The TG5 DNA marker test for marbling capacity in Australian feedlot cattle

We tested the TG5 polymorphism in the 5' leader sequence of the thyroglobulin regulatory DNA sequence on 1750 cattle drawn at random from a large feedlot over approximately 9 months in 28 separate days of sampling. The cattle were mainly Angus or Shorthorn grain-fed for 160-240 days. We have confirmed the earlier reported association between the '3' allele and higher marbling scores indicating that a DNA test based on the polymorphism should be robust for predicting marbling potential. This test detects one of the genes that contributes to the genetic potential for marbling.