Prediction of the metabolisable energy content of forages and mixed diets for horses: validation and comparison of two evaluation systems.

The research article compares two systems used to predict the true energy value (Metabolisable Energy or ME) in different horse feeds. The study found that the system developed by Institut National de la Recherche Agronomique (INRA) produced more accurate results than the one by Gesellschaft für Ernährungsphysiologie (GfE).

Background and Objective

• The study was designed to evaluate and compare the precision and accuracy of two methods for estimating the Digestible Energy (DE) and Metabolisable Energy (ME) contents in horse diets. These methods were developed by the Gesellschaft für Ernährungsphysiologie (GfE) and the Institut National de la Recherche Agronomique (INRA).
• ME, which includes the energy lost through methane and urine, is considered a better measure of the true energy value of feeds compared to DE.

Methodology

• The GfE and INRA prediction systems were tested on a total of 15 mixed diets.
• A separate study was also carried out with 24 forages to compare ME values and predicted using both GfE and the INRA systems. This included permanent meadow and lucerne hays.

Results

• The INRA system proved to be more accurate in predicting DE, GEurine (Gross Energy of urine) and ME than the GfE system. The biases for these predictions were statistically smaller in the INRA system as compared to the GfE system.
• There was no significant difference in the prediction of GEgas (Gross Energy of methane) between the two systems.
• The additional comparison study on forages showed that the INRA system predicted higher DE values than the GfE system. It also estimated lower values for GEgas and GEurine.
• In accordance with mixed diets results, the INRA system gave higher ME estimates for both permanent meadow hay and lucerne hay.

Conclusion

• The study concluded that INRA system is more accurate for predicting the ME content of forages and mixed diets for horses.
• It advised using specific equations to predict ME values of permanent meadow hays and legume hays separately, as previously stated for the DE value.