Transcriptional changes detected in fecal RNA from neonatal dairy calves of different breeds following gastrointestinal disease of varying severity

Gastrointestinal (GI) disease is a major health concern in preweaned dairy calves. The objective of this fixed cohort study was to use RNA isolated from preweaned Holstein and Jersey heifer calf feces to study the molecular adaptations to variable clinical GI disease. The study was conducted on a commercial calf ranch in the western U.S. Enrolled calves were assessed twice daily for variations in demeanor, milk intake, and hydration. Fecal consistency scores were recorded at enrollment (day 1), and on the day (day 10) that a fecal sample was collected for differential gene expression (DGE). Calves with diarrhea on either day were classified as having either uncomplicated, localized GI disease (scours), or systemic GI disease (systemic enteritis). Eighty-four calves' fecal RNA was evaluated for DGE, of which 33 calves (n = 20 Holstein; n = 13 Jersey) were consistently healthy. The remaining 51 calves (n = 23 Holstein; n = 28 Jersey) experienced varying severity of GI disease during the sampling window. Genes of interest were related to the inflammatory response (i.e., IFNG, NFKB1, NOD2, TLR2, and TLR4) and cell membrane or cytoplasmic transport (i.e., AQP3, FABP2, KRT8 and SLC5A1). Breed-specific findings indicated that AQP3, IFNG, and TLR4 were upregulated in Holsteins with systemic enteritis, whereas KRT8 was downregulated in systemically affected Jerseys. Holsteins did not appear affected by scours aside from a tendency for DGE of toll-like receptors (TLRs) on the day of diarrhea. However, Jersey calves consistently demonstrated a tendency to upregulate IFNG, NFKB1, and TLR4 when affected with either scours or systemic enteritis. These findings were more pronounced in systemically affected Jersey calves and were observed as a delayed response to both scours and systemic enteritis. These findings support previous observations suggesting that Holstein calves may be better equipped than Jersey calves to rapidly fight pathogen invasion.

Describing motivation for health and treatment decisions and communication choices of calf-care workers on western United States dairies

On large dairy farms, animal health assessments and treatments are made by farm employees. Little is known about how employees make decisions about illness detection or treatment, information critical to improving antimicrobial stewardship. The objectives of this study were to describe calf-care employee motivations for decisions associated with preweaned calf health and treatments, describe on-farm worker communication networks, and determine information sources used by these employees to support their decisions. Personal interviews were conducted with 103 calf-care employees on 28 farms in the western United States. The interview consisted of 10 motivation source type (MST) questions and questions about training, communication and educational opportunities. A latent class analysis created a summary for MST and resulted in 4 classes. Forty-three percent of calf-care employees fell into a class where responses were a combination of internal and intrinsic (personal beliefs or values and task fulfillment, respectively) and 23% were a combination of internal and goal internal (aligned with organizational goals). This latter class aligned health decisions with internal motivation and treatment decisions with goal internal. A network analysis summarized dominant communication relationships and established that feeders and treaters perceived more communication with supervisors than was reciprocated by supervisors, and that there was less communication between workers and management for tasks relative to daily work. Employee training was primarily done by herdsman, calf manager, or coworkers, and information for skill improvement and problem solving was sought from these individuals. Although veterinarians were not often involved in employee training, when they were involved, employees were likely to use them as an information source for skill improvement and problem solving. Few participants had ever used social media, but almost all had a device that could access the internet; more than 60% indicated interest in a social media platform for work-related information. Work motivation for many calf caretakers appeared to be sourced from personal beliefs, values, and job fulfillment, particularly when deciding to treat a sick calf. Investigation and incorporation of beliefs and values in training programs could help with alignment of protocols with actual treatment and further efforts to implement judicious use of antimicrobials.

A retrospective cohort study comparing dairy calf treatment decisions by farm personnel with veterinary observations of clinical signs

Antimicrobials are frequently administered to calves with diarrhea, despite evidence suggesting questionable efficacy. Even if efficacious, providing the appropriate therapy to an animal requires accurate disease detection. The objective of this study was to use previously collected data and compare clinical scoring by a veterinarian to treatment decisions by on-farm personnel. Data describing daily clinical scores and farm treatments were previously collected from 4 farms for calves from birth to age 28 d. In this data set, a total of 460 calves were enrolled. Daily observations and clinical assessments were made on each farm by the same veterinarian, for a total of 12,101 calf observation days. Farm personnel made all treatment decisions based on their own observations, and these treatments were recorded by study personnel. Overall, the cumulative incidence of a calf exhibiting at least one abnormal clinical sign over the 28-d observation period was 0.93, with cumulative incidences of 0.85 and 0.33 for diarrhea and dehydration, respectively. The cumulative incidence of any treatment (including antibiotics and electrolytes) was 0.85, although the majority of treatments used an antimicrobial. The farm-specific probabilities that a calf with clinical signs of dehydration or diarrhea, respectively, received fluid or electrolyte therapy ranged from 0.08 to 0.27 and 0.03 to 0.12. These probabilities were greater for the day a clinical sign was first observed. The farm-specific probabilities that a calf with clinical signs of diarrhea received an antimicrobial was 0.23 to 0.65, and the probability that a calf exhibiting clinical signs of respiratory disease received an antimicrobial was 0.33 to 0.76. The first observation of diarrhea had similar probabilities to those for all observations of diarrhea. There was greater probability of treatment for calves with their first observed abnormal respiratory signs. Probabilities that treatment with antimicrobials, or fluids or electrolytes, was associated with an abnormal clinical sign were low-that is, calves received treatments in the absence of any abnormal clinical signs. This study illustrates incongruity between treatment decisions by calf treaters (the designated personnel on each farm responsible for calf health assessment and treatment decisions) and those of an observer using a clinical scoring system to identify calves with abnormal clinical signs. These findings indicate opportunities and the need for dairy farmers and advisors to evaluate calf treatment protocols, reasons for treatment, and training programs for calf health and disease detection, as well as to develop monitoring programs for treatment protocol compliance and health outcomes following therapy.

Clarifying dairy calf mortality phenotypes through postmortem analysis

Health problems can be thought of as phenotypic expressions of the complex relationships between genes, environments, and phenomes as a whole. Detailed evaluations of phenotypic expressions of illness are required to characterize important biological outcomes. We hypothesized that classifying dairy calf mortality phenotypes via a systematic postmortem analysis would identify different cause-of-death diagnoses than those derived from treatments alone. This cross-sectional study was carried out on a dairy calf ranch in the northwestern United States from June to September 2017 and focused on calves ≤90 d of age. Comparisons were made between causes of death based on 3 levels of information: on-farm treatment records alone, necropsy-based postmortem analyses in addition to treatment records, and Washington Animal Disease Diagnostic Laboratory (WADDL) results in addition to all other information. A total of 210 dairy calves were necropsied during this study, of which 122 cases were submitted to WADDL. Necropsy- and WADDL-derived mortality phenotypes were in almost perfect agreement (Cohen's κ = 0.86) when broadly categorized as diarrhea, respiratory, diarrhea and respiratory combined, or other causes. The level of agreement between on-farm treatment records and postmortem-derived results was low and varied by the level of diagnostic detail provided. There was just fair agreement (κ = 0.22) between treatment-based and necropsy-based phenotypes without WADDL input and only slight agreement (κ = 0.13) between treatment-based and corresponding necropsy-based phenotypes with WADDL input. Even for those cases in which causes of death aligned along a comparable pathologic spectrum, the lack of detail inherent to standard treatment-based causes of death failed to identify meaningful target areas for intervention. This was especially apparent for numerous cases of necrotizing enteritis and typhlitis (cecal inflammation) that were variously categorized as diarrhea and pneumonia by treatment-based diagnoses. The specificity of these lesions stood in stark contrast to the otherwise generic cause of death diagnoses derived from treatments. The findings from this study supported the hypothesis and highlighted the value of on-farm necropsies and laboratory-based diagnostics to (1) detect antemortem disease misclassifications, (2) provide detail regarding disease processes and mortality phenotypes, and (3) direct disease mitigation strategies.

