Jarvis S, Van der Vegt B J., Lawrence A B., McLean K A., Deans L A., Chirnside J, Calvert S K.
Animal Behavioural Sciences Department, Animal Biology Division, SAC-Edinburgh, West Mains Road, EH9 3JG, Edinburgh, UK
Appl Anim Behav Sci. 2001 Mar 2;71(3):203-216. doi: 10.1016/s0168-1591(00)00183-0.
There is increasing evidence that restriction of pre-parturient behaviour in pigs is stress-inducing, characterised by an elevation in hypothalamic-pituitary-adrenal (HPA) activity in gilts. To determine whether pigs adapt to behavioural restriction, through modification of nest-building behaviour, we studied pre-parturient pigs in either farrowing crates (no bedding, n=7) or straw-bedded pens (n=7) in their first (gilts) and second (sows) parity, with physiological measurements being taken in the second parity. Observations and blood sampling were carried out during the pre-parturient phase. Crated pigs changed posture more often than penned pigs (F(1,12)=7.06, P<0.05), with the number of posture changes reducing across parities in both environments. The reduction in posture changing was more apparent in the crated sows which may indicate that attempted nest-building behaviour of sows with prior experience of farrowing crates is less fragmented. The crated pigs spent a greater proportion of time sitting across both parities (F(1,12)=9.4, P<0.01), and spent less time manipulating available substrates (F(1,12)=10.67, P<0.05). There was a tendency for penned pigs to spend a greater proportion of time standing (F(1,12)=3.77, P=0.076) with peak nesting behaviour occurring earlier in relation to parturition than in crated pigs. In addition penned sows performed more floor-directed behaviour than penned gilts, and at an earlier stage in relation to parturition. However, crated sows also performed peak nest-building earlier than crated gilts. Plasma cortisol profiles indicated elevated HPA activity in crated sows during the pre-parturient period (F(42,303)=1.43, P<0.05) suggesting increased physiological stress, however, the difference between crated and penned sows was less than that previously seen in gilts. The increased range of pre-parturient behaviours seen in the penned sows suggests that experience may result in an 'improvement' in their nest-building behaviour: earlier preparation of the nest site and then subsequent manipulation of substrates. The crated sows appeared to show some behavioural adaptation to the crate environment; earlier peak in floor directed behaviour and total substrate directed behaviour, reduced posture changing. In conclusion the nest-building behaviour of pigs is modified over parities with adaptation to the behavioural restrictions imposed by the farrowing crate. However, this adaptation, through prior experience, does not completely reduce the elevation in HPA activity previously reported in pre-parturient crated gilts.
越来越多的证据表明，限制母猪产前行为会导致应激，其特征是后备母猪下丘脑-垂体-肾上腺（HPA）活动增强。为了确定母猪是否通过改变筑巢行为来适应行为限制，我们研究了初产（后备母猪）和经产（经产母猪）的产前母猪，分别将它们饲养在产仔箱（无垫料，n = 7）或有稻草垫料的猪栏（n = 7）中，并在经产阶段进行生理测量。在产前阶段进行观察和采血。与饲养在猪栏中的母猪相比，饲养在产仔箱中的母猪更频繁地改变姿势（F(1,12)=7.06，P<0.05），并且在两种环境下，随着胎次增加，姿势改变的次数都在减少。产仔箱中经产母猪姿势改变次数的减少更为明显，这可能表明有产仔箱使用经验的经产母猪试图进行的筑巢行为碎片化程度较低。在两个胎次中，饲养在产仔箱中的母猪坐着的时间占比更大（F(1,12)=9.4，P<0.01），而操作可用垫料的时间更少（F(1,12)=10.67，P<0.05）。饲养在猪栏中的母猪有站立时间占比更大的趋势（F(1,12)=3.77，P = 0.076），并且与饲养在产仔箱中的母猪相比，其筑巢行为高峰相对于分娩出现得更早。此外，饲养在猪栏中的经产母猪比饲养在猪栏中的后备母猪表现出更多指向地面的行为，并且相对于分娩而言出现得更早。然而，饲养在产仔箱中的经产母猪筑巢行为高峰也比饲养在产仔箱中的后备母猪出现得更早。血浆皮质醇水平表明，产前阶段饲养在产仔箱中的经产母猪HPA活动增强（F(42,303)=1.43，P<0.05），这表明生理应激增加，不过，饲养在产仔箱和猪栏中的经产母猪之间的差异小于之前在后备母猪中观察到的差异。饲养在猪栏中的经产母猪产前行为范围的增加表明，经验可能会使其筑巢行为“改善”：更早地准备筑巢地点，随后对垫料进行操作。饲养在产仔箱中的经产母猪似乎对产仔箱环境表现出了一些行为适应；指向地面行为和总指向垫料行为的高峰出现得更早，姿势改变减少。总之，母猪的筑巢行为会随着胎次而改变，以适应产仔箱所施加的行为限制。然而，通过先前的经验，这种适应并不能完全消除之前报道的产前饲养在产仔箱中的后备母猪HPA活动的增强。
