D C Lay

Purdue University, ウェストラファイエット, Indiana, United States

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Publications (59)97.42 Total impact

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    ABSTRACT: Chronic stressors are a major health and well-being issue in animals. Immune status of animals under chronic stress is compromised, thus reducing disease resistance and compromising well-being of the animal. The objective of this study was to determine the influence of group size of veal calves on immune status and leukocyte mRNA expression of acute phase cytokines, toll-like receptor 4 (TLR4) and tachykinin 1 (TAC1) over a five-month finishing period. Holstein bull calves (n=168), 44±3 days of age were assigned to one of three treatments; 2, 4, or 8calves/pen (pen space allowance of 1.82m(2)/calf). Jugular blood samples were collected at the day of grouping and then monthly for 4 months. The differential leukocyte counts were determined and mRNA was extracted from the leukocytes. Reverse transcription-qPCR was used to measure the gene expression of interleukin-1 (IL-1β), IL-1 receptor antagonist (IL-1Ra), tumor necrosis factor (TNF-α), TLR4, and TAC1 in leukocytes. Health was evaluated before grouping and monthly for 4 months. On the 1st month after grouping, veal calves that were housed in groups of 8 have greater expression of IL-1β mRNA than calves housed in groups of 4 or 2 (treatment×month, P=0.04). Also at 1 month, groups of 8 had greater TAC1 expression (P<0.05) than calves housed in groups of 4 or 2. However, the expression of IL-1Ra, TNF-α, and TLR4 were not influenced by group size. In the first month of the trial, calves in groups of 8 coughed more (P<0.05) than calves in groups of 2 and coughed more than calves in groups of 4 and 2 during the 2nd month (treatment×month, P=0.03). Calves housed in groups of 8 tended to have greater neutrophil percentage (P=0.09), neutrophil to lymphocyte ratio (P=0.06), and had lower lymphocyte percentage (P=0.06) than those housed in groups of 4 or 2. In conclusion, the number of veal calves in a group, given the same space during the finishing period did not alter IL-1Ra, TNF-α, and TLR4 mRNA expression. However, housing of calves in groups of 8 was associated with greater expression of IL-1β and TAC1 mRNA in peripheral blood leukocytes, and coughing during the first 2 months after grouping. Therefore, housing of veal calves in larger groups may lead to greater susceptibility to respiratory disease and stress. Published by Elsevier B.V.
    Veterinary Immunology and Immunopathology 02/2015; 164(3-4). DOI:10.1016/j.vetimm.2015.01.008 · 1.75 Impact Factor
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    ABSTRACT: In some parts of the world, the laboratory pig is often housed in individual, sterile housing, which may impose stress. Our objectives were to determine the effects of isolation and enrichment on pigs housed within the PigTurn® - a novel penning system with automated blood sampling - and to investigate tear-staining as a novel welfare indicator. Twenty Yorkshire × Landrace weaner pigs were randomly assigned to one of four treatments in a 2 x 2 factorial combination of enrichment (non-enriched [NE] or enriched [E]) and isolation (visually isolated [I] or able to see another pig [NI]). Pigs were catheterized and were placed into the PigTurns 48h post-recovery. Blood was collected automatically twice daily to determine WBC differential counts and assayed for cortisol. Photos of the eyes were taken daily and tear staining was quantified using a 0-5 scoring scale and Image-J software to measure stain area and perimeter. Behavior was video-recorded and scan sampled to determine time budgets. Data were analyzed as a REML using the MIXED procedure of SAS. Enrichment tended to increase proportion of time standing and lying laterally and decrease plasma cortisol, tear stain area and perimeter. There was a significant isolation by enrichment interaction. Enrichment given to pigs housed in isolation had no effect on plasma cortisol, but greatly reduced it in non-isolated pigs. Tear staining area and perimeter were highest in the NE-I treatment compared to the other three treatments. Eosinophil count was highest in the E-NI treatment and lowest in the NE-I treatment. The results suggest that in the absence of enrichment, being able to see another animal but not interact may be frustrating. The combination of no enrichment and isolation maximally impacted tear staining and eosinophil numbers. However, appropriate enrichment coupled with proximity of another pig would appear to improve welfare.
