Influence of Ostertagia ostertagi and Cooperia infections on the energetic efficiency of steers fed a concentrate ration

Studies on effects of subclinical parasitism (low worm burden) in full-fed and maintenance-fed steers indicated that over a short interval low worm burdens do not have a statistically significant effect on the efficiency of energy utilization. In full-fed steers, energy retention tended to be higher in steers with lower worm burdens (mean 95.8 Ostertagia, 12.5 Cooperia) than in those with higher worm burdens (mean 677.5 Ostertagia, 201.8 Cooperia). Maintenance-fed steers generally had larger numbers of Ostertagia ostertagi and Cooperia spp than did the full-fed steers.     

Morphological changes in the jejunum of calves naturally infected with Giardia spp. and Cryptosporidium spp

Giardiosis and cryptosporidiosis are frequently diagnosed in calves at the large animal clinic of the veterinary school. Few studies have been reported in the literature regarding pathogenesis of these two intestinal protozoa. The aims of this study were to follow the histological changes in the villi and crypts and the changes in the number of intraepithelial lymphocytes in the jejunum of naturally infected calves during the acute phase of infection. For this purpose, 29 calves aged between 7 and 10 days were bought at a local auction. The animals were housed in individual pens to avoid cross-contamination. Fecal samples were examined microscopically for the presence of Giardia cysts and Cryptosporidium oocysts, three times per week for a period of 45 days. Six calves did not pass any cysts or oocysts and were used as controls. Fifteen calves passed Giardia cysts only, five passed both cysts and oocysts, and three passed oocysts only. The villus to crypt ratio index was 1.76 in the control group and 1.08 in the Giardia-infected group. In the Cryptosporidium-infected calves, the ratio was 1.18 and calves infected with both parasites had an index of 1.37. The number of intraepithelial lymphocytes per millimeter of jejunum tissue was 21 in the control group. This number was doubled in the calves infected with Giardia, but was slightly lower in the other infected groups. All of the infected calves had intermittent diarrhea and mucus was seen in many fecal samples.     

Evaluation of the effect of the fenbendazole sustained-release intraruminal device on the immunity of calves to lungworm

Each of 10 set-stocked calves was given a fenbendazole sustained-release intraruminal bolus at turnout for the control of parasitic bronchitis while a group of 10 similar calves was left untreated. The respiratory rates of the control calves were not greatly increased during the grazing season, but persistent coughing was evident from early July when they all had patent lungworm infections. Only occasional coughing was reported from the bolus-treated calves except for a transient increase in its frequency in late September. In mid-August, one of the treated calves was passing lungworm larvae and when they were housed six of the 10 had patent infections. In August tracer calves picked up an average of 23.5 lungworms per day from the control paddock but only 2.1 from the paddock grazed by the treated calves. In September the corresponding figures were 7.6 and 19.2 lungworms per day, respectively, from the control and 'treated' paddocks. After housing, the post mortem worm counts after an experimental challenge with Dictyocaulus viviparus larvae were reduced by 99.2 and 98.7 per cent (P < 0.0001), respectively, for the control and bolus-treated calves in comparison with weight-matched parasite-naive calves. Thus, despite a relatively low level of challenge during the grazing season, the treated animals had developed a considerable degree of protective immunity.     

Climbing the goal ladder: How upcoming actions increase level of aspiration.

Pursuing a series of progressive (e.g., professional) goals that form a goal ladder often leads to a trade-off between moving up to a more advanced level and repeating the same goal level. This article investigates how monitoring one's current goal in terms of remaining actions versus completed actions influences the desire to move up the goal ladder. The authors propose that a focus on remaining (vs. completed) actions increases the motivation to move up to a more advanced level, whereas the focus on completed (vs. remaining) actions increases the satisfaction derived from the present level. They find support for these predictions across several goal ladders, ranging from academic and professional ladders to simple, experimental tasks. They further find that individuals strategically attend to information about remaining (vs. completed) actions to prepare to move up the goal ladder. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correlations for timing consistency among tapping and drawing tasks: Evidence against a single timing process for motor control.

Three experiments were conducted to examine whether timing processes can be shared by continuous tapping and drawing tasks. In all 3 experiments, temporal precision in tapping was not related to temporal precision in continuous drawing. There were modest correlations among the tapping tasks, and there were significant correlations among the drawing tasks. In Experiment 3, the function relating timing variance to the square of the observed movement duration for tapping was different from that for drawing. The conclusions drawn were that timing is not an ability to be shared by a variety of tasks but instead that the temporal qualities of skilled movement are the result of the specific processes necessary to produce a trajectory. These results are consistent with the idea that timing is an emergent property of movement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus recognition and the mere exposure effect.

