A comparison of the effect of forage type and level of feeding on the digestibility and gastrointestinal mean retention time of dry forages given to cattle, sheep, ponies and donkeys.

The research article investigates the impact of different types of forage and feeding levels on the digestibility and mean retention times in the gastrointestinal system of various animals including cattle, sheep, ponies, and donkeys.

Research Design

• In the experiment, four cattle, sheep, ponies, and donkeys were given four different kinds of food: dehydrated lucerne, early-cut hay, late-cut hay, and barley straw. These diets were administered following a Latin square design for four periods of 35 days each.
• During the first 21 days (first sub-period), animals were allowed to eat ad libitum (as much as they wanted), and during the following 14 days (second sub-period), their food supply was restricted to only 75% of the previous intake.

Measurements and Observations

• Measurements were made of forage intake, apparent digestibilities (effectiveness with which animals extracted nutrients from their food), and the average time the food stayed in the gastrointestinal system (mean retention times, MRT).
• These measurements were carried out in the last seven days of each sub-period.

Findings

• Differences between species in terms of voluntary DM (dry matter) intake were most notable on the lucerne diet and least on barley straw. In this context, cattle had the highest intake, followed by ponies, then sheep, and donkeys.
• On a barley straw diet, cattle, donkeys, and ponies consumed roughly the same amount while sheep had the least intake.
• For hays, intake values were intermediate between lucerne and straw diets.
• Apparent digestibilities of dry matter, organic matter, neutral-detergent fibre, and acid-detergent fibre of the lucerne and hays were higher in ruminants (cattle and sheep) than in equids (ponies and donkeys).
• The food stayed less time in the gastrointestinal systems of the equids than in those of the ruminants.
• On straw diets, donkeys showed similar apparent digestibilities to those of the cattle, while the ponies had the lowest apparent digestibility from the straw diet.

Interpretation and Discussion

• The findings of the study are discussed in relation to evolutionary variances associated with whether animals predominantly ferment forage in their fore-guts (like ruminants) or hind-guts (like equids).
• The specifics of the digestive process (fore- or hind-gut fermentation) seem to determine the apparent digestibility of the feed components for different species.