Fermentation of six different forages in the semi-continuous fermentation technique Caesitec.

The research paper discusses a study that investigates the effects of changing a horse’s diet from hay to green fodder on the bacteria in its hindgut. This is studied using a technique called ‘Caesitec’, with six different types of forage being tested.

Objective of the Study

The main goal of the research was to analyze and compare the degradation of carbohydrates in forages, stored either mainly as fructan or starch, within the hindgut of horses. The researchers wanted to examine how a sudden change from a hay-based diet to a green fodder-based diet would affect the bacterial composition in the horse’s caecum, which is a pouch located at the beginning of the large intestine.

Methodology of the Study

• Six trials were conducted with different types of forage which include: English ryegrass, tall fescue, grass mixtures designed for horses, grass mixtures for cows, lucerne, and white clover.
• The Caesitec technique was used to simulate the horse’s hindgut environment in vitro, that is, outside the horse’s body in a controlled setting.
• During a 4-day stabilisation period, samples from the artificial hindgut were gathered daily before loading the fermenters with hay.
• Following the diet change to forage-based feeding, samples were collected four times a day.
• Levels of ammonia and the pH value were recorded before and at set time intervals (1, 2 and 6 hours) after loading the Caesitec system.
• Gas formation was tracked daily while bacterial numbers, lactate, and short-chain fatty acids were monitored at four separate points during each trial.

Findings of the Study

• The grass mixtures were found to contain the highest amounts of fructan, a type of carbohydrate.
• The pH values, which measure acidity or alkalinity, were in the normal physiological range of 6 to 7 for all types of forages tested.
• Gas formation, as well as numbers of both anaerobic (grow without oxygen) and aerobic (grow with oxygen) bacteria, increased after the diet was switched from hay to any type of forage.
• No long-term harmful changes were identified in the simulated hindgut environment, even with the highest amount of fructan (3.75 g/kg) found in the Swiss pasture.

In conclusion, the research study provided valuable insights into the effects of a dietary change from hay to forage on the bacterial composition in the horses’ hindgut. The study’s results can be crucial for animal husbandry practices, specifically for maintaining horse health and optimizing feeding strategies.