Dry matter (DM) determinationPrinciple:
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.
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) determinationPrinciple:
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.
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.