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The welfare implications of large litter size in the domestic pig I: biological factors

Published online by Cambridge University Press:  01 January 2023

KMD Rutherford*
Animal Behaviour and Welfare, Animal and Veterinary Science Research Group, SRUC, West Mains Rd, Edinburgh EH9 3JG, UK
EM Baxter
Animal Behaviour and Welfare, Animal and Veterinary Science Research Group, SRUC, West Mains Rd, Edinburgh EH9 3JG, UK
RB D’Eath
Animal Behaviour and Welfare, Animal and Veterinary Science Research Group, SRUC, West Mains Rd, Edinburgh EH9 3JG, UK
SP Turner
Animal Behaviour and Welfare, Animal and Veterinary Science Research Group, SRUC, West Mains Rd, Edinburgh EH9 3JG, UK
G Arnott
Animal Behaviour and Welfare, Animal and Veterinary Science Research Group, SRUC, West Mains Rd, Edinburgh EH9 3JG, UK
R Roehe
Animal Behaviour and Welfare, Animal and Veterinary Science Research Group, SRUC, West Mains Rd, Edinburgh EH9 3JG, UK
B Ask
Danish Agriculture and Food Council, Pig Research Centre, Axelborg, Axeltorv 3, DK-1609 Kbh V, Denmark
P SandØe
Department of Large Animal Sciences & Institute of Food and Resource Economics, University of Copenhagen, Groennegaardsvej 8, DK-1870 Frederiksberg, Denmark
VA Moustsen
Danish Agriculture and Food Council, Pig Research Centre, Axelborg, Axeltorv 3, DK-1609 Kbh V, Denmark
F Thorup
Danish Agriculture and Food Council, Pig Research Centre, Axelborg, Axeltorv 3, DK-1609 Kbh V, Denmark
SA Edwards
School of Agriculture, Food and Rural Development, University of Newcastle, Newcastle-upon-Tyne NE1 7RU, UK
P Berg
NordGen, Nordic Genetic Resource Center, Norway Department of Genetics and Biotechnology, University of Aarhus, DK-8830 Tjele, Denmark
AB Lawrence
Animal Behaviour and Welfare, Animal and Veterinary Science Research Group, SRUC, West Mains Rd, Edinburgh EH9 3JG, UK
* Contact for correspondence and requests for reprints:


Increasing litter size has long been a goal of pig breeders and producers, and may have implications for pig (Sus scrofa domesticus) welfare. This paper reviews the scientific evidence on biological factors affecting sow and piglet welfare in relation to large litter size. It is concluded that, in a number of ways, large litter size is a risk factor for decreased animal welfare in pig production. Increased litter size is associated with increased piglet mortality, which is likely to be associated with significant negative animal welfare impacts. In surviving piglets, many of the causes of mortality can also occur in non-lethal forms that cause suffering. Intense teat competition may increase the likelihood that some piglets do not gain adequate access to milk, causing starvation in the short term and possibly long-term detriments to health. Also, increased litter size leads to more piglets with low birth weight which is associated with a variety of negative long-term effects. Finally, increased production pressure placed on sows bearing large litters may produce health and welfare concerns for the sow. However, possible biological approaches to mitigating health and welfare issues associated with large litters are being implemented. An important mitigation strategy is genetic selection encompassing traits that promote piglet survival, vitality and growth. Sow nutrition and the minimisation of stress during gestation could also contribute to improving outcomes in terms of piglet welfare. Awareness of the possible negative welfare consequences of large litter size in pigs should lead to further active measures being taken to mitigate the mentioned effects.

Research Article
© 2013 Universities Federation for Animal Welfare

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Alonso-Spilsbury, M, Mota-Rojas, D, Villanueva-Garcia, D, Martinez-Burnes, J, Orozco, H, Ramirez-Necoechea, R, López Mayagoitia, A and Trujillo, ME 2005 Perinatal asphyxia pathophysiology in pig and human: a review. Animal Reproduction Science 90: 130CrossRefGoogle ScholarPubMed
Amarilyo, G, Oren, A, Mimouni, FB, Ochshorn, Y, Deutsch, V and Mandel, D 2011 Increased cord serum inflammatory markers in small-for-gestational-age neonates. Journal of Perinatology 31: 3032. ScholarPubMed
Andersen, IL, Naevdal, E and Boe, KE 2011 Maternal investment, sibling competition, and offspring survival with increasing litter size and parity in pigs (Sus scrofa). Behavioral Ecology and Sociobiology 65: 11591167. Scholar
Andersen, IL, Tajet, GM, Haukvik, IA, Kongsrud, S and BØe, KE 2007 Relationship between postnatal piglet mortality, environmental factors and management around farrowing in herds with loose-housed, lactating sows. Acta Agriculturae Scandinavica Section A-Animal Science 57: 3845. Scholar
Anderson, IL 1978 Growth, protein content and distribution of early pig embryos. Anatomical Record 190: 143154. ScholarPubMed
Antipatis, C, Finch, AM and Ashworth, CJ 2008 Effect of controlled alterations in maternal dietary retinol on foetal and neonatal retinol status and pregnancy outcome in pigs. Livestock Science 18: 247254. Scholar
Arango, J, Misztal, I, Tsuruta, S, Culbertson, M, Holl, JW and Herring, W 2006 Genetic study of individual preweaning mortality and birth weight in Large White piglets using threshold-linear models. Livestock Science 101: 208218. Scholar
Ashworth, CJ, Finch, AM, Page, KR, Nwagwu, MO and McArdle, HJ 2001 Causes and consequences of fetal growth retardation in pigs. Reproduction 58: 233246Google ScholarPubMed
Ashworth, CJ, Pickard, AR, Miller, SJ, Flint, APF and Diehl, JR 1997 Comparative studies of conceptus-endometrial interactions in Large White x Landrace and Meishan gilts. Reproduction, Fertility and Development 9: 217225. Scholar
Bauer, R, Gedrange, T, Bauer, K and Walter, B 2006 Intrauterine growth restriction induces increased capillary density and accelerated type I fiber maturation in newborn pig skeletal muscles. Journal of Perinatal Medicine 34: 235242. ScholarPubMed
Bauer, R, Walter, B, Bauer, K, Klupsch, R, Patt, S and Zwiener, U 2002 Intrauterine growth restriction reduces nephron number and renal excretory function in newborn piglets. Acta Physiologica Scandinavica 176: 8390. ScholarPubMed
