[Show abstract][Hide abstract] 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.
[Show abstract][Hide abstract] 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.
[Show abstract][Hide abstract] 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.
[Show abstract][Hide abstract] 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.
[Show abstract][Hide abstract] 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.
[Show abstract][Hide abstract] 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 · 3.03 Impact Factor
[Show abstract][Hide abstract] 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.
[Show abstract][Hide abstract] 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.
[Show abstract][Hide abstract] 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.
[Show abstract][Hide abstract] 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.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate stress responses evoked by 2 alternative methods for performing the following processing procedures: 1) teeth resection-clipping vs. grinding; 2) tail docking-cold vs. hot clipping; 3) identification-ear notch vs. tag; 4) iron administration-injection vs. oral; 5) castration-cords cut vs. torn. Eight to 10 litters of 8-, 2-, and 3-d-old piglets were assigned to each procedure. Within each litter, 2 piglets were assigned to 1 of 4 possible procedures: the 2 alternative methods, a sham procedure, and a sham procedure plus blood sampling. Blood was sampled before processing and at 45 min, 4 h, 48 h, 1 wk, and 2 wk postprocedure and assayed for cortisol and beta-endorphin. Procedures were videotaped 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 afterward. Lesions were scored on a scale of 0 to 5 on pigs in the identification, tail docking, and castration treatments at 24 h, 1 wk, and 2 wk postprocedure. For teeth resection, grinding took longer than clipping and resulted in greater cortisol concentration overall, poorer growth rates, and longer vocalizations compared with pigs in the control treatment (P<0.05). For tail docking, hot clipping took longer, and hot-clipped piglets grew slower than cold-clipped piglets (P<0.05). Hot clipping also resulted in longer and higher frequency squealing compared with pigs in the control treatment (P<0.01). For identification, ear notching took longer than tagging, and ear-notched piglets had worse wound scores than tagged piglets (P<0.05). Cortisol concentrations at 4 h also tended to be greater for ear-notched piglets (P<0.10). Ear notching evoked calls with higher peak frequencies than the control treatments. For iron administration, oral delivery took numerically longer than injecting, but there were no significant differences between injecting and oral delivery for any of the measures. For castration, tearing took longer than cutting the cords (P<0.05), but beta-endorphin concentrations at 45 min postprocedure were greater for cut piglets. When measures of behavior, physiology, and productivity were used, the responses to teeth resection, tail docking, and identification were shown to be altered by the procedural method, whereas responses to iron administration and castration did not differ. The time taken to carry out the procedure would appear to be an important factor in the strength of the stress response.
[Show abstract][Hide abstract] ABSTRACT: This study was conducted to determine the effect of experimentally increased glucose demand on voluntary consumption of molasses by dairy calves. Three-week-old calves received 0.365 g of phlorizin by s.c. injection. Urinary output and molasses consumption were measured hourly, and urinary glucose concentration was screened. Molasses consumption for the 24 h after treatment was (mean +/- SE) 72.0 g (+/-7) for the control group and 142 g (+/-1) for the phlorizin-treated group. Urinary output for the 8-h test period was 1.13 kg for the control group and 1.67 kg for the phlorizin-treated calves. Mean urinary glucose peaked at 10 g/L by 4 h after treatment for calves given phlorizin, whereas the concentration for the control group remained close to 0 g/L. Phlorizin treatment increased voluntary consumption of molasses in 3-wk-old Holstein calves.