    Animal welfare (South Mimms, England) 01/2015; 24:15-27. DOI:10.7120/09627286.24.1.015 · 1.23 Impact Factor
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    ABSTRACT: Free-access stalls allow sows to choose the protection of a stall or use of a shared group space. This study investigated the effect of group space width: 0.91 (SS), 2.13 (IS), and 3.05 (LS) m on the health, production, behavior, and welfare of gestating sows. Nine replications of 21 (N = 189) gestating sows were used. At gestational day 35.4 ± 2.3, the pregnant sows were distributed into 3 pens of 7 sows where they remained until 104.6 ± 3.5 d. Each treatment pen had 7 free-access stalls and a group space that together provided 1.93 (SS), 2.68 (IS), or 3.24 (LS) m(2)/sow. Baseline measurements were obtained prior to mixing. Backfat depth, BW, BCS, and lameness were measured monthly and skin lesions scored weekly. Blood was collected monthly for hematological, immunological, and cortisol analyses. Sow behavior was video recorded continuously during the initial 4 d of treatment and 24 h every other week thereafter. Behavior was analyzed for location, posture, pen investigation, social contact, and aggression. Skin response to the mitogen concanavalin A (Con A) was tested at mean gestational day 106. Litter characteristics including size and weight were collected at birth and weaning. The data were analyzed using a mixed model. Multiple comparisons were adjusted with the Tukey-Kramer and Bejamini-Hochberg methods. Group space allowance had no effect on any measure of sow health, physiology, or production (P ≥ 0.10). Sows in the SS, IS, and LS pens spent 77.88 ± 3.88, 66.02 ± 3.87, and 63.64 ± 3.91%, respectively, of their time in the free-access stalls (P = 0.12). However, SS sows used the group space less than IS and LS sows (P = 0.01). Overall, pen investigatory behavior was not affected by group space allowance (P = 0.91). Sows in the LS pens spent more time in a social group than SS sows (P = 0.02); whereas sows in IS pens were intermediate to, but not different than the other treatments (P ≥ 0.10). The size of the social groups was also affected by the group space allowance (P = 0.03) with SS sows forming smaller groups than LS sows; again, IS sows were intermediate to, but not different than the other treatments. Although the group space allowance had no measurable impact on the health, physiology, or productivity of the sows, the lower group space use and social contact of the SS sows reduced the behavioral diversity benefits of group housing and may indicate an avoidance of social stressors or a lack of physical comfort in the smallest pens.
    Journal of Animal Science 03/2014; 92(6). DOI:10.2527/jas.2013-7352 · 1.92 Impact Factor
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    ABSTRACT: After birth, piglets undergo procedures likely to cause stress. The aim of this study was to evaluate stress responses evoked by 2 combinations (More Stressful [all a] or Less Stressful [all b]) of alternative methods for performing: 1) teeth resection (TR) - [a] clip vs. [b] grind; 2) identification (ID) - [a] ear tag vs. [b] ear notch; 3) iron administration (FE) - [a] inject vs. [b] oral; 4) castration (CA) - [a] cords cut vs. [b] cords torn; 5) tail-docking (TD) - [a] cold clip vs. [b] hot clip. Ten litters of eight, 2- and 3-d-old piglets were assigned to each procedure. Within each litter 1 male and 1 female piglet was assigned to 1 of 4 possible procedures: the 2 combinations, sham procedures, and sham procedures plus blood sampling. Blood was collected before processing and at 45 min, 4 h, 48 h, 1 wk, and 2 wk afterwards and assayed for cortisol and β-endorphin concentrations. Procedures were video-taped and analyzed to evaluate the time taken to perform the procedure and the number of squeals, grunts and escape attempts. Vocalizations were analyzed to determine mean and peak frequencies and duration. Piglets were weighed before the procedure and at 24 h, 48 h, 1 wk, and 2 wk afterwards. ID, TD and CA lesions were scored on a 0 to 5 scale at 24 h, 1 wk, and 2 wk post-procedure. Both combinations of methods took longer to carry out than sham procedures and resulted in more squeals, grunts and escape attempts during the procedures and higher peak frequencies of vocalizations compared with the control treatments (P < 0.05). Cortisol concentrations 45 min after processing was also higher in the two combination treatments than in the sham treatments (P < 0.05). Comparing between procedure treatments, the More Stressful combination of methods took longer to carry out, resulted in higher β-endorphin concentrations at 1 wk, had higher peak frequency of vocalizations and increased ear (P < 0.05) and tail wound (P < 0.1) lesion scores at 1 wk than the Less Stressful combination. Growth during d 2-7 post-procedure was lower in More Stressful piglets than control piglets (P < 0.05) but by 2 wk, growth was unaffected. Using measures of behavior, physiology and productivity, the More Stressful combination of procedures decreased welfare relative to the Less Stressful combination, however both combinations decreased welfare relative to controls. The time taken to carry out the procedure would appear to be an important factor in the strength of the stress response.
