Effect of Dietary Forage: Concentrate Ratio on Pre-Caecal and Total Digestive Tract Digestibility of Diverse Feedstuffs in Donkeys as Measured by the Mobile Nylon Bag Technique.
Authors: Liu Li-Lin, Zhou Xiao-Ling, Yang Hong-Jian
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Forage-to-Concentrate Ratios and Donkey Digestive Efficiency Donkeys have distinctly different digestive physiology from horses, yet evidence-based guidance on their nutritional management remains sparse. Researchers used six caecum-fistulated Xinjiang donkeys in a Latin square design to measure how varying dietary forage:concentrate ratios (80:20, 55:45, and 35:65) affected nutrient breakdown in the small intestine and across the total digestive tract, employing mobile nylon bags to track digestion of rice straw, alfalfa hay, corn meal, and soybean meal. Surprisingly, the forage:concentrate ratio had no significant impact on digestibility of dry matter, crude protein, neutral detergent fibre, or acid detergent fibre at either the pre-caecal or total tract level, though bag retention time was shortest on the high-forage diet (2.7 hours versus 4.6–5.0 hours on lower-forage options). Instead, feed type proved decisive: soybean meal and corn meal showed substantially higher digestibility coefficients than forage sources, with the intrinsic fibre content of individual feedstuffs—rather than overall dietary ratios—driving the contribution of pre-caecal digestion. For donkey practitioners, this suggests that formulating diets within conventional forage:concentrate ranges poses minimal risk to nutrient extraction, and that feed selection should prioritise ingredient quality and fibre characteristics over achieving specific ratio targets.
Read the full abstract on PubMed
Practical Takeaways
- •Donkey nutritionists can adjust forage:concentrate ratios based on practical constraints without compromising nutrient digestibility, as the ratio itself does not significantly affect the digestive process
- •Feed quality and fiber content of individual ingredients matters more than overall ration proportions—select higher-quality forages and concentrates rather than focusing on F:C ratios
- •High-fiber rations move through the donkey's digestive tract faster (2.7 h retention); consider this when addressing specific digestive or metabolic issues
Key Findings
- •Dietary forage:concentrate ratio (ranging from 80:20 to 35:65) did not significantly affect pre-caecal or total tract digestibility of DM, CP, NDF, or ADF in donkeys
- •Bag collection percentage peaked at medium-fiber diet (73.8%) with mean retention time lowest in high-fiber diet (2.7 h)
- •Among feedstuffs tested, soybean meal and corn meal showed highest digestibility while rice straw showed lowest across all dietary treatments
- •Fiber level within individual feeds, rather than dietary F:C ratio, was the primary limiting factor for pre-caecal digestibility contribution