Bauer, R, Walter, B, Hoppe, A, Gaser, E, Lampe, V, Kauf, E and Zwiener, U 1998 Body weight distribution and organ size in newborn swine (Sus scrofa domestica): a study describing an animal model for asymmetrical intrauterine growth retardation. Experimental Toxicology and Pathology 50: 5965. ScholarPubMed
Baxter, EM, Jarvis, S, D’Eath, RB, Ross, DW, Robson, SK, Farish, M, Nevison, IM, Lawrence, AB and Edwards, SA 2008 Investigating the behavioural and physiological indicators of neonatal survival in pigs. Theriogenology 69: 773783. ScholarPubMed
Baxter, EM, Jarvis, S, Sherwood, L, Farish, M, Roehe, R, Lawrence, AB and Edwards, SA 2011 Genetic and environmental effects of piglet survival and maternal behaviour of the farrowing sow. Applied Animal Behaviour Science 130: 2841. Scholar
Baxter, EM, Jarvis, S, Sherwood, L, Robson, SK, Ormandy, E, Farish, M, Smurthwaite, KM, Roehe, R, Lawrence, AB and Edwards, SA 2009 Indicators of piglet survival in an outdoor farrowing system. Livestock Science 124: 266276. Scholar
Baxter, EM, Rutherford, KMD, D’Eath, RB, Arnott, G, Turner, SP, SandØe, P, Moustsen, VA, Thorup, F, Edwards, SA and Lawrence, AB 2013 The welfare implications of large litter size in the domestic pig II: management factors. Animal Welfare 22: 219238. Scholar
Bazer, FW, Ford, JJ and Kensinger, RS 2001 Reproductive physiology. In: Pond, WG and Mersmann, HJ (eds) Biology of the Domestic Pig pp 150224. Cornell University Press: New York, USAGoogle Scholar
Biensen, NJ, Wilson, ME and Ford, SP 1998 The impact of either a Meishan or Yorkshire uterus on Meishan or Yorkshire fetal and placental development to days 70, 90, and 110 of gestation. Journal of Animal Science 76: 21692176CrossRefGoogle ScholarPubMed
Blasco, A, Bidanel, JP and Haley, CS 1995 Genetics and neonatal survival. In: Varley, MA (ed) The Neonatal Pig: Development and Survival pp 1738. CABI: Wallingford, UKGoogle Scholar
Bonde, M 2008 Prevalence of decubital shoulder lesions in Danish sow herds. Internal Report 12, Faculty of Agricultural Sciences, University of Aarhus, DenmarkGoogle Scholar
Bonica, JJ 1986 Pain of Parturition. Clinics in Anaesthesiology 4: 131CrossRefGoogle Scholar
Campos, PHRF, Silva, BAN, Donzele, JL, Oliveira, RFM and Knol, EF 2012 Effects of sow nutrition during gestation on with-in-litter birth weight variation: a review. Animal 6: 797806. ScholarPubMed
Canario, L, Cantoni, E, Le Bihan, E, Caritez, JC, Billon, Y, Bidanel, JP and Foulley, JL 2006a Between-breed variability of stillbirth and its relationship with sow and piglet characteristics. Journal of Animal Science 84: 31853196. Scholar
Canario, L, Roy, N, Gruand, J and Bidanel, JP 2006b Genetic variation of farrowing kinetics traits and their relationship with litter size and perinatal mortality in French Large White sows. Journal of Animal Science 84: 10531058CrossRefGoogle Scholar
Cecchinato, A, Bonfatti, V, Gallo, L and Carnier, P 2008 Survival analysis of preweaning piglet survival in a dry-cured ham-producing crossbred line. Journal of Animal Science 86: 24862495. Scholar
Chaloupkova, H, Illmann, G, Bartos, L and Spinka, M 2007 The effect of pre-weaning housing on the play and agonistic behaviour of domestic pigs. Applied Animal Behaviour Science 103: 2534. Scholar
Cogan, R and Spinatto, JA 1986 Pain and discomfort thresholds in late pregnancy. Pain 27: 6368. ScholarPubMed
Corino, C, Pastorelli, G, Rosi, F, Bontempo, V and Rossi, R 2009 Effect of dietary conjugated linoleic acid supplementation in sows on performance and immunoglobulin concentration in piglets. Journal of Animal Science 87: 22992305. ScholarPubMed
Corli, O, Grossi, E, Roma, G and Battagliarin, G 1986 Correlation between subjective labour pain and uterine contractions: a clinic study. Pain 26: 5360. Scholar
Couret, D, Jamin, A, Kuntz-Simon, G, Prunier, A and Merlot, E 2009b Maternal stress during late gestation has moderate but long-lasting effects on immune system of piglets. Veterinary Immunology and Immunopathology 131: 1724. Scholar
Couret, D, Prunier, A, Mounier, AM, Thomas, F, Oswald, IP and Merlot, E 2009a Comparative effects of prenatal stress occurring during early or late gestation on pig immune response. Physiology and Behavior 98: 498504. Scholar
Cromi, A, Ghezzi, F, Raffaelli, R, Bergamini, V, Siesto, G and Bolis, P 2009 Ultrasonographic measurement of thymus size in IUGR fetuses: a marker of the fetal immunoendocrine response to malnutrition. Ultrasound in Obstetrics and Gynecology 33: 421426. ScholarPubMed
D’Amato, FR, Rizzi, R and Moles, A 2006 Aggression and anxiety in pregnant mice are modulated by offspring characteristics. Animal Behaviour 72: 773780CrossRefGoogle Scholar
Damgaard, LH, Rydhmer, L, Lovendahl, P and Grandinson, K 2003 Genetic parameters for within-litter variation in piglet birth weight and change in within-litter variation during suckling. Journal of Animal Science 81: 604610CrossRefGoogle ScholarPubMed
Damm, BI, Friggens, NC, Nielsen, J, Ingvartsen, KL and Pedersen, LJ 2002 Factors affecting the transfer of porcine parvovirus antibodies from sow to piglets. Journal Of Veterinary Medicine Series A-Physiology Pathology Clinical Medicine 49: 487495. ScholarPubMed
Da Silva-Buttkus, P, van den Hurk, R, te Velde, ER and Taverne, MA 2003 Ovarian development in intrauterine growth-retarded and normally developed piglets originating from the same litter. Reproduction 126: 249258. ScholarPubMed
D’Eath, RB 2005 Socialising piglets before weaning improves social hierarchy formation when pigs are mixed post-weaning. Applied Animal Behaviour Science 93: 199211CrossRefGoogle Scholar
D’Eath, RB and Lawrence, AB 2004 Early life predictors of the development of aggressive behaviour in the domestic pig. Animal Behaviour 67: 501509Google Scholar
D’Eath, RB, Conington, J, Lawrence, AB, Olsson, IAS and SandØe, P 2010 Breeding for behavioural change in farm animals: practical, economic and ethical considerations. Animal Welfare 19(S1): 1727Google Scholar
