Effects of social housing on dairy calf response to novelty shortly after weaning and grouping.

Dairy calf social development and responses to novelty are influenced by social contact, but longer-term implications of early life social housing for response to novelty in weaned calves are less clear. The objective of this study was to evaluate the effects of preweaning social housing on how dairy calves respond to novel feed and objects a few days following weaning and grouping. At birth, calves were alternately assigned to either individual (IH; n = 22 calves) or pair housing (PH; n = 18 pairs; 1 focal calf enrolled/pair). Following weaning (at 53.4 ± 2.0 d; mean ± standard deviation), calves were mingled between treatments and group-housed with calves born the same week (4 to 6 calves/pen; 12 total groups). Beginning at 56.4 ± 2 d of age, calves were exposed to 2 novel feed tests (sliced carrots and chopped red apples) conducted in the home pen on consecutive days. Following novel feed tests, a subset of calves (n = 11 IH and n = 9 PH calves, from separate paired pens) was exposed to a novel object test, conducted individually in a testing arena. During novel feed tests, the latency to contact the novel feed did not differ between treatments but previously IH calves spent more time at the feed trough (6.9 vs. 4.3 min/h, IH vs. PH, standard error = 0.25). In the novel object test, latency to contact the novel object and duration of contact did not differ between previous housing treatments but previously IH calves moved around the arena more. These results suggest that preweaning social housing had some carryover effects on behavioral responses during novel feed and novel object tests a few days following weaning and grouping, potentially reflecting differences in social feeding behavior and activity in a novel space, but avoidance of the novel object and feed were not affected.

Long-term effects of pre-weaning social housing on response to a social and housing transition in pregnant heifers.

Dairy cattle are routinely managed in social groups and subject to various management and social transitions, yet conventional approaches to rearing dairy calves limit social experience during early weeks of life. The objective of this study was to evaluate long-term effects of dairy calf social housing, with calves housed individually or in pairs, on long-term behavioral responses observed in pregnant heifers following social regrouping and introduction to a novel housing environment. Holstein heifers were raised during the milk-feeding period (provided 8 L/d milk replacer) in either individual pens (n = 20 heifers) or paired pens (n = 20 pens; 1 focal heifer/pen) and subsequently identically managed in groups on pasture from 9 weeks of age. At 30 d before expected calving, pregnant heifers were moved from pasture to a free stall barn, which represented introduction to a novel social group and an unfamiliar housing environment. Behavior was continuously recorded from video for 24 h, beginning at 0000 h on the day after introduction, to characterize feeding behavior, locomotor activity, and stall usage, as well as social proximity and competitive behavior surrounding the feed bunk and stall. Stocking density of the free stall barn fluctuated and was categorized as low (≤75%, 100 × animals in pen/available stalls), medium (>75%, 100%), or high (≥100%). Body weights obtained following calving indicated that previously PH heifers were heavier (632.3 vs. 593.4 kg; PH vs. IH), and body weight was included as a covariate in analysis of feeding behavior. Upon introduction to the free stall pen, previously PH heifers spent more time walking (1.9 vs. 1.3 min/h) with no effect of calf social housing on duration of lying time. However, stall use was subject to an interaction between previous housing treatment and stocking density and differed overall between previous housing treatments; previously PH heifers spent less time in the stall, particularly at high stocking density (29.4 vs. 48 min/h), due to shorter (29.6 vs. 95.7 min/visit) but marginally more frequent stall visits. Previously pair-housed heifers were also less likely to be displaced from a stall (44 vs. 85% of heifers replaced; PH vs. IH). Feeding behavior was similarly influenced by previous housing treatment particularly at high stocking density, with previously PH heifers spending more time feeding (8.2 vs. 4.2 min/h) and visiting the feed bunk more frequently (1.5 vs. 0.8 visits/h). These results suggest that preweaning social housing had long-term effects on behavior and ability to adapt to a novel environment which became most apparent under heightened competitive pressure.

Social contact from birth influences personality traits of group-housed dairy calves.

The objective of this study was to assess effects of prior social contact on the expression of personality traits in group-housed calves. Holstein heifer and bull calves were housed in either individual pens (n = 16), or in pairs (n = 8 pairs) at birth before they were mingled between treatments and moved to group pens at approximately 2 wk of life (8 calves/pen). During wk 4 of life, calves were tested in a series of standardized behavioral tests: an open field test, a novel object test, an unfamiliar calf test, and an unfamiliar human test. Responses in the open field test and novel object test were analyzed using principal component analysis, yielding 2 factors interpreted as bold and inactive/grooming. Calves housed in pairs before grouping had greater scores for bold and tended to have lower scores for inactive/grooming. Responses in the unfamiliar calf and human tests were similarly analyzed, yielding 3 factors interpreted as calf-directed, active, and human-directed. Calves housed in pairs before grouping had lower scores for calf-directed, tended to have lower scores for active, and scores for human-directed did not differ. Following grouping, average daily gain, milk replacer intake, and meal frequency did not differ between previous housing treatments. Our results suggest that behavioral traits reflective of personality in group-housed calves may be influenced by social contact from birth even following adaptation to group-housing.