    Journal of Animal Science 02/2014; 92(3). DOI:10.2527/jas.2013-6929 · 1.92 Impact Factor
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    ABSTRACT: In many mammalian species, prenatal stress masculinizes female and feminizes male offspring impairing their reproductive capacity. Regrouping gestating sows is a common, stressful production practice, but its impact on the sow's developing pigs is not fully known. This study examined the effects of regrouping gestating sows and the administration of exogenous glucocorticoids on the growth and external reproductive morphology of pigs. At 37.2 ± 0.26 d of gestation, 6 cohorts of 18 sows (N = 108) were placed in 1 of 3 treatments: socially stable (Stable), hydrocortisone acetate (HCA), or mixed (Mixed). The HCA sows were administered 70 mg HCA, a synthetic glucocorticoid, twice daily during the 21 d experimental period. Each Mixed sow was penned with 2 companion sows (Companion) and regrouped on d 7 and 14 with 2 different Companion sows in a new pen. Stable and HCA sows were penned in treatment groups of 3 sows. Sow social rank was assessed weekly during feeding. After the 21 d experimental period, all sows were housed in gestation stalls for the duration of pregnancy. During the 21 d, Companion sows gained more weight than HCA and Mixed sows (P < 0.05) with Stable sows intermediate. High ranked sows gained more weight than middle and low ranked sows (P < 0.05). Mixed sows had greater head lesion scores than Stable and HCA sows (P < 0.05) with Companion sows intermediate. Head lesions increased with lower social rank (P < 0.001). Sow treatment did not affect farrowing rate, litter size, or sex ratio (P > 0.10). Social rank also had no effect on farrowing rate (P > 0.10), but affected total litter size (P = 0.03). High ranked sows bore and weaned more live females than low ranked sows (P < 0.05), in part due to differential preweaning mortality among female pigs (P = 0.01). Only male pigs were affected by sow treatment. Preweaning mortality was higher among male pigs from HCA than from Mixed sows (P = 0.04) with other treatments intermediate. Despite no weight differences in the preweaning period, at 160 d of age males from HCA sows weighed more than males from Stable sows (P = 0.01) with other treatments intermediate. Males born to Companion sows had longer relative anogenital distances, a marker of fetal testosterone exposure, than males from Mixed sows (P = 0.03) with other treatments intermediate. The prenatal environment affected the pigs in a sex-specific manner altering the growth and reproductive morphology of the males more than that of the females.
    Journal of Animal Science 01/2014; 92(2). DOI:10.2527/jas.2013-6773 · 1.92 Impact Factor
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    ABSTRACT: Objectives of this study were to determine the physiological effects of psychological stress applied to dairy calves and to test if molasses consumption could be used to validate that a stressed condition was achieved. Twenty male calves (3 wk old) received jugular catheters and were randomly assigned to control (CTR; n = 4 pens of 1 calf per pen) or social stress treatments (STR; n = 4 pens of 4 calves per pen). The STR treatment included 5 cycles of 24-h isolation followed by regrouping with unfamiliar animals for 48 h (over 15 d). An ACTH challenge (0.1 IU/kg of body weight) was used to determine adrenal fatigue. Peak and total cortisol concentrations were greater for STR calves until the ACTH challenge. After the ACTH challenge, CTR calf cortisol increased and STR calf cortisol continued to decrease, suggesting adrenal fatigue. The number of calves that became positive for fecal shedding of Salmonella after the acute stress of being moved and the number of calves that were positive after the move decreased with each move. Fifty-six percent of STR calves changed from negative to positive for shedding after the first move compared with 18.75% of STR calves remaining negative after the third move. Difference in fecal shedding of Enterobacteriaceae from samples taken before and after moving calves on d 6 was less than that on d 2, 3, and 5. Leukocyte counts were not different, but trends for day effects were detected for neutrophil and monocyte percentages. Molasses consumption was greater for STR calves on d 2 and 11, as was total consumption. Latency to lie after eating also increased as the study progressed; STR calves required more time to lie after eating on d 12 than on d 3, and latency to lie was greater for STR than CTR on d 4, 8, 12, and 14. The STR calves also stood more than the CTR calves in the 4-h afternoon period on d 4, 5, 7, and 14. However, during the 4-h morning observations on d 14 (ACTH challenge), CTR calves stood more than STR calves. This model induced chronic stress, as characterized by adrenal fatigue, which was confirmed by molasses consumption and behavior changes. Therefore, molasses consumption could be used to confirm social stress in experimental models.