Abstract P4-01-02: Early detection of residual breast cancer through a robust, scalable and personalized analysis of circulating tumour DNA (ctDNA) antedates overt metastatic recurrence

Background:

Many breast cancer patients relapse after primary treatment but there are no reliable tests to detect distant metastases before they become overt. Here we show earlier identification of recurring patients through a scalable personalised ctDNA analysis. The method is applicable to all patients, and not limited to hot-spot mutations typically detected by gene panels.

Methods:

Forty-nine non-metastatic breast cancer patients were recruited following surgery and adjuvant therapy. Plasma samples (n=208) were serially collected semi-annually. Using the analytically validated SignateraTM workflow, we determined mutational signatures from primary tumour whole exome data and designed personalised assays targeting 16 variants with high sensitivity by ultra-deep sequencing (average >100,000X). The patient-specific assay was used to detect the presence of the mutational signature in the plasma.

Results:

In 16 of 18 (89%) clinically-relapsing patients, ctDNA was detected ahead of metastatic relapse being diagnosed by clinical examination, radiological and biochemical (CA15-3) measurements, and remained ctDNA-positive through follow-up. Of the 2 patients not detected by ctDNA, one had a small local recurrence only (now resected) and the other had three primary tumours. None of the 31 non-relapsing patients were ctDNA-positive at any time point (n=142). Metastatic relapse was predicted by Signatera with high accuracy and a lead time of up to 2 years (median=9.5 months).

Conclusions:

The use of a scalable patient-specific ctDNA-based validated workflow detects breast cancer recurrence ahead of clinical detection. Accurate and earlier prediction by ctDNA analysis could provide a means of monitoring breast cancer patients in need of second-line salvage adjuvant therapy in order to prevent overt life-threatening metastatic progression.

Citation Format: Coombes RC, Armstrong A, Ahmed S, Page K, Hastings RK, Salari R, Sethi H, Boydell A-R, Shchegrova SV, Fernandez-Garcia D, Gleason KL, Goddard K, Guttery DS, Assaf ZJ, Balcioglu M, Moore DA, Primrose L, Navarro SL, Aleshin A, Rehman F, Toghill BJ, Louie MC, Zimmermann BG, Lin C-HJ, Shaw JA. Early detection of residual breast cancer through a robust, scalable and personalized analysis of circulating tumour DNA (ctDNA) antedates overt metastatic recurrence [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-01-02.

Short communication: Predictors of time to dairy calf bucket training

The time required to adequately bucket-train a dairy calf to drink its milk allotment is unknown. Additionally, factors that could predict calves who are slow to learn have not been identified. A prospective observational study was conducted to describe timing of bucket training and possible calf birth and colostrum quality factors that might predict calves requiring extra time to train. On one dairy farm, 1,235 calves were enrolled at birth in a prospective cohort study. Calving ease score, calf presentation at birth, twinning, calf sex, and dam parity were recorded by farm personnel. An as-fed colostrum sample for each calf was collected and evaluated for total solids, total plate bacterial count, and coliform bacterial count. Calf serum total protein values were obtained by d 2 to 3 of life. Calves were observed before the morning milk feeding for attitude/posture, and after feeding for assistance needed to drink milk from their bucket. Attitude/posture was significantly associated with whether a calf required assistance or not. Almost 60% (n = 724) of calves consumed their morning milk allotment (2 L) after d 3 of life without assistance. Significant factors associated with the odds of requiring assistance with drinking after 3 d of age included calf sex, being born a twin, and the week the calf was enrolled. Knowing how long it takes to train a calf to drink from a bucket could be useful in allocating the time or labor required to successfully train calves.

Educators' experiences of managing students with ADHD: a qualitative study

BACKGROUND

The symptoms of attention-deficit/hyperactivity disorder are associated with difficulty coping with the social, behavioural and academic components of school. Compared with medication and other non-pharmacological treatment, there is less evidence relating to school-based interventions to support children with ADHD. There is additionally an absence of any research focused on the experiences and practices of educators in the UK around how they work with children who are inattentive, impulsive and hyperactive.

METHODS

Forty-two educational practitioners from primary, secondary and alternate provision schools in the UK participated in focus groups or individual interviews that explored (1) their experiences of managing students with ADHD in the classroom and (2) factors that helped and hindered them in this endeavour. Transcripts were analysed using thematic analysis.

RESULTS

Analysis identified six themes: broad strategies, student-centred, inclusive strategies, labelling, medication and relationships. Participants' experiences of managing students with ADHD drew upon a wide range of strategies that typically involved responding to individual needs in an inclusive manner, so individuals with ADHD could access the classroom with their peers. Participants spoke about three factors that helped and hindered managing students with ADHD. Labelling of students with ADHD was reported, with the negative aspects of labelling, such as stigmatization, affecting the classroom. Educators reported mixed experiences regarding the helpfulness of medication; where helpful, it allowed the use of strategies in the classroom. Although students with ADHD were described as having rollercoaster relationships, positive relationships were considered key to the support of children with these difficulties.

CONCLUSIONS

This study suggests that factors such as attitudes towards ADHD, relationships experienced by students with ADHD and other treatments being delivered need to be carefully considered before strategies are put in place in the classroom. This study supports the need for further work on the implementation of evidence-based school interventions for ADHD.

Technical note: Use of a digital and an optical Brix refractometer to estimate total solids in milk replacer solutions for calves

The Brix refractometer is used on dairy farms and calf ranches for colostrum quality (estimation of IgG concentration), estimation of serum IgG concentration in neonatal calves, and nonsalable milk evaluation of total solids for calf nutrition. Another potential use is to estimate the total solids concentrations of milk replacer mixes as an aid in monitoring feeding consistency. The purpose of this study was to evaluate the use of Brix refractometers to estimate total solids in milk replacer solutions and evaluate different replacer mixes for osmolality. Five different milk replacer powders (2 milk replacers with 28% crude protein and 25% fat and 3 with 22% crude protein and 20% fat) were mixed to achieve total solids concentrations from approximately 5.5 to 18%, for a total of 90 different solutions. Readings from both digital and optical Brix refractometers were compared with total solids. The 2 types of refractometers' readings correlated well with one another. The digital and optical Brix readings were highly correlated with the total solids percentage. A value of 1.08 to 1.47 would need to be added to the Brix reading to estimate the total solids in the milk replacer mixes with the optical and digital refractometers, respectively. Osmolality was correlated with total solids percentage of the mixes, but the relationship was different depending on the type of milk replacer. The Brix refractometer can be beneficial in estimating total solids concentration in milk replacer mixes to help monitor milk replacer feeding consistency.

A Randomized Clinical Trial Evaluating the Effects of Oligosaccharides on Transfer of Passive Immunity in Neonatal Dairy Calves

Background

Bacterial contamination of colostrum is common and can decrease IgG absorption in neonatal calves. Strategies that mitigate this situation without complicating colostrum management will benefit dairy calf health and survival.

Objectives

To evaluate the effects of supplementing colostrum with oligosaccharides (OS) on serum IgG concentration and apparent efficiency of absorption of IgG (AEA%) in calves fed unpasteurized colostrum and characterize these outcomes with respect to colostrum bacterial exposures.