Development of human-directed behavior in dairy calves reared individually or in pairs.

Although social contact between dairy calves has broad effects on their behavioral development, influences of calf social housing on human-animal relationships are less well understood, despite implications for longer-term calf management and welfare. We characterized human-animal interactions in 3 distinct testing contexts to examine effects of social housing on development of human-directed behavior. At birth, Holstein heifer calves were randomly assigned to individual housing (n = 17 calves) or pair housing (n = 17 calves; 1 focal calf/pair). A human approach test was performed twice in the home pen (wk 3 and 5 of life), within an open testing arena (13 × 7 m; wk 4 of life), and within group-housing pens 6 d after all calves were weaned, mingled between treatments, and moved to groups (4 calves/pen; wk 8 of life). For these tests, a human approached, and then extended their hand, over a 2 min period for home and group pen tests and a 5 min period for the arena test, and behavior was recorded from video. During preweaning human approach tests in the home pen, individually housed calves had shorter latencies to contact the human (22.4 vs. 45.1 s; individual vs. pair housing) and spent more time in contact with the human [80.5 vs. 41.1 s; standard error (SE) = 9.9; individual vs. pair housing], with similar responses between repeated tests. In the arena approach test, individually housed calves spent more time oriented toward the human (134.6 vs. 81.3 s; SE = 16.5; individual vs. pair housing), whereas pair-housed calves were more likely to perform pen-directed non-nutritive oral behavior (60 vs. 40% of calves; pair vs. individual housing), suggesting differences in interest directed toward the human compared with the novel environment. We also found that total duration of human contact was correlated between the first home pen approach test and the novel arena test, but that specific response to human approach varied between testing contexts. Effects of treatment persisted during the postweaning group pen approach test, with previously individually housed calves tending to spend more time looking toward the human (53.0 vs. 30.0 s; SE = 9.4; individual vs. pair housing) and more likely to contact the human (47 vs. 12% of calves; individual vs. pair housing). Overall, these results show persistent effects of early life social housing on human-directed behavior which may have implications for longer-term management.

Oxalobacter formigenes treatment confers protective effects in a rat model of primary hyperoxaluria by preventing renal calcium oxalate deposition.

In primary hyperoxaluria, increased hepatic oxalate production sometimes leads to severe nephrocalcinosis and early end-stage kidney disease. Oral administration of Oxalobacter formigenes (O. formigenes), an oxalate-degrading bacterium, is thought to derive oxalate from systemic sources by inducing net enteric oxalate secretion. Here, the impact of O. formigenes on nephrocalcinosis was investigated in an ethylene glycol rat model mimicking hepatic oxalate overproduction in primary hyperoxaluria. Eighteen rats were administered ethylene glycol (0.75% in drinking water) for 6 weeks, of which 9 were treated by oral gavage with O. formigenes and 9 received vehicle. Five control rats did not receive ethylene glycol or O. formigenes. Plasma and urinary oxalate levels, calcium oxalate crystalluria, urinary volume, fluid intake, and serum creatinine were monitored during the study. On killing, nephrocalcinosis was quantified. Ethylene glycol intake induced pronounced hyperoxalemia, hyperoxaluria, calcium oxalate crystalluria and nephrocalcinosis. Concomitant O. formigenes treatment partially prevented the ethylene glycol-induced increase in plasma oxalate and completely prevented nephrocalcinosis. Urinary oxalate excretion was not reduced by O. formigenes treatment. Nevertheless, absence of crystals in renal tissue of O. formigenes-treated ethylene glycol animals indicates that the propensity for oxalate to crystallize in the kidneys was reduced compared to non-treated animals. This is supported by the lower plasma oxalate concentrations in O. formigenes-treated animals. This study shows a beneficial effect of O. formigenes treatment on ethylene glycol-induced hyperoxalemia and nephrocalcinosis, and thus supports a possible beneficial effect of O. formigenes in primary hyperoxaluria.

Effects of early social contact on dairy calf response to initial social grouping and regrouping.

