Lowering protein consumption of pigs

Submitted by on Thu, 11/10/2018 - 15:33

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Summary

Aim of Measure:

Lowering crude protein content of animal diets can decrease NH3 loss.

Nitrogen Species:

Ammonia emissions (NH3)

Climatic Zone:

Semi-arid
Temperate
Tropical
Arid

Geographic Region:

Global

Sector:

Agriculture (livestock)

Sector Category:

Livestock Feeding

Measure Description

Measure overview:

Gaseous N losses from livestock production originate from the faeces (dung) and urine excreted by the livestock. The animal feed composition and the feed management has a strong influence on animal performance but also on the composition of the dung and urine, hence the emissions of NH₃.

Low-protein animal feeding is one of the most cost-effective and strategic ways of reducing NH₃ emissions. For each per cent (absolute value) decrease in protein content of the animal feed, NH₃ emissions from animal housing, manure storage and the application of animal manure to land are decreased by 5%–15%, depending also on the pH of the urine and dung. Low-protein animal feeding also decreases N₂O emissions, and increases the efficiency of N use in animal production.

In general, the economic costs range from -€2 to +€2 per kilogram NH₃-N saved, i.e., there are potential net gains and potential net costs. The economic cost of animal feeding strategies to lower the NH₃ volatilization potential of the animal excrements through adjusting the crude protein content depends on the initial animal feed composition and on the prices of the feed ingredients on the market. Commonly, the economic costs increase when the target for lowering the NH₃ volatilization potential increases. The increasing marginal costs relate in part to the cost of synthetic amino acids supplementation relative to using soybeans. The costs of amino acids supplementation tend to go down. The cost of supplementation of amino acids increases when the target protein content in the animal feed is lowered.

How to implement the measure:

Lowering crude protein of pig diets is an effective and category 1 strategy for decreasing NH₃ loss. The following guidelines hold:

The crude protein content of the pig ration can be reduced if the amino acid supply is optimized through the addition of synthetic amino acids (e.g., lysine, methionine, threonine, tryptophan) or special feed components, using the best available information on “ideal protein” combined with dietary supplementation.

A crude protein reduction of 2%–3% in the feed can be achieved, depending on pig production category and the current starting point. The resulting range of dietary crude protein contents is reported in the table below. The values in the table are indicative target levels and may need to be adapted to local conditions. It has been shown that a decrease of 1% crude protein in the diet of finishing pigs results in a 10% lower total ammoniacal nitrogen (TAN) content of the pig slurry and 10% lower NH3 emissions (Canh and others, 1998b).

Indicative target crude protein levels in feed for pig rations

Species	Phases	crude protein content (%)^a

Weaner	< 10 kg	19–21
Piglet	< 25 kg	17–19
Fattening pig	25–50 kg	15–17
	50–110 kg	14–15
	> 110 kg	12–13
Sows	Gestation	13–15
	Lactation	15–17

Source: Based on European Commission, 2003.

^a With adequately balanced and optimal amino acid supply. The values presented here can be considered as “medium to high ambition level” (see annex II for a further specification of target crude protein levels).

Phase feeding can be implemented to more closely match an animal's nutrient requirements at the stage it is in its life to optimise crude protein consumption. Phase feeding is a term used to describe the feeding of several diets for a relatively short period. Through phase feeding the animal’s nutrient requirements are closely matched to its growth needs, formulating diets based on digestible/available nutrients, using low-protein amino acid-supplemented diets, and feed additives/supplements. These are all considered category 1 techniques and can minimize the over- and under-feeding of nutrients. To get maximum benefit from phase feeding, diets and feed budgets must be established for each stage of production, and established based on actual animal performance and profitability/performance goals. Further techniques are currently being investigated (e.g., different feeds for males (boars and castrated males) and females) and might be additionally available in the future.

Co-benefits and trade offs:

Cost Effective: Low-protein animal feeding is one of the most cost-effective and strategic ways of reducing NH3 emissions.

Animal Welfare: As long as the requirements for all amino acids are met, there are no animal health and animal welfare implications of implementing this measure.

Challenges:

Complexity of phase feeding: The disadvantages of moving from one feed to a phase feeding system includes greater complexity in ordering feed and the potential need to install additional feed bins on the farm. However, with increased pressures on profitability, these disadvantages must be weighed against the benefits of improved animal performance and profitability.

Measure Efficiency

Indicator for the efficiency of the measure:


Nitrogen Species	Ammonia(NH3)	Ammonium Nitrate (NH4NO3)	Nitrogen Dioxide (NO2)	Nitrous Oxide (N2O)	NOx	Nr	Total N
% of Reduction	5-15%	-	-	-	-	-	-

Reference system:

The abatement strategies described are not defined and assessed against a uniform reference (or unabated or baseline) feeding strategy, because these reference feeding strategies are different for different countries and between animals.

Finanacial Implications

Financial Implications table definitions:


Cost savings and production benefits ($)	Capital costs of implementing this measure ($)	Operational costs of implementing this measure ($)
-2 euros to +2 euros per kilogram of NH3-N saved (in UNECE countries).	-2 euros to +2 euros per kilogram of NH3-N saved (in UNECE countries).	-2 euros to +2 euros per kilogram of NH3-N saved (in UNECE countries).

Refs and Further Info

References:

Bittman, S. Dedina, M. Howard, C.M. Oenema, O. Sutton, M.A. (eds) (2014) Options for Ammonia Mitigation Guidance from the UNECE Task Force on Reactive Nitrogen. Centre of Ecology and Hydrology, Edinburgh, UK.

Canh, T. T., and others (1998a). Influence of electrolyte balance and acidifying calcium salts in the diet of growing-finishing pigs on urinary pH, slurry pH and ammonia volatilisation from slurry. Livestock Production Science, vol. 56, No. 1 (October), pp. 1–13.

European Commission (2003). Reference Document on Best Available Techniques for Intensive Rearing of Poultry and Pigs. Integrated Pollution Prevention and Control (IPPC). July 2003. Available from http://eippcb.jrc.es/reference/irpp.html.