A meta-analysis of research on R. B. Zajonc's (1968) mere exposure effect indicated that stimuli perceived without awareness produce substantially larger exposure effects than do stimuli that are consciously perceived (R. F. Bornstein, 1989). However, this finding has not been tested directly in the laboratory. Two experiments were conducted comparing the magnitude of the exposure effect produced by 5-msec (i.e., subliminal) stimuli and stimuli presented for longer durations (i.e., 500 msec). In both experiments, 5-msec stimuli produced significantly larger mere exposure effects than did 500-msec stimuli. These results were obtained for polygon (Exp 1), Welsh figure (Exp 2), and photograph stimuli (Exps 1 and 2). Implications of these findings for theoretical models of the mere exposure effect are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognition memory and the mere exposure effect.

Repeated exposure to novel stimuli tends to make the stimuli better liked. Examined here is the relation between this increment in liking and recognition of the stimuli. An attempt was made to replicate findings taken as evidence that liking is used as a basis for inferring prior exposure and thus for making recognition decisions (e.g., M. W. Matlin [see PA, Vol 47:2160] and R. L. Moreland and R. B. Zajonc [see PA, Vol 62:3545]). The claim was not supported. Although in each of five experiments liking and recognition were positively correlated, liking was less sensitive to prior exposure than was recognition. Moreover, statistical anaylses suggested that if liking and recognition were causally related, recognition mediated liking rather than the other way around. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fos expression in the prefrontal cortex and nucleus accumbens following exposure to retrospective timing tasks.

The dorsal striatum and prefrontal cortex have been implicated in interval timing. We examined whether performance of temporal discrimination tasks is associated with increased neuronal activation in these areas, as revealed by Fos expression, a marker for neuronal activation. In Experiment 1, rats were trained on a discrete-trials temporal discrimination task in which a light (22 cd/m2) was presented for a variable time, t (2.5–47.5 s), after which levers A and B were presented. A response on lever A was reinforced if t t > 25 s. A second group was trained on a light-intensity discrimination procedure, in which a light of variable intensity, i (3.6–128.5 cd/m2) was presented for 25 s. A response on lever A was reinforced if i i > 22 cd/m2. In Experiment 2, bisection procedures were used to assess temporal (200–800 ms, 22 cd/m2) and light-intensity (3.6–128.5 cd/m2, 400 ms) discrimination. The increase in proportional choice of lever B as a function of stimulus duration or intensity conformed to a two-parameter logistic equation. Fos expression in the prefrontal cortex and nucleus accumbens was higher in rats performing temporal discrimination tasks than in those performing light-intensity discrimination tasks, indicating greater neuronal activation in these areas during temporal discrimination tasks. Fos expression in the dorsal striatum did not differ between rats performing temporal and light-intensity discrimination tasks. These results suggest that the prefrontal cortex and nucleus accumbens are involved in temporal discrimination. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Global precedence: The effect of exposure duration.

Stimuli consisting of large letters constructed from small letters were presented to 26 undergraduates for 10, 40, or 100 msec, and Ss were required to identify either the large letters or the small letters. At the 10-msec exposure duration, only unidirectional or global to local interference was observed. This finding is consistent with D. Navon's (see record 1978-11488-001) global precedence hypothesis. However, at the longer exposure durations equivalent global to local and local to global interference patterns were observed. Results limit the generality of any global precedence hypothesis, either perceptual or attentional, to conditions in which there are large discrepancies in the quality of the local and global information. (French abstract) (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modulating the interference effect in timing with varying stimulus onset asynchrony.

The interference effect on time judgments, when subjects are also required to perform a concurrent nontemporal task, is one of the most reliable findings in the time perception literature. In the present study, the interference between a time discrimination task (short or long tone) and a digit classification task (even or odd digit) was analysed using the overlapping tasks paradigm. Reaction times in the digit task were shorter at longer values of stimulus onset asynchrony (SOA) in Experiment 1, showing a clear modulation of interference with varying the relative position of the tasks. Using longer tone durations in Experiment 2, reaction times in the digit task were affected not only by the overlap between the tasks but also by the temporal proximity of responses in the timing and digit tasks. In Experiment 3, the effect of varying the SOA on performance on the digit task was abolished when the auditory tone was irrelevant, thus eliminating an interpretation in terms of distraction from the tone offset. We conclude that the interference effect in concurrent time discrimination and digit classification may be modulated by the degree of overlap between the tasks as well as by the overlap between late processing stages related to decision and response components in the 2 tasks. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Prior exposure to alcohol and the stress-response-dampening effect.