Social contact affects social development and response to novelty in dairy calves, but the age of introduction to social housing varies on-farm and may have implications for behavioral development and response to social grouping. The objective of this experiment was to evaluate the effects of early social contact during approximately the first 2 wk of life on calf early life behavior and performance and responses following initial social regrouping, followed by subsequent regrouping. At birth, calves were randomly assigned to individual (IH; n = 16 calves) or pair-housing (PH; n = 8 pairs). Calves were mingled between treatments and initially grouped (4 calves/pen) at 13 ± 2 d of age (mean ± standard deviation) and then regrouped (8 calves/pen) at 20 ± 5 d of age. Calf ability to learn to feed independently from the teat bucket in early life, and from the autofeeder following grouping, was monitored. Calf health, feed intake, and weight gain were recorded throughout the first 3 wk of life. Activity and social interactions were continuously recorded from video for the first 24 h following grouping and regrouping (except for allogrooming, hay consumption, and social play, which were observed for 12 h due to nighttime visibility). During the period of exposure to different housing treatments, calf feed intake and weight gain did not differ, but calves housed in pairs tended to scour for fewer days [4.1 vs. 5.6 d; PH vs. IH; standard error (SE) = 0.58]. Previously pair-housed calves spent more time lying socially (within 1 body length of another calf) than previously individually housed calves following both initial grouping (9.8 vs. 5.7 h/d; PH vs. IH; SE = 0.83) and regrouping (11.3 vs. 9.1 h/d; PH vs. IH; SE = 1.1). We saw no effects of previous social contact on duration of brush use (31.5 min/d; SE = 4.2), hay feeding (5.1 min/12 h; SE = 1.6), allogrooming (4.1 min/12 h; SE = 0.16), or social play (0.52 min/12 h; SE = 0.19) following initial grouping or regrouping. However, previously pair-housed calves tended to have greater lying time after regrouping. These results suggest that early life social contact before social grouping in the first weeks of life may not greatly affect activity within the pen or active social interactions following the transition to group housing. However, persistent differences in duration of social lying suggests that early life social contact may influence overall comfort toward other calves following social grouping.

Near-infrared autofluorescence and indocyanine green angiography in central serous chorioretinopathy.

PURPOSE: To evaluate the diagnostic potential of near-infrared (NIR) autofluorescence (AF) in central serous chorioretinopathy (CSC) and to present a method to analyze NIR-AF findings quantitatively. PROCEDURES: NIR-AF images, indocyanine green (ICG) angiograms, blue-light autofluorescence (BL-AF) images and fluorescein angiograms were recorded with the use of a confocal scanning laser ophthalmoscope in 19 eyes of 17 patients with CSC. Gray-value ratios were calculated to compare the methods. RESULTS: Using NIR-AF, hypofluorescent spots were observed at the leakage site in 18 of 19 eyes (94.7%). The mean gray-value ratio (±SD) was 0.55 ± 0.22 for the site of the leakage point with NIR-AF and 0.65 ± 0.35 with BL-AF. ICG angiography showed a gray-value ratio of 2.37 ± 2.07. Fluorescein angiography had the best contrast, with a gray-value ratio of 13.44 ± 15.02. CONCLUSION: NIR-AF demonstrated CSC in 94.7% of the cases. NIR-AF may be a noninvasive alternative to detect CSC.

Papel de la ciclooxigenasa (COX) en las alteraciones motoras gastrointestinales y la fiebre inducidas por el lipopolisacárido (LPS) en la oveja / No disponible

No disponible

Short- versus long-sequence MRI cholangiography for the preoperative imaging of the common bile duct in patients with cholecystolithiasis.

BACKGROUND: This study aimed to compare an 18-s fast spin echo magnetic resonance image sequence (coronal thick-section two-dimensional breathhold) with a three-dimensional axial and coronal thin-section sequence and its secondary reconstruction, and to assess its value in the diagnosis of bile duct pathologies, particularly common bile duct stones (CBDS) before laparoscopic cholecystectomy. METHODS: This study prospectively included 72 patients. Because of protocol violations, 14 of these patients had to be excluded. Thus, 58 patients (29 Man and 29 women with a mean age of 51 years) who had cholecystolithiasis or suspected choledocholithiasis were evaluated. Magnetic resonance cholangiopancreatography (MRCP) was performed for all patients with a fast sequence (18 s) and a long sequence (coronal oblique and axial respiratory triggered; 16 min). Two radiologists, blinded with respect to diagnosis, evaluated all the radiographic images. The MRCP results were confirmed for all the patients: 20 by endoscopic retrograde cholangiopancreatography, 46 by intraoperative cholangiography, and 2 by percutaneous transhepatic cholangiography. RESULTS: According to the findings, 16 patients (28%) had CBDS, 6 patients (10%) had common bile duct stenosis, and 36 patients (62%) had a clear bile duct. With regard to CBDS, the short sequence had 100% specificity, 94% sensitivity, and an overall accuracy of 98%. Its negative predictive value was 98%, and its positive predictive value was 100%. The long sequence had a specificity of 100% and a sensitivity of 100%. CONCLUSION: Because of its high sensitivity and specifity, MRCP has the potential to be the diagnostic method of choice for CBD evaluation. The short sequence is not suitable for the diagnosis of all CBD pathologies, but in cases of suspected CBDS, more than 80% of the patients could be diagnosed correctly, and the complete sequence could be dropped.