[Show abstract][Hide abstract] ABSTRACT: Lameness in breeding-age gilts and sows is a major cause of culling, resulting in increased economic losses and welfare concerns. This study determined if exercise during gestation would affect the musculo-skeletal system, production variables, and behavior. Gilts were blocked by BW and assigned to 1 of 3 treatment groups: control (n = 10; no exercise), low exercise (n = 14; 122 m/d for 5 d/wk), and high exercise (n = 14; 122 m/d for 2 d/wk and 427 m/d for 3 d/wk). All gilts were stall-housed during gestation, and gilts were exercised between d 35 and 110 of gestation. Lameness score, BCS, BW, and blood were taken at multiple points before gestation, and during gestation and lactation. Blood serum was analyzed for carboxy-terminal telopeptide of type I collagen. Sow lying behavior was recorded for 3 d after farrowing. Farrowing data included litter weight and size at birth and weaning, and preweaning mortality. After weaning, 38 sows were slaughtered and muscles and the bones of the left fore- and hind-limbs were harvested. Bone density and quality were determined by computed tomography (CT) scans, dual energy x-ray scans, and bone-breaking force tests. The control group took longer to lie down than both exercise groups, and the low exercise group took longer to lie down than the high exercise group (P < 0.05). The number of pigs weaned was greater in the high exercise group than the control group (P < 0.05). Piglet preweaning mortality was greatest in the control group compared with both exercise groups (P < 0.05). The low exercise treatments exhibited a greater bone density (CT) in the humerus, radius, and tibia compared with that of the control group (P < 0.05). The bone density (CT) of the humerus in the low exercise group was greater than that of the high exercise group (P = 0.03). Breaking force in the humerus and femur was greater (P < 0.05) in the low exercise group than the control group. Breaking force in the tibia of the high exercise group was greater than the control group (P = 0.01). The tibia of both the low and high exercise groups had a greater breaking force (P < 0.05) than the control group. Although there was no benefit of exercise on lameness, differences in bone density and quality, lying behavior, and piglet survivability may provide useful insight into alternative housing for sows.
[Show abstract][Hide abstract] ABSTRACT: Salbutamol has potential for use as a repartioning agent in swine. The aims of this experiment were to determine effects of salbutamol on behavior and physiology of finishing pigs. The study used 192 pigs (88.8 +/- 0.9 kg of BW) housed in groups of 6 in 32 pens and assigned to 1 of 4 treatments: 1) control-0 mg/kg of 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. Salbutamol diets were replaced with control diets 24 to 48 h before slaughter. Behavioral responses to handling during weighing were recorded immediately before assignment to the treatments (wk 0) and at weekly intervals over the next 4-wk period. Behavioral and heart rate (HR) responses to a 10-min human presence test in the home pen were measured during wk 0, wk 1, and wk 3. Heart rate responses to a 36-min transportation were recorded. One pig from each pen had blood collected 4 times: during wk 0, 2, 4, and at exsanguination. Blood was analyzed for NEFA, creatine kinase, glucose, lactate, blood urea nitrogen, ammonia, insulin, cortisol, norepinephrine, and epinephrine. Data were analyzed using PROC GLM of SAS, with pen as the experimental unit. Treatment had no effect on time spent lying laterally, overall activity, or time spent alert. Treatment had no effect on handling measures (P > 0.05) or on behavioral responses to human presence (P > 0.05), with all pigs willing to spend similar amounts of time close to and touching the human. However, during the human presence test in wk 1 and wk 3, control pigs had HR around 10 peats per minute less (P < 0.05) than pigs in the other 3 treatments. During transport, overall HR were similar across treatments (P > 0.05). However, at certain 1-min time points, control pigs had greater HR than salbutamol-treated pigs (P < 0.05). There were no treatment differences in lactate, epinephrine, or norepinephrine concentrations at any point. During wk 4, control pigs had less creatine kinase (P < 0.02) and greater blood urea nitrogen (P < 0.005) compared with pigs fed all the salbutamol treatments. The home pen behavior, handling, human presence test, and transport results indicate that salbutamol-treated pigs do not show marked differences in home pen time budgets and behavioral and HR responses to handling and transportation compared with control pigs. Thus, salbutamol did not have a negative effect on finishing pig well-being during this study.
[Show abstract][Hide abstract] ABSTRACT: Exposing a pregnant sow to stress has been shown to affect the resulting offspring. Our objective was to determine if rough handling of pregnant sows altered the physiology of her offspring and if these alterations were different from an experimentally induced model of prenatal stress. Sow treatments consisted of 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.