Animals

One hundred twenty‐three neonatal dairy calves.

Methods

Randomized, blinded, controlled clinical trial conducted at a commercial dairy operation. Calves were enrolled at birth in 1 of 4 treatment groups. Data were complete for 123 calves, which were distributed across the treatment groups as follows: mannan‐oligosaccharides (MOS), n = 33; Saccharomyces galacto‐oligosaccharides (SGOS), n = 31; Bifidobacterium galacto‐oligosaccharides (BGOS), n = 28; and lactose control (CON), n = 31. A commercial radial immunodiffusion kit was used to determine colostrum and serum IgG concentrations. Conventional microbiology methods were used to enumerate colostrum bacterial counts.

Results

Bacterial counts were not significantly different among treatment groups. Total bacterial plate counts (TPC) were relatively low for the majority of colostrum samples, but TPC had a significant negative effect on serum IgG concentration and AEA% in the lactose‐supplemented control group but not the OS treatment groups.

Conclusions and Clinical Importance

These results suggest that a complement of OS structures may mitigate adverse effects of bacteria on transfer of passive immunity (TPI).

Escherichia coli O157:H7--Discerning Facts from Fiction: An Integrated Research and Extension Project for Multiple Audiences

The O157:H7 (EcO157) epidemiology of Shiga-toxin-producing Escherichia coli (STEC) in cattle is complex, and myths about pre-harvest control are perpetuated. The objectives of this project were to identify perpetuated misinformation and inform four audiences about evidence-based risks and pre-harvest control of EcO157 by addressing: (i) EcO157 epidemiology and pre-harvest control; (ii) how food safety policy is created; and (iii) how to present accurate information about EcO157. An environmental scan using a daily Internet search helped identify themes for education. A literature review of pre-harvest control measures contributed to the development of educational materials (fact sheets, website, web presentations and conferences). Conference 1 was a webinar with 315 registrants, 10 countries including 41 US states and four Canadian provinces. Most participants felt confident in using their new knowledge, more than half felt confident enough to answer EcO157 questions from the public and many would recommend the recorded version of the webinar to colleagues. Conference 2 was live in the Washington, DC, area with most participants employed by the US government. All agreed that they better understood pre-harvest control, how food safety policy was made, and were confident they could create an effective message about STEC pre-harvest control. Videos were posted and received 348 Internet visitors within 2 months. Conference 3 was a webinar with a live audience and Twitter feeds, targeting people who give nutrition advice. Almost all ranked the programme good to excellent and relevant to their work. About 25% indicated that they would share: 'grass-fed beef is not safer than grain-fed', 25% would share information on effectiveness of cattle vaccines, and 14% would share information on message mapping. Across all conferences, major changes in knowledge included the following: there is no additional risk of EcO157 shedding from grain-fed versus grass-fed cattle, pre-harvest vaccination is efficacious, and production systems (pasture versus confinement) do not affect EcO157 shedding rates.

Influence of temperament score and handling facility on stress, reproductive hormone concentrations, and fixed time AI pregnancy rates in beef heifers

The objectives were (i) to evaluate the effect of temperament, determined by modified 2-point chute exit and gait score, on artificial insemination (AI) pregnancy rates in beef heifers following fixed time AI and (ii) to determine the effect of temperament on cortisol, substance-P, prolactin and progesterone at initiation of synchronization and at the time of AI. Angus beef heifers (n = 967) at eight locations were included in this study. At the initiation of synchronization (Day 0 = initiation of synchronization), all heifers received a body condition score (BCS), and temperament score (0 = calm; slow exit and walk or 1 = excitable; fast exit or jump or trot or run). Blood samples were collected from a sub-population of heifers (n = 86) at both synchronization initiation and the time of AI to determine the differences in serum progesterone, cortisol, prolactin and substance-P concentrations between temperament groups. Heifers were synchronized with 5-day CO-Synch+ controlled internal drug release (CIDR) protocol and were inseminated at 56 h after CIDR removal. Heifers were examined for pregnancy by ultrasound 70 days after AI to determine AI pregnancy. Controlling for synchronization treatment (p = 0.03), facility design (p = 0.05), and cattle handling facility design by temperament score interaction (p = 0.02), the AI pregnancy differed between heifers with excitable and calm temperament (51.9% vs 60.3%; p = 0.01). The alley-way with acute bends and turns, and long straight alley-way had lower AI pregnancy rate than did the semicircular alley-way (53.5%, 56.3% and 67.0% respectively; p = 0.05). The serum hormone concentrations differed significantly between different types of cattle handling facility (p < 0.05). The cattle handling facility design by temperament group interactions significantly influenced progesterone (p = 0.01), cortisol (p = 0.01), prolactin (p = 0.02) and substance-P (p = 0.04) both at the initiation of synchronization and at the time of AI. Inter- and intra-rater agreement for temperament scoring were moderate and good (Kappa = 0.596 ± 0.07 and 0.797 ± 0.11) respectively. The predictive value for calm and pregnant to AI was 0.87, and excited and non-pregnant to AI was 0.76. In conclusion, the modified 2-point temperament scoring method can be used to identify heifers with excitable temperament. Heifers with excitable temperament had lower AI pregnancy. Further, cattle handling facility design influenced the temperament and AI pregnancy.

Association of abnormal hind-limb postures and back arch with gait abnormality in dairy cattle

Detection of lameness in individual cows is important for the prompt treatment of this painful and production-limiting disease. Current methods for lameness detection involve watching cows walk for several strides. If clinical signs predictive of lameness could be observed more conveniently, as cows are undergoing regularly scheduled examinations while standing, detection levels could increase. The objective of this study was to assess the association between postures observed while cows are standing in stanchions and clinical lameness evaluated by locomotion scoring, and to evaluate the observation of these postures as a test for lameness. The study included 1,243 cows from 4 farms. Cows were observed while standing in stanchions for regularly scheduled management procedures and the presence of arched back and cow-hocked, wide-stance, and favored-limb postures were recorded. The same cows were locomotion-scored as they exited the milking parlor. The proportion of cows observed with arched back and cow-hocked and favored-limb postures increased with increasing severity of lameness (higher locomotion score) but did not increase for the wide-stance posture. For the presence of these postures as a test for lameness (locomotion score ≥3), sensitivity and specificity were 0.63 and 0.64 for back arch, 0.54 and 0.57 for cow hocks, and 0.05 and 0.98 for favored limb. Back-arched, cow-hocked, and favored limb postures were associated with lameness but were not highly sensitive or specific as diagnostic tests. However, observation of back arch may be useful to identify cows needing further examination.

Heterogeneous reduction of 239PuO2 by aqueous Fe(II) in the presence of hematite

The reduction of PuO2(am) by Fe(II) in the presence and absence of hematite was studied over a range of pH values and oxidation/reduction potentials. In contrast to thermodynamic predictions, the presence of hematite did not have a major effect on the overall reduction of PuO2(am) to aqueous Pu(III). Instead the aqueous Pu(III) concentrations at longer time frames were accurately predicted using the measured Fe(II) concentration and existing thermodynamic data for the reaction: H2O + H++ Fe2++ PuO2(am) ⇌ Pu3++ Fe(OH)3(am) with log K =− 0.6. The accuracy of this approach in all solutions containing aqueous Fe(II), coupled with the apparent lack of oxidation of Fe(II) by O2(g), suggests that the Fe(OH)3(am) is formed by the oxidation of Fe(II) to Fe(III) by radiolysis. The continued generation of reactive amorphous iron hydroxide by radiolysis prevents thermodynamic equilibrium from being reached with more stable ferric oxide compounds, except possibly under acidic conditions where amorphous ferric hydroxide is soluble. The use of measured pe values, instead of aqueous Fe(II) measurements, also yields reasonable predictions of the final Pu(III) concentrations although the predictions are more uncertain.