Role of prostaglandins in lipopolysaccharide effects on K+-induced contractions in rabbit small intestine.

AIM: The mediators of the pathophysiologcal symptoms of septic shock are not completely understood. The aim of this work was to investigate the effect of lipopolysaccharide (LPS) on the K+-induced response of longitudinal segments of rabbit small intestine in vitro and the possible role of prostaglandins. METHODS AND RESULTS: Rabbits were treated with intravenously injected LPS. After 90 min animals were killed and intestinal segments were mounted in an organ bath. Lipopolysaccharide (0.2 microg kg-1) inhibited K+-induced contractions (60 mm) by 68% in duodenum, 58% in jejunum and 52% in ileum. Indomethacin antagonized LPS actions when injected 15 min before LPS. PGE2 reduced K+-induced contractions, imitating LPS effects. In contrast, contractions induced by K+ increased when intestinal segments were incubated in vitro with LPS for 90 min. The LPS (0.3 microg mL-1) increased K+-induced contractions (60 mm) by 46% in duodenum, 63% in jejunum and 85% in ileum. The LPS effect was antagonized by indomethacin at 10-6 m in duodenum and jejunum and at 10-8 m in ileum. PGE2 evoked dose-dependent contractions when added to the bath in duodenum, jejunum and ileum. CONCLUSION: These results suggest that effect of LPS on K+-induced contractions in the rabbit small bowel may be mediated by prostaglandin E2.

Central tumour necrosis factor-alpha mediates the early gastrointestinal motor disturbances induced by lipopolysaccharide in sheep.

Cytokines are involved in fever and other symptoms of the acute phase response induced by endotoxins. The aim of this work was to study the involvement of central tumour necrosis factor-alpha (TNF-alpha) in the changes induced by lipopolysaccharide (LPS) on gastrointestinal (GI) motility in sheep. Body temperature and myoelectric activity of the antrum, duodenum and jejunum was recorded continuously. Intravenous (i.v.) administration of LPS (0.1 micro g kg-1)-induced hyperthermia, decreased gastrointestinal myoelectric activity and increased the frequency of the migrating motor complex (MMC). These effects started 40-50 min after LPS and lasted for 6-7 h. TNF-alpha (50 and 100 ng kg-1) mimicked these effects when injected intracerebroventricularly (i.c.v.) but not i.v. Pretreatment with soluble recombinant TNF receptor (TNFR:Fc, 10 micro g kg-1, i.c.v.) abolished the TNF-induced actions and reduced those evoked by LPS. Furthermore, the effects induced by either LPS or TNF were suppressed by prior i.c.v. injection of indomethacin (100 micro g kg-1). In contrast, the i.v. injections of TNFR:Fc or indomethacin were ineffective. Our data suggest that LPS disturbs GI motility in sheep through a central pathway that involves TNF-alpha and prostaglandins sequentially.

A chronoamperometric method to estimate changes in the membrane composition of ion-selective membranes.

A new chronoamperometric method is used to estimate changes in the membrane composition of mobile-site, ionophore-based membranes. The characteristic features of the chronoamperometric curves (initial current, slope, break time) of valinomycin-based, potassium-selective membranes loaded with potassium tetrakis(4-chlorophenyl)borate are correlated with the mobile-site and free ionophore concentration in the membrane. limiting cases for strong and negligible ion pair formation are distinguished. Replicate measurements indicate a relative standard deviation in the calculated values less than 10%. The practical applicability of the method was tested with membranes incorporated into conventional ion-selective electrode bodies or cast onto microfabricated planar sensor structures.

Picomolar detection limits with current-polarized Pb2+ ion-selective membranes.

Minor ion fluxes across ion-selective membranes bias submicromolar activity measurements with conventional ion-selective electrodes. When ion fluxes are balanced, the lower limit of detection is expected to be dramatically improved. As proof of principle, the flux of lead ions across an ETH 5435 ionophore-based lead-selective membrane was gradually compensated by applying a few nanoamperes of galvanostatic current. When the opposite ion fluxes were matched, and the undesirable leaching of primary ions was eliminated, Nernstian response down to 3 x 10(-12) M was achieved.