This study investigated the effect of receiving prior exposure to alcohol and the laboratory environment on the stress-reducing effects of alcohol. Sixteen heavy drinkers were matched on a measure of risk for alcoholism and assigned to 1 of 2 groups. During Days 1 and 2, the alcohol group drank alcohol (0.5 g/kg) and the placebo group drank a placebo in a distinct laboratory environment while measures of heart rate were obtained. During Day 3, both groups received a placebo in an effort to discern whether the groups differed in their response to alcohol cues. During Day 4, both groups received alcohol followed by a stressful task. The groups differed in neither their response to alcohol cues nor their initial response to alcohol. However, the alcohol group did demonstrate a reduced heart rate response during the stress phase. These results suggest that the stress-reducing effects of alcohol may reflect the influence of experiential as well as pharmacological factors related to alcohol consumption. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional modulation of the mere exposure effect.

The mere exposure effect refers to the phenomenon where previous exposures to stimuli increase participants’ subsequent affective preference for those stimuli. This study explored the effect of selective attention on the mere exposure effect. The experiments manipulated the to-be-attended drawings in the exposure period (either red or green polygons in Experiments 1 and 2; both red and green polygons in Experiments 3 and 4) and black to-be-evaluated drawings in the affective judgment period (morphologically identical to the red or green polygons in Experiments 1 and 4; morphologically identical to the composite drawings in Experiments 2 and 3). The results showed a significant mere exposure effect only for the target shapes involved in attentional selection, even when the participants could recognize the nontarget shapes. This indicates that selective attention modulated the mere exposure effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of weather in modifying the pattern of pasture larval contamination with Ostertagia circumcincta

Serum complement activity, immunoglobulin levels and the circulating auto-antibodies were studied in the course of laser treatment of 20 cases of crural ulcer. After temporary changes a normalization of the humoral immune response was observed in the healing cases, while in the stagnating ones opposite trend was manifest. In none of the groups were detected circulating auto-antibodies against the investigated antigens.     

Contribution of passive immunity to porcine respiratory coronavirus to protection against transmissible gastroenteritis virus challenge exposure in suckling pigs

OBJECTIVE: To determine the ability of porcine respiratory coronavirus (PRCV) infections to induce passive immunity in suckling pigs to transmissible gastroenteritis virus (TGEV) challenge exposure. DESIGN AND ANIMALS: 4 TGEV seronegative sows and their litters (group A) served as controls, whereas 2 other groups (B and C) of sows (also TGEV seronegative) were oronasally inoculated with live PRCV during 1 or 2 subsequent pregnancies, respectively. PROCEDURE: Effectiveness of passive immunity provided to pigs via colostrum and milk was assessed after TGEV challenge exposure, and TGEV antibody responses in colostrum and milk were analyzed. RESULTS: Mortality in the 3 groups of young pigs correlated with severity of clinical signs of TGEV infection and was highest in control litters (86% in group-A pigs) and lowest in litters of sows inoculated with PRCV in 2 subsequent pregnancies (14% in group-C pigs). Virus-neutralization and IgA and IgG TGEV antibody titers of milk collected from sows at challenge exposure had significant positive correlation with litter survival. Significantly higher numbers of TGEV-specific IgA and IgG antibody-secreting cells were found in group-A pigs than in group-C pigs, suggesting that high titer of maternal antibodies (induced in group-C sows multiply exposed to PRCV) may interfere with active antibody responses. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that, in PRCV-infected pig herds, multiple exposures of pregnant sows are associated with higher IgA and IgG antibody titers to TGEV in milk, and these titers contribute to protection against TGEV infection.     

