Who let the dogs out? Exploring the spatial ecology of free-roaming domestic dogs in western Kenya.

The spatial ecology of free-roaming dogs determines their role in the transmission of zoonoses. This study describes the geographic range of and identifies sites frequently visited by free-roaming domestic dogs in western Kenya. Eight sites in Busia county, western Kenya, were selected.

Multiple imputation in veterinary epidemiological studies: a case study and simulation.

The problem of missing data occurs frequently in veterinary epidemiological studies. Most studies use a complete case (CC) analysis which excludes all observations for which any relevant variable have missing values. Alternative approaches (most notably multiple imputation (MI)) which avoid the exclusion of observations with missing values are now widely available but have been used very little in veterinary epidemiology.

Dealing with deficient and missing data.

Disease control decisions require two types of data: data describing the disease frequency (incidence and prevalence) along with characteristics of the population and environment in which the disease occurs (hereafter called "descriptive data"); and, data for analytical studies (hereafter called "analytical data") documenting the effects of risk factors for the disease. Both may be either deficient or missing. Descriptive data may be completely missing if the disease is a new and unknown entity with no diagnostic procedures or if there has been no surveillance activity in the population of interest.

Sensitivity and specificity of repeated test results from a commercial milk enzyme-linked immunosorbent assay for detection of Mycobacterium avium subspecies paratuberculosis in dairy cattle.

Objective: To investigate the sensitivity and specificity of results of initial and repeated milk ELISAs (at 6- or 12-month intervals) to detect cows that were shedding Mycobacterium avium subsp paratuberculosis (ie, were infectious) and to evaluate factors influencing the probability that the results of a repeated milk ELISA would be positive for an infectious cow if the results of the initial milk ELISA were negative.

Design: Prospective cohort study.

Animals: 3,145 dairy cows from 32 herds.

Evaluation of environmental fecal culture for Mycobacterium avium subspecies paratuberculosis detection in dairy herds and association with apparent within-herd prevalence.

This study evaluated test characteristics of environmental culture (EC) for the detection of Mycobacterium avium subspecies paratuberculosis (MAP) in 32 herds over a 2-year period. Individual fecal samples were collected every 6 mo and environmental samples every 3 mo. Individual fecal culture was performed on samples from positive pools.

Bias--is it a problem, and what should we do?

Observational studies are prone to two types of errors: random and systematic. Random error arises as a result of variation between samples that might be drawn in a study and can be reduced by increasing the sample size. Systematic error arises from problems with the study design or the methods used to obtain the study data and is not influenced by sample size.

Differences in behavioral characteristics between dogs obtained as puppies from pet stores and those obtained from noncommercial breeders.

Objective: To compare the owner-reported prevalence of behavioral characteristics in dogs obtained as puppies from pet stores with that of dogs obtained as puppies from noncommercial breeders.

Design: Cross-sectional study. Animals-Dogs obtained as puppies from pet stores (n = 413) and breeder-obtained dogs (5,657).

Effectiveness of emamectin benzoate for treatment of Lepeophtheirus salmonis on farmed Atlantic salmon Salmo salar in the Bay of Fundy, Canada.

Emamectin benzoate (an avermectin chemotherapeutant administered to fish as an in-feed treatment) has been used to treat infestations of sea lice Lepeophtheirus salmonis on farmed Atlantic salmon Salmo salar in the Bay of Fundy, New Brunswick, Canada, since 1999. This retrospective study examined the effectiveness of 114 emamectin benzoate treatment episodes from 2004 to 2008 across 54 farms. Study objectives were to establish whether changes in the effectiveness of emamectin benzoate were present for this period, examine factors associated with treatment outcome, and determine variables that influenced differences in L.

Bulk tank milk selenium and its association with milk production parameters in Canadian dairy herds.

An observational study was conducted in 63 Canadian dairy farms to evaluate the association of bulk tank milk selenium (Se) concentration (BTSe) with average daily milk yield, milk fat and milk protein, bulk tank somatic cell count (BTSCC), and the probability of being a Staphylococcus aureus-positive herd. Bulk tank milk samples collected between March 2007 and February 2008 were evaluated for BTSCC, S. aureus culture status, and BTSe.

Selection of a cutoff value for real-time polymerase chain reaction results to fit a diagnostic purpose: analytical and epidemiologic approaches.

Diagnostic laboratories frequently select a subjective cutoff value for real-time amplification assays, above which a threshold cycle (Ct) value is deemed false. Commonly, higher Ct values are interpreted as amplification or fluorescence artifacts, or cross contaminations. Although the implementation of Ct cutoff might be reasonable, its justification and selection should be based on evidence.

Development and validation of a bilingual questionnaire for measuring udder health related management practices on dairy farms.

Questionnaires are frequently used instruments to collect data in epidemiological studies. In countries where more than one language is spoken, the development of a questionnaire in more than one language is needed. The objective of this study was to develop and test the repeatability and validity of English and French versions of a personal interview-format questionnaire designed to capture udder health related management practices used on dairy farms.

White-line disease and haemorrhages in hooves of Finnish dairy cattle.