D’Eath, RB, Tolkamp, BJ, Kyriazakis, I and Lawrence, AB 2009 ‘Freedom from hunger’ and preventing obesity: the animal welfare implications of reducing food quantity or quality. Animal Behaviour 77: 275288CrossRefGoogle Scholar
D’Inca, R, Gras-Le Guen, C, Che, L, Sangild, PT and Le Huërou-Luron, I 2011 Intrauterine growth restriction delays feeding-induced gut adaptation in term newborn pigs. Neonatology 99: 208216CrossRefGoogle ScholarPubMed
De Jong, G and Bijma, P 2002 Selection and phenotypic plasticity in evolutionary biology and animal breeding. Livestock Production Science 78: 195214. Scholar
Dekkers, JCM, Mathur, PK and Knol, EF 2011 Genetic improvement of the pig. In: Rothschild, MF and Ruvinsky, A (eds) The Genetics of the Pig pp 390425. CABI: Wallingford, UK. Scholar
De Passillé, AMB and Rushen, J 1989 Suckling and teat disputes by neonatal piglets. Applied Animal Behaviour Science 22: 2338. Scholar
De Passillé, AMB, Rushen, J and Hartsock, TG 1988 Ontogeny of teat fidelity in pigs and its relation to competition at suckling. Canadian Journal of Animal Science 68: 325338. Scholar
Devillers, N, Farmer, C, Le Dividich, J and Prunier, A 2007 Variability of colostrum yield and colostrum intake in pigs. Animal 1: 10331041. ScholarPubMed
Devillers, N, LeDividich, J and Prunier, A 2011 Influence of colostrum intake on piglet survival and immunity. Animal 5: 16051612. ScholarPubMed
Dimitsantos, E, Escorihuela, RM, Fuentes, S, Armario, A and Nadal, R 2007 Litter size affects emotionality in adult male rats. Physiology and Behavior 92: 708716. ScholarPubMed
Dziuk, PJ 1985 Effects of migration, distribution and spacing of pig embryos on pregnancy and fetal survival. Journal of Reproduction and Fertility, Supplement 33: 5763Google Scholar
Eder, K, Ramanau, A and Kluge, H 2001 Effect of L-carnitine supplementation on performance parameters in gilts and sows. Journal of Animal Physiology and Animal Nutrition 85: 7380. ScholarPubMed
Edwards, SA 2002 Perinatal mortality in the pig: environmental or physiological solutions? Livestock Production Science 78: 312. Scholar
Edwards, SA 2005 Enhancing sow performance and welfare by choice of dietary energy substrates. Biotechnology in Animal Husbandry 21: 149154. Scholar
English, PR and Smith, WJ 1975 Some causes of death in neonatal piglets. Veterinary Annals 15: 95104Google Scholar
Farmer, C and Quesnel, H 2009 Nutritional, hormonal, and environmental effects on colostrum in sows. Journal of Animal Science 87: 5664. ScholarPubMed
Farmer, C and Robert, S 2003 Hormonal, behavioural and performance characteristics of Meishan sows during pregnancy and lactation. Canadian Journal of Animal Science 83: 112. Scholar
Farmer, C, Robert, S, Matte, JJ, Girard, CL and Martineau, GP 1995 Endocrine and peripartum behavioural responses of sows fed high fiber diets during gestation. Canadian Journal of Animal Science 75: 531536. Scholar
Ferguson, EM, Slevin, J, Edwards, SA, Hunter, MG and Ashworth, CJ 2006 Effect of alterations in the quantity and composition of the pre-mating diet on embryo survival and foetal growth in the pig. Animal Reproductions Science 96: 89103. ScholarPubMed
Ferguson, EM, Slevin, J, Edwards, SA, Hunter, MG and Ashworth, CJ 2007 Beneficial effects of a high fibre diet on oocyte maturity and embryo survival in gilts. Reproduction 133: 433439. ScholarPubMed
Finch, AM, Antipatis, C, Pickard, AR and Ashworth, CJ 2002 Patterns of fetal growth within Large White x Landrace and Chinese Meishan gilt litters at three stages of gestation. Reproduction, Fertility and Development 14: 419425. Scholar
Fix, JS, Cassady, JP, Holl, JW, Herring, WO, Culbertson, MS and See, MT 2010 Effect of piglet birth weight on survival and quality of commercial market swine. Livestock Science 132: 98106. Scholar
Foxcroft, GR, Dixon, WT, Novak, S, Putman, CT, Town, SC and Vinsky, MDA 2006 The biological basis for prenatal programming of postnatal performance in pigs. Journal of Animal Science 84: E105E112CrossRefGoogle ScholarPubMed
Fraser, D 1975 The ‘teat order’ of suckling pigs II. Fighting during suckling and the effects of clipping the eye teeth. Journal of Agricultural Science 84: 393399. Scholar
Fraser, D 1980 A review of the behavioural mechanism of milk ejection of the domestic pig. Applied Animal Ethology 6: 247255. Scholar
Fraser, D 1990 Behavioural perspectives on piglet survival.Journal of Reproduction and Fertility. Supplement 40: 355370Google Scholar
Fraser, D and Rushen, J 1992 Colostrum intake by newborn piglets. Canadian Journal Of Animal Science 72: 113. Scholar
Fraser, D, Kramer, DL, Pajor, EA and Weary, DM 1995 Conflict and cooperation: sociobiological principles and the behaviour of pigs. Applied Animal Behaviour Science 44: 139157. Scholar
Gardner, IA, Hird, DW and Franti, CE 1989 Neonatal survival in swine: effects of low birth weight and clinical disease. American Journal of Veterinary Research 50: 792797Google ScholarPubMed
Gaskin, HR and Kelly, KW 1995 Immunology and neonatal mortality. In: Varley, MA (ed) The Neonatal Pig. Development and Survival pp 3956. CABI: Wallingford, UKGoogle Scholar
Geisert, RD and Schmitt, RAM 2002 Early embryonic survival in the pig: can it be improved? Journal of Animal Science 80: E54E65Google Scholar
Geisert, RD, Morgan, GL, Zavy, MT, Blair, RM, Gries, LK, Cox, A and Yellin, T 1991 Effect of asynchronous transfer and oestrogen administration on survival and development of porcine embryos. Journal of Reproduction and Fertility 93: 475481. ScholarPubMed
Gieling, ET, Park, SY, Nordquist, RE and van der Staay, FJ 2011 Cognitive performance of low- and normal-birth-weight piglets in a spatial hole-board discrimination task. Pediatric Research 71: 7176. Scholar
Gill, JC and Thomson, W 1956 Observations on the behaviour of suckling pigs. The British Journal of Animal Behaviour 4: 4651. Scholar
Gintzler, AR 1980 Endorphin-mediated increases in pain threshold during pregnancy. Science 210: 193195. ScholarPubMed
Grandinson, K 2003 Genetic aspects of maternal ability in sows. Doctoral dissertation, Swedish University of Agricultural Sciences, Uppsala, SwedenGoogle Scholar
