Biomedical subjects

W M Sischo

Publications and source records attributed to W M Sischo.

At least 19 recordsLinked to original sources

PubMed2006

Comparison of Salmonella enterica serovar distribution and antibiotic resistance patterns in wastewater at municipal water treatment plants in two California cities.

AIM: To determine Salmonella enterica serovars and antibiotic resistance (ABR) in the human waste stream. METHODS AND RESULTS: Sampling of influent wastewater at municipal treatment plants in two California cities was performed by collecting composite samples, over a 24-h period, from the treatment plants on five to six occasions. Serial water quantities were filtered and cultured with a Salmonella selective method and an oxytetracycline-supplemented Salmonella selective method. Antibiotic susceptibilities to 12 antibiotics were determined and the isolates were grouped based on ABR patterns. From 983 S. enterica isolated, 102 represented unique sampling-serovar-ABR patterns. Thirty-five different serovars were identified to be distributed over 17 different ABR patterns. The serovar distribution differed between the sampling sites, whereas there was no significant trend in levels of multiple ABR. CONCLUSIONS: Salmonella enterica was recovered with ease from small sample volumes of wastewater received by municipal water treatment plants. A large variety of serovars and ABR profiles were represented in the recovered Salmonella. SIGNIFICANCE AND IMPACT OF THE STUDY: The ease of sampling and recovery of Salmonella from municipal wastewater from treatment plants makes it a valuable sampling approach for monitoring the presence of Salmonella in the human population.

Anti-Bacterial Agents↗

PubMed2006

Genetic and phenotypic variability among Salmonella enterica serovar Typhimurium isolates from California dairy cattle and humans.

Fifty-six human and 24 adult dairy cattle isolates of Salmonella enterica serovar Typhimurium from a single county in California were compared using ribotyping, insertion sequence typing (IS200), pulsed-field gel electrophoresis, plasmid typing, phage typing, and antimicrobial resistance testing. The majority of the isolates fell into one of two groups which were phage types DT104 and DT193. Combining the information from all typing methods, a total of 45 different "clusters" were defined, with 35 of those including only a single isolate. The library of isolates had a high degree of variability, but antibiotic resistance and plasmid typing each defined single clusters in which human or bovine isolates predominated (chi2, P < 0.05).

Animals↗

PubMed2006

Embryo survival from gossypol-fed heifers after transfer to lactating cows treated with human chorionic gonadotropin.

Objectives were to determine the effects of gossypol exposure during early embryo development on embryonic survival after transfer of frozen and thawed embryos to lactating dairy cows treated with human chorionic gonadotropin (hCG). Holstein cows (n = 269) were either treated or not treated with 3,300 IU of hCG on d 5 of the estrous cycle and received an embryo collected from heifers fed or not fed gossypol. Embryo donor heifers consumed either 0 or 12 g/d of free gossypol for 76 d prior to embryo collection, resulting in mean plasma gossypol concentrations of 0 and 7.38 microg/mL, respectively. Embryos were transferred on d 7 of the estrous cycle and pregnancy diagnosed 21 and 35 d later. Progesterone was analyzed in plasma collected on d 5 and 12 of the estrous cycle. Treatment with hCG increased the total luteal area on d 12 (818.0 vs. 461.1 mm2) because of increased number of corpora lutea (2.0 vs. 1.0) and increased area of the original corpora lutea (522.7 vs. 443.5 mm2). Plasma progesterone concentrations were similar between treatments on d 5, but increased by d 12 in hCG-treated cows (6.46 vs. 4.78 ng/ mL). Pregnancy rates on d 28 and 42 were not affected by hCG. However, after transfer into lactating cows, embryos collected from heifers not fed gossypol resulted in higher pregnancy rates at 28 d (33.3 vs. 23.1%) and 42 d (29.6 vs. 20.2%) of gestation compared with embryos collected from heifers fed gossypol. Our data suggest that the negative effects of gossypol on fertility are mediated by changes in embryo viability in spite of similar grade quality at transfer.

Animals↗

PubMed2006

Effect of rubber flooring on claw health in lactating dairy cows housed in free-stall barns.

