Digestion of hay protein in different segments of the equine digestive tract.

The study examines the digestion of hay protein in various sections of a horse’s digestive tract, using ponies fitted with ileal cannulas to gauge prececal, postileal, and total tract digestion. The findings indicate that the total apparent digestibility was highest in high-protein alfalfa, followed by low-protein alfalfa and Coastal Bermuda grass, respectively. The foregut also exhibited a higher percentage of total nitrogen digestion.

Research Design and Procedure

• The experiment utilized a 3 X 3 Latin square design and involved mature ponies equipped with permanent ileal cannulas. This device helps measure the digestion happening before it reaches the large intestine, known as prececal digestion.
• The ponies were fed with coarsely chopped Coastal Bermuda grass (CB), and two types of alfalfa, one with low-protein (LA) and one with high-protein (HA). These were given a daily dose of 2% of their body weight.

Key Findings

• The study found out that the total apparent digestibility of nitrogen in High-protein Alfalfa (HA) (73.8%) was higher compared to that in Coastal Bermuda grass (CB) (57.0%) and was slightly higher than that in Low-protein Alfalfa (LA) (66.1%).
• Nitrogen in LA was apparently more digestible than in CB, suggesting the protein source impacts digestibility.
• Preccecal digestibilities of nitrogen in LA and CB were lower than in HA, meaning HA showed superior digestibility before the digestion reached the large intestine.
• The study also noted a higher concentration of total plasma free amino acids (the building blocks of protein) one hour after feeding when horses were fed alfalfa, suggesting quicker digestion and absorption.
• Nitrogen retention was higher when ponies were given HA. This means more nitrogen was absorbed and utilized by the body when HA was fed.
• Despite these differences, there were no significant variations in postileal nitrogen digestibility (digestion after passing through the small intestine) among CB, LA, and HA. This can be attributed to the large intestine’s capacity to make up for the inefficiency of nitrogen digestion in the upper tract.