Comparison of modeled sampling strategies for estimation of dairy herd lameness prevalence and cow-level variables associated with lameness

Monitoring herd lameness prevalence has utility for dairy producers and veterinarians in their efforts to reduce lameness, for animal welfare assessment programs, and for researchers. Locomotion scoring is a method used to quantify lameness and calculate prevalence. Because of the time necessary to locomotion score each cow in large dairy herds, a sampling strategy to determine herd lameness prevalence that allows scoring of fewer cows would be useful. Such a sampling strategy must be validated for accuracy compared with the lameness prevalence when all cows in a herd are locomotion scored. The purpose of this study was to assess 3 previously suggested methods of estimating lameness prevalence by strategic sampling of dairy herds. Sampling strategies tested included (1) sampling a calculated number of cows in the middle third of the milking parlor exit order for each pen, (2) sampling a calculated number of cows weighted across pens and distributed evenly within each pen, and (3) sampling all cows in the high production, low production, and hospital pens. Lactating cows on 5 dairy farms in Washington and Oregon (n=4,422) were locomotion scored using a 5-point scale to determine herd-level lameness prevalence (percentage with locomotion score ≥3). Milking parlor exit order, order in headlocks at the feed bunk within each pen, and breed were recorded for each cow. The number of days in lactation, milk production, and parity were collected from farm computer records. Pen grouping strategy for each farm was obtained by interview with farm management. Sampling strategies were modeled using the locomotion score data set for each herd. Estimates of lameness prevalence obtained from the milking parlor exit order sample and the sample distributed across pens were within 5 percentage points of the whole herd prevalence. The third strategy estimated the lameness prevalence within 5 percentage points on 4 farms, but overestimated prevalence on 1 farm. Pen-level prevalence obtained by locomotion score of all cows in the pen was variable and not reliably predictive of herd-level prevalence. Cows of Holstein breed, parity >1, and exiting the milking parlor in the last 20% of the pen had greater odds of lameness compared with other breeds, parities, and milking parlor exit order groups in a multivariate analysis. This study indicates that the sampling strategies using the middle of milking parlor exit order and a calculated sample distributed across the herd may be used to obtain an estimate of herd lameness prevalence.

Short communication: Effects of dairy calf hutch elevation on heat reduction, carbon dioxide concentration, air circulation, and respiratory rates

Heat stress affects dairy calf welfare and can result in morbidity, mortality, and lower weight gain. The purpose of this project was to evaluate the effects of elevating the back of plastic calf hutches on measures of ventilation and heat stress. A total of 15 calves housed in individual hutches were enrolled, with each calf hutch serving as its own control. Heat, humidity, carbon dioxide, and wind speed were measured inside each hutch and the observations were compared with external measurements over two 24-h periods; 1 period without and 1 with hutch elevation. Respiratory rates were measured in the morning and afternoon as an indicator of the degree of heat stress experienced by calves with and without elevation of the hutch. When the hutch was elevated, internal hutch temperatures were cooler than external temperatures, hutch carbon dioxide levels were lower and respiratory rates were lower, particularly comparing the afternoon observation periods.

Targeting therapy to minimize antimicrobial use in preweaned calves: effects on health, growth, and treatment costs

Prophylactic and therapeutic antimicrobial use in food animals is questioned because of the potential for development of resistant bacteria and future inability to use some antimicrobials for human or animal disease. The objectives of this study were to determine the effect of raising preweaned dairy calves without antimicrobials in the milk and minimizing therapeutic antimicrobial treatment on morbidity, mortality, weight gain, and treatment costs. Newborn calves (n = 358) were allocated to 1 of 4 groups, housed outdoors in individual hutches, and monitored for 28 d. Calves in the conventional therapy (CT) group were treated as per dairy protocol with sulfamethoxazole/trimethoprim, spectinomycin, penicillin, and bismuth-pectin for diarrhea. The targeted therapy (TT) group included bismuth-pectin for diarrhea and antimicrobial treatment only in cases of fever or depressed attitude. Within CT and TT groups, calves were equally assigned to receive neomycin and tetracycline in their milk for the first 2 wk of life (AB-milk) or no antimicrobials (NoAB-milk). Daily health evaluations included fecal consistency, respiratory disease, attitude, and hydration status as well as milk and grain consumption. A negative binomial model evaluated the total number of days with diarrhea days in each group. General linear models were used to assess average daily weight gain and grain consumption. Conventionally treated calves had 70% more days with diarrhea than TT calves, and AB-milk calves had 31% more days with diarrhea compared with NoAB-milk calves. The TT calves tended to have a higher average daily gain by 28 d and consumed more grain compared with CT calves. If antimicrobials were used only for diarrhea cases with fever, inappetence, or depression and no in-milk antimicrobials were used, a $10 per calf savings could be realized. Targeting antimicrobial therapy of calf diarrhea cases is prudent not only to save the drugs for future use but also to prevent the potential for antibiotic-associated diarrhea and reduce calf-rearing costs.

Evaluation of the effects of oral colostrum supplementation during the first fourteen days on the health and performance of preweaned calves

Increasing concerns about antimicrobial resistance have led to the development and implementation of alternatives to antimicrobial use in animal production. The objective of this clinical trial was to determine the effect of colostrum supplementation of the milk replacer ration on morbidity, mortality, feed intake, and weight gain of preweaned calves. Ninety 1-d-old calves on each of 3 commercial calf ranches were randomly allocated to 1 of 3 groups. Treatment-group calves received 10 g of supplemental immunoglobulin G (IgG) in the form of 70 g of colostrum powder in the milk replacer twice daily for 14 d. The placebo-group calves received a nutritionally equivalent supplement lacking IgG in the milk replacer twice daily for 14 d. Control calves received milk replacer without supplements twice daily. Calves were housed in individual hutches and were weighed on d 1, 28, and 60. Serum was collected on d 2 for serum IgG determination. Daily health evaluations for the first 28 d of life were performed by study personnel blinded to treatment group assignment. Observed illness was treated based on health assessment, rectal temperature, and specific calf ranch protocols. Feed consumption (milk and grain) was recorded. Calves receiving supplemental colostrum had less diarrhea and received fewer antimicrobial treatments than control and placebo calves. The results indicated that calf diarrhea was associated with low serum IgG levels and low-weight calves. Grain consumption and weight gain over the first 28 d of life were significantly greater in colostrum-supplemented calves compared with control calves. No differences in mortality or respiratory disease incidence among groups were detected. Supplemental colostrum during the first 2 wk of life can reduce diarrheal disease in preweaned calves on calf ranches and thereby reduce the amount of antimicrobial treatments needed.

