The effect of forage quality and level of feeding on digestibility and gastrointestinal transit time of oat straw and alfalfa given to ponies and donkeys.

The research study looks at the impact of the quality and quantity of feed on digestibility and gastrointestinal transit time of two types of straw (oat and alfalfa) in ponies and donkeys. The key findings show that donkeys digest feed more effectively than ponies, that the animals consume more alfalfa than oat straw, and that the level of feed restriction impacts the digestibility of the straw.

Research Design and Methodology

• The study was conducted by feeding four donkeys and four ponies two types of feeds – molassed dehydrated alfalfa and oat straw.
• The animals were either allowed to feed ad libitum (as much as they wanted) or their intake was restricted to about 70% of ad libitum intake.
• The feeding was done over four periods of 21 days in a Latin-square design, a research design particularly used for agricultural studies.
• Apparent digestibility and gastrointestinal transit time were measured for the last 7 days of each period.

Key Findings

• When provided ad libitum, all animals consumed significantly more alfalfa compared to oat straw. Ponies consumed more per unit of live weight as compared to donkeys.
• Donkeys generally had a higher apparent digestibility of dietary dry matter (DM), energy and fiber fractions as compared to the ponies. This increased digestibility partly compensated for the lower intake when fed freely.
• Digestibility was higher when the intake of alfalfa was restricted. This was the opposite for the straw, possibly because the restriction on low-quality diet reduced the selection of the more digestible parts of the forage.

Energy and Protein Consumption

• Both animals consumed more energy and protein than required when fed alfalfa without restriction.
• Oat straw did not meet the protein requirements for either of the animals. When the oat straw was given freely, it exceeded the energy requirement for ponies by 34-51%. For donkeys, the energy requirement was barely met.
• When the intake of straw was restricted, only 78-90% of the estimated energy requirements for donkeys were met which was less compared to 90-105% for the ponies.