[The digestibility of crude nutrients in horses. 2. Comparative studies on the digestive capacity of a thoroughbred horse, pony and wether].

This research examines how well horses, ponies, and wethers (castrated sheep) digest crude nutrients (raw, unprocessed feed materials) from various rations of feed, and how this varies according to the fiber and energy content of the feed.

Feed and Animals Used in the Study

• The researchers used six types of diet made from oats, hay, and wheat straw. In one case, they used a straw-concentrate mixture as the sole feed for the animals.
• The feed was given at two nutritional levels: 1.0 and 1.3, referring to the ratio of feed to body weight.
• The rations varied in energy concentration, ranging from 424 to 585 EFU (energy feed units for cattle) per kg of dry matter (DM).
• The crude fiber content of the rations also varied, constituting 17% to 25% of the dry matter.
• The animals studied were adult geldings (castrated male horses) of the Noble Crossbreed species, adult pony geldings, and wethers.

Comparative Digestibility of Diets

• The study compared the digestibility of the organic matter and NFE (Nitrogen Free Extract, the measure of readily available carbohydrates) between horses and ponies. Their digestive capacities in this respect were found to be largely similar. They both showed a similar ability to process these elements of their diet.
• A considerable variance was observed in the apparent digestibility of crude protein and crude fiber between the three species. The term “apparent digestibility” represents the portion of ingested food that is absorbed into the body.

Digestibility of Crude Fiber: Horses vs Sheep

• The difference in the digestibility of crude fiber increased between horses and sheep as the crude fiber content in the diet grew. This means that, compared to sheep, horses are less efficient at digesting diets with higher fiber content.
• The differences in digestibility between horses and ponies, and sheep was statistically very significant in all cases. This confirms there is a distinct difference in the way these species process their feed.