Altman DG: Practical statistics for medical research. (1st ed.). Chapman and Hall, London, 1991.
Andreasson E, Andersson C: Digivande suggor i smâ grupper. Dygnsrytm, sociala interaktioner och digivningsbeteende. (Group-housed lactating sows in small groups: diurnal rhythm, social interactions and suckling and nursing behaviour). Swedish University of Agricultural Sciences, Uppsala, Sweden. 1992, 1–56.
Beilharz RG, Cox DF: Social dominance in swine. Anim. Behav. 1967, 15, (117–122).
Bollwahn W, Meermeier D: Häufigkeit und Diagnostik chronischer Gesäugeverändrungen bei Zuchtsauen (Schlachtbefunde). (Frequency and diagnosis of chronic alterations in mammary glands of sows (abattoir survey)). Berl. Münch. Tierärztl. Wschr. 1989, 102, (223–227).
Bryant MJ, Rowlinson P: Nursing and suckling behaviour of sows and their litters before and after grouping in multi-accomodation pens. Anim. Prod. 1984, 33, (277–282).
Bryant MJ, Rowlinson P, Van Der Steen HAM: A comparison of the nursing and suckling behaviour of group- and individually-housed sows and their litters. Anim. Prod. 1983, 36, (445–451).
Bäckström L: Environment and animal health in piglet production. Acta vet. scand. 1973, Suppl 41, 1–240.
Csermely D, Wood-Gush DGM: Agonistic behaviour in grouped sows. II. How social rank affects feeding and drinking behaviour. Boll. Zool. 1990. 57, 55–58.
Delgado JA, Jones JET: An abattoir survey of mammary gland lesions in sows with special reference to bacterial flora of mammary abscesses. Br. vet. J. 1981, 137, (639–643).
Dewey CE, Wilson MR, Friendship RM, Palmer NC: An observational study of lameness in breedingstock swine in Ontario. Proc. Int. Pig Vet. Soc. Rio de Janeiro 1988, 238.
Elliot JI, Doige CE: Effects of type of confinement on performance and on the occurrence of loco-motory disturbances in market pigs. Can. J. Anim. Sei. 1973, 53, (211–217).
Grondalen T: Osteochondrosis and Arthrosis in pigs; II. Incidence in breeding animals. Acta vet. scand. 1974, 15, (26–42).
Jensen P: Observations on the maternal behaviour of free-ranging domestic pigs. Appl. Anim. behav. Sei. 1986, 16, (131–142).
Jensen P, Floren K, Hobroh B: Peri-parturient changes in behaviour in free-ranging domestic pigs. Appl. Anim. behav. Sei. 1987, 17, (69–76).
Jensen P, Redbo I: Behaviour during nest leaving in free-ranging domestic pigs. Appl. Anim. behav. Sei. 1987, 18, (355–362).
Jensen P, Wood-Gush DGM: Social interactions in a group of free-ranging sows. Appl Anim. behav. Sei. 1984, 12, (327–337).
Lambert RJ, Ellis M, Rowlinson P, Saville CA: Influence of housing/feeding system on sow behaviour. Anim. Prod. 1983, 36, (532).
Lent PC: Mother-infant relationships in ungulates. In: Geist U, Walther F (eds.): The behaviour of ungulates and its relationship to management. 1974, IUCN, Morger, Switzerland, 14–55.
Lundeheim N: Genetic analysis of osteochondrosis and leg weakness in the Swedish pig progeny testing scheme. Acta agric. scand. 1987, 37, (159–173).
Mauget R: Behavioural and reproductive strategies in wild forms of sus scrofa (European wild boar and feral pigs). Curr. Top. Vet. Med. Anim. Sei. 1981, Vol. II, 3–13.
Meese GB, Ewbank R: The establishment and nature of the dominance hierarchy in the domesticated pig. Anim. Behav. 1973, 21, (326–334).
Nakano T, Aherne FX, Thompson JR: Effect of housing system on the recovery of boars from leg weakness. Can. J. Anim. Sei. 1981, 61, (335–342).
Newberry RC, Wood-Gush DGM: The suckling behaviour of domestic pigs in a semi-natural environment. Behaviour. 1985, 95, (11–25).
Penny RHC, Osborne AD, Wright Al: The causes and incidence of lameness in store and adult pigs. Vet. Rec. 1963, 75, (1225–1235).
Penny RHC, Osborne AD, Wright Al: Foot-rot in pigs: Observations on the clinical disease. Vet. Rec. 1965, 77, (1101–1108).
Perrin WR, Bowland JP: Effects of enforced exercise on the incidence of leg weakness in growing boars. Can. J. Anim. Sei. 1977, 57, (245–253).
Reiland S: Osteochondrosis in the pig. A morphologic and experimental investigation with special reference to the leg weakness syndrome. Thesis. The Royal Veterinary College, Stockholm, Sweden. Acta Rad. 1975, Suppl. 1-118.
Ringarp N: Clinical and experimental investigations into a postparturient syndrome with agalactia in sows. Acta agric. scand. 1960, Suppl 7, 1–166.
Ross RF, Orning AP, Woods RD, Zimmermann BJ, Cox DF, Harris DL: Bactériologie study of sow agalactia. Amer. J. vet. Res. 1981, 42, (949–955).
SAS Institute Inc: SAS user’s guide. Statistics Version 5. Cary, N. C. 1985.
Sather AP: A note on the changes in leg weakness in pigs after being transferred from confinement housing to pasture lots. Anim. Prod. 1987, 44, (450–453).
Sather AP, Fredeen HT: The effect of confinement housing upon the incidence of leg weakness in swine. Can. J. Anim. Sei. 1982, 62, (119–1128).
Signoret JP, Baldwin D, Fraser D, Hafez ESE: The behaviour of swine. In: The behaviour of domestic animals. 1975, Balliere Tindal, London, 295–329.
Smith WJ, Robertson AM: Observations on injuries to sows confined in part slatted stalls. Vet. Rec. 1971, 39, (531–533).
Stängel G, Jensen P: Behaviour of semi-naturally kept sows and piglets (except suckling) during 10 days post partum. Appl Anim. Behav. Sei. 1991, 31, (211–227).
Stolba A, Henderson R, Wechsler B: The influence of different social and physical environments on the incidence of lactational oestrus in sows. Appl. Anim. Behav. Sei. 1990, 27, (269–276).
Stolba A, Wood-Gush DGM: The behaviour of pigs in semi-natural environment. Anim. Prod. 1989, 48, (419–425).
Svendsen J, Andersson M, Olsson A-C, Rantzer D, Lundqvist P: Group housing of sows in gestation in insulated and uninsulated buildings. Swedish University of Agricultural Sciences, 1990, 1–197.
Whittemore CT, Franklin MF, Pearce BS: Fat changes in breeding sows. Anim. Prod. 1980, 31, (183–190).