Effect of increasing amounts of straw on pigs' explorative behaviour

Margit Bak Jensen; Mette S. Herskin; Björn Forkman; Lene Juul Pedersen

doi:10.1016/j.applanim.2015.08.035

Effect of increasing amounts of straw on pigs' explorative behaviour

Margit Bak Jensen, Mette S. Herskin, Björn Forkman, Lene Juul Pedersen

19 Citations (Scopus)

Abstract

According to European legislation, pigs must have permanent access to sufficient quantity of material to enable manipulation activities. However, few studies have quantified how much straw is needed to fulfil the requirements of growing pigs. We investigated the effect of increasing amount of straw on pigs' manipulation of the straw, and hypothesised that after a certain point increasing straw amount will no longer increase oral manipulation further. From 30 to 80. kg live weight, pigs were housed in 90 groups of 18 pigs in pens (5.48. m. ×. 2.48. m) with partly slatted concrete floor and daily provided with fresh uncut straw onto the solid part of the floor. Experimental treatments were 10, 80, 150, 220, 290, 360, 430 or 500. g straw per pig and day. At 40 and 80. kg live weight, the time spent in oral manipulation of the straw by three focal pigs per pen (large, medium and small sized) were recorded along with the percentage of pigs manipulating straw simultaneously. This was recorded in three 1-h intervals (1h before and 1. h after straw allocation in the morning, as well as from 17 to 18. h in the afternoon). With increasing quantity of straw provided, we found a curvilinear (P<0.01) increase in the time spent in oral manipulation of the straw. Smaller pigs spent more time manipulating straw than larger and medium sized pigs (367, 274 and 252. s/h for small, medium and large sized pigs, respectively; P<. 0.001), and pigs spent more time manipulating straw at 40. kg than 80. kg live weight (356 vs. 250. s/h; P<0.001). At both live weights, pigs spent most time manipulating straw during the hour after allocation of straw. Similar effects of increasing amounts of straw were found for the percentage of pigs engaged in simultaneous manipulation of the straw. Post hoc analyses were applied to estimate the point, after which additional straw did not increase manipulation of straw any further. For the time spent manipulating straw the estimated change point was 253 (approx. 95% confidence limits (CL) 148-358) g straw per pig and day. For the number of pigs simultaneously manipulating straw the change point was 248 (CL 191-304) g straw per pig and day. These results show that increasing the quantity of straw from minimal to approximately 250. g per pig and day increased the time spent in oral manipulation of the straw, as well as the occurrence of simultaneous straw manipulation.Hence, data from the current experiment identified 250. g straw per pig per day as the amount of straw where a further increase in straw provision did not further increase neither time spent on oral manipulation of straw, nor the percentage of pigs simultaneously manipulating straw. This suggests that, within the current housing system and using this criterion, this amount of straw may be the biological turning point for increasing oral manipulation of straw.

Original language	English
Journal	Applied Animal Behaviour Science
Volume	171
Pages (from-to)	58-63
Number of pages	6
ISSN	0168-1591
DOIs	https://doi.org/10.1016/j.applanim.2015.08.035
Publication status	Published - 1 Oct 2015

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@article{9fa64ed51eaf4faebcfe67a3b98d3256,

title = "Effect of increasing amounts of straw on pigs' explorative behaviour",

abstract = "According to European legislation, pigs must have permanent access to sufficient quantity of material to enable manipulation activities. However, few studies have quantified how much straw is needed to fulfil the requirements of growing pigs. We investigated the effect of increasing amount of straw on pigs' manipulation of the straw, and hypothesised that after a certain point increasing straw amount will no longer increase oral manipulation further. From 30 to 80. kg live weight, pigs were housed in 90 groups of 18 pigs in pens (5.48. m. ×. 2.48. m) with partly slatted concrete floor and daily provided with fresh uncut straw onto the solid part of the floor. Experimental treatments were 10, 80, 150, 220, 290, 360, 430 or 500. g straw per pig and day. At 40 and 80. kg live weight, the time spent in oral manipulation of the straw by three focal pigs per pen (large, medium and small sized) were recorded along with the percentage of pigs manipulating straw simultaneously. This was recorded in three 1-h intervals (1h before and 1. h after straw allocation in the morning, as well as from 17 to 18. h in the afternoon). With increasing quantity of straw provided, we found a curvilinear (P<0.01) increase in the time spent in oral manipulation of the straw. Smaller pigs spent more time manipulating straw than larger and medium sized pigs (367, 274 and 252. s/h for small, medium and large sized pigs, respectively; P<. 0.001), and pigs spent more time manipulating straw at 40. kg than 80. kg live weight (356 vs. 250. s/h; P<0.001). At both live weights, pigs spent most time manipulating straw during the hour after allocation of straw. Similar effects of increasing amounts of straw were found for the percentage of pigs engaged in simultaneous manipulation of the straw. Post hoc analyses were applied to estimate the point, after which additional straw did not increase manipulation of straw any further. For the time spent manipulating straw the estimated change point was 253 (approx. 95% confidence limits (CL) 148-358) g straw per pig and day. For the number of pigs simultaneously manipulating straw the change point was 248 (CL 191-304) g straw per pig and day. These results show that increasing the quantity of straw from minimal to approximately 250. g per pig and day increased the time spent in oral manipulation of the straw, as well as the occurrence of simultaneous straw manipulation.Hence, data from the current experiment identified 250. g straw per pig per day as the amount of straw where a further increase in straw provision did not further increase neither time spent on oral manipulation of straw, nor the percentage of pigs simultaneously manipulating straw. This suggests that, within the current housing system and using this criterion, this amount of straw may be the biological turning point for increasing oral manipulation of straw.",

author = "Jensen, {Margit Bak} and Herskin, {Mette S.} and Bj{\"o}rn Forkman and Pedersen, {Lene Juul}",

year = "2015",

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T1 - Effect of increasing amounts of straw on pigs' explorative behaviour

AU - Jensen, Margit Bak

AU - Herskin, Mette S.

