There can be number of reasons why a feed miller experiences shrinkage of raw material

• Difference in raw material ( in ) & finish goods ( out ) – moisture loss
• Losses due to moisture reduction in processing & storage;
• Unauthorized removal of feed from site;
• Material spillage /rodents /pests /other wastages
• Dust emissions from inefficient control equipment. (mainly blower, cyclone & ducting)
• Calibration of weigh scale.

The last five can be dealt with through good management of maintenance, production and administration. Moisture loss, the most significant factor, is more complex and needs further explanation.

Moisture Loss
Moisture loss is calculated on the basis of average moisture of raw material batch minus average moisture of finish goods. Example - let us assume a standard broiler feed formulation as mentioned:

a. Maize – 60 % in formulation by weight having 14 % moisture

b. Soya Doc – 25 % in formulation by weight having 9.5 % moisture

c. DORB – 10 % in formulation by weight having 9 % moisture

d. Other material like MBM, gluten etc. – 5 % in formulation by weight having 9 % moisture

Considering 1000 kg batch; total average moisture in raw material batch is:
600 x 14 % + 250 x 9.5 % + 100 x 9 % + 50 x 9 % = 121.25 kg (moisture/water) in 1000 kg of grain. Equals to 12.125 % average moisture in complete batch…… (a)

Ideal moisture of finish pellets in bag is considered between 11 to 12 %, depending upon the atmospheric temperature & humidity. Cooling is an evaporative process, so moisture reduction is essential. But there may be times when over cooling happens leading to over drying. If average moisture of finish good is 10.5 %, considering the statement ….a, average moisture loss or shrinkage will be 12.125 – 10.5 = 1.625 %.

For a feed mill manufacturing 200 MT a day, calculation of 1.625 % @ average price of 24 Rs/kg - whole batch; daily loss = 78,000 Rs. Apart from this monetary loss there is fluctuation in formulation too.

With net profit margins in some feed companies being low as 1 to 2 %, this factor alone could influence whether or not that company returns a profit or loss, so it really is a vital part of feed mill management.

Following process can be followed to reduce /monitor this loss as mentioned:
1. Moisture check in raw material before or at the time of procurement.

2. Sampling at different locations – after batching - grinding - conditioning – pelleting – cooling and final product for moisture check – as and when required.

3. Corrective action as per reports like – temperature at grinding, moisture addition in mixer, quality & quantity of steam, retention time in conditioner, cooler setting in terms of bed level and sensor , blower valve setting as per temperature , cleaning of cyclone & ducts , moisture and weather conditions etc.

4. Various automation modules help in inventory management of raw material by getting feedback from weigh scale ( raw material in ) , Material stock in ware house & daily weight of finish goods out from feed mill. (Every10thday - thrice a month)

5. After all corrective measures; there is still some amount of shrinkage (due to limitations in raw material availability as per season, price of grains, chances of mold /fungus in finish feed in rainy season, machinery behavior & limitation w.r.t. different formulations etc.) ; it’s wise to consider 0.5 % - 0.6 % process loss in cost estimations . Also each plant should recognize where shrink or gain may occur and make the best efforts possible to control and minimize these losses.