Grandinson, K, Lund, MS, Rydhmer, L and Strandberg, E 2002 Genetic parameters for the piglet mortality traits crushing, stillbirth and total mortality and their relation to birth weight. Acta Scandinavia, A. Animal Science 52: 167173Google Scholar
Haley, CS, Lee, GJ and Ritchie, M 1995 Comparative reproductive performance in Meishan and Large White pigs and their crosses. Animal Science 60: 259267. Scholar
Hall, AD, Lo, S and Rance, KA 2002 Comparative study of the lifetime productivity and performance characteristics of Meishan and Duroc cross-bred pigs. Acta Agriculturae Scandinavica, Section A. Animal Science 52: 183188Google Scholar
Handel, SE and Stickland, NC 1987 The effects of low-birth-weight on the ultrastructural development of 2 myofiber types in the pig. Journal of Anatomy 150: 129143Google Scholar
Hartsock, TG and Graves, HB 1976 Neonatal behavior and nutrition-related mortality in domestic swine. Journal of Animal Science 42: 235241CrossRefGoogle ScholarPubMed
Haussmann, MF, Carroll, JA, Weesner, GD, Daniels, MJ, Matteri, RL and Lay, DC 2000 Administration of ACTH to restrained, pregnant sows alters their pigs hypothalamic-pituitary-adrenal (HPA) axis. Journal of Animal Science 78: 23992411CrossRefGoogle ScholarPubMed
Haussmann, MF, Lay, DC Jr, Buchanan, HS and Hopper, JG 1999 Butorphanol tartrate acts to decrease sow activity, which could lead to reduced pig crushing. Journal of Animal Science 77: 20542059CrossRefGoogle ScholarPubMed
Hayashi, M, Ingram, DL and Dauncey, MJ 1987 Heat production and respiratory enzymes in normal and runt newborn piglets. Biology of the Neonate 51: 324331. ScholarPubMed
Held, SDE and Špinka, M 2011 Animal play and animal welfare. Animal Behaviour 81: 891899. Scholar
Hellbrügge, B, Tolle, KH, Bennewitz, J, Henze, C, Presuhn, U and Krieter, J 2008 Genetic aspects regarding piglet losses and the maternal behaviour of sows. Part 1. Genetic analysis of piglet mortality and fertility traits in pigs. Animal 2: 12731280Google ScholarPubMed
Hemsworth, PH, Barnett, JL, Coleman, GJ and Hansen, C 1989 A study of the relationship between the attitudinal and behavioural profiles of stockpersons and the level of fear of humans and reproductive performance of commercial pigs. Applied Animal Behaviour Science 23: 301314. Scholar
Hemsworth, PH, Brand, A and Willems, P 1981 The behavioural response of sows to the presence of human beings and its relationship to productivity. Livestock Production Science 8: 6774. Scholar
Hemsworth, PH, Coleman, GJ, Cronin, GM and Spicer, EM 1995 Human care and the neonatal pig. In: Varley, MA (ed) The Neonatal Pig: Development and Survival pp 313331. CABI: Wallingford, UKGoogle Scholar
Hemsworth, PH, Pedersen, V, Cox, M, Cronin, GM and Coleman, GJ 1999 A note on the relationship between the behavioural response of lactating sows to humans and survival of piglets. Applied Animal Behaviour Science 65: 4352. Scholar
Herpin, P, Damon, M and Le Dividich, J 2002 Development of thermoregulation and neonatal survival in pigs. Livestock Production Science 78: 2545. Scholar
Herpin, P, Le Dividich, J and Amaral, N 1993 Effect of selection for lean tissue growth on body composition and physiological state of the pig at birth. Journal of Animal Science 71: 26452653CrossRefGoogle ScholarPubMed
Herpin, P, Le Dividich, J, Hulin, JC, Fillaut, M, DeMarco, F and Bertin, R 1996 Effects of the level of asphyxia during delivery on viability at birth and early postnatal vitality of newborn pigs. Journal of Animal Science 74: 20672075CrossRefGoogle ScholarPubMed
Herskin, MS, Bonde, MK, JØrgensen, E and Jensen, KH 2011 Decubital shoulder ulcers in sows: a review of classification, pain and welfare consequences. Animal 5: 757766. ScholarPubMed
Hirooka, H, de Koning, DJ, Harlizius, B, van Arendonk, JA, Rattink, AP, Groenen, MA, Brascamp, EW and Bovenhuis, H 2001 A whole-genome scan for quantitative trait loci affecting teat number in pigs. Journal of Animal Science 79: 23202326CrossRefGoogle ScholarPubMed
Holl, JW and Johnson, RK 2005 Incidence of splayleg pigs in Nebraska litter size selection lines. Journal of Animal Science 83: 3440CrossRefGoogle ScholarPubMed
Janczak, AM, Braastad, BO and Bakken, M 2000 Fear-related behaviour in two mouse strains differing in litter size. Animal Welfare 9: 2538Google Scholar
Jarvis, S, McLean, KA, Chirnside, J, Deans, LA, Calvert, SK, Molony, V and Lawrence, AB 1997 Opioid-mediated changes in nociceptive threshold during pregnancy and parturition in the sow. Pain 72: 153159. ScholarPubMed
Jarvis, S, Moinard, C, Robson, SK, Baxter, E, Ormandy, E, Douglas, AJ, Seckl, JR, Russell, JA and Lawrence, AB 2006 Programming the offspring of the pig by prenatal social stress: neuroendocrine activity and behaviour. Hormones and Behavior 49: 6880. ScholarPubMed
Jean, KB and Chiang, SH 1999 Increased survival of neonatal pigs by supplementing medium-chain triglycerides in late-gestating sow diets. Animal Feed Science and Technology 76: 241250. Scholar
Johnson, RK, Nielsen, MK and Casey, DS 1999 Responses in ovulation rate, embryonic survival, and litter traits in swine to 14 generations of selection to increase litter size. Journal of Animal Science 77: 541557CrossRefGoogle Scholar
Kapell, DNRG, Ashworth, CJ, Knap, PW and Roehe, R 2011 Genetic parameters for piglet survival, litter size and birth weight or its variation within litter in sire and dam lines using Bayesian analysis. Livestock Science 135: 215224. Scholar
Kapell, DNRG, Ashworth, CJ, Walling, GA, Lawrence, AB, Edwards, SA and Roehe, R 2009 Estimation of genetic associations between reproduction and production traits based on a sire and dam line with common ancestry. Animal 3: 13541362. ScholarPubMed
Kerr, JC and Cameron, ND 1995 Reproductive performance of pigs selected for components of efficient lean growth. Animal Science 60: 281290. Scholar
Klemcke, HG, Lunstra, DD, Brown-Borg, HM, Borg, KE and Christenson, RK 1993 Association between low birth weight and increased adrenocortical function in neonatal pigs. Journal of Animal Science 71: 10101018CrossRefGoogle ScholarPubMed
Knap, PW 2005 Breeding robust pigs. Australian Journal of Experimental Agriculture 45: 763773. Scholar
