Optimal Feed Mix Decision Support Tool

The Decision Support Tool (DST) was developed to support dairy farmers in providing feeds for their dairy cattle in the appropriate quantities and with the required quality. Previous research has shown that in many instances dairy cattle produce milk in amounts much lower than expected due to poor feeding.

The DST has therefore been developed to provide information to farmers and their advisors on quantities of available feeds that they can use to meet the feed requirement of their animals depending on the various characteristics. Feed requirements in this case have been based on 2 major feeds components namely metabolisable energy (ME) and crude protein (CP). Such characteristics include the type of animal whether cow, bull or heifer and its physiological state. The DST also provides information on the cost effectiveness of using the feed formulation in consideration.

The DST was developed for farmers who have access to and can use computers. It was also developed for extension personnel to use as basis for advising farmers and for researchers who wish to develop appropriate dairy feeding packages for their research cattle. The tool will also be useful for students and lecturers for purposes of training. The tool will also provide information for guiding policy.

Information already existing in the tool
The feed types and their ME and CP contents are present in the tools database (we are glad to receive input on additional feeds to update our database).
The ME is provided in terms of

      Information that must be selected in the tool
This is information about the cattle to be fed and exists in tool and all that the user does is to select what applies for their situation.

Table 1.           Tool options for selection of cattle type that fits that for which feed formulation is required

Cattle type

No. of Lactations

Stage of Lactation


1st - 3rd


Cow-dry pregnant

4th - 6th



7th and above





NB: Calves and weaners are not yet catered for by the DST

      Information that must be calculated
The costs of providing a Kg of each feed type has been calculated and included in the tool. However, these costs vary depending on numerous factors and therefore can not be applied to all situations. The costs included in the tool were obtained from information collected from the districts of Luwero and Kayunga in October-December 2008.

It is advisable, therefore, that if the cost-effectiveness of the formulated feeds will be of interest to the user that cost of production for a Kg of each feed be calculated. These should use the current costs for the location and should then be entered into the tool.

Costs per Kg for purchased feeds is obvious and readily available, however, cost per kg of farm grown feeds should include costs of

  1. Average of cost of land preparation 1 acre
  1. Average of cost of seed for 1 acre
  1. Average of planting 1 acre
  1. Average of cost of weeding 1 acre from planting to harvesting
  1. Cost of harvesting & delivering to animals feed from 1 acre
  1. Total cost per acre (production + delivery)
  1. Kgs(dry matter) of feed from 1 acre from 1 harvest - these are given in Table 2
  1. Cost of production per kg DM (prodn + delivery)
  1. Maintenance cost per harvest

Table 2.           Yields (Kg per acre per harvest) from the feed types included in the DST

Feed Type

Kg (dry matter) of feed from 1 acre from 1 harvest

Calliandra 1,042
Desmodium (green leaf and silver leaf) 1,042
Gliricidia 1,042
Lablab 1,250
Leucaena leucocephala 1,042
Elephant grass 1,875
Natural pasture 938
Roadside grass (cut and carry type) 1,400
Forage maize 1,250
Bean haulms/Maize stover 1,100
Banana stems 1,188


  1. For pastures that were already established and are only maintained, the establishment costs are not included rather the costs related with maintenance and taking the animals to the pasture are the ones considered.
  2. For the crop residues, only a proportion of the cost is claimed towards production of the feed material. We assume that generally crop residues are 10% of the total harvest. As such the cost of production for the crop residues is 10% of the total cost of production for the entire crop.

2.4       Converting the tool output into a usable form
The tool will provide 2 major outputs.

Output 1: A combination of feeds and their respective amounts (Kg dry matter) that provide a daily the feed requirement for the cattle specifications you gave

Output 2: The cost of the feed combination given in Output 1

As shown under Output 1, the values for the feed type quantities will be according to the dry matter basis. However, on farms we weigh the feeds on fresh weight basis. Hence the quantities given by the tool will have to be converted to fresh weight by a simple calculation shown in equation 1.

Equation 1.      DM% of the Feed Type x Feed Quantity in Output 1 = Fresh Weight
Peter can we inbuild the above step into the DST

The dry matter percentages for the feeds are provided in the Feeds list in the DST and the Feed Quantity will be that obtained in the tool output.