11th International Conference on Life Cycle Assessment of Food (LCA Food 2018) in conjunction with the 6th LCA AgriFood Asia and 7th International Conference on Green and Sustainable Innovation (ICGSI) 16-20 October 2018, Bangkok, Thailand

A framework to account for the potential environmental impacts that may arise from genetic changes in pigs

Mathias Bo Ottosen, Stephen Mackenzie, Michael Wallace, Ilias Kyriazakis

Agriculture, SNES, Newcastle University, Newcastle Upon Tyne, England


We have developed a framework to account for the environmental impacts that may arise from genetic changes in pigs. An LCA model was built for a typical commercial Danish pig system, taking into account a number of pig traits that may be genetically correlated; the traits included were both sow- and growing pig-related. Through testing traits systematically both one at a time and in correlated clusters, i.e. accounting for the fact that some traits are genetically correlated, our model was able to show the importance of considering correlation between traits when modelling the environmental impact of breeding strategy. The model was highly sensitive to average daily gain between 30-100kg and energy used for maintenance, but also for clusters containing typical sow performance traits, such as weight gains and losses through gestation and lactation, and lactation feed intake. In future work we will consider how changes in these traits will affect the environmental impact of pig systems. This is the first time an LCA capable of showing the implications of breeding strategies for environmental impact has been developed for pig systems.

69th Annual Meeting of the EAAP, Dubrovnik, Croatia, 2018

Relationship between feed efficiency and physiological stress parameters in duroc x iberian pigs

W.M. Rauw *, E. De Mercado ⁑, L.A. Garcia Cortés *, L. Gomez Raya *, L. Silió *, M.C. Rodriguez *, E. Gómez Izquierdo ⁑
*INIA, Dept Mejora Genética Animal, Ctra de La Coruna km 7, 28040 Madrid, Spain
ITACyL, Centro de Pruebas de Porcino, Ctra. Riaza-Toro, s/n, 40353 Hontalbilla, Spain
Selection for improved feed efficiency may reduce the ability of animals to respond to environmental challenges. Alternatively, selection may result in animals with a reduced stress response. Fifty-three crossbred Duroc × Iberian barrows were used in this study. During the fattening period, feed consumed and body weight were recorded 22 times every 3 to 8 days over a period of 124 days. Body weight gain (BWG) was calculated and residual feed intake (RFI) was estimated for three consecutive periods of 56 (P1), 35 (P2), and 33 (P3) days. Blood samples were collected on day one of the experiment (P1), on day 78 of the experiment (P2) and at slaughter (day 125; P3); plasma cortisol, lactate and glucose levels were measured. In P2, pigs with lower RFI (high efficient) had lower levels of glucose (r=0.32, P<0.05) and tended to have lower levels of cortisol (r=0.29, P=0.06). In P3, Pigs with lower RFI had lower levels of lactate at slaughter (r=0.37, P<0.01). Overall, pigs with higher levels of lactate also had higher levels of glucose. This was significant in P2 (r=0.53, P<0.001) and a tendency in P1 (r=0.23, P=0.09). At slaughter, pigs with higher levels of cortisol had higher levels of lactate (r=0.48, P<0.001) but lower levels of glucose (r=-0.35, P<0.05). The latter may reflect a faster exhaustion of glycogenic stores at the time of slaughter resulting from stress. The results indicate that increased levels of physiological stress parameters negatively affected feed efficiency in Iberian pigs. Conversely, selection for improved feed efficiency may result in a reduced stress response. This work was funded by the Ministerio de Economía y Competitividad of the Spanish Government (AGL2016-75942-R, IBERFIRE), in support of SusAn ERA-Net ‘SusPig’.

69th Annual Meeting of the EAAP, Dubrovnik, Croatia, 2018

Does selection for feed efficiency in pigs improve robustness to heat stress?

W.M. Rauw ⁑, J. Mayorga Lozano *, J.C.M. Dekkers *, J.F. Patience *, N. Gabler *, S. Lonergan *, and L.H. Baumgard *
⁑ INIA, Dept Mejora Genética Animal, Ctra de La Coruña km 7, 28040, Madrid, Spain
* Iowa State University, Dept of Animal Science, Kildee Hall, 50011, Ames, IA, USA
Heat stress (HS) accounts for over $900 million loss annually in the U.S. swine industry resulting from slower growth rates, reduced feed efficiency and poor reproduction. Pigs with increased feed efficiency have lower basal metabolic rates and reduced metabolic heat production. Therefore, genetic selection for improved feed efficiency may reduce susceptibility to HS. Study objectives were to investigate the effects of selection for residual feed intake (RFI) on growth and feed intake in response to repeated exposures to HS. A total of 35 and 31 pigs from a divergent selection line for low (LRFI) and high RFI (HRFI), respectively, where subjected three separate times to a 4-d HS load, which was preceded by a 9-d thermal neutral (TN) adaptation period and alternated by 7-d TN conditions: 1-TN adaptation, 2-HS, 3-TN, 4-HS, 5-TN, 6-HS, and 7-TN. Average daily body weight gain (BWG) and daily feed intake (FI) were calculated for each period; feed efficiency (FE) was estimated as BWG/FI. Overall, between TN and HS, the change in BWG tended to be larger in LRFI (- 306 g/d) than in HRFI pigs (+ 12 g/d; P=0.09), but the change in FI was similar (a decrease of 542 and 509 g/d, respectively). Overall, FE was not significantly affected by HS in either line. Selection for improved FE did not reduce susceptibility to HS. In contrast, results show that LRFI pigs (high efficient) were slightly, albeit non-significantly, more affected by HS (less robust) than HRFI pigs. Although water intake was not recorded in the present study, other studies suggest that water consumption may be greater in HRFI than in LRFI animals, which may result in a higher capacity for heat dissipation. This work was funded by the Iowa Pork Producers Association (14-243) and USDA NIFA-AFRI award number 2011-68004-30336, in support of SusAn ERA-Net ‘SusPig’.

