Evaluation of methodological aspects of digestibility measurements in ponies fed different haylage to concentrate ratios.

This research explores the methodology of digestibility measurements in Welsh pony geldings consuming a haylage-based diet with increasing proportions of a pelleted concentrate. The study concludes that the use of Titanium Dioxide (Ti) is preferred as a marker in digestibility trials in equines instead of Acid-Detergent Lignin (ADL) and Acid-Insoluble Ash (AIA).

Research Design and Methodology

• The study involved four Welsh pony geldings consuming a haylage-based diet mixed with varying proportions of a pelleted concentrate.
• The experiment followed a 4×4 Latin square design, which is used to minimize the influence of external factors by ensuring equal representation of all variables.
• Four experimental iso-energetic (based on net energy) diets were prepared, differing in the proportions of haylage (H) and concentrate (C). The diets were:
• 100% H (4.48 kg of H)
• 75% H and 25% C (3.36 and 0.73 kg of H and C respectively)
• 50% H and 50% C (2.24 and 1.45 kg of H and C respectively)
• 25% H and 75% C (1.12 and 2.17 kg of H and C respectively)
• All diets were supplemented with vitamins, minerals, and Ti.

Data Collection and Analysis

• Voluntary voided faeces were collected quantitatively daily for 10 consecutive days and tested for moisture, ash, ADL, AIA and Ti.
• The study recommends a minimum faeces collection period of 6 days along with a 14-day period to adapt the animals to different diet compositions and faeces collection procedures.
• The aim was to accurately estimate the rate of dry matter digestibility and organic matter digestibility (OMD) in the ponies when consuming haylage-based diets supplemented with different proportions of concentrate.
• Recovery of AIA, ADL and Ti was determined and evaluated to judge their effectiveness as markers in digestibility trials.

Findings and Conclusion

• The study established that cumulative faecal recovery of AIA differed significantly between treatments, suggesting AIA is not a reliable marker to estimate the OMD in ponies as its variability was high
• The accuracy of prediction of OMD was higher when Ti was used as a marker compared to ADL. This demonstrates greater consistency of Ti as a marker in digestibility studies in ponies.
• The study concludes that in digestibility trials with equines fed haylage-based diets with varying amounts of pelleted concentrate, Ti is preferred as a marker.