[Show abstract][Hide abstract] ABSTRACT: Proceedings of the 9th International Multidisciplinary Conference «Stress and Behavior» Saint-Petersburg, Russia, 16–19 May 2005.Exposing pregnant mammals to prenatal stress has been shown to alter the stress response of their resulting offspring. Most stressors are a combination of psychological and physical stressors; therefore, we designed the following study to separate some confounding factors. One of our objectives was to determine which physiological factors, altered by prenatal stress, are due to the dam experiencing psychological stress versus physical stress. Previous work in our laboratory has shown that male pigs at 2 months of age have greater concentrations of hypothalamic CRF and b-endorphin if they were born to dams who had received injections of ACTH during pregnancy.Methods: In this study, sows treatments consisted of i.v. injections of adrenocorticotrophin (ACTH, 1 IU/kg BW) (n = 11), exposure to rough handling for a 10 min (n = 13), or no treatment (control, n = 13) once a week during d42–77 of gestation. Injections of ACTH were used to elevate plasma glucocorticoids, without causing the psychological stress assumed to result from rough handling.Results: We found that when pigs were subjected to the stress of weaning, those that were born to dams who were roughly handled during pregnancy had a lower (P < 0.05) free cortisol index (FCI, cortisol concentration divided by corticosteroid binding globulin concentration) when compared to pigs from dams who served as controls or were injected with ACTH. Furthermore, we found that pigs from control dams exhibited a FCI that continued to remain elevated (P < 0.05) at 6 days after weaning while pigs from ACTH treated and roughly handled dams reached a lower index.Conclusions: These data indicate that prenatal stress causes offspring to have less biologically available plasma cortisol in response to the chronic stress of weaning. In addition, these data indicate that the effects of prenatal stress are derived, in part, from direct activation of the hypothalamic-pituitary-adrenal axis. It is likely that severity and type of psychological stress will influence the degree to which prenatal stress effects are observed in offspring.
[Show abstract][Hide abstract] ABSTRACT: Inducing hens to molt increases egg quality, egg production and extends the productive life of hens. It has been previously demonstrated that melengestrol acetate (MGA), an orally active progestin, decreased gonadotropic support for the ovary, which decreased the steroidogenic support for the oviduct and resulted in the cessation of lay. Estradiol produced by the theca cells of small follicles stimulates the production of the yolk proteins vitellogenin II and apolipoprotein II by the liver and supports the oviductal epithelial cells. The objective of the present experiment was to determine gene expression for yolk proteins and oviductal epithelial cell turn-over in response to a MGA-induced molt. Hy-Line W-36 laying hens were fed either 0 or 8mg MGA per day for 28 days in a balanced diet and then returned to a standard layer ration until day 36. Four birds per treatment on days 1, 8, 16, 28 and 36 were euthanized and the liver was removed and snap frozen in liquid nitrogen until RNA was extracted. Expression of vitellogenin II and apolipoprotein II genes was determined using real-time RT-PCR. A portion of the magnum was removed to determine proliferation and programmed cell death for secretory and ciliated luminal epithelium. Vitellogenin II and apolipoprotein II gene expression was reduced in hens fed 8mg MGA compared to those fed 0mg MGA. There was no effect of day on gene expression of either yolk protein. Cell proliferation was increased in the ciliated epithelial cells of the oviduct in hens receiving 8mg MGA compared to those receiving 0mg. However, programmed cell death of the ciliated epithelial cells was not different between controls and MGA treatment. Programmed cell death and proliferation increased in the secretory epithelial cells in hens receiving 8mg MGA compared to controls. Therefore, utilizing MGA as an alternative method to induce molt results in some, but not all, of the physiological changes previously described for hens molted by feed withdrawal. These findings lead us to suggest that some of the observed physiological changes resulting from feed withdrawal are required to increase egg quality and egg production following molt and other changes are not necessary, but are just a result of nutrient deprivation.
