Interaction between the sequence of feeding of hay and concentrate, and boiling of barley on feed intake, the activity of hydrolytic enzymes and fermentation in the hindgut of Arabian mares.
Authors: Kiani A, Hoseini F, Ghorbaninejad P, Azarfar A, Kreuzer M, Azizi A
Journal: Journal of animal physiology and animal nutrition
Summary
# Editorial Summary Feeding sequence and grain processing have long been recognised as potential tools for managing hindgut fermentation in horses, yet their interactive effects remain poorly characterised. Kiani and colleagues investigated these interactions using six Arabian mares fed a 70:30 alfalfa-to-concentrate ration across four 14-day periods, systematically varying whether concentrate was offered 30 minutes before hay (CH) or after (HC), and whether barley was milled or boiled. Concentrate-before-hay feeding increased dry matter intake and elevated the acetate-to-propionate ratio whilst reducing amylase activity in rectal samples, suggesting a shift towards a less acidogenic fermentation profile; boiling barley produced similar effects with the added benefit of higher cellulase activity, indicating enhanced fibre degradation capacity. The two interventions demonstrated mostly additive effects on hindgut VFA patterns and enzyme activities, with synergistic interactions observed for carboxymethyl cellulase activity and propionate concentration. For practitioners working with Arabian horses or similar breeds predisposed to hindgut acidosis, these findings support a practical dual approach—prioritising hay consumption before concentrate and considering thermal processing of cereal grains—as a means to promote a more stable and favourable fermentation environment, though individual response variation and breed specificity warrant ongoing monitoring in practice.
Read the full abstract on PubMed
Practical Takeaways
- •Feeding concentrates before hay rather than after may improve dry matter intake and shift fermentation toward a more favorable acetate-dominant pattern in Arabian mares
- •Boiling barley represents a practical thermal processing method to modulate hindgut fermentation and potentially reduce digestive disturbances associated with concentrate feeding
- •Combining both strategies (concentrate-first feeding plus boiled grains) may provide superior hindgut health benefits compared to either approach alone
Key Findings
- •Feeding concentrate before hay (CH) increased dry matter intake and acetate:propionate ratio compared to hay-before-concentrate (HC) feeding sequence
- •Boiled barley reduced rectal volatile fatty acid and propionate concentrations while increasing acetate:propionate ratio compared to milled barley
- •Boiled barley increased microcrystalline cellulase activity but decreased α-amylase activity in rectal content versus milled barley
- •Feeding concentrate before hay and boiling barley showed additive and sometimes synergistic effects on hindgut fermentation parameters