The effects of feeding sericea lespedeza hay on growth rate of goats naturally infected with gastrointestinal nematodes

Goat production is increasing in the United States due to high ethnic demand, but infection with gastrointestinal nematode (GIN) parasites is a major constraint to the industry. Increasing GIN resistance to chemical anthelmintics worldwide has led to the development of alternative control strategies, including use of forages containing condensed tannins (CT). An experiment was designed using infected and dewormed male kids (Kiko x Spanish, 6 mo old, 18.9 +/- 3.25 kg) fed diets containing 25% concentrate and either 75% sericea lespedeza [SL; Lespedeza cuneata (Dum-Cours.) G. Don], a high CT forage (87 to 181 g of CT/kg), or 75% bermudagrass [BG; Cynodon dactylon (L.) Pers.] hay (n = 10/treatment). The kids were weighed every 14 d, and fecal and blood samples were taken weekly for fecal egg counts and packed cell volume determination, respectively. Fecal cultures were processed every 14 d to determine CT effect on larval development. At slaughter, adult GIN were collected from the abomasum and small intestines for counting and speciation. Blood samples were also analyzed for plasma urea-N, and ruminal VFA and pH were determined. The infected SL-fed kids had consistently lower (P < 0.05) fecal egg counts than the infected BG goats throughout the trial and greater (P < 0.05) packed cell volume beginning by d 77. Average daily gain was greater (P < 0.001) in kids fed SL- than BG-based diets, regardless of infection status (104.3 +/- 5.0 and 75.5 +/- 4.8 g/d, respectively). Total VFA and acetate concentrations were greater (P < 0.001) in the BG- than in SL-fed goats, whereas propionate levels were unaffected by diet. Acetate:propionate ratio (P = 0.01) and plasma urea-N (P = 0.03) levels were greater in BG-fed goats, whereas rumen pH was greater (P < 0.001) in the SL-fed goats. Feeding SL hay can reduce GIN infection levels and increase performance of goats compared with BG hay.

Thermodynamics and solubility of (U x Np1- x )O2(am) solid solution in the carbonate system

The formation of a solid solution can significantly affect the solubility of a minor component. The objectives of this study were to determine the nature of U(IV) and Np(IV) solid solutions and their thermodynamic properties. For this purpose, (U x Np1- x )O2(am) precipitates with values of x varying from 0.05 to 0.95 were prepared, characterized, and used to determine their solubility in dilute to concentrated K2CO3 and KHCO3 solutions. The solubility data show that the equilibrium in these systems is reached in < 7 days, the solubility-controlling solids are amorphous, and that we were successful in maintaining U and Np in the tetravalent state. A scanning electron microscope equipped with energy dispersive spectrometry and X-ray absorption spectroscopic analyses of the solids indicated the quilibrated co-precipitates to be solid solutions. A close agreement between the thermodynamic predictions, assuming an ideal solid solution, and the experimental solubilities shows that U(IV) and Np(IV) form an ideal solid solution and that non-ideal solid solution behavior for this system can be ruled out.

Effect of pelleting on efficacy of sericea lespedeza hay as a natural dewormer in goats

Resistance of gastrointestinal nematodes (GIN) to anthelmintic treatment has increased pressure to find alternative, non-chemical control methods. Feeding hay of the high condensed tannin (CT) forage sericea lespedeza [SL; Lespedeza cuneata (Dum-Cours.) G. Don.] to sheep and goats has reduced GIN fecal egg count (FEC) and worm numbers in the abomasum and small intestines. This effect has been reported with both unground (long) and ground hay. Pelleting of ground hay increases ease of storage, transport, and feeding, but heating during the pelleting process could reduce biological activity of CT. Eighteen naturally GIN-infected 5-6-month-old Kiko-Spanish cross bucks were fed pelleted and ground SL hay and ground bermudagrass [BG; Cynodon dactyon (L.) Pers.] hay diets (n=6 per treatment) in a confinement trial. The bucks were fed the ground BG hay (75% of daily intake) plus a pelleted 16% CP commercial goat chow (25% of daily intake) for 3 weeks, after which they were assigned to treatment groups based upon FEC, 12 animals were switched to ground and pelleted SL hay plus goat chow for 4 weeks, and then all animals were fed the BG ration for one additional week. Throughout the trial, feces and blood were collected from individual animals weekly to determine FEC and blood packed cell volume (PCV), respectively. All goats were slaughtered at the end of the trial, with adult worms in the abomasum and small intestines recovered, counted, and identified to species. Both forms of SL hay reduced (P<0.05) FEC in goats relative to BG hay-fed animals, with a greater reduction in goats fed the SL pellets. There was no effect on PCV until the final sampling date, when the SL pellet-fed goats' PCV increased (P<0.05) compared with the other treatments. Feeding pelleted SL reduced (P<0.05) abomasal worms, primarily Haemonchus contortus, relative to the BG hay-fed goats. Worm numbers in the goats fed ground SL hay were intermediate. Pelleting SL hay enhanced its efficacy against parasitic nematodes and may facilitate the broader use of this forage in small ruminant GIN control programs.

An Evaluation of Dairy Producer Emergency Preparedness and Farm Security Education

Dairy producer education on securing the milk and meat supply is important to reduce the food system's vulnerability to contamination, and reduce the likelihood for disease transmission onto and within the farm. The purpose of this project was to develop and test a producer-audience curriculum on emergency preparedness and biosecurity awareness. Forty-three attendees from 3 organizations responded to pre- and posttests and a course evaluation. After the program, most of the participants found the program relevant (95%), that it provided practical solutions to biosecurity (97%), were very likely to assess their farms for biosecurity and security (70%), and would suggest the program to other producers (98%). Participants who strongly agreed that the program was relevant and provided practical solutions to biosecurity were very likely to assess their farms. Awareness and knowledge are the first steps toward changing attitudes and behavior and can be accomplished with directed, relevant, practical educational programs.

Technical Note: Effects of Adding Shade and Fans to a Feedbunk Sprinkler System for Preparturient Cows on Health and Performance

The purpose of this study was to examine the effects of adding shades and fans to a feedbunk-mounted sprinkler system on preparturient Holstein cows during summer heat stress. Outcome variables included postpartum milk production, changes in body condition score, changes in serum concentrations of nonesterified fatty acids (NEFA), and incidence of postparturient disorders. Four hundred and seventy-five prepartum multiparous cows, 250 to 257 d pregnant, were randomly allocated to 2 study pens. Treatments consisted of sprinklers over the feed bunk (n = 236); and sprinklers, fans, and shades over the feed bunk (n = 239). Data were used from cows spending a minimum of 14 d in their assigned pen. After parturition, all cows were housed and managed under identical conditions. Data recorders in each pen recorded environmental temperature and humidity every 30 min. Body condition scores were taken at study enrollment, parturition, and 60 d in lactation. Following parturition, the presence of retained placenta, metritis, milk fever, and displaced abomasum were recorded for the length of the study. Milk production was measured using twice-monthly Dairy Herd Improvement Association tests for the first 60 d in lactation. Blood was sampled twice weekly in 98 cows and analyzed for serum NEFA during the last 3 wk before parturition. Cows spent approximately 28 d in their respective treatments. Average daily environmental temperature (+/- SD) in the sprinkler only treatment was 26.4 +/- 7.2 vs. 25.1 +/- 8.6 degrees C in the shade, fans, and sprinkler treatment during the length of the trial. There was no difference in body condition score changes, incidence of postparturient disorders, or serum NEFA concentrations. There was a significant difference in total 60-d milk production, and an economic benefit over the preexisting cooling system.