Multiparous dairy cows between 10 to 30 d in milk (DIM) were enrolled in a clinical trial to evaluate the effects of rubber flooring on the development of claw lesions, locomotion scores, clinical lameness, and rates of hoof growth and wear. Two groups of cows were housed in identical free-stall facilities, except that 1 pen (rubber, n = 84) had rubber alley mats covering the entire concrete floor of the pen, whereas cows in the second pen were exposed to concrete flooring (concrete, n = 82) without rubber alley mats. All cows were evaluated 3 times between 10 and 30, 74 and 94, and 110 and 130 DIM for 1) the presence of claw lesions on their rear feet, 2) the occurrence of clinical lameness based on a locomotion score, and 3) rates of claw growth and wear as observed on the dorsal wall of the right lateral claw. No differences between flooring groups at the time of enrollment were detected for lactation number, mean DIM at first examination, body condition score, and proportion of cows with claw lesions at the first examination. Odds of developing claw lesions between examinations were not different for cows exposed to the rubber surface compared with those exposed to concrete. Cows on concrete, however, had greater odds of developing or exacerbating existing heel erosion than cows on rubber flooring. Regardless of the flooring surface, the lateral claw was more likely to develop lesions than the medial claw. Odds of becoming lame by the third examination and the proportion of cows requiring therapeutic hoof trimming because of lameness were greater for concrete-exposed cows than those on rubber. Cows on rubber flooring had decreased claw growth and wear between the first and last examination compared with cows on concrete. Regardless of flooring surface, second-lactation cows had greater wear rates than those in third or greater parities. Results of our study suggest that a soft flooring surface, such as interlocking rubber, is beneficial for hoof health.

Animals↗

PubMed2005

Animal and farm influences on the dynamics of antibiotic resistance in faecal Escherichia coli in young dairy calves.

It is believed that the intensive use of antibiotics in the management of disease in pre-weaned calves contributes to high levels of antibiotic resistance in commensal and pathogenic bacteria. We described the temporal dynamics of antibiotic-susceptibility patterns seen in bovine enteric Escherichia coli in pre-weaned calves on dairy farms and dedicated calf-rearing facilities. Cohorts of 30 calves at each of six farms were sampled at 2-week intervals during the pre-weaning period. Faecal E. coli isolates were analyzed for antibiotic susceptibility to 12 antibiotics with the disk-diffusion method and grouped using cluster analysis of inhibition-zone patterns. The influences of calf age, farm-type, and individual-calf antibiotic therapy on the clusterings were assessed using stratified analyses and cumulative multinomial logistic regression using generalized estimating equation with antibiotic-resistance cluster as an ordinal-dependent variable. The model controlled for farm and cohort by a nested design and included a repeated measure on calf at each sampling occasion. E. coli from calves 2 weeks of age were more likely to be increasingly multiply resistant than E. coli from day-old calves (OR = 53.6), as were 4- and 6-week-old calves (OR = 29.8 and 16.4, respectively). E. coli from calves on dedicated calf-rearing facilities were more likely to be increasingly multiply resistant than E. coli from dairy-reared calves (OR = 2.4). E. coli from calves treated with antibiotics within 5 days prior to sampling were also more likely to be increasingly multiply resistant than E. coli from calves not exposed to individual antibiotic therapy (OR = 2.0).

Animal Husbandry↗

PubMed2005

Comparison of reproductive performance by artificial insemination versus natural service sires in California dairies.

This study compared the calving to conception intervals for cows in AI pens with cows exposed to natural service sires, controlling for milk production, mastitis occurrence, parity and calving month effects. Records from 10 western United States dairy herds (mean herd size = 2058 cows) were evaluated retrospectively over an 18-month period. Eight bull breeding analysis cohorts were created (the first cohort 0-50 days in milk and the remaining cohorts at 25 days in milk intervals through 226 days). The cohorts contained non-pregnant cows that were first moved into bullpens during the described cohort period. Equal numbers of non-pregnant cows only exposed to AI during the cohort period were randomly selected from the pool of eligible non-pregnant cows. An AI cow was used only once in the data analysis, but was included in a bull breeding cohort at a later date if she remained non-pregnant and was transferred to a bullpen. Univariate and multivariate survival analysis was used to compare the calving to conception intervals. Cows in AI groups had higher hazard rates for pregnancy across all cohorts. Parity and milk production were significantly associated with risk for pregnancy. In herds that practice a mixture of AI and bull breeding, overall herd reproductive performance might be improved by allowing cows more opportunities at AI prior to moving them into clean-up bullpens.

Animals↗

PubMed2005

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.

Animals↗

PubMed2003

Assessing antibiotic resistance in fecal Escherichia coli in young calves using cluster analysis techniques.

This study uses cluster analysis techniques to describe the antibiotic susceptibility patterns seen in calf fecal Escherichia coli (E. coli). Cohorts of 30 dairy calves at six farms were sampled at 2-week intervals during the pre-weaning period. At each sampling occasion five fecal E. coli isolates per calf were analyzed for antibiotic susceptibility to 12 antibiotics using the disk diffusion method. All isolates had a profile consisting of the aggregate measured inhibition zone size for each of the evaluated antibiotics. Several cluster analytic algorithms were assessed to partition the E. coli isolates. For our data, Ward's minimum variance method met the objectives of the study. Relative to the number of possible combinations of resistance clusters, a parsimonious set of 14 patterns was developed. This set of E. coli isolates exhibited a limited set of resistance patterns to the different antibiotics indicating that certain resistance genes may be linked.

