Prenatal stress effects on pig development and response to weaning

Posted in: Welfare by admin on January 1, 2008 | No Comments

Prenatal stress, the stress imposed on a pregnant dam that may influence her subsequent offspring, has been shown to have profound effects on behavior and physiology of many species, including swine (Haussmann et al., 2000; Tuchscherer et al., 2002; Kanitz et al., 2003; Otten et al., 2004). Research in our laboratory (Haussmann et al., 2000) has shown that prenatal stress, including restraint and ACTH injection of the sow, caused offspring to have altered neurohormones and adrenal gland morphology, greater plasma cortisol in response to stress, and less ability to heal a wound. Similarly, another research team has recently published a series of papers (Tuchscherer et al., 2002; Kanitz et al., 2003; Otten et al., 2004) in which they used either 5-min restraint stress or exogenous ACTH administration during sow gestation to cause prenatal stress. Those researchers found that prenatal stress impaired the immune function, increased the maximum binding capacity of glucocorticoids receptors in the central nervous system immediately after birth, and caused an increase in fetal cortisol that may be the mechanism by which prenatal stress causes its effects. Kranendonk et al. (2005) recently reported that oral administration of glucocorticoids to pregnant sows might prove to be a useful model for studying its deleterious effects. The phenomenon of prenatal stress demands our complete understanding to optimize both welfare and productivity in farm animals because prenatal stress can affect both the physiology and behavior of animals and it affects a wide array of species. Thus, to further explore the phenomenon of prenatal stress and its effects in swine, we subjected gestating sows to i.v. injections of ACTH (1 IU/kg of BW), exposure to rough handling for 10 min (Rough), or no treatment (Control) once a week during d 42 to 77 of gestation. To determine the plasma cortisol response to treatments, blood (5 mL) was collected from 30 sows after treatment administration. To conduct the prenatal stress study, a separate group of 56 sows was used in 1 of 4 replicates. At birth, production data were collected for each litter, including birth weight, number born, anogenital distance, and pig viability. At weaning, pigs were blocked by BW and sex, and placed in a nursery pen of 6 pigs, with 2 pigs from each treatment group. To assess the effect of treatments on cortisol, corticosteroid- binding globulin (CBG), and hematological cell profiles, blood was collected every other day for 10 d after weaning. Application of treatments caused plasma cortisol concentrations to be greatest in ACTH sows compared with Control sows (P < 0.001), with Rough sows having intermediate values (P = 0.07). Treatments did not affect the number of pigs born, number of stillborn, or pig viability (P > 0.40). The ratio of cortisol to CBG did not differ between treatments (P = 0.09). Hematological variables did not differ between treatments (P > 0.19). Pigs born to ACTH sows had a smaller anogenital distance compared with controls (P < 0.03), with pigs from Rough sows being intermediate. Our data indicate that swine exposed to prenatal stress (ACTH injection) can have alterations in sexual morphology without effects on growth or the immune cell populations measured in this study.

For more information the full article can be found at http://jas.fass.org/

The ear skin temperature as an indicator of the thermal comfort of pigs

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The aim of the study was to investigate the relationship between the ear skin temperature and the behaviour of pigs. Fifty-four pigs weighing 75 ± 5 kg were used in three replications (18 pigs per replication) and housed in pens (six pigs per pen) in a controlled climate facility. The room temperature was changed by 2 °C from 18 °C down to 10 °C and up again to 22 °C. The ear skin temperature (EST) was continuously recorded and the activity, lying posture, location and contact with pen mates were scored by 12 min scan sampling for 24 h at the set point temperatures 18 °C, 10 °C and 22 °C. A diurnal rhythm in the EST, the posture and the lying behaviour was found. The EST was highest at night and lowest in the afternoon. During night the pigs had more physical contact to pen mates than during day time. For all three
set point temperatures the predominant lying position during the night was the fully recumbent position. The room temperature affected the lying behaviour and the EST. With decreasing room temperature the pigs increased their contact to pen mates and fewer pigs were observed lying in the fully recumbent position. The EST decreased with decreasing room temperature, and the range in the EST’s at the three set point temperatures was larger during day than night (4 °C versus 2 °C). The results indicate that pigs adjust their behaviour to a higher EST when resting than when they are active, and they use behavioural adjustment (e.g. increased/decreased contact to pen mates) to bring their skin temperature into a preferred interval.

For more information the full article can be found at http://journals.elsevierhealth.com/periodicals/applan/issues

Livestock industry tackles new era in animal welfare

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New trends, the latest research and leading strategies on farm animal welfare. All were featured at the 2008 Livestock Care Conference in Red Deer, Alberta. The annual conference, featuring international heavyweights in the field, is hosted by Alberta Farm Animal Care (AFAC), a partnership of Alberta’s major livestock groups with a mandate to promote responsible, humane animal care within the livestock industry. A list is provided regarding the feature articles presented at the conference.