    Journal of Dairy Science 09/2013; 96(11). DOI:10.3168/jds.2013-6944 · 2.55 Impact Factor
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    ABSTRACT: The objective of this study was to investigate the effect of group size on behavior, growth, health, and welfare of veal calves. Holstein-Friesian bull calves (n = 168; 44 ± 3 d of age) were assigned randomly to 1 of 3 treatments of group housing with 2, 4, or 8 calves/pen. The pens used for housing were 3 × 1.20 m (2 calves/pen), 3 × 2.40 m (4 calves/pen), and 3 × 4.80 m (8 calves/pen), supplying a total pen space allowance of 1.82 m(2) /calf, regardless of pen size. Behavior was recorded from video data throughout the day from 0700 to 1900 h, during a single day each month for 5 mo using scan sampling every 5 min within 30-min observation sessions. On d 0, 1, 5, 14, 42, and 70 after grouping, continuous focal sampling around feeding time (30-min intervals before, during, and after feeding) focused on oral and aggressive behaviors. Calves housed in large groups (4 or 8 calves/pen) showed more (P ≤ 0.001) conspecific contact, walking, and standing, and less (P < 0.001) manipulation of objects, self-licking, and lying when compared to calves housed in small groups (2 calves/pen). Group size had no effect on play behavior (P = 0.11) throughout the experiment. During feeding times group size had no (P ≥ 0.07) effect on any behavioral patterns except for duration of conspecific contact (P < 0.01). Aggression at feeding time was not (P > 0.23) affected by treatment. Group size treatments were similar for hip height change (P = 0.41) and heart girth change (P = 0.18) over the duration of the experiment; however, both hip height and heart girth increased (P = 0.001) with calf age. During mo 1, calves in groups of 8 or 4 coughed more than calves in groups of 2, whereas calves in groups of 8 coughed more than calves in groups of 4 or 2 in mo 2 (treatment × month, P = 0.03). Furthermore, during mo 4, calves in groups of 8 had less nasal discharge than calves in groups of 2 or 4 (treatment × month, P = 0.02). Ocular discharge, ears, and fecal scores did not differ (P ≥ 0.05) among treatments. Plasma cortisol was not (P ≥ 0.37) affected by group size. The number of veal calves in a group when given the same space did not affect production and physiological indicators of welfare but had a transient effect on health during the 5-mo finishing period. If increased play, social contact, and decreased aggression are considered as primary indicators of welfare, group size did not alter calf welfare.
    Journal of Animal Science 08/2013; 91(11). DOI:10.2527/jas.2013-6308 · 1.92 Impact Factor
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    R L Dennis, D C Lay, H W Cheng
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    ABSTRACT: Serotonin (5-HT) acts as a neurogenic compound in the developing brain; however serotonin altering drugs such as SSRIs are often prescribed to pregnant and lactating mothers. Early agonism of 5-HT receptors could alter the development of serotonergic circuitry, altering neurotransmission and behaviors mediated by 5-HT signaling, including memory, fear and aggression. This study was designed to investigate the effects of early serotonin agonism on later behaviors. An extremely aggressive White leghorn strain (15I5) was used in the study. The chicks were injected with 5-MT (a serotonin agonist) at 2.5mg/kg (low dose), 10mg/kg (high dose) or saline (control) on the day of hatch and a second dose 24h later (n=9/sex/trt). Chicks' fear response and memory were tested at 2 weeks of age. In the fear test, chicks were subjected to a social isolation test for 20minutes, time to first vocalization and numbers of vocalizations were recorded. In the memory test, chicks were placed in a running wheel and presented with an imprinted object (white box with a red light) and a similar shaped novel object (blue box with a white light), respectively. The distance traveled in the wheel toward each object was measured. At 10 weeks of age birds were tested for aggression and concentrations of catecholamines were determined from the raphe nucleus and hypothalamus by HPLC (n=12). Expression of 5-HT1A and 5-HT1B receptor genes were measured by RT-PCR. Both high and low dose chicks tended to have shorter latency to first vocalization and a greater number of vocalizations compared with control chicks. Memory test showed that chicks from all groups traveled a similar distance toward a familiar object. However, control chicks walked the least toward a novel object, low dose chicks tended to walk further, and high dose chicks walked significantly further for a novel object. In aggression tests, both high and low dose males exhibited greater frequency of aggressive behaviors compared to controls, while no difference in aggression was evident in the females. Norepinephrine concentrations were also reduced in the low dose birds in the hypothalamus and in the raphe nucleus. Serotonin concentrations tended to be lower only in the both hypothalamus and raphe nucleus of the low dose birds. 5-HT1A expression was greatest in the hypothalamus and raphe nucleus of low dose birds. The agonism of the serotonin system during neural development of birds genetically predisposed to aggression alters both the dopaminergic and serotonergic systems further increasing their aggressiveness.
    Behavioural brain research 08/2013; 253. DOI:10.1016/j.bbr.2013.07.043 · 3.39 Impact Factor
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    ABSTRACT: Agonistic interactions are a powerful stressor. Conversely, positive social interactions can reduce the adverse effects of social stress. This possibly occurs through the action of oxytocin (OT), a neuropeptide able to reduce activation of the hypothalamo-pituitary-adrenal (HPA) axis. We hypothesized that repeated OT intranasal administration to neonatal pigs could provide long-lasting protective effects against social stress. In each of six litters, two pigs per litter received 0.5mL of saline containing 24IU (or 50μg) of OT intranasally and two control littermates received 0.5mL of saline as a control at 1, 2 and 3days of age. Contrary to our predictions, when socially mixed after weaning at 17days of age, neonatally OT-administered pigs received more aggressive interactions and performed more aggressive interactions in return, showed greater locomotion, spent less time in social contact, and had greater cortisol concentrations than control pigs. When this social mixing was repeated at 8weeks of age, OT pigs still performed more aggressive interactions and had greater adrenocorticotropic hormone concentrations than control pigs. A dexamethasone suppression test and corticotropic releasing hormone administration challenge at 11weeks of age revealed that OT pigs were less responsive to dexamethasone than control pigs, suggesting a deficient HPA axis' negative feedback control. Postnatal repeated OT administration altered social behavior and resulted in a long-term dysregulation of the HPA axis. These findings highlight the complex, fine-tuning of the neurobiological mechanisms regulating the development of social behavior and suggest caution in the application of neonatal peptide treatments during early development.