Animals↗

PubMed2002

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.

Animals↗

PubMed2001

Reproductive effects of estradiol cypionate in postparturient dairy cows.

OBJECTIVE: To determine the effects of estradiol cypionate (ECP) on measures of reproductive efficiency in postparturient dairy cows. DESIGN: Randomized clinical trial. ANIMALS: 273 cows in a single herd in California. PROCEDURE: Twenty-four hours after parturition, 122 cows were treated with ECP (4 mg, IM); the remaining 151 cows were untreated controls. Percentages of cattle with abnormal findings during uterine palpation 27 to 40 days after parturition were compared between groups, along with days to first artificial insemination (AI), percentages of cows that were not pregnant after the first AI, and days to pregnancy. RESULTS: Treatment with ECP did not have a significant effect on whether results of uterine palpation 27 to 40 days after parturition were abnormal, days to first AI, or odds that a cow would be pregnant after the first AI. Treatment with ECP appeared to have a negative effect on days to pregnancy (hazard ratio, 0.72) CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that prophylactic administration of ECP during the early postparturient period in dairy cows did not have measurable beneficial effects on reproductive efficiency.

Animals↗

PubMed2001

Bioluminescence as a technique to evaluate udder preparation.

Food production processes are increasingly influenced by quality and safety concerns. For dairy production, one of the food quality outcomes is a low level of bacteria in unprocessed milk. A putative on-farm control point for low levels of bacteria is teat and udder cleaning before milking. Currently there are no appropriate on-farm schemes to monitor the effectiveness of different processes used to prepare cows for milking. The purpose of this project was to compare levels of teat skin bioluminescence with direct bacterial culture as a tool to evaluate teat cleanliness of dairy cows. Bioluminescence demonstrated average changes in cow cleanliness as animals proceeded through the premilking sanitation steps and, in that manner, could be used as a tool to demonstrate the effectiveness of the process.

Animals↗

PubMed2000

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.

Animals↗

PubMed2000

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.

Adolescent↗

PubMed2000

Cryptosporidia on dairy farms and the role these farms may have in contaminating surface water supplies in the northeastern United States.

The prevalence and risk factors for shedding of cryptosporidia by dairy cattle and calves and the prevalence and risk factors for cryptosporidia in surface waters associated with dairy farms were determined for a well-defined watershed in the northeastern United States. Eleven dairy farms were enrolled in the study and subjected to monthly sampling over a 6-month period. Animal-, water-, and manure-management practices were determined by survey and fecal, on-farm water, and stream samples were obtained monthly and evaluated for the presence of cryptosporidia. Ninety-one percent of the dairy farms in our study had Cryptosporidium on their premises. Fifteen percent of the sampled calves 0-3 weeks of age were shedding cryptosporidia. The risk factors for calves shedding cryptosporidia were contact between calves and frequent bedding changes. The probability of shedding cryptosporidia decreased with age. Nine percent of farm-associated stream samples were cryptosporidia-positive. The single risk factor for detecting cryptosporidia in surface water was increasing frequency of spreading of manure on fields. The probability of detecting cryptosporidia in streams decreased as 5-day cumulative precipitation increased. There were no animal-associated or barnyard-management features associated with detecting cryptosporidia in farm-impacted streams.

Agriculture↗

PubMed2000

A computerized mastitis decision aid using farm-based records: an artificial neural network approach.

A computer module was developed and tested that used field survey and Dairy Herd Improvement Association (DHIA) data to broadly classify bacterial causes of mastitis in dairy herds. Further development of the computer model could aid interpretation of DHIA data by dairy record processing centers and herd consultants. This diagnostic module was developed with an artificial neural network, a technology that processes complex data in a manner similar to human brain function. Information describing herd management practices, quarter milk samples, and monthly DHIA data was collected from Pennsylvania dairy herds with moderate to high somatic cell counts. This information was used to develop or train an artificial neural network model that discriminated among four categories of bacterial organisms (contagious, environmental, no significant growth, and other) associated with clinical and subclinical mastitis. After training the model, new DHIA and management data were presented to the model to assess its ability to classify bacteriological etiology. When the artificial neural network was used, the probabilities of diagnosing the bacteriologic status from three randomly selected cow groups and from new untested herds ranged from 57 to 71%. Performance of the artificial neural network model was best in herds with higher frequency of minor and contagious pathogens. Prediction results for the same test data with linear discriminant analysis were less successful, ranging from 42 to 57%.

