Equine Breeding Soundness Examination: Mare Evaluation

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

Key Takeaways

• The Equine Breeding Soundness Examination (BSE) for mares is a predictive assessment to estimate conception and pregnancy maintenance probability, performed in pre-purchase, pre-breeding, or infertility investigation contexts.
• Key diagnostic components include historical assessment (age, parity, breeding history), physical examination (perineal conformation), transrectal palpation and ultrasonography (endometrial edema, uterine fluid, follicular status), endometrial cytology (neutrophil count), uterine culture (pathogen identification), and uterine biopsy (Kenney and Doig classification for endometrial fibrosis and glandular atrophy).
• The examination is optimally performed during estrus to facilitate cervical relaxation and uterine sampling, with findings interpreted in conjunction with the mare's cycle stage, age, and reproductive history.
• Endometrial biopsy is crucial for assessing long-term fertility potential, with Kenney and Doig Grade III lesions indicating a poor prognosis for carrying a foal to term due to severe fibrosis and glandular atrophy.
• Uterine lavage with sterile saline is a primary treatment for endometritis, often followed by ecbolic therapy (oxytocin or prostaglandin) if uterine clearance is poor, and antimicrobial therapy guided by culture and sensitivity results.
• Complications of sampling procedures, such as uterine perforation during biopsy or post-procedural endometritis, necessitate careful technique and monitoring, with early detection relying on ultrasonography and clinical signs.

The breeding soundness examination (BSE) of the mare is a structured, problem-oriented assessment performed to estimate the probability of conception and maintenance of pregnancy within a defined breeding season. It serves the practicing veterinarian in three distinct contexts: the pre-purchase or pre-breeding evaluation of a maiden or barren mare, the investigation of a mare that has failed to conceive despite adequate breeding management, and the establishment of a reproductive baseline before a breeding contract. This article outlines the components of the examination, including history, physical examination, transrectal palpation and ultrasonography, endometrial cytology and culture, and uterine biopsy, with emphasis on interpretation and clinical decision-making.

The BSE differs fundamentally from a diagnostic workup of acute illness. It is a predictive exercise, and its predictive value depends on the examiner's ability to integrate findings across multiple organ systems and time points. A single abnormal finding rarely determines prognosis. Instead, the clinician weighs the mare's age, parity, reproductive history, and current cycle stage against the objective findings of the examination. The Society for Theriogenology publishes professional resources on breeding soundness evaluation and reproductive health management that provide a framework for standardizing these assessments across practices Society for Theriogenology resources.

The examination is best performed during estrus, when the cervix is relaxed, the uterus is most accessible for sampling, and follicular status can be assessed. Diestrual examinations are useful for confirming luteal function but limit the interpretation of uterine culture and cytology because the cervix is closed and the uterus is under progestin dominance. The clinician should record the mare's cycle stage at the time of examination and interpret findings accordingly.

At a Glance

Historical Assessment and Signalment

The history is the most cost-effective component of the BSE and should be obtained systematically before any physical manipulation. Record the mare's age, breed, parity, and current reproductive status. Age is a dominant predictor of uterine health. Endometrial fibrosis, lymphatic lacunae, and periglandular fibrosis accumulate with each pregnancy and with advancing age, and the Society for Theriogenology resources emphasize that age-related endometrial changes are a primary determinant of the prognosis for future fertility Society for Theriogenology resources.

Obtain a complete breeding history for the current and previous seasons. Document the number of cycles bred, the breeding method (live cover, fresh cooled, or frozen semen), the number of cycles per conception, and any history of dystocia, retained placenta, or postpartum metritis. A mare that conceived on the first cycle of the previous season but has now failed over six cycles presents a different diagnostic problem than a maiden mare that has never been bred. The former suggests an acquired uterine or cervical lesion, while the latter raises questions about congenital abnormalities or breeding management.

Ask specifically about the mare's behavior during estrus, the length of the estrous cycle, and the timing of breeding relative to ovulation. A history of short interestrous intervals, prolonged estrus, or erratic cycles may indicate ovarian pathology or persistent endometrial inflammation. Also inquire about prior treatments, including the use of oxytocin, prostaglandins, uterine lavage, and intrauterine antibiotics, because these interventions can alter the flora and cytology of the uterus and confound the interpretation of culture results.

Physical Examination and Perineal Conformation

The general physical examination precedes the reproductive evaluation and should include body condition scoring, assessment of the udder and external genitalia, and evaluation of the mare's gait and demeanor. Chronic lameness or systemic disease can suppress cyclicity and reduce fertility independent of the reproductive tract. The MSD Veterinary Manual provides species-specific clinical guidance on the physical examination of the mare and the interpretation of reproductive findings MSD Veterinary Manual.

Perineal conformation deserves particular attention. The vulva should be assessed for vertical length, angle, and symmetry. A sunken anus, a tilted vulva, or a vulva that fails to seal completely during standing predisposes the mare to pneumovagina and ascending contamination of the reproductive tract. The Caslick index, calculated by measuring the length of the vulva above the pelvic floor, is a practical tool for identifying mares at risk. A Caslick index greater than 5 cm in a pluriparous mare warrants consideration of a vulvoplasty, although the decision to perform the procedure should be based on the complete examination, not the index alone.

