Lättlösliga kolhydrater i vallfoder och i hästens grovtarm

Sammanfattning: The purpose of this study was to investigate how the content of glucose, fructose, sucrose and fructan (WSC) varied in silage, haylage and hay harvested from the same field and at the same time of harvest. The study also investigated if differences in the WSC-fraction in the forages caused differences in composition of WSC in the colon of horses fed the forages. Hay, haylage and silage were harvested in the first week of June 2005 and stored for about nine months before feeding. Horses that were fistulated in right ventral colon and caecum were used, but only the colon fistula was used for sampling. The fresh crop and the conserved hay, haylage and silage were analyzed for chemical composition and WSC-fraction. The content of fructan was lower in the fresh crop of hay than in the fresh crop of silage and haylage. In the conserved feed, hay had the highest content of DM, sucrose and fructan. Haylage had the highest content of glucose, whereas DM, fructan, acetic acid, ethanol and pH-value were intermediates between hay and silage. Silage had the highest content of succinic acid, lactic acid, acetic acid and 2,3-butanediol, and the lowest DM, fructan and pH-value compared to hay and haylage. Horses were fed each forage for 21 days in a changeover-experiment, and were sampled via the colon fistula at 0, 2, 4, 8, and 12 h after feeding. The content of glucose, fructose, sucrose and fructan in colon samples were analyzed. The WSC-fraction did not differ in the colon content when horses were fed hay, haylage or silage. Also, there was no difference in WSC-fraction between sampling times, and no difference among individual horses. Generally, the amount of WSC was very low in the colon fluid. There were no interactions between forage type and time of sampling.