Animals↗

PubMed1999

Survey of veterinary extension in the United States.

OBJECTIVE: To assess veterinary extension in the United States as perceived by veterinary extension personnel. DESIGN: Cross-sectional survey. SAMPLE POPULATION: Extension veterinarians in the United States. PROCEDURE: 2 surveys were designed and mailed to extension veterinarians listed by the USDA and the American Association of Extension Veterinarians. RESULTS: 34 states had > or = 1 extension veterinarian. The majority (> 60%) of extension veterinarians did not commit time to resident education and were not involved in research activities. Paradoxically, 23% of responding extension veterinarians did not report extension work. Programs for food animal producers, horse owners, and companion animal owners were provided by 100, 63, and 37% of states, respectively. Continuing education (CE) programs were provided for food animal veterinarians, equine veterinarians, and companion animal veterinarians by 96, 63, and 52% of states, respectively. Challenges facing veterinary extension included limited recognition of veterinary extension activities by universities, lack of university personnel to support CE programs, and decreased support for companion animal extension programs. CONCLUSIONS AND CLINICAL RELEVANCE: Extension veterinarians need to identify and clearly articulate the mission of veterinary extension, develop more collaborative programs across regions, and continue to serve as catalysts to bring diverse constituents together. Extension veterinarians must distinguish their mission not solely as information transfer, which can be accomplished in a variety of ways outside of extension, but as a coherent and consistent program of education and policy developed on a national level and distributed locally.

Agriculture↗

PubMed1999

Use of the Food Animal Residue Avoidance Databank (FARAD).

OBJECTIVES: To report the results of 3 surveys evaluating the extent that the Food Animal Residue Avoidance Databank (FARAD) is used by veterinarians, the profession's perception of the need for the program, barriers that prevent veterinarians from fully using the service, and the perceptions that animal production industry groups have regarding FARAD. DESIGN: Telephone and mail surveys were used to collect information using cross-sectional, case-control, and directed sample studies. SAMPLE POPULATION: Food animal veterinarians and veterinarians and nonveterinarians in allied animal industries or with special interest in production animal medicine. RESULTS: The use of FARAD was high among dairy and general practitioners, but low among beef practitioners and veterinarians with minor commitment to food animal medicine. Solo practitioners and veterinarians with less than 13 years in practice were less likely to use FARAD. Dairy practitioners who had not used FARAD were most likely to prescribe extralabel products. CLINICAL IMPLICATIONS: Results imply that dairy and general food animal practitioners have either greater need or access through educational networks and are more aware of FARAD than practitioners who work with beef and those with a minor component of their practice involving food animals. The difference in familiarity and use of FARAD between practice type is an important finding, but the root of the difference is not clear; it may be attributable to a difference in the effectiveness of knowledge transfer for the groups, or the message is ignored because the issue of drug residues is less compelling for veterinarians and their clients in the beef sector.

Animal Husbandry↗

PubMed1998

Management and environmental risk factors for Salmonella enteritidis contamination of eggs.

OBJECTIVE: To analyze data for 60 poultry flocks voluntarily enrolled in the Pennsylvania Salmonella enteritidis Pilot Project and determine management and environmental risk factors associated with production of S enteritidis-contaminated eggs. SAMPLE POPULATION: 60 flocks for which at least 1 environmental sample (manure or egg-handling equipment) was positive for S enteritidis. PROCEDURE: Samples of manure, egg-handling equipment, and mice were submitted for bacterial culture of S enteritidis. When S enteritidis was isolated from environmental samples, 1,000 eggs were collected from the flock every 2 weeks for 8 weeks and submitted for bacterial culture. RESULTS: 18 flocks were found to have produced contaminated eggs. Estimated overall prevalence of contaminated eggs was 2.64/10,000 eggs produced, but flock-specific prevalence ranged from 0 to 62.5/10,000 eggs. Flocks with high levels of manure contamination were 10 times as likely to produce contaminated eggs as were flocks with low levels. However, 5 flocks with low levels of manure contamination produced contaminated eggs. CONCLUSIONS: Evaluation of the level of manure contamination could be used to help identify flocks at risk of producing S enteritidis-contaminated eggs. CLINICAL RELEVANCE: Flocks with high levels of S enteritidis-contaminated manure appeared to pose the greatest public health threat, and on-farm programs to reduce the prevalence of egg contamination should be developed for farms with high levels of manure contamination. Efforts to reduce the overall number of on-farm pathogens should decrease the incidence of foodborne disease in humans.

Animal Husbandry↗