[Show abstract][Hide abstract] ABSTRACT: Traditionally, molting was initiated by withdrawing feed. However, public criticism of feed deprivation, based on the perception that it inhumanely increases hunger, has led the poultry industry to ban the practice. Thus far, alternatives have not been demonstrated to ameliorate the increase in hunger that led to the ban on inducing molting by feed deprivation. Incorporating melengestrol acetate (MGA), an orally active progestin, into a balanced layer diet induces molting and increases postmolt egg quality. Hy-Line W-98 hens (n = 60) were randomly assigned to a balanced layer ration (control), a balanced layer ration containing MGA, or a 94% wheat middlings diet (wheat) for 20 d, or were feed deprived for 8 d. Hens were trained to peck a switch to receive a feed reward based on a progressive ratio reinforcement schedule. Motivation of hens to acquire feed was measured as the total number of pecks recorded in 15 min on d 0, 4, 8, 12, 16, and 20. On d 20, abdominal fat pad and digesta-free gizzards were weighed. The number of pecks in the feed-deprived group was greater than controls by d 4 and remained greater at d 8, when these hens were removed from the experiment. Hens in the wheat group that were rewarded with a layer diet pecked more than controls from d 8 to 20. Hens in the MGA group pecked for a reward at the same rate as control hens throughout the experiment. Hens fed the wheat diet had heavier gizzards compared with control and MGA-fed hens. Hens fed MGA had greater abdominal fat pad compared with wheat and control hens. Hens molted using a diet containing MGA have a similar motivation to obtain feed as control hens; therefore, this alternative does not appear to increase hunger. However, hens molted with a wheat middling diet appear to be as motivated to obtain feed as did the feed-deprived hens.
[Show abstract][Hide abstract] ABSTRACT: Dramatic changes in the livestock industry have brought about widespread concern regarding the welfare of animals in terms of the hunger that they may experience. Despite this concern, animal science has not been able to provide a methodology that can objectively determine whether the welfare of animals is compromised by hunger. The current work sought to provide data that characterized the physiological and behavioral responses of animals experiencing 57 h of food deprivation. For this purpose, 2 separate experiments were conducted, in which physiological or behavioral measures were collected from swine deprived of feed for 21 to 57 h or fed normally (physiology, n = 20/treatment; behavior, n = 8/treatment). Treatment x time interactions were found (P < 0.02) for insulin, beta-hydroxybutyrate, NEFA, drinking, standing, inactivity, lying sternal, lying lateral, and total lying. Animals appeared to adjust appropriately to the metabolic challenge imposed, as suggested by increases in alternative energy substrates (NEFA, beta-hydroxybutyrate). Additionally, feed-deprived animals appeared less active than control animals until after 45 h of feed deprivation, when the former appeared to be more active. Our results suggest that feed deprivation of finishing pigs for durations greater than 45 h produced behavioral changes that may be related to increased sensations of hunger and which possibly are dependent on the use of alternative energetic substrates. Our data link behavioral and physiological changes after the imposition of feed deprivation.
[Show abstract][Hide abstract] ABSTRACT: Transporting swine to slaughter is often linked with an increase in shedding of Salmonella, but little information exists to explain the role of stress. Recent research has suggested the catecholamine norepinephrine (NE) as a potential host signal during stress. The current study sought to investigate the prevalence of Salmonella enterica serovar Typhimurium in fecal samples and various tissues following inoculation with S. Typhimurium exposed to NE in vitro. The samples were collected at 3 and 24 h post-inoculation (p.i.) from pigs inoculated with S. Typhimurium cultured in either Luria–Bertani medium (LBC) or NE-infused, SAPI minimal medium (NEC). Bacterial quantification of tissue and fecal samples revealed a difference in the concentration of Salmonella between the two infections for six tissues at the two time points, five of which were greater in the NEC animals (p<0.05). Upon observing an increase in the number of Salmonella associated with the stomach wall tissues at 3 h p.i. for the NEC culture, an experiment was conducted using an ex vivo swine contents assay to determine the effect of NE exposure on the ability of the organism to survive the conditions of the porcine stomach; NE treatment enhanced the survival of S. Typhimurium more than 2 logs (p<0.007). Our results demonstrate an increase in the number of Salmonella associated with various swine tissues following experimental inoculation with NE-treated S. Typhimurium; thus, a possible scenario could be envisioned with a Salmonella-infected pig being stressed during transportation/mixing, resulting in the shedding of NE-stimulated Salmonella and exposure of naïve, stress-compromised penmates with a “primed” microorganism.
Journal of Experimental Animal Science 02/2007; 43(4-43):329-338. DOI:10.1016/j.jeas.2006.09.007