An experiment was carried out to study the lying postures, space occupation and percentage of space-sharing (as a consequence of huddling behaviour) in pigs. Information about these lying characteristics is essential for the calculation of lying space requirements, e.g. for pen design legislative purposes. The study included two replicates of eight groups of eight pigs each. Pigs were housed at thermoneutral conditions in 8 m(2) partly (40%) slatted pens from 25 to 100 kg live weight. Lights were on from 06:30 until 18:30 h. Feed and water were available ad libitum. Behaviour of the pigs was recorded for 48 h on video tape at approximately 30, 50, 80 and 100 kg live weight. General activity, lying posture (sternum, half recumbent, fully lateral recumbent) and space-sharing percentage were scored by 20 min scan sampling. The results confirmed that pigs of all weight categories lie down for a great part of the day: the average numbers of pigs that were lying were 83.8, 85, 86.3 and 87.5% at 30, 50, 80 and 100 kg live weight. Especially at night (18:30-06:30 h), the fully recumbent lying posture is predominant. The percentages of lying pigs that lied in the fully recumbent position in that period were 65.7, 66.4, 67.7 and 69.1 for 30, 50, 80 and 100 kg pigs, respectively. In our study, we observed that pigs spent little time in contact with conspecifics: space-sharing percentages were 20-40%. There was a significant period effect for the space-sharing data; pigs showed more 'social lying behaviour', i.e. tended to huddle more during the night in comparison to the day since the space-sharing percentages were higher during the night (P <0.01). Based on the observations carried out in this study, average space occupation figures were calculated for lying pigs: 0.30, 0.46, 0.64, 0.76 m(2) for 30, 50, 80 and 100 kg pigs. The present study confirms the suggestion of Petherick (1983) that, as a starting point for discussions about space requirements for pigs, the floor area occupied by lying pigs at thermoneutral conditions should on average be based on the estimated floor area for half recumbent pigs, i.e. area = 0.033 x bodyweight(0.66). (C) 2003 Elsevier Science B.V. All rights reserved.
[1]
W. Close,et al.
The effects of ambient temperature and air movement on heat loss from the pig
,
1981
.
[2]
Sue J. Welham,et al.
Genstat 5 release 3 reference manual
,
1994
.
[3]
Y. Ruckebusch.
The relevance of drowsiness in the circadian cycle of farm animals.
,
1972,
Animal behaviour.
[4]
P. McCullagh,et al.
Generalized Linear Models
,
1972,
Predictive Analytics.
[5]
R. Johnson,et al.
Effects of feeder type, space allowance, and mixing on the growth performance and feed intake pattern of growing pigs.
,
1998,
Journal of animal science.
[6]
S. Edwards,et al.
The effect of space allowance on performance, aggression and immune competence of growing pigs housed on straw deep-litter at different group sizes
,
2000
.
[7]
P. McCullagh,et al.
Generalized Linear Models, 2nd Edn.
,
1990
.
[8]
J. Blackshaw.
Environmental effects on lying behaviour and use of trough space in weaned pigs
,
1981
.
[9]
Eric R. Ziegel,et al.
Generalized Linear Models
,
2002,
Technometrics.
[10]
J. M. Bruce,et al.
Models of heat production and critical temperature for growing pigs
,
1979
.
[11]
John J. McGlone,et al.
Space requirements for finishing pigs in confinement: behavior and performance while group size and space vary
,
1994
.
[12]
S. Edwards,et al.
Legislative methods for specifying stocking density and consequences for the welfare of finishing pigs.
,
2000
.
[13]
J. Doe.
Space requirements of barrows and gilts penned together from 54 to 113 kilograms. NCR-89 Committee on Confinement Management of Swine.
,
1993,
Journal of animal science.
[14]
T. Whatson,et al.
Sleep in piglets: An observational study
,
1979
.
[15]
H. H. Spechter,et al.
Effects of floor area allowance on performance of growing pigs kept on fully slatted floors
,
1988
.