Knap, PW and Bishop, SC 2000 Relationships between genetic change and infectious disease in domestic livestock. In: Hill, WG, Bishop, SC, McGuirk, B, McKay, JC, Simm, G and Webb, AJ (eds) The Challenge of Genetic Change in Animal Production pp 6580. British Society of Animal Science: Edinburgh, UKGoogle Scholar
Knol, EF, Ducro, BJ, Van Arendonk, JAM and van der Lende, T 2002a Direct, maternal and nurse sow genetic effects on farrowing, pre-weaning and total piglet survival. Livestock Production Science 73: 153164. Scholar
Knol, EF, Leenhouwers, JI and Van der Lende, T 2002b Genetic aspects of piglet survival. Livestock Production Science 78: 4755. Scholar
Kolmodin, R and Bijma, P 2004 Response to mass selection when the genotype by environment interaction is modelled as a linear reaction norm. Genetics Selection Evolution 36: 435454. ScholarPubMed
Krackow, S 1997 Further evaluation of the developmental asynchrony hypothesis of sex ratio variation. Applied Animal Behaviour Science 51: 243250. Scholar
Kranendonk, G, Hopster, H, Fillerup, M, Ekkel, ED, Mulder, EJ, Wiegant, VM and Taverne, MA 2006 Lower birth weight and attenuated adrenocortical response to ACTH in offspring from sows that orally received cortisol during gestation. Domestic Animal Endocrinology 30: 218238. ScholarPubMed
Larson, G, Cucchi, T and Dobney, K 2011 Genetic aspects of pig domestication. In: Rothschild, MF and Ruvinsky, A (eds) The Genetics of the Pig pp 1437. CABI: Wallingford, UKCrossRefGoogle Scholar
Lawrence, AB, Petherick, JC, McLean, K, Gilbert, CL, Chapman, C and Russell, JA 1992 Naloxone prevents interruption of parturition and increases plasma oxytocin following environmental disturbance in parturient sows. Physiology and Behavior 52: 917923CrossRefGoogle ScholarPubMed
Laws, J, Litten, JC, Laws, A, Lean, IJ, Dodds, PF and Clarke, L 2009 Effect of type and timing of oil supplements to sows during pregnancy on the growth performance and endocrine profile of low and normal birth weight offspring. British Journal of Nutrition 101: 240249. ScholarPubMed
Lay, DC, Kattesh, HG, Cunnick, JE, Daniels, MJ, McMunn, KA, Toscano, MJ and Roberts, MP 2008 Prenatal stress effects on pig development and response to weaning. Journal of Animal Science 86: 13161324. ScholarPubMed
Lay, DC, Matteri, RL, Carroll, JA, Fangman, TJ and Safranski, TJ 2002 Preweaning survival in swine. Journal of Animal Science 80: E74E86Google Scholar
Le Dividich, J, Mormède, P, Catheline, M and Caritez, JC 1991 Body composition and cold resistance of the neonatal pig from European (Large White) and Chinese (Meishan) breeds. Biology of the Neonate 59: 268274. ScholarPubMed
Le Dividich, J, Rooke, JA and Herpin, P 2005 Nutritional and immunological importance of colostrum for the new-born pig. Journal of Agricultural Science 143: 469485. Scholar
Lee, GJ and Haley, CS 1995 Comparative farrowing to weaning performance in Meishan and Large White pigs and their crosses. Animal Science 60: 269280. Scholar
Leenhouwers, JI, van der Lende, T and Knol, EF 1999 Analysis of stillbirth in different lines of pig. Livestock Production Science 57: 243253. Scholar
Leonard, SG, Sweeney, T, Bahar, B, Pierce, KM, Lynch, BP and O’Doherty, JV 2010 The effects of maternal dietary supplementation with seaweed extract and fish oil on the humoral immune response and performance of suckling piglets. Livestock Science 134: 211214CrossRefGoogle Scholar
Litten, JC, Drury, PC, Corson, AM, Lean, IJ and Clarke, L 2003 The influence of piglet birth weight on physical and behavioural development in early life. Biology of the Neonate 84: 311318. ScholarPubMed
Long, HF, Ju, WS, Piao, LG and Kim, YY 2010 Effect of dietary energy levels of gestating sows on physiological parameters and reproductive performance. Asian-Australasian Journal of Animal Science 23: 10801088. Scholar
Lund, MS, Puonti, M, Rydhmer, L and Jensen, J 2002 Relationship between litter size and perinatal and pre-weaning survival in pigs. Animal Science 74: 217222CrossRefGoogle Scholar
Mainau, E and Manteca, X 2011 Pain and discomfort caused by parturition in cows and sows. Applied Animal Behaviour Science 135: 241251. Scholar
Mainau, E, Dalmau, A, Ruiz-de-la-Torre, JL and Manteca, X 2010 A behavioural scale to measure ease of farrowing in sows. Theriogenology 74: 12791287. ScholarPubMed
Marchant-Forde, JN 2009 Welfare of dry sows. In: Marchant-Forde, JN (ed) The Welfare of Pigs pp 95139. Springer: Berlin, Germany. Scholar
Mark, T and SandØe, P 2010 Genomic dairy cattle breeding: risks and opportunities for cow welfare. Animal Welfare 19: 113121Google Scholar
McDade, TW, Beck, MA, Kuzawa, C and Adair, LS 2001 Prenatal undernutrition, postnatal environments, and antibody response to vaccination in adolescence. American Journal of Clinical Nutrition 74: 543545CrossRefGoogle ScholarPubMed
Mellor, DJ 2010 Galloping colts, fetal feelings, and reassuring regulations: putting animal-welfare science into practice. Journal of Veterinary Medical Education 37: 94100. Scholar
Melzack, R 1992 Labour pain as a model of acute pain. Pain 53: 117120. Scholar
Merks, JWM, Mathur, PK and Knol, EF 2010 New phenotypes for new breeding goals in pigs. Proceedings of the 61st Annual Meeting of the European Association for Animal Production. 23-27 August 2010, Heraklion, Crete, GreeceGoogle Scholar
Meunier-Salaün, MC, Gort, F, Prunier, A and Schouten, WPG 1991 Behavioural patterns and progesterone, cortisol and prolactin levels around parturition in European (Large-White) and Chinese (Meishan) sows. Applied Animal Behaviour Science 31: 4359. Scholar
Miles, JR, Vallet, JL, Ford, JJ, Freking, BA, Cushman, RA, Oliver, WT and Rempel, LA 2012 Contributions of the maternal uterine environment and piglet genotype on weaning survivability potential: I. Development of neonatal piglets after reciprocal embryo transfers between Meishan and White crossbred gilts. Journal of Animal Science 90: 21812192. ScholarPubMed
Milligan, BN, Fraser, D and Kramer, DL 2001 The effect of littermate weight on survival, weight gain, and suckling behavior of low-birth-weight piglets in cross-fostered litters. Journal of Swine Health and Production 9: 161166Google Scholar
