Susanne Stern’s research while affiliated with Swedish University of Agricultural Sciences and other places

It is generally accepted that gastrointestinal short-chain fatty acids (SCFAs) – acetic, propionic and butyric acid – are mostly derived from carbohydrates, while iso-butyric and iso-valeric acids are from protein sources. We have investigated the faecal SCFAs and the correlation between the branched-chain fatty acids iso-butyric and iso-valeric in humans, rats, horses and pigs. The subjects were of different ages, fed on different diets and housed in different environments. High differences in the total output of SCFAs were observed within and between species. Despite these differences, a remarkable correlation between the iso-butyric and the iso-valeric acids was found. The fact that the correlation is strong irrespective of species, age, diet and living conditions indicates a common source actually reaching the hindgut. We hypothesize that this source is intestinal sloughed cells.

Sustainability within agriculture is a complex issue. In this study we have worked with a forecasting scenario technique. A methodology for working with scenarios for future agricultural production systems was developed. The scenarios can then be evaluated both quantitatively, e.g. economy and life cycle analysis (LCA), and qualitatively, e.g. animal health and welfare. The method has been used on pig production, beef production, dairy production and the production of food potatoes.

A major QTL for fatness and growth, denoted FAT1, has previously been detected on pig chromosome 4q (SSC4q) using a Large White - wild boar intercross. Progeny that carried the wild boar allele at this locus had higher fat deposition, shorter length of carcass, and reduced growth. The position and the estimated effects of the FAT1 QTL for growth and fatness have been confirmed in a previous study. In order to narrow down the QTL interval we have traced the inheritance of the wild boar allele associated with high fat deposition through six additional backcross generations. Progeny-testing was used to determine the QTL genotype for 10 backcross sires being heterozygous for different parts of the broad FAT1 region. The statistical analysis revealed that five of the sires were segregating at the QTL, two were negative while the data for three sires were inconclusive. We could confirm the QTL effects on fatness/meat content traits but not for the growth traits implying that growth and fatness are controlled by distinct QTLs on chromosome 4. Two of the segregating sires showed highly significant QTL effects that were as large as previously observed in the F2 generation. The estimates for the remaining three sires, which were all heterozygous for smaller fragments of the actual region, were markedly smaller. With the sample sizes used in the present study we cannot with great confidence determine whether these smaller effects in some sires are due to chance deviations, epistatic interactions or whether FAT1 is composed of two or more QTLs, each one with a smaller phenotypic effect. Under the assumption of a single locus, the critical region for FAT1 has been reduced to a 3.3 cM interval between the RXRG and SDHC loci. We have further characterized the FAT1 QTL on pig chromosome 4 and refined its map position considerably, from a QTL interval of 70 cM to a maximum region of 20 cM and a probable region as small as 3.3 cM. The flanking markers for the small region are RXRG and SDHC and the orthologous region of FAT1 in the human genome is located on HSA1q23.3 and harbors approximately 20 genes. Our strategy to further refine the map position of this major QTL will be i) to type new markers in our pigs that are recombinant in the QTL interval and ii) to perform Identity-By-Descent (IBD) mapping across breeds that have been strongly selected for lean growth.

To study future, sustainable production systems, a step-wise method was used to create three future scenarios for pig production based on different sustainability goals. The first scenario focused on animal welfare and the natural behavior of the animals. The second targeted low impacts on the environment and the efficient use of natural resources. The third scenario aimed at product quality and safety. Each scenario fulfilled different aspects of sustainability, but there were goal conflicts because no scenario fulfilled all sustainability goals. The scenarios were then parameterized. The environmental impact was calculated using the life-cycle assessment (LCA) methodology, and the economic cost was calculated from the same data set. The cost per kilo of pork was highest for the animal welfare scenario and similar for the other two scenarios. The environmental scenario had the lowest environmental impact, and the product-quality scenario the highest. The results are discussed based on different future priorities.

