Comparative digestibility and gas production kinetics of Tifton 85 hay in donkeys and horses.
Authors: de Morais Clairton Bruno Rodrigues, Santiago Juliano Martins, da Silva Alisson Herculano, Nascimento Daniel Bezerra do, de Farias Igor Masterson, da Silva Dias Weslla, Taran Fernanda Melo Pereira, Lucena Jorge Eduardo Cavalcante
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Digestibility and Gas Production in Donkeys versus Horses Fed Tifton 85 Hay Nordestino donkeys have long been valued for their perceived digestive efficiency on poor-quality forage, yet direct comparative evidence with horses remains limited. Researchers conducted a controlled trial using four donkeys and four horses fed Tifton 85 hay at two maturity stages—higher quality (Hay 1) and lower quality (Hay 2)—measuring apparent nutrient digestibility via total faecal collection and fermentation characteristics through in vitro gas production analysis. When consuming the higher-quality hay, both species showed comparable digestibility across most nutrients, though horses produced significantly more gas (69.02 versus 58.37 mL/g dry matter), suggesting more rapid fermentation of non-fibre carbohydrates; however, when fed the lower-quality hay, donkeys demonstrated superior fibre digestive efficiency despite producing less total gas and lower crude protein digestibility (90.84% versus 93.15%). The practical implication is reassuring for practitioners: donkeys consuming quality forage perform as efficiently as horses, but their digestive advantage becomes apparent on poor-quality, high-fibre diets—a finding particularly relevant for donkey owners managing marginal grazing or relying on mature hay, whilst horses may require supplementation to maintain nutrition on equivalent forage.
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Practical Takeaways
- •Nordestino donkeys can be fed high-quality hay with digestibility equivalent to horses at 2% live weight daily, offering equivalent nutritional value.
- •Donkeys show superior fiber digestive efficiency when consuming lower-quality or mature hay, making them more economical for operations with poor forage availability.
- •Consider species-specific feeding strategies: horses perform better on high-quality hay while donkeys maintain efficiency across hay quality ranges, informing pasture and supplementation decisions.
Key Findings
- •No significant difference in apparent digestibility of high-quality hay between donkeys and horses, except donkeys showed lower crude protein digestibility (90.84% vs 93.15%) and neutral detergent insoluble protein digestibility (25.36% vs 48.09%) in lower-quality hay.
- •Horses produced higher total gas volume with high-quality hay (69.02 mL/g MS) compared to donkeys (58.37 mL/g MS), while donkeys produced comparable gas volume with lower-quality hay (55.27 mL/g MS vs horses 45.67 mL/g MS).
- •Donkeys demonstrated greater digestive efficiency of the fiber fraction when consuming lower-quality hay, suggesting superior adaptation to poor-quality forage.
- •Gas production from digestible fiber fraction was higher for lower-quality hay in both species, indicating different fermentation patterns based on hay maturity.