Milligan, BN, Fraser, D and Kramer, DL 2002 Within-litter birth weight variation in the domestic pig and its relation to pre-weaning survival, weight gain, and variation in weaning weights. Livestock Production Science 76: 181191. Scholar
Mollard, RC, Kohut, J, Zhao, JP and Weiler, HA 2004 Proximal intestinal absorption of calcium is elevated in proportion to growth rate but not bone mass is small for gestational age piglets. Journal of Nutritional Biochemistry 15: 149154. Scholar
Moore, SE, Cole, TJ, Collinson, AC, Poskitt, EME, McGregor, IA and Prentice, AM 1999 Prenatal or early postnatal events predict infectious deaths in young adulthood in rural Africa. International Journal of Epidemiology 28: 10881095. ScholarPubMed
Morgane, PJ, Austinlafrance, R, Bronzino, J, Tonkiss, J, Diazcintra, S, Cintra, L, Kemper, T and Galler, JR 1993 Prenatal malnutrition and development of the brain. Neuroscience and Biobehavioral Reviews 17: 91128. ScholarPubMed
Morise, A, Louveau, I and Le Huërou-Luron, I 2008 Growth and development of adipose tissue and gut and related endocrine status during early growth in the pig: impact of low birth weight. Animal 2: 7383. ScholarPubMed
Mormède, P, Foury, A, Terenina, E and Knap, PW 2011 Breeding for robustness: the role of cortisol. Animal 5: 651657. ScholarPubMed
Mota-Rojas, D, Martinez-Burnes, J, Trujillo-Ortega, ME, Alonso-Spilsbury, M, Ramirez-Necoechea, R and Lopez, A 2002 Effect of oxytocin treatment in sows on umbilical cord morphology, meconium staining, and neonatal mortality of piglets. American Journal of Veterinary Research 63: 15711574. ScholarPubMed
Mota-Rojas, D, Rosales, AM, Trujillo, ME, Orozco, H, Ramirez, R and Alonso-Spilsbury, M 2005 The effects of vetrabutin chlorhydrate and oxytocin on stillbirth rate and asphyxia in swine. Theriogenology 64: 18891897. ScholarPubMed
Mota-Rojas, D, Trujillo-Ortega, ME, Villanueva-Garcia, D, González-Lozano, M, Orozco-Gregorio, H, Ramirez-Necoechea, R, Olmos-Hernández, A and Alonso-Spilsbury, M 2006 Can uterotonics reduce fetal and newborn piglet mortality by perinatal asphyxia and improve functional vitality? Journal of Medical Sciences 6: 884893. Scholar
Mulder, HA, Bijma, P and Hill, WG 2008 Selection for uniformity in livestock by exploiting genetic heterogeneity of residual variance. Genetics Selection Evolution 40: 3759Google ScholarPubMed
Munsterhjelm, C, Valros, A, Heinonen, M, Hälli, O, Siljander-Rasi, H and Peltoniemi, OAT 2010 Environmental enrichment in early life affect cortisol patterns in growing pigs. Animal 4: 242249. Scholar
Musser, RE, Goodband, RD, Tokach, MD, Owen, KQ, Nelssen, JL, Blum, SA, Dritz, SS and Civis, CA 1999 Effects of L-carnitine fed during gestation and lactation on sow and litter performance. Journal of Animal Science 77: 32893295CrossRefGoogle ScholarPubMed
Newberry, RC and Wood-Gush, DGM 1985 The suckling behaviour of domestic pigs in a semi-natural environment. Behaviour 95: 1125. Scholar
Nielsen, B, Su, G, Lund, MS and Madsen, P 2013 Selection for increased number of piglets at day five after farrowing has increased litter size and reduced piglet mortality. Journal of Animal Science. Scholar
Norring, M, Valros, A, Munksgaard, L, Puumala, M, Kaustell, KO and Saloniemi, H 2006 The development of skin, claw and teat lesions in sows and piglets in farrowing crates with two concrete flooring materials. Acta Agriculturae Scandinavica Section A. Animal Science 56: 148154Google Scholar
Oostindjer, M, Bolhuis, JE, van den Brand, H, Roura, E and Kemp, B 2010 Prenatal flavor exposure affects growth, health and behavior of newly weaned piglets. Physiology and Behavior 99: 579586. ScholarPubMed
Otten, W, Kanitz, E, Tuchscherer, M, Puppe, B and Nurnberg, G 2007 Repeated administrations of adrenocorticotropic hormone during gestation in gilts: effects on growth, behaviour and immune responses of their piglets. Livestock Science 106: 261270. Scholar
Pedersen, LJ, Berg, P, JØrgensen, G and Andersen, IL 2011a Neonatal traits of importance for survival in crates and indoor pens. Journal of Animal Science 89: 12071218. Scholar
Pedersen, ML, Moustsen, VA, Nielsen, MBF and Kristensen, AR 2011b Improved udder access prolongs duration of milk letdown and increases piglet weight gain. Livestock Science 140: 253261. Scholar
Perry, JS and Rowell, JG 1969 Variations in foetal weight and vascular supply along uterine horn of pig. Journal of Reproduction and Fertility 19: 527534. ScholarPubMed
Poore, KR and Fowden, AL 2003 The effect of birth weight on hypothalamic-pituitary-adrenal axis function in juvenile and adult pigs. Journal of Physiology 547: 107116. Scholar
Poore, KR, Forhead, AJ, Gardner, DS, Giussani, DA and Fowden, AL 2002 The effects of birth weight on basal cardiovascular function in pigs at 3 months of age. Journal of Physiology 15: 969978. Scholar
Pope, WF 1994 Embryonic mortality in swine. In: Geisert, RD and Zavy, MT (eds) Embryonic Mortality in Domestic Species pp 5378. CRC Press: Boca Raton, USAGoogle Scholar
Prager, G, Stefanski, V, Hudson, R and Rödel, H 2010 Family matters: maternal and litter-size effects on immune parameters in young laboratory rats. Brain, Behavior and Immunity 24: 13711378. ScholarPubMed
Prunier, A, Heinonen, M and Quesnel, H 2010 High physiological demands in intensively raised pigs: impact on health and welfare. Animal 4: 886898. ScholarPubMed
Pumfrey, RA, Johnson, RK, Cunningham, PJ and Zimmerman, DR 1980 Inheritance of teat number and its relationship to maternal traits in swine. Journal of Animal Science 50: 10571060CrossRefGoogle ScholarPubMed
Quesnel, H 2011 Colostrum production by sows: variability of colostrum yield and immunoglobulin G concentrations. Animal 5: 15461553. ScholarPubMed
Quesnel, H and Prunier, A 1995 Endocrine bases of lactational anoestrus in the sow. Reproduction Nutrition and Development 35: 395414. ScholarPubMed
Quesnel, H, Brossard, L, Valancogne, A and Quiniou, N 2008 Influence of some sow characteristics on within-litter variation of piglet birth weight. Animal 2: 18421849. ScholarPubMed
Quesnel, H, Farmer, C and Devillers, N 2012 Colostrum intake: influence on piglet performance and factors of variation. Livestock Science 146: 105114. Scholar