Zinc oxide and amino acids as sources of dietary zinc for calves: effects on uptake and immunity

Calf starter diets were formulated to contain 60 ppm of Zn, 150 or 300 ppm of Zn in the form of Zn-Met and Zn-Lys, or 300 ppm of Zn in the form of ZnO to compare relative bioavailability and effects on immunity. Holstein heifer calves were weaned at wk 5 and fed experimental starter diets from wk 6 to 12. Feed intake, body weight, Zn concentrations in liver and serum fractions, and mineral concentrations in serum were measured to determine the effects of treatment. In addition, peripheral blood lymphocyte blastogenesis, interleukin-2 production, cytotoxic activity, and the ability of blood neutrophils to phagocytose and kill bacteria were assessed at wk 0, 2, 4, and 6 of the trial. Feed intakes and body weight gains were similar among calves. Concentrations of Zn in serum were elevated in calves fed 300 ppm of Zn as Zn-Met and Zn-Lys but not in calves fed ZnO. Concentrations of Zn in liver were significantly elevated by 300 ppm of Zn in the form of Zn-Met and Zn-Lys (360 micrograms/g) but not by the other Zn treatments or by the control (245 micrograms/g). No treatment had an effect on the concentrations of Lys and Met in serum; however, concentrations of Lys did decrease in serum as the age of the calves increased. There was no significant treatment effect on mitogen-induced lymphocyte blastogenesis, interleukin-2 production, lymphocyte cytotoxicity, or phagocytic and intracellular killing ability of blood neutrophils. These data indicated greater absorption and retention of Zn when administered in the form of Zn-Met and Zn-Lys than that when ZnO was administered to young calves. However, there was no advantage to the immune function of extra dietary Zn.     

In vivo activities of ceftriaxone and vancomycin against Borrelia spp. in the mouse brain and other sites

Borrelia burgdorferi, the agent of Lyme disease, and B. turicatae, a neurotropic agent of relapsing fever, are susceptible to vancomycin in vitro, with an MIC of 0.5 microgram/ml. To determine the activity of vancomycin in vivo, particularly in the brain, we infected adult immunocompetent BALB/c and immunodeficient CB-17 scid mice with B. burgdorferi or B. turicatae. The mice were then treated with vancomycin, ceftriaxone as a positive control, or normal saline as a negative control. The effectiveness of treatment was assessed by cultures of blood and brain and other tissues. Ceftriaxone at a dose of 25 mg/kg of body weight administered every 12 h for 7 to 10 days eliminated cultivable B. burgdorferi or B. turicatae from all BALB/c or scid mice in the study. Vancomycin at 30 mg/kg administered every 12 h was effective in eliminating infection from immunodeficient mice if treatment was started within 3 days of the onset of infection. If treatment with vancomycin was delayed for 7 days or more, vancomycin failed to eradicate infection with B. burgdorferi or B. turicatae from immunodeficient mice. The failure of vancomycin in eradicating established infections in immunodeficient mice was associated with the persistence of viable spirochetes in the brain during antibiotic treatment.     

Overshadowing and the outcome-alone exposure effect counteract each other.

Three conditioned lever-press suppression experiments with rats investigated the interaction between overshadowing and outcome-alone exposure effects. Experiment 1 found in first-order conditioning that combined overshadowing and outcome-preexposure treatments attenuate the response deficit produced by either treatment alone. Experiments 2 and 3 investigated the interaction between overshadowing and outcome pre- and postexposure effects in sensory preconditioning, varying retention intervals to engage recency and primacy effects with respect to treatment order. Contrary to when a solitary cue is conditioned, responding to a cue conditioned in compound appeared positively correlated with the context's associative status. These findings suggested that some of the basic laws of learning applicable to cues conditioned alone do not similarly apply to a component of a compound cue. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cellular and chemical mediators of type 1 hypersensitivity in calves infected with Ostertagia ostertagi: histamine, prostaglandin D2, prostaglandin E2 and leukotriene C4

Plasma histamine, prostaglandin E2 (PG) D2, PGE2, and leukotriene (LT) C4 levels were determined in 26 Holstein steers before and after natural or experimental infection with Ostertagia ostertagi. Post-infection abomasal lymph was also assayed for PGD2, PGE2, and LTC4. Histamine determinations were performed on abomasal tissue from three locations. Results showed that: (1) tissue histamine levels increased in steers with type 2 ostertagiosis, (2) lymphatic PGD2 and PGE2 levels were increased, probably as a result of macrophage activity, (3) lymphatic LTC4 levels increased in steers with type 1 ostertagiosis, and were correlated with tissue eosinophilia, and (4) plasma levels of PGD2, PGE2, LTC4 and histamine were not useful for predicting worm burdens. These findings suggest a functional role for eosinophils and mast cells in the pathophysiology of ostertagiosis, through mediation of a type 1 hypersensitivity reaction.