Dry Matter

Dry matter (DM) determination

Principle:
DM is the nutrient content minus water. All foodstuff- and faeces samples were mixed for sub-sampling and weighed in two previously weighed containers (in duplicate). The containers were placed in an oven at 60°C for 72 ours. The containers were reweighed and the weight of the samples was determined. The loss of weight is an indication for the amount of water and DM.
Calculation:
To calculate the percentage of DM, the weight of the sample after drying was divided by the weight of the sample before drying and multiplied by 100.

Air-dry (AD) determination

Principle:
Air-dry refers to the DM content of foodstuffs that have been allowed to dry to an equilibrium state under air exposure. By calculating the air-dry matter, the total DM of the ground samples can be determined. The ground foodstuff- and faeces samples were weighed and dried overnight at 105°C. After cooling in a desiccator, the samples were reweighed. The loss of weight indicates the amount of water in the air-dry samples.
Calculation:
To calculate the percentage of DM in air-dry samples, the weight of the sample after drying was divided by the weight of the sample before drying and multiplied by 100.