Quiniou, N, Dagorn, J and Gaudre, D 2002 Variation of piglets birth weight and consequences on subsequent performance. Livestock Production Science 78: 6370. Scholar
Randall, GCB 1972 Observations on parturition in the sow I. Factors associated with the delivery of the piglets and their subsequent behaviour. Veterinary Record 90: 178182. Scholar
Reese, D, Prosch, A, Travnicek, DA and Eskridge, KM 2008 Dietary fibre in sow gestation diets: an updated review. Nebraska Swine Report 2008: 1418Google Scholar
Rodenburg, TB, Bijma, P, Ellen, ED, Bergsma, R, de Vries, S, Bolhuis, JE, Kemp, B and van Arendonk, JAM 2010 Breeding amiable animals? Improving farm animal welfare by including social effects in breeding programmes. Animal Welfare 19(S): 7782Google Scholar
Roehe, R 1991 Development of optimal selection strategies when using an animal model in the nucleus of swine breeding programs. PhD Thesis, University of Kiel, GermanyGoogle Scholar
Roehe, R 1999 Genetic determination of individual birthweight and its association with sows’ productivity traits using Bayesian analysis. Journal of Animal Science 77: 330343CrossRefGoogle Scholar
Roehe, R and Kalm, E 2000 Estimation of genetic and environmental risk factors associated with pre-weaning mortality in piglets using generalized linear mixed models. Animal Science 70: 227240CrossRefGoogle Scholar
Roehe, R, Shrestha, NP, Mekkawy, W, Baxter, EM, Knap, PW, Smurthwaite, KM, Jarvis, S, Lawrence, AB and Edwards, SA 2009 Genetic analysis of piglet survival and individual birth weight of first generation data of a selection experiment for piglet survival under outdoor conditions. Livestock Science 121: 173181. Scholar
Roehe, R, Shrestha, NP, Mekkawy, W, Baxter, EM, Knap, PW, Smurthwaite, KM, Jarvis, S, Lawrence, AB and Edwards, SA 2010 Genetic parameters of piglet survival and birth weight from a two-generation crossbreeding experiment under outdoor conditions designed to disentangle direct and maternal effects. Journal of Animal Science 88: 12761285. ScholarPubMed
Romano, T, Wark, JD, Owens, JA and Wlodek, ME 2009 Prenatal growth restriction and postnatal growth restriction followed by accelerated growth independently program reduced bone growth and strength. Bone 45: 132141. ScholarPubMed
Rooke, JA, Sinclair, AG, Edwards, SA, Cordoba, R, Pkiyach, S, Penny, PC, Penny, P, Finch, AM and Horgan, GW 2001 The effect of feeding salmon oil to sows throughout pregnancy on pre-weaning mortality of piglets. Animal Science 73: 489500CrossRefGoogle Scholar
Rosendo, A, Druet, T, Gogué, J, Canario, L and Bidanel, JP 2007 Correlated responses for litter traits to six generations of selection for ovulation rate or prenatal survival in French Large White pigs. Journal of Animal Science 85: 16151624. ScholarPubMed
Rutherford, KMD, Baxter, EM, Ask, B, Berg, P, D’Eath, RB, Jarvis, S, Jensen, KK, Lawrence, AB, Moustsen, VA, Robson, SK, Roehe, R, Thorup, F, Turner, SP and SandØe, P 2011 The ethical and welfare implications of large litter size in the domestic pig: challenges and solutions. Project report 17, Danish Centre for Bioethics, Denmark and Risk Assessment and Scottish Agricultural College, UKGoogle Scholar
Rutherford, KMD, Robson, SK, Donald, RD, Jarvis, S, Sandercock, DA, Nolan, AM and Lawrence, AB 2009 Prenatal stress amplifies spontaneous behavioural responses to acute pain in the neonatal pig. Biology Letters 5: 452454. Scholar
Rydhmer, L, Lundeheim, N and Canario, L 2008 Genetic correlations between gestation length, piglet survival and early growth. Livestock Science 115: 287293. Scholar
Scheel, DE, Graves, HB and Sherritt, GW 1977 Nursing order, social dominance, and growth in swine. Journal of Animal Science 45: 219229CrossRefGoogle Scholar
Sellier, P and Ollivier, L 1982 A genetic study of splayleg in the new-born piglet I. Multifactorial model with one threshold. Annales de Genetique et de Selection Animale 14: 7792. Scholar
Sinclair, AG, Edwards, SA, Hoste, S and McCartney, A 1998 Evaluation of the influence of maternal and piglet breed differences on behaviour and production of Meishan synthetic and European White breeds during lactation. Animal Science 66: 423430. Scholar
Smulders, FJM 2009 A practicable approach to assessing risks for animal welfare: methodological considerations. In: Smulders, FJM and Algers, B (eds) Welfare of Production Animals: Assessment and Management of Risks pp 239274. Wageningen Academic Publishers: Wageningen, The NetherlandsCrossRefGoogle Scholar
SØrensen, D, Vernersen, A and Andersen, S 2000 Bayesian analysis of response to selection: a case study using litter size in Danish Yorkshire pigs. Genetics 156: 283295CrossRefGoogle ScholarPubMed
Spötter, A and Distl, O 2006 Genetic approaches to the improvement of fertility traits in the pig. The Veterinary Journal 172: 234247. Scholar
Star, L, Ellen, ED, Uitdehaag, K and Brom, FWA 2008 A plea to implement robustness into a breeding goal: Poultry as an example. Journal of Agricultural and Environmental Ethics 21: 109125. Scholar
Strange, T 2011 Genetic parameters of piglet mortality traits in Danish crossbred pigs. Masters Thesis, University of Copenhagen, Faculty of Life Sciences, Department of Basic Animal and Veterinary Sciences, DenmarkGoogle Scholar
Su, G, Lund, MS and SØrensen, D 2007 Selection for litter size at day five to improve litter size at weaning and piglet survival rate. Journal of Animal Science 85: 13851392. ScholarPubMed
Su, G, SØrensen, D and Lund, MS 2008 Variance and covariance components for liability of piglet survival during different periods. Animal 2: 184189. ScholarPubMed
Svendsen, LS, Westrom, BR, Svendsen, J, Olsson, AC and Karlsson, BW 1991 Blood serum characteristics of newborn pigs: comparison of unaffected pigs with pigs belonging to five mortality groups. Acta Veterinaria Scandinavica 32: 287299CrossRefGoogle ScholarPubMed
Taylor, G, Roese, G and Hermesch, S 2005 Breeds of pigs: Large White. Primefact 62. New South Wales Department of Primary Industries: Orange, New South Wales, AustraliaGoogle Scholar