Effect of space allowance during rearing and selection criteria on performance of gilts over three parities in a commercial swine production system

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A total of 1,257 gilts were used to determine the effect of space allowance during rearing and age at puberty on total pigs produced and removal rate over 3 parities. There were 2 treatments. In treatment 1, gilts were given a space allowance of 1.13 m2/ gilt (15 gilts per pen), and in treatment 2, gilts were given 0.77 m2/gilt (22 gilts per pen). Gilts (38 kg and 75 d of age) were individually weighed upon entry and before leaving the rearing site. They were scanned for backfat thickness and loin depth and had their feet and legs scored for structure, movement, and toe evenness before leaving the rearing site. Commencing at approximately 140 d of age, gilts were exposed to a vasectomized boar once daily with age of puberty recorded for all gilts attaining puberty before leaving the rearing site. Gilts were then moved to a specialized gilt breeding farm. When confirmed pregnant, they were moved to 1 of 9 sow farms at random, where gilts remained
until removal from that herd. Space allowance in rearing had no effect (P > 0.29) on growth rate in rearing, backfat thickness and loin depth, total pigs produced, or removal rate. A greater percentage of gilts attained puberty (P = 0.02) and attained puberty at a younger age (P < 0.01) when given the greater space allowance in rearing. Gilts given the lower space allowance in rearing had more (P = 0.04) cracks on their rear hooves. Gilts attaining puberty at a younger age ( d) had a greater growth rate in rearing, greater backfat thickness at 200 d of age, and produced more (P < 0.05) pigs over parities 1 to 3. Gilts in the fastest growthrate group in rearing (>860 g/d) had greater (P < 0.05) total born in parity 1, but total pigs produced to the end of parity 3 was not different (P = 0.47). Contrary to expectation, a fast growth rate in rearing did not negatively affect removal rate. Gilts served between 240 to 260 d of age produced more (P < 0.01) pigs by the end of parity 3 than those served at >260 d of age, whereas a greater (P < 0.01) percentage of gilts served
at >280 d of age were removed by the end of parity 3. In conclusion, space allowance in rearing did not affect total pigs produced or removal rate; however, gilts that attained puberty at a younger age produced more pigs over parities 1 to 3.

For more information the full article can be found at http://jas.fass.org/

Novel object test can detect marginal differences in environmental enrichment in pigs

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At present research is being conducted to develop animal-based monitoring schemes for on farm welfare assessment at the European level (Blokhuis et al., 2003; Butterworth, 2005; Velarde and Geers, 2007). As part of this work a semi-automated novel object test was developed to measure the level of environmental enrichment and/or the level of positive welfare (positive emotions) in the pigs. When play would indicate ‘having fun’ (Spinka et al., 2001) the exploration of a novel object, i.e. object play, could, perhaps, be used to measure the pigs’ residual need (i.e. their remaining motivation) to explore/play. If so, we would expect an inverse relationship between the interaction with the novel object and the level of enrichment in the pen. The level of enrichment is known to have an effect on both play behaviour and on redirected activities (e.g. Wood-Gush and Vestergaard, 1991; Fraser et al., 1991; for a review see Bracke et al., 2006). In search for a test measuring positive emotions in pigs for application in on-farm welfare auditing, three small experiments were conducted to examine the sensitivity of a novel object test designed to measure the pigs’ (residual) need/motivation for enrichment. In the experiments the interactions with a novel piece of rope were measured at pen level using a so-called AMI sensor (AMI: animal–material interactions). Measurements were taken at several points in time over a 1–2 h period in order to test the effects of marginal enrichments, namely the provision of a jerrycan canister (Experiments 1a and 1b) and the provision of some sawdust and/or removal of the metal chain (Experiment 2). The first experiment was replicated in, respectively, 8 and 15 matched pairs of pens with groups of about 11 growing pigs per pen. A jerrycan was provided in one pen of each pair as of the day before the novel object test. In the first replicate (Experiment 1a) only a main effect of time was found in that AMI decreased over time. In the second replicate (Experiment 1b) the provision of the jerrycan significantly reduced AMI. A sign test also confirmed this effect for the data in the first replicate. The recent provision of a jerrycan, therefore, marginally, but statistically significantly, reduced AMI in the novel object test. Experiment 2 was a 2 x 2 factorially designed study conducted in 40 pens containing groups of 24 weaned piglets. Factors were sawdust provision and chain removal. The four treatment combinations were applied as of 45 min before the test. In addition to a main effect of time, it was found that AMI significantly increased when the chain had been removed (P = 0.006), and that the provision of sawdust tended to depress AMI at 10 min, while tending to enhance AMI at 30 min (interaction between time and sawdust provision: P = 0.097). The results indicate that the novel object test may be used to detect relatively minor differences in environmental enrichment.

