calf Serum (NBCS) is collected from calves between 3 and 10 days old. It can be used as a high-grade substitute for Fetal Bovine Serum. In comparison to Fetal Bovine Serum (FBS), Bovine Calf Serum, obtained from animals that are not more than 12 months old, and Newborn Calf Serum contain more immunoglobulins and have an increased protein content. They are cost-effective alternatives to FBS.