Tomiyama, M, Kubo, S, Takagi, T and Suzuki, K 2011 Evaluation of genetic trends and determination of the optimal number of cumulative records of parity required in reproductive traits in a Large White pig population. Animal Science Journal 82: 621626. Scholar
Tuchscherer, M, Kanitz, E, Otten, W and Tuchscherer, A 2002 Effects of prenatal stress on cellular and humoral immune responses in neonatal pigs. Veterinary Immunology and Immunopathology 86: 195203. ScholarPubMed
Tuchscherer, M, Puppe, B, Tuchscherer, A and Tiemann, U 2000 Early identification of neonates at risk: Traits of newborn piglets with respect to survival. Theriogenology 54: 371388. ScholarPubMed
Turner, SP, Farnworth, MJ, White, IMS, Brotherstone, S, Mendl, M, Knap, P, Penny, P and Lawrence, AB 2006 The accumulation of skin lesions and their use as a predictor of individual aggressiveness in pigs. Applied Animal Behaviour Science 96: 245259. Scholar
Uvnäs-Moberg, K 1989 The gastrointestinal-tract in growth and reproduction. Scientific American 261: 7883. ScholarPubMed
Van den Brand, H, Soede, NM and Kemp, B 2006 Supplementation of dextrose to the diet during the weaning to estrus interval affects subsequent variation in within-litter piglet birth weight. Animal Reproduction Science 91: 353358. Scholar
Van den Brand, H, van Enckewort, LCM, van der Hoeven, EM and Kemp, B 2009 Effects of dextrose plus lactose in the sows diet on subsequent reproductive and within litter birth weight variation. Reproduction in Domestic Animals 44: 884888. ScholarPubMed
Vanderhaeghe, C, Dewulf, J, DeVliegher, S, Papdopoulos, GA, deKruif, A and Maes, D 2010a Longitudinal field study to assess sow level risk factors associated with stillborn piglets. Animal Reproduction Science 120: 7883. Scholar
Vanderhaeghe, C, Dewulf, J, Jourquin, J, deKruif, A and Maes, D 2011 Incidence and prevention of early parturition in sows. Reproduction in Domestic Animals 46: 428433. ScholarPubMed
Vanderhaeghe, C, Dewulf, J, Ribbens, S, deKruif, A and Maes, D 2010b A cross-sectional study to collect risk factors associated with stillbirths in pig herds. Animal Reproduction Science 118: 6268. Scholar
Van Der Heyd, H, De Mets, JP, Porreye, L, Henderickx, H, Calus, A, Bekaert, H and Buysse, F 1989 Influence of season litter size parity gestation length birth weight sex and farrowing pen on frequency of congenital splayleg in piglets. Livestock Production Science 21: 143156. Scholar
Van der Lende, T and de Jager, D 1991 Death risk and preweaning growth rate of piglets in relation to the within-litter weight distribution at birth. Livestock Production Science 28: 7384. Scholar
Van der Lende, T, Knol, EF and Leenhouwers, JI 2001 Prenatal development as a predisposing factor for perinatal losses in pigs. Journal of Reproduction and Fertility, Supplements 58: 247261Google ScholarPubMed
Van Dijk, AJ, van Rens, BTTM, van der Lende, T and Taverne, MAM 2005 Factors affecting duration of the expulsive stage of parturition and piglet birth intervals in sows with uncomplicated, spontaneous farrowings. Theriogenology 64: 15731590. ScholarPubMed
Vidović, V, Lukač, D, Štrbac, L, Višnjić, V, Punoš, D, Šević, R, Krnjajić, J and Stupar, M 2012 Genetic trend for certain traits in pigs using different selection criteria. Animal Science and Biotechnologies 45: 274279Google Scholar
Vogt, DW, Gipson, TA, Akremi, B, Dover, S and Ellersieck, MR 1984 Associations of sire, breed, birth weight, and sex in pigs with congenital splayleg. American Journal of Veterinary Research 45: 24082409Google ScholarPubMed
Vonnahme, KA, Wilson, ME and Ford, SP 2002 Conceptus competition for uterine space: different strategies exhibited by the Meishan and Yorkshire pig. Journal of Animal Science 80: 13111316CrossRefGoogle ScholarPubMed
Wang, JJ, Chen, LX, Li, DF, Yin, YL, Wang, XQ, Li, P, Dangott, LJ, Hu, WX and Wu, GY 2008 Intrauterine growth restriction affects the proteomes of the small intestine, liver, and skeletal muscle in newborn pigs. Journal of Nutrition 138: 6066CrossRefGoogle ScholarPubMed
Wang, T, Huo, YJ, Shi, F, Xu, RJ and Hutz, RJ 2005 Effects of intrauterine growth retardation on development of the gastrointestinal tract in neonatal pigs. Biology of the Neonate 88: 6672. ScholarPubMed
Weary, DM, Pajor, EA, Thompson, BK and Fraser, D 1996 Risky behaviour by piglets: a trade off between feeding and risk of mortality by maternal crushing? Animal Behaviour 51: 619624. Scholar
Webb, AJ 1998 Objectives and strategies in pig improvement: an applied perspective. Journal of Dairy Science 81: 3646. Scholar
Wilcox, AJ 2001 On the importance, and the unimportance, of birthweight. International Journal of Epidemiology 30: 12331241. ScholarPubMed
Wilson, ME, Biensen, NJ, Youngs, CR and Ford, SP 1998 Development of Meishan and Yorkshire littermate conceptuses in either a Meishan or Yorkshire uterine environment to day 90 of gestation and to term. Biology of Reproduction 58: 905910. ScholarPubMed
Winkler, GC and Cheville, NF 1985 Morphometry of postnatal development in the porcine lung. The Anatomical Record 211: 427433. ScholarPubMed
Wolf, J, Žáková, E and Groeneveld, E 2008 Within-litter variation of birth weight in hyperprolific Czech Large White sows and its relation to litter size traits, stillborn piglets and losses until weaning. Livestock Science 115: 195205. Scholar
Wu, G, Bazer, FW, Burghardt, RC, Johnson, GA, Kim, SW, Li, XL, Satterfield, MC and Spencer, TE 2010 Impacts of amino acid nutrition on pregnancy outcome in pigs: mechanisms and implications for swine production. Journal of Animal Science 88: E195E204. ScholarPubMed
Xu, RJ, Mellor, DJ, Birtles, MJ, Reynolds, GW and Simpson, HV 1994 Impact of intrauterine growth retardation on the gastrointestinal tract and the pancreas in newborn pigs. Journal of Pediatric Gastroenterology and Nutrition 18: 231240. ScholarPubMed
Zou, S, McLaren, DG and Hurley, WL 1992 Pig colostrum and milk composition: comparisons between Chinese Meishan and US breeds. Livestock Production Science 30: 115127. Scholar
Zurbrigg, K 2006 Sow shoulder lesions: risk factors and treatment effects on an Ontario farm. Journal of Animal Science 84: 25092514. Scholar