Impact of water-soaking on the nutrient composition of UK hays

EQUINE metabolic syndrome (EMS), defined as obesity, insulin resistance and an increased risk of laminitis, is becoming increasingly recognised as an important condition with serious welfare implications (Frank and others 2010). Dietary restriction is critical for the management of EMS, and using a low starch and sugar content diet has been shown to improve insulin sensitivity in overweight and obese horses and ponies (Dugdale and others 2010, Argo and others 2012). Feeding hay with a non-structural carbohydrate (NSC) content of <10–12 per cent dry matter (DM), equivalent to approximately 8–10 per cent DM water-soluble carbohydrate (WSC), has been advised for EMS cases (Frank 2009, Frank and others 2010). Feeding hay with a low (4 per cent) or moderate (10 per cent) NSC content has been shown to induce lower insulinaemic and glycaemic responses compared with hay of high NSC content (17 per cent) (Borgia and others 2011). McGowan and others (2013) demonstrated that restricted daily energy provision in the form of soaked hay promoted weight loss and improved insulin sensitivity in horses and ponies with EMS. Soaking hay has been recommended as a practical method to reduce the caloric content of hay for the management of conditions such as EMS (Frank and others 2010). There is, however, limited evidence on the effect of soaking hay on its nutrient composition. Studies that have assessed the effects of soaking on the energy and nutrient composition of hay have been inconsistent and contradictory (Warr and Petch 1992, Cottrell and others …