A comparison between the 2N and 4N HCl acid-insoluble ash methods for digestibility trials in horses.

This article explores the comparison of 2N and 4N HCl acid-insoluble ash (AIA) methods in determining the digestibility of horse feeds. The research found no difference between the two methods with respect to accuracy, and concludes that the 2N HCl method, being easier and cheaper, can effectively be used in field conditions.

Investigation Methods and Objectives

• The researchers embarked on seven digestibility trials using a group of six Standardbred horses to test the methods of determining the digestibility of horse feeds.
• The methodological approach involved comparing two techniques for measuring the AIA content in horse feed: a 2N solution of hydrochloric acid and a 4N solution of the same.
• The researchers aimed to determine which method provides a more accurate, efficient, and economical way of ascertaining the digestibility of different types of feed.

Dietary Trials

• The horses’ diets consisted of a mix of first-cut meadow hay, supplemented with three different cereals – barley, oats, and corn – for various trials. The ratio of hay to concentrate was either 60:40 or 70:30 on a dry matter basis, depending on the trial.
• AIA was used as a natural indigestible marker, which was beneficial for the field conditions as it did not require any changes to the normal ration.

Findings

• The study found nothing to indicate a significant difference in the concentration of AIA in the feed assessed using either a 2N HCL or 4N HCL technique.
• The digestion coefficients for each diet did not vary depending on the AIA method applied, in spite of minor disruptions affecting the aggregate scores in some trials.

Conclusions

• The research concludes that, given the comparable accuracy of both methods and the fact that the 2N HCL process is simpler and more cost-effective, the latter is particularly suitable for field conditions.
• Therefore, the 2N HCL method is recommended as a viable tool for conducting digestibility trials for horses fed hay-based diets. This includes identifying the content of acid-insoluble ash in animal feed, a key step in gauging its digestibility.