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Prairie Swine Centre is an affiliate of the University of Saskatchewan
Prairie Swine Centre is grateful for the assistance of the George Morris Centre in developing the economics portion of Pork Insight.
Financial support for the Enterprise Model Project and Pork Insight has been provided by:
Analysis and evaluation of mortality losses of the 2001 African swine fever outbreak, Ibadan, Nigeria
Posted in: Welfare by admin on January 1, 2007 | No Comments
Effect of environmental enrichment and breed line on the incidence of belly nosing in piglets weaned at 7 and 14 days-of-age
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Studies have repeatedly shown that belly nosing is the most common abnormal behaviours exhibited by early-weaned pigs, and as weaning age decreases, the incidence of belly nosing increases (Gonyou et al., 1998; Worobec et al., 1999). Furthermore, the effect of early weaning on behaviour persists well into the grow-finish phase of development (Gonyou et al., 1998; Worobec et al., 1999). Among members of the same litter and between litters, there is considerable variation in the incidence of belly nosing as well as in the amount of time it takes for the behaviour to commence following weaning (Fraser, 1978; Li and Gonyou, 2002). Li and Gonyou (2002) studied the temporal association of belly nosing with other behaviours in an attempt to identify the proximate cause of the behaviour. The authors found that the social environment can have a profound effect on the incidence of belly nosing, possibly explaining some of the variation in belly nosing observed between litters. Welfare concerns regarding the incidence of belly nosing in early-weaned pigs have reflected the environmental contribution to the development of the aberrant behaviour while the genetic component has not been researched beyond preliminary findings (Bench, 2005). The effect of enrichment and breed line on belly nosing in early-weaned pigs was investigated over two studies. In a preliminary study, 291 piglets were weaned at 7 days-of-age and observed over two consecutive days (pigs ranged from17 to 30 days-of-age at time of observation). Piglets were fed a liquid milk replacer diet for either 7 or 14 days following weaning. The pen environment was enriched by providing either an air-filled inner tube (Tube), rubber nipples in the feed trough (Nipple), or neither (Control). Pens were segregated by sex with 14–16 pigs per pen. Within pens, there were both Duroc and Yorkshire pigs. Instantaneous scan sampling by two observers was used to determine the incidence of belly nosing, belly sucking, and nosing and sucking other parts of the body. Yorkshire line pigs engaged in more belly sucking (3.97% versus 1.59%; P < 0.01), total sucking (4.30% versus 2.21%; P < 0.05), and belly-directed behaviour (9.2% versus 6.21%; P = 0.089) than did Duroc line pigs. Nipple enrichment effectively reduced the level of belly sucking, overall sucking and belly-directed behaviours in the Yorkshire line pigs, while Tube enrichment reduced other nosing and oral–nasal vices directed away from the belly in the Duroc line pigs. The second study investigated the effect of sire breed and sire within breed on the proportion of time early-weaned pigs spent belly nosing and belly sucking. Two hundred and forty-two crossbred pigs sired by Duroc (n = 120) and Large White (n = 122) boars were weaned at 14 days-of-age and observed at 18, 23, 28, 50, 63 and 91 days-of-age for belly nosing, belly sucking, other nosing and sucking, tail biting and other biting behaviours during the nursery and grow-finish phases of development. Continuous observations done live at 21 and 35 days-of-age were used to determine mean belly nosing and belly sucking bout durations. Pigs sired by Large White boars spent a greater proportion of time belly nosing (2.040%; P<0.01) and belly sucking (0.440%; P < 0.01) compared with pigs sired by Duroc boars (1.597% and 0.308%, respectively). In contrast, Duroc-sired pigs spent a greater proportion of time conducting other nosing (0.356%; P < 0.01) and other sucking (2.496%; P < 0.001) behaviours compared with Large White-sired pigs (0.173% and 2.063%, respectively). Individual sire also had a significant effect on belly nosing (P < 0.001), belly sucking (P < 0.001) and other sucking (P < 0.01) behaviours post-weaning. It was concluded that breed line differences might affect the incidence of nosing and sucking behaviours in early-weaned pigs, which may be reduced through the use of environmental enrichment tailored to the specific abnormal behaviours being performed.