For more information the full article can be found at http://journals.elsevierhealth.com/periodicals/applan/issues

Sow responsiveness to human contacts and piglet vocalization during 24 h after onset of parturition

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Sow responsiveness towards external disturbances and concurrent postural changes are proposed to be an
important cause of early piglet crushing. The aim of the present study was to assess whether loose housed
sows change their responsiveness over time within the first 24 h after birth of the first piglet upon exposure to
different types of human contact and towards piglets’ scream. The responsiveness of the sows (n = 17) was
scored during: (i) blood sampling of the sow during 24 h after the onset of parturition, (ii) human handling of
a piglet at 0, 30 min, 1, 2, 4, 8 and 24 h after birth, (iii) screaming when a piglet was trapped underneath the
sow and (iv) exposure to playback of piglets’ screams at 10 and 24 h after the onset of parturition. A sow was
scored as responsive if she changed her posture in response to the stimuli. The behavioral scores were
analyzed during three predefined periods: parturition (from birth of first piglet to birth of last piglet), phase 1
(from birth of last piglet to 12 h after birth of first piglet) and phase 2 (from 12 h after birth of first piglet to
24 h after birth of first piglet). The responsiveness of sows towards humans during blood sampling differed
between the three periods ( p < 0.01), whereas it did not differ between periods during human handling of
piglets. During blood sampling, fewer sows were responsive during phase 1 (5%) compared to during
parturition (11%) and the later phase 2 (17%). We did not detect any temporal changes in sow responsiveness
towards natural incidences of screaming of own trapped piglet between the three periods (it
remained high: 80%), whereas sows exposed to playback of piglet screams had a higher probability
( p < 0.05) to react at 12 h (50%) than at 24 h (25%). In conclusion, the responsiveness of sows toward direct
human contact was lower during the first 12 h postpartum. The careful handling of piglets in the home pen
had a minimal effect on the probability of postural changes in sows. However, sows were highly reactive
towards the screaming of own trapped piglet during the whole 24 h period pp. The relative lower responsiveness towards playbacks, decreasing from 12 to 24 h pp, cast doubt upon the piglet scream
playback test as a useful approach to evaluate maternal responsiveness in sows.

For more information the full article can be found at http://journals.elsevierhealth.com/periodicals/applan/issues

Crate flooring can affect a sow’s comfort and health

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Choosing the right slatted flooring in farrowing crates could increase sow comfort and reduce shoulder pressure
lesions. That’s one of the observations coming out of a study by Kathy Zurbrigg, a surveillance analyst with the
Ontario Ministry of Agriculture, Food and Rural Affairs. The study set out to determine if a human pressure measurement system could be effectively used to measure the pressure exerted on a sow’s shoulder when it lays down to
farrow and nurse. Tests were conducted using two types of farrowing crate flooring – cast iron and triangular bar. It was found that the triangular bar flooring has narrower slats and wider slots (the openings between slats) than the cast iron slatted floor,” the study’s author observed. “The resulting decreased surface area for contact with the shoulder increases the pressure exerted on those areas that contact the slats, particularly the bony prominence of the scapula, because there is less surface area over which to distribute the sow’s weight. In this study, the addition of a rubber mat over part
of the farrowing crate floor significantly reduced the contact areas of the sow’s shoulder.

Dietary tryptophan helps to preserve tryptophan homeostasis in pigs suffering from lung inflammation

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In pigs, inflammation modifies Trp metabolism and consequently could impact on Trp requirement for growth. In this study, the effects of lung inflammation, induced by the intravenous injection of complete Freund’s adjuvant, and dietary Trp content on Trp metabolism and availability were investigated. Two dietary Trp contents, one corresponding to a low- Trp diet (1.5 g of Trp/kg of diet, Basal diet) and the second to an adequate-Trp diet (2 g of Trp/kg of diet,
TRP diet), were used. Ten blocks of 4 littermate piglets were selected at 40 d of age. Within each block, piglets were randomly assigned to 1 of the 4 experimental treatments: (1) healthy control and Basal diet, (2) inflammation and Basal diet, (3) inflammation and Basal diet + antioxidant, and (4) inflammation and TRP diet. Inflammation induced an increase in indoleamine 2,3 dioxygenase (IDO) activity, an enzyme involved in Trp catabolism, in lung, lymph nodes, heart, and spleen (P < 0.01). Contrary to piglets fed the TRP diet, pigs suffering from inflammation did not maintain
their plasma Trp concentrations when they were fed the Basal diet. Furthermore, pigs fed the TRP diet had decreased plasma haptoglobin concentrations, IDO activity, and lung weight than those fed the Basal diet, indicating that the inflammatory response was moderated with the greater Trp supply. Antioxidant addition in the Basal diet decreased the effects of inflammation on plasma Trp concentrations and IDO activity. These results indicated that inflammation increases Trp catabolism and thus may decrease Trp availability for growth.

