Pragmatic vs Explanatory Trials in Veterinary Clinical Research

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-11

Key Takeaways

• Explanatory trials assess if an intervention works under ideal, controlled conditions (efficacy), using highly selected, homogeneous populations in specialized settings with standardized delivery and often surrogate endpoints like laboratory biomarkers.
• Pragmatic trials evaluate if an intervention works in real-world clinical practice (effectiveness), employing broad, representative populations in routine settings with flexible intervention delivery and patient-relevant outcomes such as survival or quality of life.
• The PRECIS-2 tool operationalizes the explanatory-pragmatic continuum across nine domains (eligibility, recruitment, setting, care organization, intervention flexibility, adherence flexibility, follow-up, outcome relevance, analysis) to guide and document design decisions, ensuring alignment between the research question and study architecture.
• Participant selection is a critical differentiator: explanatory trials use narrow criteria to reduce variance and detect biological effects, while pragmatic trials broaden criteria to enhance generalizability to diverse clinical populations.
• Outcome measurement distinguishes the designs: explanatory trials often use mechanistic or surrogate endpoints (e.g., serum drug concentration), whereas pragmatic trials prioritize clinically meaningful outcomes that matter to patients and owners (e.g., owner-reported pain scores, return to function).
• Analysis methods diverge: explanatory trials may use per-protocol analysis to assess efficacy when delivered as intended, while pragmatic trials typically employ intention-to-treat analysis to reflect real-world outcomes when an intervention is prescribed.

Veterinary clinical researchers face a fundamental choice when designing a study: should the trial measure whether an intervention works under ideal conditions, or whether it works when applied in real clinical practice? The distinction between explanatory and pragmatic trials shapes every downstream decision, from participant selection to outcome measurement to statistical analysis. This article provides a structured comparison of these two trial architectures for veterinary researchers designing clinical studies across species, with emphasis on how the choice affects validity, generalizability, and the conclusions that can legitimately be drawn.

The explanatory trial asks whether an intervention produces a biological effect when all variables are controlled. The pragmatic trial asks whether an intervention produces a benefit when deployed in the messy reality of clinical practice. Both questions are legitimate, but they are different questions, and conflating them produces research that answers neither. This article equips the veterinary researcher with the conceptual framework, design criteria, and reporting standards needed to select the appropriate trial architecture for a given research question and to interpret the results accordingly.

At a Glance

The Explanatory-Pragmatic Continuum

The distinction between explanatory and pragmatic trials is not a binary classification but a continuum. A trial may be highly explanatory in some domains and highly pragmatic in others. The PRECIS-2 tool, developed by the Consolidated Standards of Reporting Trials (CONSORT) group, operationalizes this continuum across nine domains: eligibility criteria, recruitment pathway, setting, organization of care, flexibility of intervention delivery, flexibility of adherence, follow-up intensity, primary outcome relevance, and primary analysis method. Each domain is scored from 1 (very explanatory) to 5 (very pragmatic), producing a wheel diagram that displays the trial's design profile at a glance.

For veterinary researchers, the PRECIS-2 framework offers a systematic method for making design decisions explicit instead of implicit. A trial that enrolls only purpose-bred dogs with experimentally induced disease, delivers treatment according to a rigid protocol in a single referral hospital, and measures a laboratory biomarker as the primary outcome is clearly explanatory. A trial that enrolls client-owned animals presenting to multiple primary care practices, allows clinicians to adjust dosing within a specified range, and measures owner-reported quality of life is clearly pragmatic. Most veterinary trials fall between these poles, and the PRECIS-2 scoring process forces the research team to justify each design choice instead of defaulting to habit.

Why Trial Architecture Matters

The consequences of choosing the wrong trial architecture extend beyond academic criticism. An explanatory trial that demonstrates efficacy in a homogeneous population may fail to reproduce those results in practice because real patients differ in ways that matter. Conversely, a pragmatic trial that shows no overall benefit may obscure a genuine effect in a specific subgroup that the broad inclusion criteria diluted. The veterinary literature contains numerous examples of interventions that appeared promising in tightly controlled studies but failed to deliver in clinical settings, and the reverse pattern also occurs when pragmatic trials reveal harms that explanatory trials missed due to narrow participant selection.