Comparative sequences of the canine and feline vasopressin prohormones
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Dietary fibre for gestating sows: effects on parturition progress, behaviour, litter and sow performance
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In the European Union, animal welfare legislation (European Council, 2001) imposes the provision of bulky or high-fibre (HF) diets to pregnant sows to improve sow welfare. Such practices intend to fulfill feeding motivation in sows by increasing the daily feed allowance without increasing the energy intake during gestation, and thus avoiding overweight at farrowing which can be detrimental for piglets’ survival (Dourmad et al., 1994). Many studies have highlighted the beneficial effects of fibrous components in the gestation diet or through the litter on sow welfare (Meunier-Salaün et al., 2001). Dietary fibres are also known to reduce sow digestive disorders such as constipation (Wenk, 2001; Tabeling et al., 2003) as well as excessive body fatness at farrowing, that has been shown to lead to longer parturition length and increased piglet losses (Bilkei Papp, 1990). Approximately 75% of the 8% of stillborn piglets generally reported in usual rearing conditions die during parturition (Van Dijk et al., 2005), mainly as a result of asphyxia (Van Rens and Van Der Lende, 2004). Last-born piglets are more likely to suffer from asphyxia resulting from the cumulative effects of successive contractions or from a rupture of umbilical cord as parturition progresses (Randall, 1971 and 1972; Herpin et al., 1996). The aim of this study was to investigate the impact of feeding a high-fibre (HF) diet during gestation on parturition progress and reproductive performance of sows. Forty-two primiparous sows (Large-White3Landrace crossbred) were fed during gestation either a control diet (C diet; 2.40 kg/day, 3.2% crude fibre, in % of dry matter (DM)), or a HF diet (2.80 kg/day, 12.4% crude fibre, in % of DM). All sows received 33MJ digestible energy per day. Continuous video recordings were done on the parturition day to determine postural changes (standing, sitting, lying) and behavioural activities (nesting behaviour, uterine contractions, restlessness, social behaviour towards piglets) during parturition. Duration of parturition and individual birth intervals were also measured. Piglets’ growth was evaluated by weekly weighing from birth until weaning, at
26.5 days of age. Sows were weighed and backfat thickness was measured at mating, on day 105 of gestation, on the 1st day post partum, and at weaning. Durations of parturition and of birth intervals were not affected by the gestation diet and averaged 211 ± 12 min and 16.5 ± 0.9 min (mean ± s.e.), respectively. During the parturition progress, the gestation diet did not affect the frequency and the time devoted to postural and behavioural activities. Dietary treatment during gestation did not influence duration of gestation and weaning-to-oestrus interval, as well as litter size, and number of stillborn and weaned piglets. Piglet weight at birth did not differ between gestation dietary treatments but piglets nursed by HF sows showed a 13.5% greater growth rate during the 1st week of life (P<0.01) and tended to be heavier at weaning (P=0.06) compared with C piglets. The HF sows were leaner at the end of gestation (P<0.05), but variations of sows’ weight during gestation and lactation were not affected by the gestation diet. All sows lost the same amount of backfat thickness during lactation. During lactation, the average daily feed intake was not significantly affected by the gestation diet. This study shows that substituting a control diet for a HF diet during gestation has limited effects on farrowing progress and reproductive performance, but improved piglets’ growth rate during the 1st week of life and tended to increase their live weight at weaning.
