An investigation into the impact of soaking time on the nutritional content of hay and haylage for horses in the UK

Iona Robinson, Hieke Brown

Research output: Contribution to conferencePoster


Background: Previous research has shown significant decreases in water-soluble carbohydrate (WSC) levels in hay and haylage after soaking, assisting weight loss in overweight horses. However, soaking practices in industry are variable.

Aim: This study aimed to compare nutritional changes in hay and haylage during a 12-hour soaking period.

Methods: Three hay and three haylage nets (2.7kg each) were filled from randomly selected hay and haylage bales from the same batch, based on the method by Bochnia et al., (2021). Nets were submerged in cold water (4 °C) in individual 40L buckets for 12 hours. One 100g (DM) sample was collected from each net prior to soaking (T0), and after 4 hours (T4), 8 hours (T8), and 12 hours
(T12) (n=12 for hay and n=12 for haylage). Following the protocol of Owens et al., (2019), each sample consisted of smaller sub-samples, collected from different locations within the forage net. One mixed sample from each net (n=6 per treatment) was analysed by external industry standard laboratories for WSC (NIRS), acid detergent fibre (ADF), neutral detergent fibre (NDF), crude protein
(CP) and dry matter (DM) (Wet Chem). Following assumption testing, a Mann-Whitney U test was used to determine significant differences (p<0.05) between forage sources at T0, T4, T8 and T12. Differences in nutritional content for each forage type, a Friedman’s ANOVA by ranks test was used. Data is given in median and range.

Results: DM, ADF, NDF, CP and WSC content did not differ significantly between hay and haylage at T0, T4, T8 and T12. During soaking, DM for hay significantly (p<0.01) decreased between T0 (median 86.4%, range 86.1%-86.8%) and T8 (median 54.0%, range 50.8%-60.7%). Similarly, DM for haylage decreased significantly (p<0.01) between T0 (median 77.6%, range 76.3%-77.9%) and
T8 (median 35.71%, range 33.06%-50.02%). No changes were found between T8 and T12 for each forage type. Both ADF and NDF fractions increased significantly (p<0.05) within haylage between T0 and T12 (median ADF change +28.6%, range 24.6%-29.2%; median NDF change +24.3%, range 23.8%-25.4%), but no significant changes were observed within hay during soaking. CP content remained consistent for both forage sources throughout. WSC content in hay decreased between T0 and T12, from 167.7 g/kg DM (range 105.5-202.7 g/kg DM) to 71.6 g/kg DM (range 67.7-101 g/kg DM). WSC content in haylage decreased between T0 and T12, from 154.4 g/kg DM (range 154.1-166 g/kg DM) to 38.7 g/kg DM (range 38.7-62g/kg DM). However, these decreases were not significant.

Conclusion: Although not significant, the decrease in WSC for hay and haylage is comparable with previous research. The higher WSC losses in haylage during soaking support its inclusion in feeding management plans for overweight horses.

Funding statement: This study was in collaboration with Baileys Horse Feed. We would also like to thank Hartpury Equine Centre and Eurobale for the contribution of forage for the purpose of the study.
Original languageEnglish
Number of pages1
Publication statusPublished - 23 Mar 2023
EventEuropean Equine Health and Nutrition Congress - University of Ghent, Ghent, Belgium
Duration: 23 Mar 202324 Mar 2023
Conference number: 11th edition


ConferenceEuropean Equine Health and Nutrition Congress


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