Goal, Scope and Method The purpose of this environmental system analysis was to investigate the impact of feed choice in three pig production scenarios using substance flow models complemented by life cycle assessment methodology. The function of the system studied was to grow piglets of 29 kg to finished pigs of 115 kg. Three alternative scenarios of protein supply were designed, one based on imported soybean meal (scenario SOY); one based on locally grown peas and rapeseed cake (scenario PEA) and one based on Swedish peas and rapeseed meal complemented by synthetic amino acids (scenario SAA). The environmental impact of both feed production as such and the subsequent environmental impact of the feed in the pig production sub-system were analysed. The analysed feed ingredients were barley, wheat, peas, rapeseed meal, rapeseed cake, soybean meal and synthetic amino acids. The crude protein level of the feed affected the nitrogen content in the manure, which in turn affected nitrogen emissions throughout the system and the fertilising value of the manure, ultimately affecting the need for mineral fertiliser application for feed production. Results and Discussion The results showed that feed production contributed more than animal husbandry to the environmental burden of the system for the impact categories energy use, global warming potential and eutrophication, whereas the opposite situation was the case for acidification. The environmental impacts of scenarios SOY, PEA and SAA were 6.8, 5.3 and 6.3 MJ/kg pig growth; 1.5, 1.3 and 1.4 kg CO2-eq/kg pig growth; 0.55, 0.55 and 0.45 kg O2-eq/kg pig growth; and 24, 25 and 20 g SO2-eq/kg pig growth, respectively. The results suggested that scenario SAA was environmentally preferable, and that the reason for this was a low crude protein level of the feed and exclusion of soybean meal from the feed. Conclusions Feed choice had an impact on the environmental performance of pig meat production, not only via the features of the feed as fed to the pigs, such as the crude protein content, but also via the raw materials used, since the environmental impact from the production of these differs and since feed production had a large impact on the system as a whole.

The objective of this study was to investigate the effect of outdoor rearing on the fatty acid (FA) composition and contents of tocopherols of M. longissimus dorsi polar (PL) and neutral lipids (NL) in entire males, castrated males and female pigs. Fat content did not differ between genders or rearing conditions. In PL of the indoor pig muscle the level of n-6 highly unsaturated fatty acids (HUFA) was higher in females and entire males compared with castrated males. The outdoor environment resulted in a slightly higher level of n-3 polyunsaturated FA (PUFA) in muscle PL and NL of entire males compared with females and castrated males. We also found an increased level of 18:2 n-6 in the muscle PL of outdoor reared females compared with the indoor females. The higher levels of PUFA in the entire male muscle, in both PL and NL, were not accompanied by a higher level of vitamin E.

This study investigates how direct (h2) genetic effects, maternal (m2) genetic effects, and litter environmental (c2) effects influence the early growth, fattening performance, and carcass traits of pigs. This study provides new genetic knowledge about the relationship between early and later growth. Individual piglet weight records at birth, at 3 weeks, at weaning, and at 9 weeks were available for about 20,000 Yorkshire piglets. Performance records; average daily gain between birth and 90 kg live weight (DG0–90), between 25 and 90 kg live weight (DG25–90), and ultrasonic backfat thickness (at 90 kg live weight) were available for about 4000 pigs. The carcass records available for about 3000 pigs were linear backfat thickness, carcass length, and percentage of meat and bone in ham. Univariate and bivariate analyses were used to estimate (co)variance components. Piglet weight before weaning was influenced more by c2 and m2 than by h2. The m2 for individual piglet weight decreases with age from 0.18 to 0.09 between birth and 9 weeks, and h2 increases from 0.07 to 0.12. No significant m2 were present for DG0–90 and DG25–90. Estimation of m2 and the correlation between direct and maternal genetic effects depend on data structure and pedigree relationships. Low direct genetic correlations between piglet weight and growth during the fattening period were found (−0.00 to 0.37), which indicates together with the different origin (direct or maternal) of the genetic control for these traits the possibility to treat them separately in a breeding evaluation program.

The objective of the study was to compare production results and technological meat quality for pigs born outdoors and reared indoors or outdoors during the summer period. A total of 279 pigs was reared in a large pen on deep litter, or outdoors. Daily weight gain and lean meat percentage were higher for pigs outdoors than indoors during year one (864 vs. 841g; 56.9 vs. 55.9%), but were similar for year two (859 vs. 844g; 55.9 vs. 55.6%). Outdoor pigs grew faster when fed ad libitum, but slower during the second phase when restricted, with inferior feed conversion. Most technological meat quality traits (surface and internal reflectance, marbling, pHBF, filter paper wetness, cooking loss and maximal Warner-Bratzler shear force) were similar between rearing systems, whereas pHLD was higher indoors. Total work of Warner-Bratzler shear force was lower in outdoor reared pigs. Maternal sire breed (Duroc or Landrace) and sex (castrate or gilt) did not notably affect meat quality traits. RN genotype had a stronger impact on meat quality than rearing system. It can be concluded from the similarities in production results and meat quality in both systems, that both indoor and outdoor rearing are good alternatives for summer rearing of pigs.