FEED SAFETY ▶▶▶


Rancidity of feed may lead to di- gestive upsets and reduced performance among chickens.


storage over an extended period. On the other hand, un- ground feed grains such as maize, whole oats, barley, and un- processed grain sorghum will tolerate somewhat higher lev- els of moisture in storage without spoilage. Because of this, whole grains containing more than about 11.0% moisture should not be used in the production of ground mixtures to be held in storage for more than just a few days, especially during warm weather. Small grains such as barley, oats, and grain sorghum will tolerate up to about 13% moisture in stor- age, while shelled maize will tolerate up to about 15.5%.


Storage facilities Proper storage of feed is an important factor in preserving the quality of feed and protecting it from damage by mould


Table 3: Effect of oxidized fat feeding on feed intake, weight gain, and mortality of broiler chickens


Feed intake (g/14 days) Bodyweight (g/14 days) Feed: Gain ratio Mortality (%)


Source: K. Takahashi and Y. Akiba (1999) References are available upon request. 30 ▶ ALL ABOUT FEED | Volume 29, No. 4, 2021


Oxidized Fat 753 540


1.39 7


Control 760 584


1.30 0


and other factors. Field studies in Egypt, for example, have re- vealed that on most farms feed is stacked under shelters where it is frequently subject to mould damage and invasion by rodents, wild birds, and/or insects. A microbial assay of feed at one farm revealed a mould value of 22,000 c.f.u./g, as opposed to the normal level of only 5,000 c.f.u. In this case, poor feed efficiency and reduced growth rates were encoun- tered. Such problems could have been alleviated if the feed was stored in silos. Moneywise, it was estimated that the cost of a 20-tonne silo can be recovered in just three years as a re- sult of savings of up to 16,000 Egyptian Pounds per year (the value of the feed damaged under poor storage conditions).


Use of chemicals Organic acids are the major compounds that have been used as chemical preservatives of high-moisture grain, with propi- onic and acetic acid or combinations of these being most fa- voured. Propionic acid is toxic to moulds and is used as a grain preservative at about ten times the level that is theoret- ically necessary for the control of fungi. The level of organic acid required for satisfactory preservation of grain increases with the moisture content of the grain and the length of stor- age required. In general, the feeding value of acid-preserved grain is similar to that of dry grain.


PHOTO: KOOS GROENEWOLD


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