Effect of period, water temperature and agitation on loss of water-soluble carbohydrates and protein from grass hay: implications for equine feeding management.
Authors: Longland A C, Barfoot C, Harris P A
Journal: The Veterinary record
Summary
# Editorial Summary: Water-Soaking Hay for Carbohydrate Reduction Longland, Barfoot and Harris (2014) investigated how soaking duration, water temperature and mechanical agitation affect the removal of water-soluble carbohydrates (WSC) and protein from UK hay samples—a clinically relevant question for managing equine metabolic conditions, particularly insulin dysregulation and laminitis. Four hay types with initial WSC concentrations of 154–216 g/kg dry matter were subjected to four soaking protocols: 16 hours at 8°C, 16°C, 16°C with agitation, or initial temperature of 49°C. Warmer water proved significantly more effective: whilst cold soaking (8°C) removed only 28 per cent of total WSC, soaking at 16°C achieved 46 per cent loss, rising to 49 per cent with agitation; notably, sucrose removal improved dramatically from 55 per cent at 8°C to 86–91 per cent at warmer temperatures, though fructan (the primary storage carbohydrate in temperate grasses) showed more modest losses of 16–39 per cent across all conditions. Importantly, no treatment significantly depleted hay crude protein, preserving nutritional value whilst reducing non-structural carbohydrates. Practitioners should note that warm-water soaking yields superior WSC reduction within practical timeframes, though the authors caution that extended soaking at elevated temperatures risks bacterial proliferation in the soak water—balancing efficacy against microbial contamination remains a key consideration for at-risk horses.
Read the full abstract on PubMed
Practical Takeaways
- •Soaking hay at warmer temperatures (16°C or above) significantly increases water-soluble carbohydrate removal compared to cold water, making it an effective management tool for laminitis-prone horses during winter months
- •Agitation or rinsing improves WSC removal efficiency at room temperature and may be preferable to extended soaking at warm temperatures to reduce microbial contamination risk in soak water
- •Since crude protein is not lost during soaking treatments, this management practice can safely reduce WSC intake without compromising nutritional adequacy of the forage
Key Findings
- •Soaking hay at 16°C for 16 hours removed 46% of WSC compared to 28% at 8°C, with agitation at 16°C achieving 49% loss
- •Sucrose was most effectively removed (82-91% loss at warmer temperatures) compared to fructan (16-39% loss) across all treatment groups
- •Water temperature had greater effect on WSC removal than soaking duration alone, with 49°C initial temperature achieving 44% WSC loss similar to room temperature agitation
- •Hay crude protein content remained unchanged across all soaking treatments, indicating no nutritional compromise from WSC reduction protocols