Poor Management of Chemical Inputs

The environmental problems associated with the poor management of chemical inputs to industrial production systems overlap with problems associated with the poor management of animal wastes and discharge of effluents. | Feed Additives Prophylactic Use of Chemicals, Pesticides and Drugs Environmental Assessment: Pressure State Response Indicators Policy Pressures and Policy Options Technology Options

The management of chemical inputs to induistrial production systems also has considerable overlap with the problems of chemical inputs to both grazing and mixed production systems and these will therefore be considered together.

Feed Additives

Feed stocks often contain traces of heavy metals, with copper and zinc added as supplements and growth stimulants, as well as accidentally introduced pollutants such as cadmium.

Surplus quantities of heavy metals in the animal feed are excreted with the manure. Through the manure these heavy metals can come into the environment (on land or ground and surface water). Accumulation of heavy metals in the soil may be expected to occur, when their supply through animal manure exceeds crop uptake. This might apply when pig or poultry manure is applied at high rates for a long period of time. In the long term may threaten the multi-functionality of the soils.

- Copper (Cu) is added to feed for pigs as an essential trace mineral and the positive influence it has on the growth performance, particularly at sub-optimal management levels. However, it physiological effect is not exactly known and present experience shows that the Cu levels in the feed could be reduced considerably without affecting the growth performance of pigs.
- Zinc (Zn) is frequently added as a trace mineral to the feed of pigs and poultry. However, the exact requirements can never be exactly determined, because they strongly interact with other nutrients in the feed causing fluctuations in Zn availability.
- Cadmium (Cd) is only a pollutant of animal feed mainly introduced via feed phosphates. The Cd content of feed phosphates depends on the source. The Cd content of feed can be reduced by reducing the level of feed phosphates and by using feed phosphates low in Cd.

Prophylactic Use of Chemicals, Pesticides and Drugs

The concentration of livestock into intensive production units, increases disease risks. In response to this risk, there is a need to maintain high standards of hygiene. This involves the use of large volumes of water for cleaning as well as the use of chemical and biological cleaning agents, which tend to be discharged in effluents. Fungicides and other chemicals are also routinely used.

However, despite these precautions, the potential for cross-infection between stock is very high, and as a result there is a tendency to use antibiotics as a precautionary measure - and as a means of promoting growth.

In less intensive systems, e.g. Grazing and Mixed livestock production, chemical inputs are also used and these may also pose a threat to the environment. One example is the recent development of Pour-on Technology for control of ecto-parasites, particularly insect disease vectors such as TseTse fly. There is mounting concern of the widespread adoption and use of this technology, which is driven by an apparent reduced cost compared with alternatives, due to the potential environmental impacts.

Residues from these activities will end up in the environment, with potentially major impacts on environmental health, and aquatic and terrestrial ecosystems.

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