Evaluation of methodological aspects of digestibility measurements in ponies fed different grass hays.

The study evaluates the methods of measuring how well ponies digest different types of grass hay. It is found that at least five consecutive days of fecal collection are needed to accurately estimate digestibility, and that acid detergent lignin (ADL) and titanium are the preferred markers for these measurements.

Design of the Study

• The research involved four Welsh pony geldings who were subjected to four different grass-hay diets. These diets had varying levels of acid detergent fiber (ADF): low (L), medium (M), high (H), and very high (VH).
• The diets were also complemented with additional minerals, vitamins, and titanium dioxide (TiO).
• The trial was conducted in a 4 × 4 Latin square design, which is a standard method used in scientific trials to reduce bias.

Data Collection

• The excrement of the ponies was collected and analyzed daily over a ten-day period. The researchers were looking at its moisture, ash, acid detergent lignin (ADL), acid insoluble ash (AIA), and titanium (Ti) content.
• The researchers then determined how long the fecal collections needed to be to accurately estimate how well the ponies absorbed organic matter from the grass hay diets.

Findings

• A minimum of five consecutive days of fecal collection was determined to be necessary for accurate estimation of dry matter digestibility (DMD) and apparent organic matter digestibility (OMD) in ponies.
• Before the collection days, a 14-day adaptation period should be allotted for the animals to adjust to the diets and become familiar with the collection procedures.

Evaluation of Fecal Recovery

• The mean recoveries over the ten day period for ADL, AIA, and Ti were 93.1%, 98.9%, and 97.1% respectively.
• The variation in fecal recovery of titanium and acid detergent lignin was found to be relatively low compared to acid insoluble ash.

Conclusion

• The researchers conclude that internal ADL and externally supplemented titanium are the best markers to be used in digestibility trials for equine animals fed grass hay diets.