The use of inert markers in the measurement of the digestibility of cubed concentrates and of hay given in several proportions to the pony, horse and white rhinoceros (Diceros simus).

The research examines how the use of inert markers can aid in assessing the digestibility of concentrated and hay diets in ponies, horses, and white rhinoceros. The results showcase similarities in digestion between the species, a substantial rise in starch content in horse diets resulting in an increase in fecal ciliate protozoa, and satisfactory maintenance of a rhinoceros’ condition with the daily intake of 109 kJ apparent DE per kg bodyweight.

Rate of Chromic Oxide Passage

• This part of the study involved observing the rate at which chromic oxide (Cr), an inert marker, moves through the digestive tracts of the pony and the rhinoceros.
• The researchers found that chromic oxide’s transit was comparable in both species, thus indicating potential similarities in their digestion processes.

Measurement of Amounts Digested

• The researchers used 4N-HCl-insoluble ash (AIA), another inert marker, to measure the amounts of the feed materials that were digested by the two species.
• They found that the AIA revealed higher apparent amounts digested than did Cr, leading to the conclusion that AIA might provide a more sensitive measure of digestion rates.
• Notwithstanding, the overall digestibilities as determined by both AIA and Cr were found to be similar in both species.

Impact of Starch Content on Faecal Ciliate Protozoa

• The researchers observed that an abrupt increase in the starch content of the horse diets led to an increase in the number of fecal ciliate protozoa, microorganisms involved in the digestion process.
• Interestingly, they found that only when the overall feed intake increased in horses consuming a high starch diet were the numbers of these microorganisms reduced, possibly indicating that a certain balance in feed composition might be necessary for optimal digestion.

Optimal Energy Intake for Rhinoceros

• The researchers also studied the energy requirements of rhinoceros and found that when the rhinoceros received 109 kJ apparent DE (Digestible Energy) per kg bodyweight daily, it managed to maintain a normal condition.
• This finding may lay the foundations for setting optimal feed energy levels for rhinoceros, thus contributing significantly to their care and conservation efforts.