SusPig - Sustainability of pig production through improved feed efficiency

Aim of the project:

To enhance sustainability of European pig production through improved feed efficiency on local diets and feedstuff co-products


Genetically improved high producing pigs require high-quality feeds that allow the expression of production traits, which otherwise may result in reduced resilience to environmental stressors and the genesis of production diseases. Modern livestock diets consist of feed resources with high nutritional and commercial value that is sourced from international markets. For example, soybean meal is a major ingredient in livestock feeds, however, Europe is heavily reliant on its import. Due to the notion of the unsustainability of this heavy overreliance on imported feed resources in the EU, there is an increased interest in using local feed resources and feedstuff co-products in pig production. Because the quantity and quality of feed resources limits productive output, a different type of animal may be required with different performance characteristics than those currently selected in intensive, high-quality input – high output production systems. Our research evaluates if improved feed efficiency (FE) can be sustained with climate change and with more reliance on local feeds with suboptimal quality, and to evaluate the environmental, social and economic impacts of this strategy. SusPig’s goals are achieved through multi-disciplinary research involving pig production, animal physiology, nutrition, genetics, environmental and social impact, and system modelling.

What: Feed efficiency and robustness traits in response to local pig diets and feedstuff co-products will be evaluated in experimental and commercial pigs. An environmental and social life cycle assessment analysis will be performed on the impacts of pig production as enhanced by transforming low-quality feed. In addition, future sustainable pig production systems will be modelled.

Why: Efficient use of resources will improve the productivity, resilience and competitiveness of European pig production. Environmental sustainability will be enhanced by transforming low quality, local feed resources and feedstuff co-products to meat. The goal is also to enhance animal welfare, breeding strategies and consumer acceptance of pig production and breeding practices.

Where: The research is been done in eight academic centres in Spain, France, Norway, Sweden, and the UK, USA and Australia.

Main project activities:

Genetic selection for improved feed efficiency is required for sustainable pig production but needs to take account of potential negative effects on animal health and welfare. Livestock production is moving towards an increased use of local feed resources and feedstuff co-products. This may require a different type of animal than those currently selected in intensive, high quality input – high output production systems. The objectives are in support of sustainable intensification, i.e. improving efficiency and productive output while maintaining animal health and welfare (10.1002/jsfa.10338).

Interim research findings:

To evaluate environmental stress related to climate change, we evaluated the effect of heat stress on feed efficiency. We tested the effect of heat stress in fast growing commercial pigs in a repeated heat stress challenge (10.3389/fgene.2017.00155), as well as in slow growing local pig breeds in different seasons (10.1038/s41598-020-58981-w). Blood biomarkers related to feed efficiency and indicative of health and fitness are being collected from 300 pigs divergently selected for feed efficiency and 700 commercial pigs. Most notably, our results showed reduced feed intake under heat stress, but some pigs are better able to sustain weight gain than other animals. We observed that pigs with lower growth rates are more robust to heat stress. Therefore, our results show that even within currently-available pig breeds, some cope better with higher temperatures associated with climate change or even perform better when transforming local forages into meat. This opens perspectives for selecting for a new type of pig.

To evaluate nutritional stress, we replaced soybean meal with different locally grown alternatives. A meta-analysis was conducted to quantify the effect of dietary inclusion rate of canola/rapeseed meal on average daily gain, average daily feed intake, and feed conversion in weanling and growing-finishing pigs.  It was concluded that canola/rapeseed meal can be included as a protein source in nutritionally balanced diets for growing-finishing pigs without adverse effects on growth performance. When soybean meal was replaced by dietary inclusion of rapeseed meal, the dietary alteration reduced growth performance, and altered several carcass traits and transcriptional responses in the skeletal muscle, but did not affect measured meat quality traits (10.1371/journal.pone.0220441). On a rapeseed and faba bean diet, which fast-growing commercial breeds received, feed efficiency was reduced but overall, growth performance and carcass quality was comparable to soybean-based diets and improved meat quality was also observed (10.1016/j.meatsci.2020.108134). The improved quality, which was evaluated by a taste panel, is particularly important because it may open the possibility to maintain profitability by selling these pork products under a different label. On a Narbon vetch diet, Duroc × Iberian pigs, a local Spanish cross, were able to sustain feed efficiency but needed more time to reach slaughter weight (10.3390/su12103993). Meat quality was evaluated in samples of cured loin. The results showed that inclusion of Narbon vetch in the diet showed no significant effect on intramuscular fat, protein and moisture in loin samples. In addition, no difference was found in intensity of the texture, marbling, aroma and colour of loin from samples with 5% Narbon vetch inclusion compared to the soybean meal diet (in prep). Lastly, the ability to predict production performance in an extensive production system from measurements of feed efficiency measured intensively, and the relationship between feed efficiency and meat quality was investigated in Iberian pigs. Pigs that were more feed efficient on concentrate, were less feed efficient on acorns and had higher body weight gain when fattened extensively. Improved feed efficiency on acorns reduced the concentration of α-linolenic and linoleic fatty acid composition of subcutaneous fat, but feed efficiency showed no further relationship with any of the meat quality traits (10.37496/rbz4920200009).

Different theoretical studies in genetics were developed. The genome-wide levels of third order linkage disequilibrium were investigated in a composite line founded by admixture of four Iberian pig strains. Third order linkage disequilibrium is common among linked markers in the analyzed pig line and may have been generated by population admixture of multiple populations or by genetic drift (10.1186/s12863-018-0661-4). Also, autozygosity and genetic differentiation were investigated in Landrace by Large-White breeds by using the genotypic information of SNP arrays in crossbreds. Genes with biological functions associated with production, such as tissue development, anatomical structure, and animal organ development, were overrepresented in regions with a high Wright’s FST (10.3389/fgene.2019.00739).

A novel Life Cycle Analysis model was developed to investigate the environmental impacts of breeding pigs for improved performance resulting from genetic change through selection. The research shows that is it essential to include correlated genetic traits in the sensitivity analysis. Finisher growth rate, body protein-to-lipid ratio, and energy maintenance was found to be important reducing the environmental impacts, however, mortalities and sow robustness had little effect (0.1007/s11367-019-01686-8). In a second LCA study, a novel model was developed to account for individual animal performance to quantify the responses to selection for residual feed intake. The research confirmed the importance of improvement in feed efficiency to reduce environmental impacts, and shows that more optimal criteria for efficient environment-friendly selection can be expected through restructuring the selection indexes from an environmental point of view (10.1017/S175173112000138X).

A third LCA study describes the first social life cycle assessment for pork consumption in Europe, and the risk of negative social impacts in Swedish pork production systems, including workers, farmers, consumers, local community, society, and pigs as stakeholders (10.1007/s11367-020-01811-y). The research concludes that Swedish pork production has lower risk of negative social impacts than the average European social conditions for most of the stakeholders, whereas farmers and society at the subsystem pig farm have the same risk of negative social impacts as the average European social conditions.

Project consortium:

Coordinated by: Dr. Wendy Rauw - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (SPAIN)

  • FRANCE: Institut national de la recherché agronomique and Institut du Porc
  • NORWAY: Norges miljø- og biovitenskapelige universitet
  • SPAIN: Instituto Tecnológico Agrario
  • SWEDEN: Swedish University of Agricultural Sciences
  • UNITED KINGDOM: Newcastle University
  • USA: Iowa State University
  • AUSTRALIA: University of New England