The welfare of gestating sows in conventional stalls and large groups on deep litter
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Confinement of breeding sows and gilts is one of the most controversial issues in livestock production, together with floor space allowance and lack of bedding (Barnett et al., 2001). However, consideration of the welfare implications of group versus stall housing during gestation is complex. Both housing systems have some clear advantages and disadvantages in relation to pig welfare. For example, individual housing in stalls restricts the sows’ opportunities to exercise, socially interact and interact with other features of the environment, but on the other hand, group housing raises welfare issues concerning space allowance and level of aggression. About 70% of the breeding sows are kept in stalls during gestation (Barnett et al., 2001). The ongoing welfare debate about stall housing has led to the examination of alternative housing systems for breeding sows. There is little information in the scientific literature on the welfare of gestating sows in groups of more than 40 animals and there is no scientific literature on housing breeding sows or gilts in large groups on deep litter. The present experiment measured aspects of the welfare of gestating sows housed in either large groups on deep litter (Hoops) or conventional stalls (Stalls). Six hundred and forty sows were studied, with 40 recently mated sows weekly entering each treatment over an 8-week period; groups of 85 were formed using 40 experimental and 45 non-experimental animals. Sows in Hoops had a higher number of scratches, a higher return rate to oestrus after mating (13.20% versus 7.35%) and there was a trend for higher salivary cortisol concentrations in week 1 of gestation (6.29 nM versus 4.03 nM). Sows in Stalls had a higher incidence of lameness at weeks 9 and 15 of gestation (13.8% versus 0.8% at week 15). There were changes in some leucocyte sub-populations in the Stalls treatment late in gestation: the percentage of neutrophils was higher (46% versus 41% of WBC), the number and percentage of lymphocytes was lower (41.6% versus 46.5% of WBC) and consequently there was a higher neutrophil:lymphocyte ratio (1.22 versus 0.94). There was a trend for a lower reproductive failure in the Stalls treatment (14.5% versus 27.3%); farrowing rate was higher (76.8% versus 66%), and while sows in Stalls weaned fewer piglets per litter (8.31 versus 8.97), the average weaning weight of these piglets was higher (8.69 kg versus 8.01 kg). The combination of these reproductive parameters resulted in sows in the Stall treatment weaning the equivalent of 39 more piglets per 100-mated sows. The results suggest that sows in large groups on deep litter faced greater welfare challenges in the early stages of gestation based on the findings of increased scratches, a higher rate of return to oestrous and a trend for higher cortisol concentrations early in gestation, all possibly a consequence of aggression. In contrast sows in stalls faced greater welfare challenges later in gestation based on a higher incidence of lameness and an increased neutrophil:lymphocyte ratio perhaps as a consequence of increased stress. In conclusion, these data suggest that in both housing systems the welfare advantages and disadvantages change overtime.
Cognitive enrichment affects behavioural reactivity in domestic pigs
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Environmental enrichment can be defined as an increase of the biological relevance of captive environments by appropriate modifications resulting in an improvement of the biological functioning of captive animals (Newberry, 1995). In general, enrichment should present objects or situations to act with a rewarding outcome. In applied ethology improved animal welfare and health as well as an adequate coping with stress are major indicators for assessing the relationship between farm animals and their housing environment. Animals interpret their interactions with the environment in an emotional way on the basis of present and previous experience (Wiepkema and Koolhaas, 1992). This will be the case especially if an animal can expect a rewarding result (Spruijt et al., 2001). Up to now, the development of cognitive tasks to study emotional or hedonic states in animals is rather rare and predominantly restricted to laboratory animals (e.g. Harding et al., 2004; Van der Harst et al., 2005). Therefore, there is an urgent need for increasing experimental research on this field, which should necessarily include farm animals. For this purpose we have recently developed a food-rewarded learning system for pigs using acoustic cues in a combination of classical and operant conditioning techniques (Ernst et al., 2005). The purpose of the present paper was to verify that automated feeding by offering cognitive challenges is functioning reliably and does not impair weight development in replicated trials with