AU - Forkman, Björn

AU - Pedersen, Lene Juul

PY - 2015/10/1

Y1 - 2015/10/1

N2 - According to European legislation, pigs must have permanent access to sufficient quantity of material to enable manipulation activities. However, few studies have quantified how much straw is needed to fulfil the requirements of growing pigs. We investigated the effect of increasing amount of straw on pigs' manipulation of the straw, and hypothesised that after a certain point increasing straw amount will no longer increase oral manipulation further. From 30 to 80. kg live weight, pigs were housed in 90 groups of 18 pigs in pens (5.48. m. ×. 2.48. m) with partly slatted concrete floor and daily provided with fresh uncut straw onto the solid part of the floor. Experimental treatments were 10, 80, 150, 220, 290, 360, 430 or 500. g straw per pig and day. At 40 and 80. kg live weight, the time spent in oral manipulation of the straw by three focal pigs per pen (large, medium and small sized) were recorded along with the percentage of pigs manipulating straw simultaneously. This was recorded in three 1-h intervals (1h before and 1. h after straw allocation in the morning, as well as from 17 to 18. h in the afternoon). With increasing quantity of straw provided, we found a curvilinear (P<0.01) increase in the time spent in oral manipulation of the straw. Smaller pigs spent more time manipulating straw than larger and medium sized pigs (367, 274 and 252. s/h for small, medium and large sized pigs, respectively; P<. 0.001), and pigs spent more time manipulating straw at 40. kg than 80. kg live weight (356 vs. 250. s/h; P<0.001). At both live weights, pigs spent most time manipulating straw during the hour after allocation of straw. Similar effects of increasing amounts of straw were found for the percentage of pigs engaged in simultaneous manipulation of the straw. Post hoc analyses were applied to estimate the point, after which additional straw did not increase manipulation of straw any further. For the time spent manipulating straw the estimated change point was 253 (approx. 95% confidence limits (CL) 148-358) g straw per pig and day. For the number of pigs simultaneously manipulating straw the change point was 248 (CL 191-304) g straw per pig and day. These results show that increasing the quantity of straw from minimal to approximately 250. g per pig and day increased the time spent in oral manipulation of the straw, as well as the occurrence of simultaneous straw manipulation.Hence, data from the current experiment identified 250. g straw per pig per day as the amount of straw where a further increase in straw provision did not further increase neither time spent on oral manipulation of straw, nor the percentage of pigs simultaneously manipulating straw. This suggests that, within the current housing system and using this criterion, this amount of straw may be the biological turning point for increasing oral manipulation of straw.

AB - According to European legislation, pigs must have permanent access to sufficient quantity of material to enable manipulation activities. However, few studies have quantified how much straw is needed to fulfil the requirements of growing pigs. We investigated the effect of increasing amount of straw on pigs' manipulation of the straw, and hypothesised that after a certain point increasing straw amount will no longer increase oral manipulation further. From 30 to 80. kg live weight, pigs were housed in 90 groups of 18 pigs in pens (5.48. m. ×. 2.48. m) with partly slatted concrete floor and daily provided with fresh uncut straw onto the solid part of the floor. Experimental treatments were 10, 80, 150, 220, 290, 360, 430 or 500. g straw per pig and day. At 40 and 80. kg live weight, the time spent in oral manipulation of the straw by three focal pigs per pen (large, medium and small sized) were recorded along with the percentage of pigs manipulating straw simultaneously. This was recorded in three 1-h intervals (1h before and 1. h after straw allocation in the morning, as well as from 17 to 18. h in the afternoon). With increasing quantity of straw provided, we found a curvilinear (P<0.01) increase in the time spent in oral manipulation of the straw. Smaller pigs spent more time manipulating straw than larger and medium sized pigs (367, 274 and 252. s/h for small, medium and large sized pigs, respectively; P<. 0.001), and pigs spent more time manipulating straw at 40. kg than 80. kg live weight (356 vs. 250. s/h; P<0.001). At both live weights, pigs spent most time manipulating straw during the hour after allocation of straw. Similar effects of increasing amounts of straw were found for the percentage of pigs engaged in simultaneous manipulation of the straw. Post hoc analyses were applied to estimate the point, after which additional straw did not increase manipulation of straw any further. For the time spent manipulating straw the estimated change point was 253 (approx. 95% confidence limits (CL) 148-358) g straw per pig and day. For the number of pigs simultaneously manipulating straw the change point was 248 (CL 191-304) g straw per pig and day. These results show that increasing the quantity of straw from minimal to approximately 250. g per pig and day increased the time spent in oral manipulation of the straw, as well as the occurrence of simultaneous straw manipulation.Hence, data from the current experiment identified 250. g straw per pig per day as the amount of straw where a further increase in straw provision did not further increase neither time spent on oral manipulation of straw, nor the percentage of pigs simultaneously manipulating straw. This suggests that, within the current housing system and using this criterion, this amount of straw may be the biological turning point for increasing oral manipulation of straw.

U2 - 10.1016/j.applanim.2015.08.035

DO - 10.1016/j.applanim.2015.08.035

M3 - Journal article

SN - 0168-1591

VL - 171

SP - 58

EP - 63

JO - Applied Animal Behaviour Science

JF - Applied Animal Behaviour Science

ER -

Effect of increasing amounts of straw on pigs' explorative behaviour

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