    Physiology & Behavior 02/2013; DOI:10.1016/j.physbeh.2013.02.007 · 3.03 Impact Factor
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    ABSTRACT: The search for alternative methods to euthanize piglets is critical to address the public's concern that current methods are not optimal. Scientific evidence support that blunt force trauma is humane when carried out correctly, but most people find it visually difficult to accept. The use of CO2 is often recommended, at the same time it is criticized as being aversive to pigs. This research sought to: 1) identify a method of scientifically determining if piglets find a gas aversive, using an approach-avoidance test which relies on the piglet's perspective, and 2) test different gas mixtures to determine if they are effective and humane for neonatal piglet euthanasia. Pigs were allowed to walk freely between 1 chamber filled with air and another chamber either gradually filled with gas mixtures (Experiment 1) or pre-filled with gas mixtures (Experiment 2). Experiment 1 tested CO2 (90%) and air (10%); N2O (60%) and CO2 (30%); Ar (60%) and CO2 (30%); and N2 (60%) and CO2 (30%). Since piglets had to be removed when they started to flail, the test was shortest (P < 0.01) for the pigs in the CO2 treatment compared with pigs in the N2O/CO2, Ar/CO2, and N2/CO2 treatments, 3.1 ± 0.2, 8.5 ± 0.6, 9.6 ± 0.4, and 9.9 ± 0.1 min, respectively. Nonetheless, all gas mixtures adversely affected the pigs, causing the pigs to leave the test chamber. In Experiment 2, piglets were allowed to enter a chamber pre-filled with N2/CO2 or N2O/CO2 (both 60%/30%). Pigs exposed to the pre-fill chambers started to flail in less than 20 s, much faster in comparison to the gradual fill method, which support that this method was more aversive. In Experiment 3, piglets were euthanized using a 2-step procedure. Pigs were first placed in a gradual fill chamber with 1 of 4 gas mixtures: 90% CO2, N2/CO2, N2O/CO2 or N2O/O2 (the last 3 mixtures at 60%/30%) followed by placement into a 90% CO2 pre-fill chamber when the pigs started to flail or were anesthetized. All 3 gas treatments that contained CO2 killed pigs more quickly than N2O/O2 (P < 0.05). However, N2O/O2 was the only treatment that anesthetized the pigs instead of causing squeals or flailing, although requiring about 12 min longer. Although longer, a 2-step procedure in which pigs are anesthetized with a mixture of N2O and O2 prior to being euthanized by immersion in CO2 may prove to be more humane than CO2 alone.
    Journal of Animal Science 01/2013; 91(4). DOI:10.2527/jas.2012-5761 · 1.92 Impact Factor
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    ABSTRACT: Pigs may be housed individually in both production and research settings. Gregarious by nature, pigs kept in isolation may show behavioural and physiological signs of stress. In this study we investigated the preference of individually housed pigs, for social and non-social enrichments. Three enrichment items were compared: a mat (MAT), a companion (COM) and a mirror (MIR). Fourteen weaner pigs (Yorkshire × Landrace) were housed individually with continuous access to 4 adjacent pens. One pen was a control (CTRL) and had no enrichment; the others had one enrichment each, either a mat on part of the woven wire floor (MAT), a companion visible across the passageway (COM) or a mirror on one wall (MIR). Pigs spent more proportion of time (P = 0.021) in the COM pen (0.65 ± 0.07) compared to the CTRL pen (0.31 ± 0.07) with the MAT pen (0.57 ± 0.07) and the MIR (0.42 ± 0.07) pen as intermediates. They also spent more total time engaged in investigative and inactive behaviours in the COM pen compared to the CTRL pen (P = 0.007). A second analysis was performed to investigate changes in preferences in the presence or absence of a human in the room. The pens were then combined into two categories: social pens (COM and MIR) and nonsocial pens (MAT and CTRL). The probability of a pig being observed in the MIR pen when a human was present was significantly higher (P = 0.0001), than when absent. Within the social enrichments, the probability of the animal being observed in either MIR or COM pen was not different (P = 0.017). Our results confirm that preference studies may be highly sensitive to experimental conditions. Thus, the assumption that the most important preference is the one the animal spends most of its time with can be misleading. It appears that a mirror may be used by the animal for social support during periods of perceived threat, however further investigation is warranted.