The reporting of trial design is equally important. The ARRIVE guidelines, published by the NC3Rs, specify the minimum information required for transparent and reproducible reporting of animal research, including clear description of the experimental design and the rationale for the chosen approach. The EQUATOR Network maintains a comprehensive library of reporting guidelines, including the CONSORT extension for pragmatic trials, which requires authors to explicitly describe how each design element was handled. Transparent reporting allows readers to assess whether the trial's conclusions are warranted by its design, instead of relying on the authors' characterization of the study as "pragmatic" or "explanatory" without supporting detail.

Participant Selection and Setting

Participant selection is often the most visible difference between explanatory and pragmatic designs. Explanatory trials typically employ narrow inclusion criteria and extensive exclusion criteria to create a homogeneous study population. This approach reduces variance and increases the probability of detecting a biological effect, but it also limits generalizability. A drug that works in young, healthy, otherwise uncomplicated patients may fail in the elderly patient with comorbidities, and an explanatory trial will not detect this failure because such patients were excluded.

Pragmatic trials deliberately broaden eligibility criteria to capture the full spectrum of patients who would receive the intervention in practice. This approach increases external validity but introduces heterogeneity that can obscure modest treatment effects. The veterinary researcher must weigh these competing considerations in light of the research question. If the question is mechanistic, explanatory selection is appropriate. If the question is whether to adopt an intervention in practice, pragmatic selection provides more useful information.

The trial setting follows from the participant selection strategy. Explanatory trials typically occur in specialized referral centers where investigators can control the environment and ensure protocol adherence. Pragmatic trials occur in the settings where the intervention will actually be used, which in veterinary medicine means primary care practices, mixed animal practices, and production animal operations. The MSD Veterinary Manual notes that clinical management varies substantially across practice types and species, and this variation is precisely what pragmatic trials must accommodate to produce generalizable results.

Intervention Delivery and Comparator Choice

Explanatory trials standardize intervention delivery to minimize variation. Investigators follow detailed protocols, monitor adherence closely, and may exclude participants who deviate from the protocol. This approach isolates the biological effect of the intervention from the effects of how it is delivered. Pragmatic trials allow intervention delivery to vary within the bounds of acceptable clinical practice, recognizing that real clinicians will adapt protocols to individual patients and circumstances.

The choice of comparator is equally consequential. Explanatory trials often use placebo or a tightly defined alternative to maximize the contrast between treatment and no treatment. Pragmatic trials typically compare the intervention against usual care, which may vary across sites and over time. This design choice reflects the decision that practitioners actually face: should I use this new intervention or continue with what I currently do? The ARRIVE guidelines emphasize that the comparator must be described with sufficient detail for readers to understand what the intervention was compared against, a requirement that becomes more complex when usual care varies across participating sites.

Outcome Measurement and Analysis

Explanatory trials favor surrogate outcomes that can be measured precisely and that reflect the biological mechanism of action. Pragmatic trials favor outcomes that matter to patients and their owners, such as survival, quality of life, return to function, or owner satisfaction. The choice of outcome determines the trial's ability to inform clinical decisions. A trial that shows a statistically significant change in a laboratory parameter may not demonstrate any meaningful benefit to the patient, while a trial that shows improvement in owner-assessed quality of life provides directly actionable information.

The primary analysis approach also differs. Explanatory trials often analyze per-protocol populations, excluding participants who deviated from the protocol, because the question is whether the intervention works when actually delivered as intended. Pragmatic trials analyze by intention-to-treat, including all randomized participants regardless of adherence, because the question is whether the intervention works when prescribed to the target population. The intention-to-treat approach preserves the benefits of randomization and reflects the reality that some patients will not adhere to treatment.

Choosing the Design: PRECIS-2 in Veterinary Settings

The PRECIS-2 tool provides a structured framework for locating a trial along the explanatory-pragmatic continuum. It assesses nine domains, each scored from 1 (very explanatory) to 5 (very pragmatic). These domains are eligibility criteria, recruitment path, setting, organization of care, flexibility of intervention delivery, flexibility of adherence, follow-up, primary outcome, and primary analysis. Scoring a protocol across these domains forces explicit decisions about where the trial sits on the continuum and whether those decisions match the research question.

