D. glomerata (Cocksfoot) has previously been highlighted for having elevated protein contents, in comparison to other forage grass species. The biorefining of such proteins is of interest within British agriculture, as both costs and CO2 emissions from soy imports used as a livestock feed supplement could be reduced. The presented research will explore how protein contents determined by near-infra red spectroscopy (NIRS) compare to protein yield (quantified via Lowry assay) following a TCA/phenol/SDS extraction method, in freeze dried leaf tissue sub-samples cut from thrice replicated yield plots in August 2020. The estimation of total protein per hectare (NIRS and extracted) can be calculated as a product of dry matter yield, giving indication of protein yields from biorefining. Further analysis of extracted protein curds on PAGE gels will reveal the amino acid composition across four commercial varieties and eight half-sib families, identifying differences and similarities between genotypes. If substantial differences in amino acid profile are observed between genotypes, the quality of a protein extract from Cocksfoot could be dependent on the commercial variety sown, which requires consideration when cultivating the grass as a biorefining crop. This could also lead to further investigation into the genetic influence on amino acid profile and exploration of any potential improvements through selective breeding. This research is funded through the Joy Welch charitable trust.