Disposition of lead (Pb) in saliva and blood of Sprague-Dawley rats following a single or repeated oral exposure to Pb-acetate

Biological monitoring for lead (Pb) is usually based upon a determination of blood Pb concentration; however, saliva has been suggested as a non-invasive biological matrix for assessing exposure. To further evaluate the potential utility of saliva for biomonitoring, the disposition of Pb was evaluated in whole blood (WB), red blood cells (RBC), plasma, parotid gland, bone, and saliva following either a single oral dose of 100mg Pb-acetate/kg body weight in rats or approximately 1-week after 5 sequential daily oral gavage doses of 1, 10, or 100mg Pb-acetate/kg/day. Saliva volume, pH, total saliva protein, and alpha-amylase activity were also determined. At specified times post-dosing groups of animals were anesthetized and administered pilocarpine to induce salivation. Saliva was collected, the animals were humanely sacrificed, and tissue samples were likewise collected, weighed, and processed for Pb analysis. Following a single dose exposure to Pb-acetate, Pb was detectable in all samples by 30 min post-dosing. For both the single and repeated dose treatments the concentration of Pb was highest in WB and RBC relative to plasma and saliva. However, the Pb rapidly redistributed (within 5-days post-treatment) from the blood into the bone compartment based on the substantial decrease in WB and RBC Pb concentration, and the concurrent increase in bone Pb following repeated exposure at all dose levels. Although there is clear variability in the observed Pb concentrations in plasma and saliva, there was a reasonable correlation (r(2)=0.922) between the average Pb concentrations in these biological matrices, which was consistent with previous observations. The single oral dose of Pb-acetate resulted in a decrease in salivary pH which recovered by 24h post-dosing and a decrease in alpha-amylase enzyme activity which did recover within 5-days of ceasing exposure. It is currently unclear what impact these slight functional changes may or may not have on Pb salivary clearance rates. These results demonstrate a feasibility to rapidly detect Pb in saliva and suggest that saliva may correlate best with plasma Pb concentration.

A Clinical Trial Evaluating Prophylactic and Therapeutic Antibiotic Use on Health and Performance of Preweaned Calves

The objective of this clinical trial was to evaluate the influence of prophylactic and therapeutic antibiotics on health and performance in preweaned dairy calves on a calf ranch. One hundred twenty 1-d-old calves were enrolled into 3 management systems for antibiotic use and raised until 4 wk of age. Sixty calves were not eligible to receive prophylactic or therapeutic antibiotics. Thirty calves were eligible to receive individual antibiotic treatment for disease, but no prophylactic antibiotics in milk replacer. The remaining 30 calves received milk replacer medicated with neomycin and tetracycline HCl, and could be treated with antibiotics. Health status and treatments were monitored and recorded daily. The primary study outcomes were weight gain, morbidity, and mortality. The most important factor associated with morbidity and mortality was passive immune transfer through colostrum. In-feed antibiotics delayed onset of morbidity, decreased overall morbidity, and increased weight gain. Nonantibiotic therapies for clinical disease were associated with increased mortality and morbidity compared with antibiotic treatments. The study has shown that minimizing or eliminating the use of antibiotics in the feed requires measures to ensure adequate passive transfer of immunity, but that in the face of inadequate passive transfer of immunity, animal welfare may be endangered by replacing medicated milk replacer with nonmedicated milk replacer, and therapeutic antibiotics with nonantibiotic alternatives.

DairyBeef: Maximizing Quality and Profits—A Consistent Food Safety Message

To respond to meat safety and quality issues in dairy market cattle, a collaborative project team for 7 western states was established to develop educational resources providing a consistent meat safety and quality message to dairy producers, farm advisors, and veterinarians. The team produced an educational website and CD-ROM course that included videos, narrated slide sets, and on-farm tools. The objectives of this course were: 1) to help producers and their advisors understand market cattle food safety and quality issues, 2) help maintain markets for these cows, and 3) help producers identify ways to improve the quality of dairy cattle going to slaughter. DairyBeef. Maximizing Quality & Profits consists of 6 sections, including 4 core segments. Successful completion of quizzes following each core segment is required for participants to receive a certificate of completion. A formative evaluation of the program revealed the necessity for minor content and technological changes with the web-based course. All evaluators considered the materials relevant to dairy producers. After editing, course availability was enabled in February, 2003. Between February and May, 2003, 21 individuals received certificates of completion.

Using time-lapse video photography to assess dairy cattle lying behavior in a free-stall barn

The objectives of this observational study were to use time-lapse video photography to document dairy cow behavioral patterns, examine factors affecting lying behavior, and to develop guidelines for visual assessment of free-stall usage during summer conditions in a high producing dairy. Four video cameras were placed in a free-stall pen containing 144 stalls and 129 high producing cows. The videos were recorded over a 6-d period in July 1999 and then were reviewed using 60-min scan sampling techniques. Cows were counted as lying, standing in alley without eating, standing in free stalls, or eating in each of the four sections of the pen. Temperature probes were placed on the feedline, free stalls, on both ends of the pen, and at an outside location. Relationships between proportion eligible lying and ambient temperature, feeding time, and time since milking were examined. Proportion eligible lying was equal to number of cows lying divided by total number of cows lying or standing but not eating. Cattle showed a significant pattern of temporal cyclicity in their lying behavior, with the highest average proportion of eligible cows lying at 6:00 a.m. (85%) and the lowest at 9:00 p.m. (53%). Increasing environmental temperatures and time elapsed since milking negatively impacted proportion of eligible cows observed lying when evaluated using 60-min scan sampling techniques.

Efficacy of a nonantimicrobial cream administered topically for treatment of digital dermatitis in dairy cattle

OBJECTIVE

To compare efficacy of a topically administered nonantimicrobial cream with that of lincomycin for treatment of digital dermatitis in dairy cattle.

DESIGN

Randomized clinical trial.

ANIMALS

98 cows from a commercial Holstein dairy herd.

PROCEDURE

Cows with active lesions of digital dermatitis identified on a single observation day were randomly assigned to receive a nonantimicrobial cream, lincomycin paste, or no treatment. Cows were examined approximately every 4 weeks for 130 days after treatment for lesion maturity score, score for signs of pain, lesion size, and lesion activity.

RESULTS

29 days after a single treatment, both treated groups had significantly reduced scores for signs of pain, lesion activity, lesion size, and the decision to retreat, compared with findings in the untreated group. Efficacy of the 2 treatments was not significantly different for decreasing pain score or lesion activity or for increasing lesion maturity score, but lincomycin was significantly more efficacious in decreasing lesion size and avoiding retreatment. By use of multivariate logistic regression, lactation number was a significant treatment effect modifier on the outcome of a healed lesion after treatment. Cows with > or = 3 lactations were more likely to have a healed lesion at 29 days, compared with first- and second-lactation cows.

CONCLUSIONS AND CLINICAL RELEVANCE

Because antimicrobial treatments for digital dermatitis in cows require a veterinarian's prescription, the nonantimicrobial cream could serve as a viable but less consistently effective alternative to antimicrobials and could be applied by veterinarians, hoof trimmers, and others.

Negotiation

The first part of this paper traces a short history of the psychological study of negotiation. Although negotiation was an active research topic within social psychology in the 1960s and 1970s, in the 1980s, the behavioral decision perspective dominated. The 1990s has witnessed a rebirth of social factors in the psychological study of negotiation, including social relationships, egocentrism, motivated illusions, and emotion. The second part of this paper reviews five emerging research areas, each of which provides useful insight into how negotiators subjectively understand the negotiation: (a) mental models in negotiation; (b) how concerns of ethics, fairness, and values define the rules of the game being played; (c) how the selection of a communication medium impacts the way the game is played; (d) how cross-cultural issues in perception and behavior affect the negotiation game; and (e) how negotiators organize and simplify their understandings of the negotiation game when more than two actors are involved.

Etiology and natural history of neutropenia in human immunodeficiency virus disease: a prospective study

The objective of this prospective, observational study was to define the natural history of neutropenia in human immunodeficiency virus (HIV) disease. Eighty-seven consecutive patients developing neutropenia (absolute neutrophil count [ANC], <1000 cells/mm(3)) were recruited and closely followed for the duration of the episode. Episodes lasted a median of 13 days, with a mean ANC nadir of 660 cells/mm(3). Presumed or proven infection occurred in 12 (17%) of 71 evaluable subjects, and culture-proven infection occurred only in 6 (8%) of 71. Most of the episodes of neutropenia were brief, mild to moderate in nadir, and self-limiting without complications. Myelosuppressive therapies were implicated in almost all episodes. Serious infections occurred infrequently and were associated with low ANC nadirs but not with duration of the neutropenic episode. Low CD4(+) cell counts also increased the risk of infection complicating an episode of neutropenia.