Can european pigs thrive on local feedstuffs like rapeseed meal and DDGS? 

SusPig was presented at the Feed Protein Vision 2018 event on 6-7 March in Amsterdam, The Netherlands. 

Margareth Øverland from NMBU and Wendy Rauw from INIA presented examples of pig production moving towards an increased use of local feedstuffs.


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A Hypothesis and Review of the Relationship between Selection for Improved Production Efficiency, Coping Behavior, and Domestication

WM Rauw, AK Johnson, L Gomez-Raya, JCM Dekkers

Frontiers in Genetics 2017, Volume 8, Article 134, pp 1-13

Coping styles in response to stressors have been described both in humans and in other animal species. Because coping styles are directly related to individual fitness they are part of the life history strategy. Behavioral styles trade off with other lifehistory traits through the acquisition and allocation of resources. Domestication and subsequent artificial selection for production traits specifically focused on selection of individuals with energy sparing mechanisms for non-production traits. Domestication resulted in animals with low levels of aggression and activity, and a low hypothalamic–pituitary–adrenal (HPA) axis reactivity. In the present work, we propose that, vice versa, selection for improved production efficiency may to some extent continue to favor docile domesticated phenotypes. It is hypothesized that both domestication and selection for improved production efficiency may result in the selection of reactive style animals. Both domesticated and reactive style animals are characterized by low levels of aggression and activity, and increased serotonin neurotransmitter levels. However, whereas domestication quite consistently results in a decrease in the functional state of the HPA axis, the reactive coping style is often found to be dominated by a high HPA response. This may suggest that fearfulness and coping behavior are two independent underlying dimensions to the coping response. Although it is generally proposed that animal welfare improves with selection for calmer animals that are less fearful and reactive to novelty, animals bred to be less sensitive with fewer desires may be undesirable from an ethical point of view.


Effects of Diet and Genetics on Growth Performance of Pigs in Response to Repeated Exposure to Heat Stress

WM Rauw, EJ Mayorga, SM Lei, JCM Dekkers, JF Patience, NK Gabler, SM Lonergan, LH Baumgard

Frontiers in Genetics 2017, Volume 8, Article 155, pp 1-18

Heat stress (HS) is one of the costliest issues in the U.S. pork industry. Aims of the present study were to determine the consequences of repeated exposure to HS on growth performance, and the effects of a high fiber diet, the genetic potential for high lean tissue accretion, and the genetic potential for residual feed intake (RFI) on resilience to HS. Barrows (n = 97) from three genetic lines (commercial, high RFI, low RFI) where subjected three times to a 4-day HS treatment (HS1, HS2, and HS3) which was preceded by a 9-day neutral (TN) adaptation period (TN1) and alternated by 7-day periods of neutral temperatures (TN2, TN3, and TN4). Body weight gain (BWG), feed intake (FI), feed conversion efficiency (FCE), RFI, and the drop in BWG and FI between TN and HS were estimated for each period, and slaughter traits were measured at the end of TN4. Commercial pigs had lower FI when fed a high fiber diet compared to a regular diet (2.70 ± 0.08 vs. 2.96 ± 0.08 kg/d; P < 0.05), while no differences were found for BWG, RFI or FCE. HS reduced FI, BWG, and FCE, increased RFI, and resulted in leaner pigs that generate smaller carcasses at slaughter. In TN, commercial pigs grew faster than the low and high RFI pigs (1.22 ± 0.06 vs. 0.720 ± 0.05 and 0.657 ± 0.07; P < 0.001) but growth rates were not significantly different between the lines during HS. Growth rates for the low RFI and high RFI pigs were similar both during TN and during HS. Pigs of interest for genetic improvement are those that are able to maintain growth rates during HS. Our results show that response in growth to HS was repeatable over subsequent 4-d HS cycles, which suggests the potential for including this response in the breeding index. The best performing animals during HS are likely those that are not highly superior for growth in TN.