The PRECIS-2 wheel, a graphical display of the nine domain scores, helps reviewers and funders see at a glance whether a trial design matches its stated purpose. A trial intended to inform clinical decision-making should cluster toward the pragmatic pole. A trial intended to establish mechanistic efficacy under ideal conditions should cluster toward the explanatory pole. Mismatches, such as a pragmatic research question answered with explanatory eligibility criteria, produce results that neither estimate real-world effectiveness nor cleanly establish efficacy.

Applying PRECIS-2 to Veterinary Trial Planning

The first step in using PRECIS-2 is to assemble the trial protocol and score each domain independently with at least two reviewers. Disagreements of two or more points on any domain signal a need for discussion and protocol clarification. The scoring should occur before recruitment begins, because changing eligibility or outcome measurement after enrollment compromises the design.

Species and production system alter the correct placement on several domains. In companion animal practice, owner-reported outcomes carry weight because owners make treatment decisions and bear costs. A pragmatic trial in dogs or cats might therefore use owner-assessed functional recovery or quality of life as the primary outcome. In food animal medicine, the client is the producer, and outcomes such as weight gain, milk production, or carcass quality may be more clinically meaningful than laboratory parameters. The MSD Veterinary Manual provides species-specific guidance on clinical assessment and disease monitoring that informs outcome selection.

Herd-level trials in cattle, pigs, or poultry introduce a further consideration. The unit of randomisation may be the herd or flock instead of the individual animal, and the organization of care domain must reflect how veterinary advisors and producers interact. A pragmatic production animal trial typically allows the attending veterinarian to adjust treatment protocols within label limits, whereas an explanatory trial would mandate identical interventions for every animal.

Available equipment and staffing constrain the pragmatic pole. A practice without access to diagnostic imaging cannot implement an imaging-based outcome, regardless of how clinically meaningful it might be. The trial designer must match the follow-up and outcome domains to the capabilities of the participating sites. The EQUATOR Network reporting guidelines library includes extensions for cluster trials and pragmatic trials that help authors document these decisions transparently.

Worked Example: Anesthetic Technique and Cancer Outcomes

The GA-CARES trial, a randomised multicentre study of propofol versus volatile inhalational anesthesia for cancer resection surgery, illustrates pragmatic design choices in a clinical setting. The trial enrolled adults with known or suspected cancer undergoing one of eight oncologic surgeries at five sites. Randomisation was stratified by center and surgery type, and the intervention was assigned through a web-based system. The pragmatic elements include broad eligibility across cancer types, multiple participating centers, and an intervention that reflects real clinical alternatives. The primary outcome, cancer recurrence, is clinically meaningful instead of mechanistic.

Scoring this protocol on PRECIS-2 would place eligibility near the pragmatic pole because it includes any adult with suspected cancer scheduled for a qualifying procedure. The setting domain is pragmatic because the trial operates within routine surgical services. The flexibility of delivery domain is moderately pragmatic: the protocol specifies propofol or volatile agent for maintenance, but the anesthetist manages the case within that assignment. The primary outcome is strongly pragmatic because recurrence is the outcome that matters to patients and surgeons.

A veterinary analogue might compare two anesthetic protocols for oncologic surgery in dogs. An explanatory version would enrol only healthy dogs with a single tumor type, use a fixed anesthetic protocol with invasive monitoring, and measure a surrogate outcome such as perioperative immune function. A pragmatic version would enrol any dog presented for tumor resection, allow the attending anesthetist to adjust the protocol within defined limits, and follow dogs for recurrence or survival. The choice between these designs depends on whether the question is "can this anesthetic technique alter immune function" or "does choosing this anesthetic technique change cancer outcomes in practice."

Reporting Standards and Transparency

Reporting guidelines support the interpretation of pragmatic and explanatory trials by requiring authors to document design decisions explicitly. The ARRIVE guidelines specify the minimum information needed for transparent reporting of animal research, including details of randomisation, blinding, sample size, and statistical methods. The EQUATOR Network hosts the CONSORT statement and its extensions, including CONSORT for pragmatic trials, which requires authors to describe how the trial addresses each pragmatic domain.

For veterinary trials, the REFLECT statement, available through the EQUATOR Network, provides reporting guidance specific to randomised controlled trials in livestock and food safety research. It addresses herd-level randomisation, clustering, and the reporting of husbandry and production conditions. Using these reporting standards at the planning stage, instead of after data collection, improves the likelihood that the final publication will allow readers to judge where the trial sits on the explanatory-pragmatic continuum.

