Sheep and goats are capable of selecting for leaf and leaf sheath, if offered barley straw generously i.e. allowing the animals to refuse about half the amount offered (Wahed et al., 1990). Recent results (M.R. Islam, unpublished results, Reading University) indicate sheep to be capable of selecting when offered oat straw generously. Factors affecting the botanical composition of straws will therefore affect their nutritive value, especially for small ruminants. The increasing use of oat and naked oat grain for humans will mean greater production of oat straw in the future. However, little is known of how agronomic factors affect the botanical fractions of oat straw. In the present study, straw was generated as part of an agronomic experiment sown in autumn 1993 at ADAS High Mowthorpe.