    Applied Animal Behaviour Science 01/2013; 143(2-4):96-103. DOI:10.1016/j.applanim.2012.10.007 · 1.63 Impact Factor
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    ABSTRACT: A pure form of salbutamol has the potential to deliver positive production benefits to the swine industry. The aim of this experiment was to determine the effects of salbutamol on growth, carcass measures and health of finishing pigs. The study used 192 pigs (89 ± 1 kg BW) housed in groups of 6 in 32 pens and assigned to 1 of 4 treatments: 1) control (CTL) - 0 mg/kg salbutamol, 2) 2R - control diet with 2 mg/kg of the pure R-enantiomer of salbutamol, 3) 4R - control diet with 4 mg/kg of pure R-salbutamol, or 4) 8RS - control diet with 8 mg/kg of a 50:50 mixture of the R- and S- enantiomers. All diets were offered ad libitum for 4 wk. All pigs were weighed and pen feed intakes recorded weekly. At slaughter, individual hot carcass weights (HCW) and measurements of the 10(th) rib loin muscle area (LMA), color, marbling, firmness, and backfat, last lumbar and midline backfat depths were collected. Data were analyzed using Proc GLM of SAS, with pen as the experimental unit. Overall, 2R and 4R pigs had greater ADG than CTL pigs (P < 0.05) and at slaughter, were heavier than CTL pigs (P < 0.01). Overall, 8RS pigs had lower ADFI (P < 0.05) and CTL pigs had poorer G:F (P < 0.001) than the other three treatments respectively. All salbutamol fed pigs had 5-6 kg greater HCW (P < 0.001), 2-3% increased carcass yield (P < 0.001), 5.6 cm(2) larger LMA (P < 0.01), 3-4 mm less 10(th) rib backfat (P < 0.01) and 2 mm less lumbar backfat (P < 0.05) than CTL pigs. However, control pigs had higher loin muscle color scores (P < 0.05) and marbling scores (P < 0.001) than all salbutamol-treated pigs. Taken together, these data indicate that as little as 2 mg/kg R-salbutamol has a positive effect on pig growth and carcass composition. However, the effects of salbutamol on meat quality require further research.
    Journal of Animal Science 08/2012; 90(11). DOI:10.2527/jas.2011-4423 · 1.92 Impact Factor
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    ABSTRACT: The purpose of this study was to determine how increasing the frequency of co-mingling affected piglets' behavior development before and after weaning. Co-mingling once (CM1), piglets interacted with 1 unfamiliar litter Days 10-18 after birth; co-mingling twice (CM2), piglets interacted with 1 unfamiliar litter Days 10-14; and with another, Days 14-18. Control (CM0) piglets did not interact with unfamiliar litters before Day 18 (n = 16 litters per treatment). The study weighed piglets and recorded ear-injury scores throughout the experiment; however, there were no treatment differences. The CM2 piglets spent less time engaged in aggressive interactions (p < .05) than did CM0 piglets following mixing at weaning. During the social challenge, CM2 piglets spent more time in proximity to one another, had shorter latencies to first aggressive interaction, and spent less time fighting than did CM0 piglets (p < .05). During the social recognition test, CM2 piglets recognized the stimulus piglet at a faster rate than did CM0 piglets (p < .05). Overall, CM2 resulted in changes to some social behaviors compared with CM0 but not with CM1.
    Journal of Applied Animal Welfare Science 04/2012; 15(2):163-80. DOI:10.1080/10888705.2012.658333 · 0.69 Impact Factor
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    ABSTRACT: Castration of male livestock being reared for meat has long been practiced, to prevent unwanted breeding, make management and handling easier, and to improve meat quality. However, castration is a painful procedure for the animal and has increasingly come under scrutiny from animal welfare lobbyists. Depending on the species, a number of different methods are available which include surgical removal of the testes following scrotal incision, crushing of the blood and nerve supply using clamps, rubber rings or latex bands, the destruction of testicular tissue using chemicals or vaccination against hormones such as GnRH and LH that control testicular function (immuno-castration). The degree of pain experienced by the animal may depend on the method used and the age at which the procedure is carried out. This is characterized by an activation of the HPA axis, resulting in a large cortisol response, and obvious display of pain-related behaviours including abnormal posture, increased inactivity, and attention directed towards the site of injury. Use of anaesthetics and analgesics impact the degree of pain experienced. As alternatives, such as immuno-castration or the rearing of intact males become more prevalent, the needs for castration will diminish. However, in the meantime, castration will continue to be seen by many producers as a “routine” procedure, subject to varying degrees of recommendation of best practice or legislation depending on country, and subject to attention from animal welfare groups and policy-makers. Further science is needed to best inform all stakeholders as to the longer-term implications of castration methods on pain and welfare of individuals.