Documenting Design Decisions for Funders and Ethics Review

Funding bodies and animal ethics committees increasingly expect investigators to justify their choice of trial design. A protocol that uses narrow eligibility criteria and intensive follow-up should explain why an explanatory approach is necessary, such as when the research question concerns mechanism or when variability would obscure a small effect. A protocol that uses broad eligibility and routine care settings should explain how the trial will maintain data quality without the controls of an explanatory design.

The documentation should include a completed PRECIS-2 score sheet, a narrative justification for each domain score, and a statement of how the results will be used. If the trial aims to change clinical practice, the protocol should show that the design reflects the conditions of that practice. If the trial aims to support a regulatory claim, the design may legitimately lean explanatory, because regulators typically require demonstration of efficacy under controlled conditions before effectiveness in the field is assessed. The WOAH terrestrial animal health standards and national veterinary regulatory bodies set expectations for the evidence base supporting product authorisation, and these expectations shape how pragmatic a registration trial can be.

Common Errors in Design Selection

A recurring error is labeling a trial pragmatic because it was conducted in a clinical setting, while retaining explanatory features such as narrow eligibility or protocol-mandated follow-up. This mislabelling misleads readers who apply the results to broader populations. Another error is choosing a pragmatic design for a mechanistic question, producing results too confounded to support causal inference about the intervention's mode of action.

A third error is failing to align the analysis with the design. A pragmatic trial analyzed per-protocol loses the benefit of randomisation because the groups being compared are no longer prognostically balanced. An explanatory trial analyzed by intention-to-treat may dilute a real treatment effect and fail to detect efficacy that exists under ideal conditions. The PRECIS-2 primary analysis domain forces this decision into the open at the planning stage.

The choice between pragmatic and explanatory designs is not a choice between good and bad science. It is a choice between different questions. A trial that asks whether an intervention works under ideal conditions requires explanatory features. A trial that asks whether it works in ordinary practice requires pragmatic features. Scoring the protocol on PRECIS-2 before recruitment begins, documenting the scores, and reporting them with the results gives readers the information they need to judge the applicability of the findings to their own patients.

Recognized Complications and Early Detection

Pragmatic trials in veterinary medicine fail most often through design drift, not through flawed execution. Design drift occurs when the trial that is actually delivered diverges from the trial that was planned. The most common form is progressive tightening of eligibility criteria. Recruitment pressure leads teams to exclude animals with comorbidities, concurrent medications, or atypical signalment, each exclusion moving the trial toward the explanatory end of the continuum. Detect this early by auditing screening logs monthly. Compare the proportion of screened animals excluded against the protocol specification. A rising exclusion rate with stable referral populations signals drift.

A second recognized failure mode is intervention contamination. In veterinary practice, the same clinician often manages both trial arms, and cross-over of management habits is difficult to prevent. The clinician who believes the experimental intervention is superior may unconsciously apply its principles to control animals. Detection requires process measures, not outcome measures. Record protocol adherence indicators such as timing of drug administration, use of permitted rescue interventions, and documentation of concurrent care. Stepped-wedge designs, as used in the NOHARM protocol for a stepped-wedge cluster-randomized pragmatic trial, reduce contamination risk by assigning whole clusters to intervention timing, but they do not eliminate within-cluster drift.

Third, outcome ascertainment bias emerges when the individuals measuring outcomes are not blinded to allocation. Pragmatic trials often justify open-label designs on the grounds of real-world applicability, but subjective outcomes such as owner-reported pain scores or clinician-assessed lameness grades remain vulnerable. Early detection requires periodic inter-rater reliability checks. If two assessors disagree on more than a prespecified threshold, retraining or reblinding is indicated.

Common Errors in Early-Career Researchers

Less experienced investigators frequently conflate pragmatism with methodological laxness. A pragmatic trial still requires randomisation, prespecified analysis, and complete outcome ascertainment. The ARRIVE guidelines 2.0 for reporting animal research specify the minimum information required for transparent and reproducible publications, and they apply with equal force to pragmatic and explanatory designs. The corrective action is to treat pragmatism as a decision about what is measured and how, not as a license to omit measurement.

A second error is selecting outcomes that are convenient instead of meaningful. Owner-reported quality of life is harder to collect than survival time, but for many companion animal conditions it is the outcome that matters to the decision. The corrective action is to involve owners and referring veterinarians in outcome selection during the design phase, then pilot the measurement instrument for feasibility and floor or ceiling effects.

