Estimation of In Vitro True Digestibility and Fiber Degradation from Feedstuff Fiber Composition When Incubated in Equine Fecal Inoculum.
Authors: Springer Ryon W, Cherry Nichole M, Raub Randel H, Wellmann Kimberly B, Jones Trinette N
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Predicting feedstuff digestibility is crucial for formulating balanced equine diets, yet existing prediction models rely primarily on ruminant data, which may not accurately reflect equine digestive physiology. Springer and colleagues used the DaisyII incubator with equine faecal inoculum to develop predictive equations for in vitro true digestibility (IVTD) and fibre degradation measures across six common feedstuffs (alfalfa, Coastal Bermudagrass hay, soybean meal, rice bran, hempseed meal, and a commercial pellet), modelling these against neutral detergent fibre (NDF) and acid detergent fibre (ADF) composition. A two-way interaction model combining NDF and ADF most accurately predicted IVTD (R² = 0.959), whilst ADF alone was a strong predictor of in vitro ADF digestibility (R² = 0.835), though NDF digestibility prediction was more modest (R² = 0.749). For farriers and nutritionists particularly, these validated equations could refine forage and supplement selection by moving beyond generic ruminant-derived predictions; however, the authors appropriately flag that in vivo validation studies remain necessary before these models should guide clinical feeding decisions, as in vitro results don't always translate reliably to actual digestive outcomes in horses.
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Practical Takeaways
- •Equine practitioners can use simple fiber analysis (NDF and ADF percentages) as a practical tool to predict feedstuff digestibility and nutritional value for horses without expensive laboratory testing
- •The predictive models provide a non-invasive method to compare forage and supplement quality, helping optimize rations for different horses and conditions
- •Results are promising but require further in vivo validation before routine implementation in feeding programs—use as a supplementary assessment tool alongside traditional nutritional evaluation
Key Findings
- •NDF and ADF interaction model predicted IVTD with high accuracy (Adjusted R² = 0.959): 10003.32 - 0.2904 × NDF - 0.4220 × ADF - 0.0010 × NDF × ADF
- •ADF alone moderately predicted IVNDFD (Adjusted R² = 0.835) using equation: 881.91 - 1.5952 × ADF
- •Feedstuff fiber composition (NDF and ADF) effectively predicts in vitro digestibility measures in equine fecal inoculum
- •Models developed from six feedstuff types (alfalfa hay, Coastal Bermudagrass, soybean meal, rice bran, hempseed meal, and commercial pellets)