For more information the full article can be found at http://jas.fass.org/

Maternal infanticide in sows: Incidence and behavioural comparisons between savaging and non-savaging sows at parturition

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Failure to establish normal maternal bonds occurs in individuals of many species. In some animals this may simply show as abandonment or refusal to care for offspring. An extreme behaviour, usually associated with litter bearing species, involves active maternal aggression towards newborns, up to and including infanticide. This behaviour has been observed in domestic sows (Harris et al., 2003) causing both significant economic losses to the pig industry and problems of animal welfare. Piglet mortality before weaning within commercial pig production is about 10% in Europe. One reason for these losses is sow aggression towards piglets (Lay et al., 2002). Aggression of sows towards their newborn offspring, a syndrome usually abbreviated by stockmen to ‘savaging’, has been described in large surveys of commercial piggeries in Europe with an incidence of 8% (Knap and Merks, 1987) and 7–12% (van der Steen et al., 1988). Harris and Gonyou (2003) also reported that the incidence came up with 5.3% of gilts in large study in the US. The behaviour may be defined as an active attack of piglets, using the jaws, that results in serious or fatal bite wounds. It almost always occurs during farrowing or immediately afterwards. The aims of this study were to investigate the incidence and nature of this behaviour and to compare other behaviours between savaging and non-savaging sows around parturition in 226 F2 sows that were produced by two highly divergent pig breeds of Chinese Erhualian and western Duroc with significantly genetic difference on maternal behaviours and were raised at three different pig farms. Each of these sows was housed in individual 2 m x 2.5 m pens with concrete floors. Three kilograms of fresh straw was provided to sows before parturition. Behaviour observations were made from 5 h before parturition to 24 h afterward using real time 1:0 sampling. Savaging sow was defined as an apparently deliberate attack on one or more piglets that resulted in the death, by biting, of at least one piglet. The incidence of savaging was: farm 1, 10.7% in gilts and 5.3% at the second farrowing; farm 2, 14.6% and 6.25%, respectively; farm 3, 6.8% at the second farrowing and 3.2% at the third farrowing. The incidence of savaging tended to be higher in gilts although some savaging gilts were killed before their second litters. There was no effect of the different farms on incidence of savaging. Prepartum nest building behaviours were not a predictor for savaging, but savage sows had a greater frequency of posture change from before parturition through the expulsive phase. This restlessness included an increase in rearing behaviour and a reduced ability to lie down carefully without endangering piglets. This study suggests that savaging is part of a more generalized behavioural pathology that includes increased excitability and is not specifically piglet directed.

For more information the full article can be found at http://journals.elsevierhealth.com/periodicals/applan/issues

Maternal responsiveness of sows towards piglet’s screams during the first 24 h postpartum

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In this study we focused on sow responsiveness towards piglet screams which are proposed to have an
important link to posture changes and early piglet crushing. A sow’s responsiveness to screams of her piglets was
investigated along the first 24 h after birth, the period of highest mortality, in 15 lactating sows housed in
farrowing crates.We compared the sow’s response to playbacks of screams of trapped piglets to her response to a
control sound during birth, 8–12 h postpartum and 20–24 h postpartum. We did the same with playbacks of
screams of fighting piglets during nursings 8–12 h postpartum and 20–24 h postpartum. The sow’ responsiveness
to screams of own trapped piglets was analyzed within the whole 24 h and to screams of fighting piglets
30 min between 8 and 12 h postpartum and 30 min between 20 and 24 h postpartum. A sow was scored as
responsive if she changed her posture in response to the stimuli. Sows had a four times higher response towards
playbacks with screams than towards the control stimulus. The proportion of the sows’ responsiveness to
screams (44%) of trapped piglets did not change significantly between birth, 8–12 h postpartum and 20–24 h
postpartum. Sows responded to 28% of playbacks of fighting piglets by terminating a nursing independently
from the time after birth. Playbacks and real screams of own piglets were similarly effective in evoking a
response for both types of screams. There was no significant association between the sows’ responsiveness to
screams of trapped piglets and piglet mortality nor between screams of fighting piglets and weight gain. In
conclusion our results indicate that sows maintained their responsiveness towards piglet screams during trapping
and during fighting for teats within the first 24 h. Playbacks and real screams were similarly effective in evoking a
response. We discuss the importance of the sound characteristics of piglet screams related to the sows’ response.

For more information the full article can be found at http://journals.elsevierhealth.com/periodicals/applan/issues