Submitted to: Applied Animal Behaviour Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2003
Publication Date: 9/5/2003
Citation: PEDERSEN, L.J., DAMM, B.I., MARCHANT FORDE, J.N., JENSEN, K.H. EFFECTS OF FEED-BACK FROM THE NEST ON MATERNAL RESPONSIVENESS AND POSTURAL CHANGES IN PRIMIPAROUS SOWS DURING THE FIRST 24 HOURS AFTER FARROWING ONSET. APPLIED ANIMAL BEHAVIOR SCIENCE. 2003.
Interpretive Summary: Around the time of giving birth, the domestic pig carries out a unique set of behaviors. Under natural conditions, she isolates herself from the herd and spends a great deal of time and effort selecting a nest site and constructing a nest in which to give birth. Once satisfied with the nest, she burrows into the bedding and delivers her litter. It has been proposed that this sequence of nesting behaviors is initially internally-driven, by changing hormone levels, but that nest-building completion is reliant on environmental feedback - i.e. the presence of a suitable nest. The majority of sows in industrialized pig industries give birth in farrowing crates with little or no access to nest-building material and it has been shown that many sows under these conditions continue to perform nest-building-type behaviors, even during the time that they are giving birth. It has also been proposed that the lack of a completed nest is stressful, disrupting hormonal balances and potentially affecting piglet viability and survival. Our study aimed to investigate whether manual disruption of nest-building did affect the sow's stress levels and her subsequent behavior towards her piglets. This paper deals with the second aspect. We found that disrupting the nest led to increased maternal responsiveness after farrowing, especially during the 2 hours after the birth of the first piglet. Disrupting the nest also resulted in the piglets taking longer to find the udder and suckle after they had been born. There was no difference between treatments in number of posture changes or in heart rate. Around farrowing, it is actually advantageous for maternal responsiveness to be low, as to be reactive at this time places the piglets at greater risk of crushing and prevents the piglets from accessing colostrum. These results indicate that undisturbed access to nesting material, allowing the sow to construct a functional nest could have production advantages, especially in farrowing systems other than conventional crates, where sow behavior is extremely important for piglet survival. As society begins to question the intensive way in which sows are housed, this study shows that using alternatives to confinement, non-bedded systems for sows around the time of giving birth, may actually produce positive changes for swine farming in terms of productivity and image.
Technical Abstract: In order to elucidate whether feed-back from a farrowing nest affects the sows' activity level and responsiveness to piglets during the first 24 h after the onset of parturition, 18 primiparous Landrace x Yorkshire sows were given the opportunity to build a farrowing nest of peat, straw and branches in Schmid pens. Eight treatment sows then had their nest removed 8-10 h after the onset of nest-building and again every 4 h until farrowing began, whereas 10 control sows were allowed to keep the nest. During the first 24 h after birth of the first piglet the behaviour of the sows and piglet was observed and heart rate of the sows monitored using a transmitter belt and watch receiver. The frequency of postural changes and a maternal responsiveness index was calculated. In addition, time from birth of each piglet until it suckled for the first time was calculated. In the treatment group there was a constantly higher level of maternal responsiveness (P < 0.0001), but the frequency of postural changes did not differ from that of control sows. The timing of maternal responsiveness was not affected by treatment, but in both treatment groups maternal responsiveness was significantly higher during the first 2 h after birth of the first piglet than in the following 6 h (P < 0.0001). Hereafter (8-24 h postpartum) the maternal responsiveness significantly increased (P = 0.05). The frequency of postural changes also was higher during the first 2 hours (P < 0.0001) than in the following 6 hours after which it increased again (P = 0.05). Heart rate gradually declined over the first 8 hours after birth of the first piglet (P < 0.0001) after which it stayed level. Piglets from treatment sows took significantly longer to suckle for the first time compared to piglets from control sows (P < 0.05). The decrease in activity and maternal responsiveness shortly after parturition has begun is likely to be advantageous for the piglets as it reduces the risk of piglet crushing while at the same time giving early access to the udder and to warmth from the sow. The results emphasise the importance of a proper farrowing environment and the opportunity to construct a nest, particularly in loose housed sows where the survival and vigorousness of the piglets depend greatly on the behaviour of the sow because the piglets are not protected by pen features as is the case in farrowing crates.