    Applied Animal Behaviour Science 12/2011; 135(3). DOI:10.1016/j.applanim.2011.10.017 · 1.63 Impact Factor
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    ABSTRACT: Sows subjected to prenatal stress have been found to produce offspring that have altered responses to stress. Our objective was to determine if exposing a sow to stress would alter the response of the offspring to lipopolysaccharide (LPS) at 2 mo of age or their response to mixing stress at 4 mo of age. Sow treatments consisted of intravenous injections of ACTH (1 IU/kg of BW), exposure to rough handling for a 10-min duration (rough), or no treatment (control) once per week from d 42 to 77 of gestation. At 2 mo of age, pigs from each treatment, 1 per litter (n = 21, 17, and 15 for the ACTH, rough, and control treatments, respectively), were challenged with 2 μg of LPS/kg of BW or saline, or served as a noninjected control. Their behavioral response to a human approach test and salivary cortisol were measured. At 4 mo of age, 1 pig from each treatment (n = 14, 14, and 15 for the ACTH, rough, and control treatments, respectively) was taken from its home pen and placed in a pen of unfamiliar pigs. At this time, a punch biopsy wound (6 × 6 mm) was created to measure the ability of the pig to heal the wound. At this same time, each pig received a 1-mL intramuscular injection of 20% ovine red blood cells (oRBC), and then a second injection of oRBC at 21 d postmixing. Blood samples were collected 3 times per week for 2 wk and then once a week for 4 more weeks. Blood samples were analyzed for cortisol, porcine corticosteroid-binding globulin, antibody response to oRBC, and nitric oxide production by macrophages. Behavior was recorded during the first 5 d after mixing. All pigs in the LPS challenge responded with characteristic sickness behavior; however, pigs in the rough treatment showed less sickness behavior than those in the other 2 treatments (P < 0.05). Maternal stress treatment did not affect (P < 0.43) salivary cortisol. Pigs from all treatments responded similarly to mixing stress with regard to cortisol, porcine corticosteroid-binding globulin, antibody titers, nitric oxide production, and hematology measures, and all pigs experienced the same amount of aggression in response to mixing. Without altering peripheral measures of stress responsivity, prenatal stress enhanced the ability of pigs to cope with a simulated immune challenge, which could prove to be an adaptation to challenging environments.
    Journal of Animal Science 06/2011; 89(6):1787-94. DOI:10.2527/jas.2010-3612 · 1.92 Impact Factor
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    J-L Rault, D C Lay
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    ABSTRACT: Surgical castration is performed on most male piglets in the United States. However, castration is painful and analgesics have been considered to relieve pain. Inhalant gases with analgesic properties allow for a fast induction, have short-term and reversible effects, and are a needle-free option. Nitrous oxide (N(2)O; "laughing gas") has been widely used in human surgery and dental offices as an analgesic, sedative, and anxiolytic drug, yet N(2)O has not been thoroughly investigated for use in farm animals. We hypothesized that the analgesic effect of N(2)O could reduce the pain experienced by piglets during or immediately after castration. Twenty-four male piglets, from 12 litters, were castrated at 3 d of age. One piglet received N(2)O and a littermate received air as a control. After 150 s of exposure to the gas, castration was performed while the piglet remained exposed to the gas. Agitation scores and total vocalization length were recorded during castration. Behavioral observations were continued for 3 d postcastration by using a 5-min scan-sampling method for 4 h the first morning and for 2-h periods in the morning and afternoon of each day thereafter. Body weight gain was measured on the day before castration, at 3 d postcastration, and at weaning. Data were analyzed using a mixed model in SAS (Cary, NC). Nitrous oxide successfully induced anesthesia in all N(2)O piglets, as validated by a skin pinch test and the loss of the palpebral reflex. Total vocalization length was shorter in piglets receiving N(2)O during the induction phase (P = 0.003) but was not different during castration itself because piglets receiving N(2)O awoke and vocalized as much as control piglets (P = 0.87). Agitation scores during the whole procedure were reduced in piglets receiving N(2)O in both frequency (P = 0.005) and intensity (P = 0.026). For 2 h after castration, piglets receiving N(2)O displayed less huddling behavior than did control piglets (P = 0.01). Over the 3 d, piglets receiving N(2)O performed more tail wagging (P = 0.02) and tended to show fewer sleep spasms (P = 0.06) than did control piglets. Piglets given N(2)O tended to have a reduced growth rate compared with control piglets at 3 d postcastration and at weaning (P = 0.05 and P = 0.06, respectively). Nitrous oxide was effective in inducing anesthesia in neonatal piglets during handling. Nonetheless, its analgesic effects appeared insufficient in preventing castration-induced pain.