pig groups, as should be expected by a successful learning behaviour. However, the main goal was to investigate the effects of a sustained cognitive enrichment on the general behavioural reactivity of domestic pigs. The present study investigated the characteristics of learning behaviour in seven experimental groups (n = 8 individuals each) of growing pigs in postnatal weeks 7–20. The behavioural budget of each group was observed weekly within the housing environment and compared to seven conventionally fed control groups (n = 8), which were supplied with an equal food amount. The alterations of individual behavioural responses after 6 and 12 weeks of cognitive enrichment were analysed in combined open-field/novel-object tests and compared to controls. All experimental pigs were able to discriminate reliably an individual tone that was associated with a locally changing feeding site. Generally, the animals were also willing to work for food (push a button) but this motivation varied considerably between the groups ranging from FR 1 to 10. Sustained cognitive enrichment also affected other behavioural patterns within the housing environment as indicated by an increased locomotor behaviour and less belly nosing. Behavioural test responses were altered towards a greater reduction in open-field activity as well as a reduced excitement and fear behaviour compared to control pigs. Behavioural differences seem to be more pronounced the longer pigs were faced with the cognitive challenge. However, with equal food intake, the weight gain of the experimental pigs was not different compared to the controls. The present study suggests that, in domestic pigs, the presented cognitive enrichment may induce repeated positive appraisals in pigs by the association of successful coping with a demanding behavioural task rewarded by several small portions of food during the day. This appears to agree very well with pigs’ motivational needs and may also be applicable for animal welfare enhancing management of feeding.
The value assigned to six different rooting materials by growing pigs
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Several studies have shown that straw provides an outlet for the foraging and explorative motivation of pigs and that the provision of straw reduces abnormal manipulation of pen mates (e.g. Bolhuis et al., 2005). Alternatives to straw have also been investigated, for instance peat (Beattie et al., 2001), which was found to have the same beneficial effect as straw, and which was preferred to straw (Pedersen et al., 2005). Various so-called ‘toys’ have also been suggested as rooting materials. The pig producers may prefer the toys, because they do not interfere with the slurry system, but pigs prefer chewable toys to more ‘durable’ toys (Apple and Craig, 1992). Furthermore, straw bedding (Guy et al., 2002; Van de Weerd et al., 2005, 2006) and mushroom peat (Beattie et al., 2001) are the only rooting materials that have been reported to reduce tail biting. The rooting materials must enable the pigs to perform investigation and manipulation, and the literature suggests that materials that are complex, manipulative and edible (Van deWeerd et al., 2003; Olsen et al., 2000) stimulate the most investigation and manipulation. In a recent study Pedersen et al. (2005) developed a method using concurrent schedules of reinforcement to assess the strength of pigs’ preferences for different rooting materials. When animals work on concurrent schedules of reinforcement for food, or other valued resources, they adjust their efforts according to how difficult it is to get access (the workload) to either of the two resources and the quality (the value) of the two resources in relation to the underlying motivation. Based on the trade-off between workload and value we can calculate how much more they value one resource relative to the other. The aim of the present experiment was to assess the relative value of six rooting materials based on the cross point between demand functions derived using concurrent schedules of reinforcement. Twelve pigs were tested with all six combinations of the reference material (peat) and one of the six test materials in a balanced design. The cost of access to both reference material and test material was varied. For each combination, demand functions for both materials were estimated as a function of the cost of the reference material leading to a cross point of the two demand functions. The cross points revealed the following ranking (the lower values are the most preferred): maize silage with straw (14.2 (9.5–18.5)), spruce chips (18.0 (13.8–21.9)), compost (18.2 (13.8–22.3)), sisal rope (25.5 (21.4–29.6)), seed grass hay (27.1 (22.7–31.8)), chopped straw (28.5 (24.5–32.8)). All the tested materials were valued as much as chopped straw, but maize silage with straw, spruce chips and compost were valued higher. The results confirm that pigs prefer more complex and compound rooting materials.