A third error is failing to prespecify the analysis of protocol deviations. Pragmatic trials analyze by intention to treat, but the handling of animals that never received the intervention, that crossed over, or that were lost to follow-up must be defined in advance. Post hoc decisions about exclusions are a recognized source of bias and invite scepticism from reviewers.

Limitations of the Current Evidence

The veterinary literature contains few head-to-head methodological comparisons of pragmatic and explanatory designs. Most guidance is extrapolated from human medicine, where the EQUATOR Network reporting guidelines provide a structured library of reporting standards including CONSORT extensions for pragmatic trials. Whether those extensions translate directly to veterinary settings remains uncertain. Species differences in outcome measurement, owner involvement in care decisions, and the economic realities of production animal practice all create distinct challenges that human-focused guidance does not address.

Expert opinion still differs on the role of cluster randomisation in veterinary pragmatic trials. Some argue that cluster designs are essential because interventions such as herd health programs or practice-level protocols cannot be applied to individuals in isolation. Others contend that individual-level randomisation within practices is feasible and statistically more efficient. The choice depends on the intervention, the species, and the production system, and no universal recommendation is possible.

Evidence is also limited on how pragmatic veterinary trials should handle missing data. Owner-reported outcomes in companion animal studies and production records in livestock studies both suffer from incomplete ascertainment, but the mechanisms of missingness differ. The MSD Veterinary Manual professional edition provides species-specific clinical context that can inform whether missing data are likely to be informative, but it does not resolve the statistical question.

Referral, Consultation, and Regulatory Reporting

Statisticians with expertise in cluster randomisation and pragmatic trial design should be consulted before the protocol is finalised, not after recruitment begins. Veterinary epidemiologists with species-specific experience can advise on outcome measurement and contamination risk. Institutional animal care and use committees and ethics review boards should review the protocol with specific attention to the consent process, since pragmatic trials often involve interventions delivered as part of routine care.

Regulatory reporting obligations vary by jurisdiction and by product. Investigators using licensed veterinary products outside their approved indications should confirm whether the study constitutes a clinical trial requiring notification to the relevant authority. The WOAH terrestrial animal health standards address surveillance and disease control obligations that may apply when trials involve notifiable diseases or production animals entering the food chain. The AVMA practice resources provide guidance on professional obligations in clinical research settings. When in doubt, consult the relevant regulatory body before enrollment begins.

Frequently Asked Questions

How Much More Does a Pragmatic Trial Cost Than an Explanatory Trial?

Pragmatic trials are not necessarily cheaper. They often avoid expensive placebo manufacture, sham procedures, and intensive monitoring visits, which lowers per-patient cost. However, they may require larger sample sizes to detect smaller effect sizes, multiple sites, and substantial investment in electronic data capture and staff training. The stepped-wedge design used in the Mayo Clinic NOHARM protocol illustrates how pragmatic trials can spread implementation costs across sites and time. Budget for data quality audits, site coordination, and contingency funds for protocol drift. A pragmatic trial that loses data because of underfunded follow-up is more wasteful than a smaller explanatory trial that answers a narrow question cleanly.

What Should I Do When the Ideal Pragmatic Setting Is Not Available?

When referral caseload or facilities cannot support a fully pragmatic design, move along the continuum instead of abandoning the approach. Use a single center with multiple practitioners, standardize only the intervention trigger while leaving delivery flexible, or use consecutive eligible cases instead of random sampling. The GA-CARES protocol randomised across five sites with eight surgery types, showing that pragmatic features can be preserved within a constrained multicentre structure. Document every compromise explicitly in the protocol and report it under the relevant EQUATOR reporting guideline. Reviewers accept pragmatic elements that are acknowledged and justified. What they reject is an explanatory trial mislabelled as pragmatic, or a pragmatic trial that quietly becomes explanatory through convenience.

Does the Explanatory-Pragmatic Balance Change for Production Animals Versus Companion Animals?