    Journal of Animal Science 05/2011; 89(10):3318-25. DOI:10.2527/jas.2011-4104 · 1.92 Impact Factor
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    ABSTRACT: Finishing pigs infected with Salmonella pose significant food safety risks by carrying the pathogen into abattoirs. This study was conducted to determine the dynamics of Salmonella infection in finishing pigs, and associated immunological, physiological, and behavioral alterations, by longitudinally comparing infected to noninfected pigs during 6 weeks postinfection (p.i.). Bacteriological data revealed that all inoculated pigs started shedding Salmonella within 2 h p.i., and persistently shed the bacteria up to the end of the study. Ileal and cecal contents, as well as mesenteric lymph node samples, were all positive throughout the study, containing 3-4 log(10) cfu/g of Salmonella at 24 h p.i., and 4-5 log(10) cfu/g of Salmonella up to 4 weeks p.i. Levels of Salmonella dropped markedly (p < 0.05) in all samples at 5 weeks p.i. There was no difference between groups for blood cell counts. Tumor necrosis factor-α was greater (p < 0.05) in infected pigs: (1) in the mesenteric lymph nodes by 48 h p.i.; (2) at 24 h and 3 weeks p.i. in the ileum; and (3) in the cecum and spleen at 3 weeks p.i. Interleukin-12, interleukin-1 and its antagonist, and a porcine-specific antimicrobial peptide RNA expression in tissues changed over time, but were not different between groups. Infected pigs spent more time in ventral recumbency, standing, and sitting than controls (p < 0.01). Infected pigs were also more active (p < 0.01), and approached a novel object more quickly than control pigs (p < 0.05). No treatment differences were detected for rectal temperature or plasma cortisol (p > 0.10). This study shows that finishing pigs can carry high levels of Salmonella for up to 4 weeks p.i. in the gastrointestinal contents and mesenteric lymph nodes, shedding high levels of the bacteria without developing clinical symptoms, but developing an immune response throughout the intestinal tract. Moreover, subtle behavioral changes measured as postures were detected, and therefore warrant additional investigation.
    Foodborne Pathogens and Disease 05/2011; 8(5):623-30. DOI:10.1089/fpd.2010.0735 · 2.09 Impact Factor
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    ABSTRACT: Understanding autonomic nervous system functioning, which mediates behavioral and physiological responses to stress, offers great potential for assessing farm animal stress and welfare. Evaluation of heart rate variability (HRV) and blood pressure variability (BPV), using time and frequency domain analyses may provide a sensitive and reliable measure of affective states and stress-mediated changes in sympathetic and parasympathetic tones. The aim of this research was to define low (LF) and high frequency (HF) power spectral ranges using pharmacological autonomic blockade, and to examine HRV and BPV parameter changes in response to atropine and propranolol in swine. Ten, 13-week old, barrows (n=6) and gilts (n=4) underwent surgery to place an intra-cardiac electrode and a blood pressure catheter attached to a biotelemetric transmitter; pigs had a 3-week recovery period prior to data collection. Each pig was subjected to administration of 4 intravenous (i.v.) drug treatments: a control treatment, 3 mL of saline, and 3 blockade treatments; 0.1 mg/kg of atropine, 1.0 mg/kg of propranolol, and .1 mg/kg of atropine together with 1.0 mg/kg of propranolol. All treatments were delivered by injection in the jugular vein with a minimum of 48 h between individual treatments. Behavior, ECG and blood pressure data were recorded continuously for a total of 1h, from 30 min pre-injection to 30 min post-injection. For data analyses, two 512-beat intervals were selected for each treatment while the pig was lying and inactive. The first interval was selected from the pre-injection period (baseline), and the second was selected between 10 and 30 min post-injection. Time and frequency domain (power spectral density) analyses were performed on each data interval. Subsequent, LF and HF bands from the power spectral densities were defined based on general linear and regression analyses. The HRV and BPV were computed with a covariate (baseline) factorial analysis of treatment by sex interaction, and day of injection, with mixed models and Tukey's post-hoc tests. The best-fit range for LF was 0.0-0.09 Hz, and HF was 0.09-2.0 Hz (r²: 0.41 and 0.43, respectively). Propranolol and saline injections led to a greater overall total power and overall higher inter-beat interval, HF and LF power. Atropine led to a dominant sympathovagal balance of the cardiac activity in pigs. In addition, atropine led to an increase in LF power of both systolic and diastolic blood pressures in gilts suggesting vagal tone mediation of BPV. The understanding of autonomic regulation of HRV and BPV in domestic swine facilitates our ability to detect and quantify stress responses, and broadens its application in assessing farm animal welfare.
    Physiology & Behavior 05/2011; 103(2):188-96. DOI:10.1016/j.physbeh.2011.01.019 · 3.03 Impact Factor

Publication Stats

796 Citations
97.42 Total Impact Points

Institutions

  • 2007–2014
    • Purdue University
      • • USDA-ARS Livestock Behavior Research Unit
      • • Department of Animal Sciences
      ウェストラファイエット, Indiana, United States
    • West Virginia University
      • Division of Animal and Nutritional Sciences
      Morgantown, WV, United States
  • 2011
    • Agricultural Research Service
      Kerrville, Texas, United States
  • 2000–2002
    • Iowa State University
      • Department of Animal Science
      Ames, IA, United States
  • 1991–1998
    • Texas A&M University
      • Department of Animal Science
      College Station, Texas, United States
  • 1997
    • Southern University Agricultural Research and Extension Center
      Baton Rouge, Louisiana, United States