Most pork producers think that feed wastage is simply feed that is offered to a pig but is not consumed. Poor feeder design, broken troughs or floor feeding are often the culprit. But thinking "outside the box" as to where nutrients are lost or not properly accounted for gives a new dimension to the feed wastage.

Although usually overlooked, feed wastage can have considerable impact in regards to both economics and nutrition. Feed wastage can account for 5 to 20% of all feed disappearance on a farm. When average feed cost is US$350/metric ton, a potential reduction of 10% in feed wastage is worth US$35/metric ton. For every 100 sows farrowing to finish (100 kilogram live weight) is about US$17,500 per year.

Daily feed intake and feed conversion figures are calculated based on feed disappearance rather than true feed intake. Feed wastage can, therefore, make these measures much less meaningful. A 10% improvement can obviously reduce the whole herd feed conversion from 3.9 to 3.6, for example.

Points of feed wastage can be divided into three key areas: feed ingredient, milling technology and farm management.

Knowledge of nutrient profiles

Feed formulation uses estimates of the bio-available nutrient levels, although not all nutrients are fully available after digestion and additional dietary support is needed.

Ingredients are frequently traded by a descriptive name and not always by their nutrient content. This can result in inaccurate feed formulations. For instance, soyabean meal can be 48% protein with 3.5% fibre or 46% protein with 7% fibre. This affects both the digestible amino acid and digestible energy values. Another example would be meat and bone meal. This can range in fat content from 2 to 14% and ash content from 15 to 30%. Be sure you know the nutrient profile before appearing to purchase a cheaper feed ingredient.

The enzyme phytase unlocks phytate phosphorus in cereal grains and soyabean meal that is chemically bound and not normally available to the animal, releasing additional amino acids and energy. The use of phytase enzyme can increase dietary net energy, enabling the reduction of protein levels and lessening the need for meat and bone where it is used as the phosphorus source. A typical cost saving is US$3-5/ metric ton and meat and bone reduction of 1 to 3%.

Enzymes can improve nutrient availability

Less-digestible parts of cereal grains and other protein sources can yield nutrients if appropriate enzymes are added to the feed. The addition of suitable enzymes like xylanase and beta glucanase can break down the fibrous seed coats of some grains and release up to 3 to 5% additional energy.

The enzyme alpha-galactosidase can break down indigestible carbohydrates in soyabean meal. Formulations should reflect the benefit of adding the enzymes. An additional DE of 0.4 to 0.7 Megajoules/kg diet can be achieved.

The opportunity to use higher levels of synthetic amino acids and lower dietary crude protein levels can help to reduce cost and also decrease the amount of nitrogen (protein) excreted into the effluent. This also has the benefit of improving the net energy yield of the diet as less energy is wasted in the excretion process.

Maintaining ideal particle size

There are several aspects of the milling process that can influence nutrient loss. Reduction of whole grain to the ideal and uniform particle size allows for more surface area for digestive enzyme action and more complete digestion. Particles too fine can result in dust that is lost in the feed handling system, while particles too coarse may not be digested.

Milling technology needs to be adapted to suit the particular grain and its physical characteristics. Ideal particle size ranges from 400 to 500 microns for piglet starter diets, to 700 to 800 microns for growing-finishing pigs to 1,000 microns for sows and boars.


Periodic checking of hammer mills can reveal screen damage (whole grains seen in the mix) and hammer wear (increased variation in particle size). Both can reduce digestibility and nutrient loss.

Roller mills should ideally be a double stacked system where the top set of rolls breaks the grain and the second set rolls the grain. A differential speed of at least 25% should be used for each of the rolls in the pair to increase friction. Inadequate adjustment can result in whole grains going through the mill and grain will be seen in the faeces. A 20% loss of grain through the digestive system can reduce the diet DE by 2.0MJ/kg, giving a loss of US$40 to 70/metric ton feed for the respective cereals.

If complete feeds are purchased in pellet form, they need to remain in pellet form all the way to the feed trough. The fines and broken pellets should be less than 7%. Pigs will sort pellets from fines and discard the fines, adding to feed wastage.

When mixing on the farm, avoid unnecessary waste of high-cost ingredients and weight to the nearest kilo for accuracy.

Management practices affect loss

The producer should look critically at various areas of feed management that could save on feed wastage and apparent nutrient loss from inappropriate practices.

>Scoop/dipper.  This is a volumetric measure that needs to equate with a gravimetric (weight) measure. All feed formulations are different so calibration of the scoop/dipper is vitally important to be certain of the amount of feed being given. Check it out whenever there is a feed formulation change.

>Floor feeding groups of pigs.  Normally this entails over-feeding to ensure each animal consumes its appropriate feed allowance. However, feed is always wasted by losses through the slats, feed caught on the body of the animals and through contamination with faeces on the floor. Consider using a feeder.

>Creep feeding.  Many farms start creep feeding too early, at four to seven days of age. Piglets will not consume any noticeable amount of creep until at least 10 to 14 days when the litter growth rate starts to exceed the sow milk yield. Even after this time, unless the creep feed is put into a container and maintained in a fresh state, there can still be considerable wastage of a very high-priced feed.

>Feeder adjustment.  Pigs need to "work for feed," but not too hard. Pellets flow easier through feeders than meal diets and feeders normally have a tighter adjustment for pellets. Changing over from creep pellets to weaner meal needs careful attention to ensure that a wider adjustment is used to aid the flow of meal forms. The feeder pan should never have more than about 25% cover of feed.

Weaner diets of high nutrient density tend to be "sticky" due to added fat and fish/milk powder levels. The feeder needs daily adjustment to ensure feed is maintained readily and available in a palatable state.

>Liquid feeders.  The discharge pipe from the feed line to the trough can cause excessive spillage if at right angles to the trough and delivery is under high pressure. Placing the downpipe with a T-piece on the end in the centre of the trough will help get feed to flow in two directions and can help to correct this problem.

>Continuous troughs.  These are often used to deliver water to the pregnant sows. It is important to ensure only a minimum amount of water remains when the feed is dropped into the trough. The individual sow may not get her specific allocation of feed if the feed can be easily "flushed" between the individual feeding stalls. This can increase variation in body condition of sows.

>Feed intake.  It is critically important to know the daily feed intake of pigs at all stages of production as this can allow for improved diet specifications to ensure the correct daily nutrient intake is achieved, minimising nutrient wastage.

You may not be able to influence feed ingredient pricing but you can make sure that you maximise nutrient consumption for better pig performance and minimise feed wastage and nutrient losses. This is a good way to improve farm profitability.