Nutrient manager uses an Explorer-type tree to organise information. This set-up is entirely user controlled, with the usual right-click options (new, delete, rename etc.) being available. Both folders and items within folders can be sorted according to a user-defined alpha-numeric sort order. This order, once set, is available in all working windows of the program. There is no restriction on the number of nutrients that can be entered into the database. It is possible also to specify whether or not the nutrient has an associated digestibility, allowing the user to work with either total or digestible nutrient concentrations. Default bounds and some information about a nutrient is also stored.
It is possible to set up more than one digestibility group, allowing a different digestibility value to be entered for each animal.
WinFeed also allows the user to create nutrients defined as ratios of other nutrients. The ratios are automatically updated when the parent values are changed. The digestibility values are correctly maintained if the parent values have digestibilities.
Nutrients may also be created and then defined as linear expressions of other nutrients. A simple example would be to define total essential amino acids as the sum of the individual values. More complex expressions may be used to calculate the net energy values of ingredients. These calculations may also include digestibility values.
The calculations may apply to all values of a nutrient (e.g. the effective energy content of an ingredient), or to the value in a single nutrient/ingredient cell. This latter facility allows amino acid contents in an ingredient to be expressed in terms of the protein content of the ingredient, these expressions being different for each amino acid in each ingredient. As the protein content of the ingredient is changed by the user, so the amino acid contents would be changed accordingly.