ARS | Publication request: Soaking Hay in Water to Reduce Soluble Carbohydrate Concentrations Prior to Horse Feeding

Submitted to: American Dairy Science Association Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: February 26, 2010
Publication Date: July 11, 2010
Citation: Martinson, K.L., Sheaffer, C.C., Jung, H.G. 2010. Soaking Hay in Water to Reduce Soluble Carbohydrate Concentrations Prior to Horse Feeding [abstract]. Journal of Animal Science. 88(E-Supplement 2):202.

Technical Abstract: Administering high concentrations of fructan to horses has resulted in laminitis. Cool season grasses accumulate fructan, which is estimated as the difference between water soluble carbohydrates (WSC; sucrose, fructose, glucose, fructans) and ethanol soluble carbohydrates (ESC; sucrose, fructose, glucose). Reducing fructan content in hay is critical for susceptible horses. The objective was to determine loss of WSC, ESC, and fructan from different hay types soaked in warm or cold tap water for various lengths of time. Five hays were evaluated; early bud (AB) and full flower (AF) alfalfa, mixed alfalfa orchardgrass (AO), and vegetative (VO) and mature (MO) orchardgrass. Soaking treatments included cold (22 degrees C) and warm (39 degrees C) water for 15, 30, and 60 min; cold tap water for 12 h; and a non-soaked control. One "flake" from each of six bales was randomly assigned to treatments. Hays were weighed, placed in mesh bags, and submerged in 25 L of fresh tap water. After soaking, flakes were drained for 30 min before drying at 60 degrees C for 72 h. Each flake was ground and sent to a forage testing laboratory for WSC and ESC analysis. Hays contained 81, 73, 114, 134, 129 g/kg WSC; 57, 48, 88, 68, and 66 g/kg ESC; and 24, 25, 27, 66 and 63 g/kg fructans (AB, AF, AO, VO, and MO, respectively). However, alfalfa does not contain fructan and AB and AF results probably reflect WSC extracted pectin. Soaking reduced WSC, ESC, and fructan content in all hays (P<0.001), except AO fructan. Except AB WSC and AO fructan, 15 min cold water soaking resulted in the least reduction of WSC, ESC, and fructan (P <0.001), while the 12 h cold soak had the greatest reductions (P<0.001). Soaking AF, AO, MO, and VO in warm water for 60 min had greater reductions in WSC compared to 60 min in cold water (P<0.001). Reductions in MO fructan content were greater after soaking in warm vs. cold water for 60 min (P<0.001). Forage type, soaking length, and water temperature all affected reductions in WSC, ESC, and fructan. Hay soaking is a viable method to reduce WSC, ESC, and fructan in hays.