The Finnish Healthy Hooves Project was set up to determine the frequency of, and risk factors for, various hoof lesions in Finnish dairy herds. Data were collected in 2003 and 2004. A large data set of >74,000 cow-level observations recorded by hoof-trimmers were merged with production data from the Finnish Agricultural Data Processing Centre Ltd.

Use of register data to assess the association between use of antimicrobials and outbreak of Postweaning Multisystemic Wasting Syndrome (PMWS) in Danish pig herds.

In 2001, the first case of Postweaning Multisystemic Wasting Syndrome (PMWS) was reported in the Danish pig population. During subsequent years, the number of affected farms increased exponentially. The aim of this study was to determine how this increase influenced the use of antimicrobials between 2002 and 2004.

Sole ulcers in Finnish dairy cattle.

The Finnish Healthy Hooves project was set up to determine the frequency of, and risk factors for various hoof lesions in Finnish dairy herds. Data were collected in the years 2003 and 2004. A large dataset of over 74,000 cow-level observations recorded by hoof trimmers was merged with production data from the Finnish Agricultural Data Processing Centre Ltd.

Relationships among milk urea-nitrogen, dietary parameters, and fecal nitrogen in commercial dairy herds.

Our study objective was to determine the ability of milk urea-nitrogen concentrations ([MUN]) to predict fecal nitrogen concentrations ([Fecal N]) in commercial dairy herds. A total of 83 dairy herds were each visited 3 times within 48 h after a monthly herd milk test. For each farm visit, forages were sampled for nutrient analyses, which were entered into a computerized ration evaluator, and fecal samples were taken per rectum from each of 6 cows (2 early-, 2 mid-, and 2 late-lactation).

Estimate of the direct production losses in Canadian dairy herds with subclinical Mycobacterium avium subspecies paratuberculosis infection.

The objective of this study was to estimate the annual losses from Mycobacterium avium subspecies paratuberculosis (MAP) for an average, MAP-seropositive, Canadian dairy herd. A partial-budget simulation model was developed with 4 components of direct production losses (decreased milk production, premature voluntary culling, mortality, and reproductive losses). Input values were obtained primarily from a national seroprevalence survey of 373 Canadian dairy farms in 8 of 10 provinces.

Quantitative epidemiology: progress and challenges.

This manuscript is derived from a presentation at the 2006 AVEPM--Schwabe Symposium which honoured the 2006 recipient of the Calvin Schwabe Award--Dr. S. Wayne Martin.

Factors affecting Canadian veterinarians' use of analgesics when dehorning beef and dairy calves.

Data collected through a national, randomized mail survey (response rate 50%) were used to identify reasons why veterinarians were likely (i) to use analgesic drugs when dehorning calves, and (ii) to perceive dehorning without analgesia as very painful. Logistic regression analysis indicated that veterinarians were more likely to be analgesic users the more they perceived that dehorning without analgesia was painful (OR = 1.7, P < 0.

Canadian veterinarians' use of analgesics in cattle, pigs, and horses in 2004 and 2005.

Anecdotal evidence suggests that many veterinarians may not use analgesics in livestock for routine surgical procedures or painful disease states. To investigate this, we conducted a national mail survey of a random sample of 1431 Canadian veterinarians (response rate, 50.1%).

Assessment of antimicrobial transfer from treated to untreated mammary gland quarters by use of high-pressure liquid chromatography for detection of cloxacillin in milk samples from nonlactating dairy cows.

Objective: To determine whether half-udder intramammary infusion of cloxacillin results in transfer of cloxacillin from treated to untreated mammary gland quarters within nonlactating cows, and, if so, at what concentrations, and to determine whether selection of ipsilateral versus diagonal-contralateral quarters for treatment affects cloxacillin transfer among quarters.

Animals: 20 Holstein-Friesian cows from a dairy herd.

Procedures: A within-cow half-udder comparison trial was used in which 2 of 4 mammary gland quarters (ipsilaterally or diagonally) received an intramammary infusion of cloxacillin on day 1 of the nonlactating period.

Factors affecting the use of postincisional analgesics in dogs and cats by Canadian veterinarians in 2001.

Factors affecting the postincisional use of analgesics for ovariohysterectomy (OVH) in dogs and cats were assessed by using data collected from 280 Canadian veterinarians, as part of a national, randomized mail survey (response rate 57.8%). Predictors of analgesic usage identified by logistic regression included the presence of at least 1 animal health technician (AHT) per 2 veterinarians (OR = 2.

Efficacy of using an internal teat sealer to prevent new intramammary infections in nonlactating dairy cattle.

Objective: To determine whether insertion of an internal teat sealer (ITS) at the end of lactation would prevent development of new intramammary infections (IMIs) during the nonlactating period.

Design: Controlled clinical trial.

Animals: 939 Holstein-Friesian dairy cows from 16 herds.

Perioperative use of analgesics in dogs and cats by Canadian veterinarians in 2001.

A random sample of 652 Canadian veterinarians was surveyed to determine perioperative use of analgesics in dogs and cats following common surgeries. The response rate was 57.8%.

Management factors affecting stereotypies and body condition score in nonracing horses in Prince Edward Island.

In North America, there are few representative data about the effects of management practices on equine welfare. In a randomized survey of 312 nonracing horses in Prince Edward Island (response rate 68.4%), owners completed a pretested questionnaire and a veterinarian examined each horse.