Direct evidence of ionic fluxes across ion-selective membranes: a scanning electrochemical microscopic and potentiometric study.

Scanning electrochemical microscopy (SECM) supplemented with potentiometric measurements was used to follow the time-dependent buildup of a steady-state diffusion layer at the aqueous-phase boundary of lead ion-selective electrodes (ISEs). Differential pulse voltammetry is adapted to SECM for probing the local concentration profiles at the sample side of solvent polymeric membranes. Major factors affecting the membrane transport-related surface concentrations were identified from SECM data and the potentiometric transients obtained under different experimental conditions (inner filling solution composition, membrane thickness, surface pretreatment). The amperometrically determined surface concentrations correlated well with the lower detection limits of the lead ion-selective electrodes.

Analytical performance characteristics of thin and thick film amperometric microcells.

The analytical performance of amperometric microcells with different electrode geometries is compared for enzyme activity measurements. The microcells were fabricated with thin film photolithography or thick film screen-printing in four different designs. The cells made with the thin film process used flexible substrate with microelectrode array or a circular, disk-shaped working electrode. The screen-printed working electrodes had semicircle or disk shape on ceramic chips. Putrescine oxidase (PUO) activity measurement was used as a model. The determination of PUO activity is important in the clinical diagnosis of premature rupture of the amniotic membrane. An electropolymerized m-phenylenediamine size-exclusion layer was used to eliminate common interferences. The size exclusion layer revealed also to be advantageous in protecting the electrodes from fouling by putrescine (enzyme substrate). The electrode fouling of bare electrodes was insignificant for screen-printed electrodes, but very severe for electroplated platinum working electrodes. The microelectrode array electrodes demonstrated smaller RSD and higher normalized sensitivities for hydrogen peroxide and PUO activity. All the other electrodes were demonstrating comparable analytical performances.

[Spiral CT cholangiography is not suitable for routine diagnosis before laparoscopic cholecystectomy]. / Die Spiral-CT-Cholangiographie ist für die Routinediagnostik vor laparoskopischer Cholecystektomie nicht geeignet.

INTRODUCTION: The purpose of this prospective controlled study was to evaluate the diagnostic potential of spiral computed tomographic (CT) cholangiography in patients undergoing laparoscopic cholecystectomy. METHODS: 60 patients (17 men, 43 women, mean age 54.5 years, range 15-84 years) with symptomatic cholecystolithiasis were included in this study. After infusion of meglumine jodoxamate, all patients underwent upper abdominal spiral CT. The results of the spiral CT scan were then compared with endoscopic retrograde cholangiography (ERC) or intraoperative cholangiography. RESULTS: In 53 patients (88%) CT cholangiography was considered to be technically adequate for interpretation, but was suboptimal in 4 patients (7%) and nondiagnostic in 3 patients (5%), respectively. CT cholangiography showed a stone free common bile duct in 51 patients which was correct in all cases. CT cholangiography predicted a common bile duct stone in 6 patients which proved to be correct in 4 patients but was found to be incorrect in 2 patients. CONCLUSION: Spiral CT cholangiography is useful for the diagnosis of common bile duct stones. Because of the low positive predicting value routine use before laparoscopic cholecystectomy is not justified.

Can monovalent hepatitis A and B vaccines be replaced by a combined hepatitis A/B vaccine during the primary immunization course?

A combined hepatitis A/B vaccine (Twinrix Adult) has been licensed in Germany since 1997. We investigated possible differences in immunogenicity and safety when changing over from vaccinations with monovalent vaccines made by different manufacturers to vaccinations with the combined hepatitis A/B vaccine in an open, randomized, multicenter trial. We therefore compared four different schemes changing over from concomitant vaccinations with monovalent vaccines against hepatitis A and B (Havrix 1440+Engerix-B or Vaqta+Gen H-B-Vax) to combined vaccination against hepatitis A+B with three injections of the combined hepatitis A/B vaccine (0, 1, and 6 month schedule). Local and general symptoms were mostly mild in all five groups. With complete three-dose course using the combined vaccine or an early changeover from monovalent vaccines to the combined vaccine, higher overall anti-HBs seroprotection rates and geometric mean concentrations (GMCs) against hepatitis B could be achieved as early as after 2 months as compared to those groups switching later to the combined vaccine. This study demonstrated for the first time that switching from monovalent hepatitis A and B vaccinations to the combined hepatitis A and B vaccination has no negative influence on the tolerability and improves the immunogenicity.