Buying feed at the right price, Buying feeds on a protein value basis

Buying feeds on a ‘protein value’ basis

Early in a drought, when there is ample quantity of dry pasture available, a suitable feeding strategy may involve the feeding of a protein source to balance the animals’ diet and improve intake levels. This strategy is only suitable for dry stock and will not be adequate for stock with higher demands (pregnancy, lactation or growth). To choose feeds in these circumstances first determine the cost per kilogram of crude protein (CP) provided.

To determine protein costs we first need to determine the cost per kilogram of dry matter as before, and then divide that value by the crude protein percentage (CP%) and multiply by 100. The following example shows the calculation for the cost of lupin protein—lupins are a popular choice as a protein-rich supplement.

Lupins
Cost per tonne = $450
DM = 90%
CP = 32%
Cost per kg DM = $450 × 10 ÷ 90 = 50c/kg DM

Lupins have an average crude protein percentage of 32%.

Therefore:

Protein cost = 50c/kg ÷ 32 ×100 = $1.56/kg CP

Another alternative often used to supplement crude protein is urea lick blocks. These supply a non-protein nitrogen source. A typical commercial 10% urea block with some additional monoammonium phosphate (MAP) will supply the equivalent of around 40%CP.


Urea lick blocks
Cost per 20 kg block = $17
CP = 40%

Cost per kg = $17 ÷ 20 = 85c/kg

Therefore:

Protein cost = 85c/kg ÷ 40 × 100 = $2.12/kg CP

These calculations show that lupins are far cheaper than urea lick block in providing crude protein. Lupins also contain energy which blocks do not provide.

There are many other possible alternatives to providing protein to stock. This method will determine the most cost-effective alternative.

http://www.dpi.nsw.gov.au/agriculture/livestock/nutrition/values