Nutritional value of mixed grass haylage in Icelandic horses

The influence of cutting time of mixed grass haylages on energy and nitrogen (N) metabolism, and the coefficients of total tract apparent digestibility (CTTAD) were studied in four mature Icelandic geldings by performing total collection of faeces and urine. The experiment was arranged as 4 x 4 balanced Latin square The four haylages used were harvested at different times and were considered to be representative in botanical composition for mixed grass haylages in Iceland.The CTTAD of dry matter (DM), organic matter (OM), crude protein, neutral detergent fibre, acid detergent fibre (ADF) and energy were different (p < 0 05) in the haylage batches The CTTAD of all dietary components and energy decreased with time of cutting. The content of ADF (% in DM) accounted for a major part of the difference in CTTAD of OM (r(2) = 0.95) between haylage batches. The urinary nitrogen losses decreased with date of cutting, while the energy losses in urine (as % of digestible energy intake) were unaffected (p > 0 05). The digestible energy content of the haylages studied ranged from 13.4 to 10.8 MJ/kg DM. (C) 2010 Elsevier B V All rights reserved