Development and evaluation of a leadership program for veterinary students

Leadership skills are important for many facets of professional life, but no known leadership training programs exist in North American veterinary schools. It was the purpose of this project to develop, deliver, and evaluate a leadership program for first-year veterinary students. Leadership attributes emphasized in the course included effective communication, openness to learning from others, self-awareness, commitment beyond self-interest, motivation, decision making, understanding issue complexity, and team building. The five-day course was delivered to 21 new veterinary students randomly selected just prior to their first-year orientation in the fall of 2000. Participants ranked themselves higher than non-participants in a post-course evaluation on their ability to be effective leaders. Participants reported an increase in self-confidence and a clearer understanding of their leadership roles. Participants also noted new support systems among co-participants and expressed a new ability to consider complex issues more broadly. Most reported that they frequently used enhanced skills in giving and receiving feedback and team building. Other leadership tools identified as valuable included negotiation, group dynamics, a structured approach to problem solving, time management, and an awareness of personal learning style preferences as a means to improve communication.

Motivations for and barriers to engaging in continuing veterinary medical education

OBJECTIVE

To identify reasons for engagement in continuing veterinary medical education (CVME) activities, obstacles to participation, ways to provide more effective programs, and ideas to improve participation in CVME.

DESIGN

Focus group interviews.

SAMPLE POPULATION

Selected practicing veterinarians from a state that did mandate continuing education for relicensure.

PROCEDURE

12 focus group interviews were held throughout the state of California between May and September 1998. Practitioners were asked to respond to questions about where they obtain information to improve their practice, what value they see in CVME, what motivates them to participate, what obstacles to CVME participation exist, and ways CVME providers and practitioners could overcome those obstacles.

RESULTS

84 practitioners participated in the focus group interviews. In addition to the educational value of CVME, participation was used to rejuvenate practice life and prevent feelings of isolation. Continuing education activities ranged from problem-oriented chats with colleagues to formal educational programs. Timing of events, distance, money, solo practice, stage of career, and family demands were identified as barriers to participation. Designing and marketing CVME with specific learning objectives and for specific career stages and using new educational delivery technologies were suggested to overcome some of these barriers.

CONCLUSIONS AND CLINICAL RELEVANCE

If CVME is to improve practice and patient care, it should be integrated into a practice's strategic planning and considered a legitimate business expense. Decisions about CVME participation are made easier if program objectives are clearly outlined.

Continuing education needs assessment for on-farm food safety services

OBJECTIVE

To identify the perceived market or client demand for dairy on-farm food safety services by veterinarians, the need for a food safety continuing education program, and the educational issues that might be addressed in an on-farm food safety curriculum.

DESIGN

Survey.

STUDY POPULATION

Consulting dairy veterinarians, government veterinarians located in California, and meat packers slaughtering cull dairy cows in California.

PROCEDURE

Results of a questionnaire supplied to veterinarians and telephone interviews with meat packer representatives were analyzed by use of univariate and multivariate logistic regression procedures.

RESULTS

Some meat packers considered the quality of incoming cull dairy cattle as a control point for food safety hazards. More than 50% of dairy and government-employed veterinarians believed that a current market for on-farm food safety services exists; > 85% believed that a potential market exists. Duration since graduation was negatively correlated with belief in a current market. Government-employed veterinarians were more likely to believe in a current market. Veterinarians were more likely to express a strong interest in offering on-farm food safety services if they believed a current market exists, indicated that they already offer such services, or listed residues and pathogens as the most important issues facing the dairy industry.

CONCLUSIONS AND CLINICAL RELEVANCE

Although a potential market for on-farm food safety services is perceived, veterinarians are unsure of their role in this area. new demands of meat packers slaughtering cull dairy cows may be the motivation practitioners need to broach the subject of food safety with clients.

Animal bite epidemiology and surveillance for rabies postexposure prophylaxis

OBJECTIVES

To understand the epidemiology of animal bites and exposure, evaluate the animal exposure reporting system for surveillance of rabies postexposure prophylaxis (PEP), and identify opportunities to reduce PEP.

DESIGN

Period prevalence survey.

STUDY POPULATION

Pennsylvania residents in 1995.

PROCEDURE

Data from animal bite reports from Pennsylvania county health offices were summarized for 1995. Animal bite incidences for the state, counties, various age groups, and various population densities were calculated. Animal species, treatment, location of wounds, and PEP recommendations were evaluated for exposures.

RESULTS

More than 16,000 animal-related potential rabies exposures were reported from 65 of 67 counties in Pennsylvania. The highest incidence was in children less than 5 years old (324/100,000). Of the 75% of victims requiring wound treatment, 50% received antimicrobials, 29% received a tetanus toxoid, and 19% had wounds sutured, were admitted to hospitals, or were referred for plastic surgery. Although 75% of exposures were to dogs, victims exposed to cats were 6 times as likely to receive PEP (relative risk, 6.1; 95% confidence interval, 5.1 to 7.4). Thirty percent of 556 PEP were given for exposures to dogs, 44% for cats, 7% for raccoons, 4% for bats, 2.5% for squirrels, 2.1% for groundhogs, 2% for foxes, and 8% for exposures to other species. Fifty-nine percent of owned dogs were up-to-date on rabies vaccinations compared with 41% of owned cats.

CONCLUSION

Interventions, such as dog bite prevention education, vaccination of pets against rabies, appropriate use of PEP, and reduction of feral cat populations, should be instituted, enhanced, or better enforced in communities.

How generalizable are the results of large randomized controlled trials of antiretroviral therapy?

OBJECTIVES

To examine the generalizability of two large randomized controlled clinical trials of antiretroviral therapy in HIV-infected individuals.

METHODS

The demographic, clinical and laboratory characteristics of HIV-infected participants in two antiretroviral trials (Concorde and Delta) at three study sites were compared with those of two other groups of patients to whom the trial results would be applicable: eligible patients who were screened for the trials but who did not enrol, and eligible patients who were not approached or screened for the trials.

RESULTS

Among enrolled participants in the Concorde and Delta trials there was an under-representation of patients who had acquired HIV infection heterosexually (P = 0.014) or through injecting drug use (P = 0.03), and a greater representation of homosexual men (P < 0.001) compared to non-enrolled participants. Trial participants in Concorde had significantly less advanced immunosuppression compared to non-trial participants (P = 0.0001), while in Delta the converse was true. Concorde participants were also much less likely to be lost to follow-up for more than a year (9%) compared to eligible but unscreened patients (40%) (P < 0.001), and screened but unenrolled patients (22%) (P = 0.035).

CONCLUSIONS

In applying the findings of large randomized clinical trials, it is important to establish whether there are systematic differences between the characteristics of trial participants and eligible non-participants, which might affect the generalizability of the study results. A log of the characteristics of enrolled as well as eligible but non-enrolled patients should be maintained so that the representativeness of the trial population can be evaluated.

Tuberculous peritonitis: part of the differential diagnosis in ovarian cancer

We report a case of tuberculous peritonitis in a young woman who was initially thought to have ovarian cancer. We emphasize the misleading raised CA 125 levels and radiologic pictures and the importance of frozen-section analysis for definitive diagnosis to avoid unnecessary surgery.

