Get a DNA Kit from the American Aberdeen Association. To get a kit: Order Online Here. 2. Once you have received your DNA kit, obtain a blood sample, TSU or hair sample. See How to collect DNA from cattle. Cattle over 6 months – you will need a hair sample, blood sample or a TSU (Tissue Sampling Unit). Cattle under 6 months – you will need a blood sample or a TSU (Tissue Sampling Unit). 3. Then submit DNA and Register Cattle For instructions see the Register Cattle page and go to step #3.