Yes, and the differences are substantial. Production animal trials usually operate within single ownership groups, which simplifies consent and follow-up but introduces clustering effects from herd or flock management. Outcome measurement is often production-based, such as weight gain or milk yield, which is inherently pragmatic. Companion animal trials face fragmented follow-up, owner-reported outcomes, and variable adherence to treatment protocols. The MSD Veterinary Manual notes that species-specific physiology and husbandry alter how clinical signs present and how treatments are evaluated. For food animals, withdrawal periods and trade implications may constrain comparator choices in ways that shift the design toward explanatory. For companion animals, owner expectations and quality-of-life measures push the design toward pragmatism. Plan the PRECIS-2 scoring separately for each species and justify the differences.

How Should I Document Protocol Deviations in a Pragmatic Trial?

Record every deviation with a timestamp, the responsible individual, and the reason. Classify deviations as acceptable flexibility or protocol violations. Acceptable flexibility includes minor variations in drug administration timing or client communication style. Violations include wrong drug, wrong dose, or unblinded outcome assessment. The ARRIVE guidelines require transparent reporting of all deviations that could affect interpretation. In pragmatic trials, some deviation is expected and reflects real-world conditions, but you must distinguish between variation that is part of the intervention and variation that corrupts it. Use a deviation log reviewed at each monitoring meeting. Predefine which deviations trigger per-protocol analysis and which are handled in the intention-to-treat analysis. Do not delete deviations from the dataset.

How Do I Explain a Pragmatic Design to an Owner or Practice Manager?

Frame the explanation around what the trial will change in everyday practice. Owners want to know whether their animal receives the same care they would get outside the trial, and whether participation affects cost or convenience. Explain that the trial compares two acceptable approaches that are already used in practice, and that the choice is made by chance to produce unbiased results. Practice managers need to understand staffing, appointment time, and billing implications. The AVMA practice resources provide general guidance on communicating research participation to clients. Avoid promising individual benefit. Emphasize that the trial answers a question that will improve care for future patients. If the practice cannot accommodate the protocol, say so before enrollment begins instead of after the first deviation.

What Are the Minimum Data Elements I Must Collect in a Pragmatic Trial?

Collect only data that answer the primary question, but collect those data completely. Minimum elements include eligibility screening logs, randomisation assignment, the intervention as actually delivered, the primary outcome, and a small set of baseline covariates for prognostic balance. The WOAH terrestrial animal health standards illustrate how international standards define minimum data requirements for animal health surveillance, and the same principle applies to trials. Resist the temptation to add exploratory endpoints that will not be analyzed. Each extra variable increases missing data risk and staff burden. Predefine how missing primary outcome data will be handled, because pragmatic trials commonly lose follow-up when owners move or decline further visits. A complete dataset on 90 percent of patients is more valuable than a partial dataset on 100 percent.

Related Clinical & Scientific Guides

• Conducting Systematic Reviews of Veterinary Diagnostic Test Accuracy
• Bias in Veterinary Research: Types, Sources, and Mitigation
• Cluster Randomized Trials in Veterinary Research: Design and Analysis

References and Further Reading

• Endometriosis as a chronic endothelial disorder: thromboinflammation, vascular reprogramming, and systemic cardiovascular risk.. 2026.
• Non-pharmacological Options in Postoperative Hospital-Based and Rehabilitation Pain Management (NOHARM): Protocol for a Stepped-Wedge Cluster-Randomized Pragmatic Clinical Trial.. 2022.
• General Anesthetics in CAncer REsection Surgery (GA-CARES) randomized multicenter trial of propofol vs volatile inhalational anesthesia: protocol description.. 2023.
• ARRIVE Guidelines 2.0 for Reporting Animal Research. PLOS Biology, 2020.
• EQUATOR Network Reporting Guidelines. EQUATOR Network.
• MSD Veterinary Manual, Professional Edition. MSD Veterinary Manual.
• American Veterinary Medical Association Practice Resources. American Veterinary Medical Association.
• WOAH Terrestrial Animal Health Code. WOAH.

Related Articles

• Implementing Adaptive Trial Designs in Veterinary Clinical Research
• Designing Adaptive Clinical Trials for Veterinary Medicine
• Cross-Over Designs in Veterinary Clinical Trials: Advantages and Limitations
• Blinding in Veterinary Clinical Research: Methods and Challenges
• Handling Missing Data in Veterinary Clinical Research

This article is educational professional reference material for veterinary audiences. It is not a substitute for veterinary diagnosis, individual clinical judgment, current product labeling, or applicable regulatory requirements.