A retrospective study of neutropenia in HIV disease

In aiming to define the characteristics of HIV-infected subjects developing neutropenia and describe the causes, features and effects of neutropenia we undertook a retrospective study in a dedicated HIV unit in London, UK. Two hundred and forty-four patients with documented neutropenia, defined as absolute neutrophil count (ANC) < 1,000/mm3, during a 12-month period were studied. First neutropenia occurred at a median CD4 count of 30 cells/mm3. Low CD4 count was associated with longer episodes of neutropenia with a more profound nadir. Two-thirds of episodes lasted less than 2 weeks. ANC nadir was < 500 cells/mm3 in 45% of episodes. Infections were most frequent in patients with profound but brief neutropenic episodes. Neutropenia was generally mild, short-lived and associated with late-stage disease. However, profound neutropenia did develop suddenly in some patients with no prior history of neutropenia (in 13% first neutropenic ANC recorded was < or =500 cells/mm3), and at CD4 count > 200 cells/mm3. Most patients were receiving multiple myelosuppressive therapies. Infection was associated with brief, profound neutropenia.

Positive Illusions and Forecasting Errors in Mutual Fund Investment Decisions

This study examines the portfolio allocation decisions of 80 business students in a computer-based investing simulation. Our goal was to better understand why investors spend so much time and money on actively managed mutual funds despite the fact that the vast majority of these funds are outperformed by pas sively managed index funds. Participants' judgments and decisions provided evidence for a number of biases. First, most participants consistently overestimated both the future perfor mance and the past performance of their investments. Second, participants overestimated the intertemporal consistency of portfolio performance. Third, participants were more likely to shift their portfolio allocation following poorer performance than following better performance, and this tendency had a negative impact on portfolio returns. We speculate that these biases in investor behavior may contribute to suboptimal investment decisions in real financial markets. Copyright 1999 Academic Press.

Spatial diffusion of raccoon rabies in Pennsylvania, USA

Identification of the geographic pattern of diffusion of a wildlife disease could lead to information regarding its control. The objective of this study was to model raccoon-rabies diffusion in Pennsylvania to identify geographic constraints on the diffusion pattern for potential use in bait-vaccination strategies. A trend-surface analysis (TSA) was used as a spatial filter for month to first report by county location. A cubic polynomial model was fitted (R2 = 0.80). Velocity vectors were calculated from the partial derivatives of the model and mapped to demonstrate the instantaneous speed of diffusion at each location. A main corridor of diffusion through the ridge and valley section of the state was evident early in the outbreak. Once the disease reached the northern counties, the disease moved west toward Ohio. I believe that TSA was useful in identifying the pattern of raccoon-rabies diffusion across the stage from the inherent noise of disease-reporting data.

Upper respiratory tract infections

In reviewing recent advances in upper respiratory tract infections, we focus on five key topics. First, the use of ribavirin in the treatment of respiratory syncytial virus infection has been limited to the immunosuppressed. Prophylaxis in high-risk patients with specific immunoglobulin is effective and a new monoclonal antibody shows promise. Second, the efficacy of neuraminidase inhibitors in the treatment of influenza has become established. There are unresolved concerns about early implementation of therapy without a firm diagnosis; resource implications are enormous. Third, an outbreak of influenza due to avian influenza virus (H5N1) raised the possibility of a new pandemic. However, there was minimal person-to-person spread although much was learned about pathogenesis of infection. Fourth, evidence favoring the use of ciprofloxacin rather than rifampicin for meningococcal chemoprophylaxis is reviewed. Efficacy in eradicating nasopharyngeal carriage is excellent. Finally, the management of sore throat has been considered. This remains controversial but evidence supporting antibiotic therapy in adults is lacking. If treatment is indicated in childhood, shorter courses of antibiotics may be effective.

Long and Short Routes to Success in Electronically Mediated Negotiations: Group Affiliations and Good Vibrations

To understand why e-mail negotiations break down, we investigated two distinct elements of negotiators' relationships with each other: shared membership in a social group and mutual self-disclosure. In an experiment, some participants negotiated with a member of an outgroup (a student at a competitor university), whereas others negotiated with a member of an ingroup (a student at the same university). In addition, some negotiators exchanged personal information with their counterparts, whereas others did not. When neither common ingroup status nor a personalized relationship existed between negotiators, negotiations were more likely to end in impasse. These results are attributable to the positive influence of mutual self-disclosure and common group membership on negotiation processes and rapport between negotiators. Copyright 1999 Academic Press.

Persistence of Pseudomonas aeruginosa strains in respiratory infection in AIDS patients

OBJECTIVES

To establish the clinical pattern of Pseudomonas aeruginosa respiratory infections in HIV-seropositive patients and to determine whether repeated isolation of the organism represents reinfection or recurrence and to assess whether common source, nosocomial infection occurred.

DESIGN AND METHODS

Evaluation of the clinical pattern of P. aeruginosa respiratory infections by case note review and epidemiological characterization of P. aeruginosa by serotype determination and Xbal DNA macrorestriction analysis. Serum sensitivity testing of strains was performed to further define phenotypic characteristics of the isolated organisms.

RESULTS

Seventy-three per cent (29 out of 40) of individuals had P. aeruginosa isolated on two or more occasions in the setting of clinical respiratory infection. Overall, 85% had evidence of P. aeruginosa to within 2 months of study completion or death. Epidemiological characterization revealed persistence of unique single strains in 93% of individuals where multiple isolates were available for testing, whereas only two patients harboured a common strain. The serotype distribution of strains was similar to that reported from non-HIV-positive patients.

CONCLUSIONS

Once established, eradication of P. aeruginosa from the respiratory tract of HIV-seropositive individuals with advanced immunosuppression is problematic and a chronic infective state appears common. There was no evidence of nosocomial transmission. Serotype loss and development of sensitivity to normal human serum were both observed and were highly correlated. This represents truncation of O-antigenic lipopolysaccharide on the cell surface of P. aeruginosa and may reflect progression to phenotypes commonly associated with chronic infection in other clinical settings such as cystic fibrosis.

Neutrophil adhesion molecules in HIV disease

Neutrophil dysfunction in HIV disease is well described. We examined the expression of neutrophil adhesion molecules amongst 72 HIV-infected subjects using a whole blood flow cytometric assay with FITC- and R-PE-labelled isotype-specific MoAbs. We report lesser expression of CD11a (LFA-1) and L-selectin (CD62L) on the circulating neutrophils of HIV+ subjects compared with HIV- controls. Expression of CD11b (Mac-1) was unchanged. Shedding of L-selectin and up-regulation of CD11b in response to in vitro stimulation with N-formyl-methionyl-leucyl-phenylalanine (fMLP) were less in HIV+ compared with HIV- subjects, most markedly in subjects with CD4 cell counts < 100 cells/mm3. These results suggest that neutrophil dysfunction in HIV disease, which increases with disease progression, may be attributable to dysregulated adhesion molecule expression.

Paediatric enema syndrome in a rural African setting

We have observed a distinct clinical syndrome amongst acutely unwell children frequently associated with the administration of a traditional medicine enema. We describe the clinicopathological features of this 'enema syndrome' based on retrospective case note review of 50 consecutive admissions to a South African rural district hospital. Admission was frequently prompted by sudden, marked clinical deterioration following enema administration (68% seen within 24 h). Respiratory distress with tachypnoea, abdominal distension, hypotonia and loss of consciousness occurred frequently. In-hospital mortality was 28% and was higher in those receiving herbal (43%) rather than chemical (21%) enemas. Hyperkalaemia, leucocytosis (> 15,000 mm3) and respiratory distress occurred more frequently in those who died. Diagnosis of an underlying illness was established in 78%. Whilst the majority of enemas are given without incident, children struggling with an underlying illness may be unable to tolerate rectally administered traditional medicines. Toxic chemical substances in frequent use may increase complication rates.