The vestibule and vagina should be examined with a sterile speculum. Note the color and moisture of the vaginal mucosa, the presence of urine pooling, and the appearance of the cervix. The cervix should be evaluated for lacerations, adhesions, and fibrosis. A cervical laceration that extends through the full thickness of the cervical wall is a significant finding because it compromises the competence of the cervix during pregnancy. The MSD Veterinary Manual describes the normal appearance of the equine cervix during estrus and diestrus, and deviations from these norms should be recorded MSD Veterinary Manual.

Transrectal Palpation and Ultrasonography

Transrectal palpation and ultrasonography are performed together to characterize the reproductive tract and confirm the stage of the cycle. Palpation provides information about uterine tone, cervical tone, and the size and consistency of the ovaries. During estrus, the uterus is edematous and turgid, and the cervix is relaxed. During diestrus, the uterus is flaccid and the cervix is tightly closed. The ovaries should be examined for the presence of follicles, corpora lutea, and any abnormal structures such as hematomas or neoplasms.

Ultrasonography adds objective measurements to the palpation findings. The endometrium should be evaluated for the degree of edema, which is graded on a scale of 0 to 3. A grade of 0 indicates a homogeneous, non-edematous endometrium typical of diestrus or anestrus. Grade 3 indicates marked endometrial edema with a characteriztic cartwheel appearance, typical of peak estrus. The presence of endometrial edema outside of estrus, or the absence of edema during estrus, suggests hormonal imbalance or endometrial pathology.

Uterine luminal fluid is a critical finding. Small volumes of fluid, less than 1 cm in diameter, may be normal during estrus. Larger volumes, or fluid that persists after breeding, are associated with reduced fertility. The echogenicity of the fluid should be noted. Anechoic fluid is typically serous, while echogenic fluid suggests cellular debris or exudate. The MSD Veterinary Manual describes the ultrasonographic appearance of uterine fluid and its association with endometritis MSD Veterinary Manual.

The ovaries should be measured and the follicles counted. The diameter of the dominant follicle should be recorded, and the mare should be examined at intervals to confirm ovulation. A follicle that fails to ovulate, or that ovulates at an abnormal size, may indicate ovarian dysfunction. The corpus luteum should be identified and its echogenicity assessed. A corpus luteum with a central cavity, the corpus luteum hematoma, is a normal finding and should not be mistaken for a pathological structure.

Uterine Cytology and Endometrial Culture

Uterine cytology and culture are performed when the history, physical examination, or ultrasonographic findings suggest endometrial contamination or persistent post-breeding inflammation. The two tests are complementary and should be interpreted together, because cytology detects active inflammation while culture identifies the organizm present.

A guarded swab or double-guarded culture instrument is passed through the cervix into the uterine body. The perineum is prepared as for any intrauterine procedure, with particular attention to the vulvar lips and clitoral fossa. The examiner's arm and the tail are wrapped, and the vulva is cleansed with a non-residual antiseptic. The guarded swab is advanced through the cervix only after the cervix is located by transrectal palpation. Once the swab is within the uterine lumen, the inner guard is advanced and the swab is exposed to the endometrium for 15 to 30 seconds. The swab is withdrawn into the guard before removal through the cervix.

For cytology, the swab is rolled gently onto a clean glass slide and stained with a modified Wright stain or Diff-Quik. The slide is scanned at 100x magnification to identify areas of cellularity, then examined at 400x to 1000x for neutrophils. More than two neutrophils per high-power field in a cycling mare, or more than five in a mare during estrus, indicates active inflammation. The presence of intracellular bacteria within neutrophils supports a diagnosis of bacterial endometritis. A negative cytology with a positive culture suggests contamination or a low-grade infection, while positive cytology with negative culture may indicate fungal endometritis, foreign body reaction, or inflammation from a previous examination.

Culture swabs are placed in transport medium and submitted for aerobic culture. Anaerobic culture is rarely indicated in the mare. A uterine culture obtained during estrus is more likely to reflect true contamination because the cervix is relaxed and the uterus is more susceptible to ascending infection. Samples collected during diestrus are less contaminated but may miss organizms that are cleared by uterine defense mechanisms. The clinical significance of a positive culture depends on the organizm isolated, the quantity of growth, and the presence of concurrent cytologic inflammation. Growth of a single organizm in pure culture with positive cytology is significant. Growth of multiple organizms or a light growth of a commensal organizm with negative cytology is more likely contamination.

Endometrial Biopsy

Endometrial biopsy provides the only direct assessment of the endometrium's ability to support pregnancy. The biopsy is indicated in mares with a history of pregnancy loss, repeated failure to conceive, or abnormal findings on ultrasonography such as endometrial cysts, uterine fluid, or a thickened endometrium. It is also recommended in older mares and in any mare that has failed to conceive after two or more breeding cycles.

The biopsy is obtained using a uterine biopsy punch, typically 30 to 40 cm in length with a 3 to 5 mm basket. The mare is restrained in stocks, and the perineum is prepared as for culture. The biopsy instrument is guided through the cervix by transrectal manipulation. The sample is taken from the base of a uterine horn, preferably at the junction of the uterine body and horn, avoiding the endometrial folds and the area near the tubal papilla. The punch is closed and withdrawn, and the sample is placed in 10% neutral buffered formalin.

The biopsy is graded according to the Kenney and Doig classification system, which assigns a grade of I, IIA, IIB, or III based on the degree of endometrial fibrosis, inflammation, and glandular atrophy. Grade I endometrium has no pathologic changes. Grade IIA has mild, scattered inflammatory infiltrates or early periglandular fibrosis. Grade IIB has moderate, diffuse inflammation or fibrosis that is more extensive but still leaves areas of normal endometrium. Grade III has severe, diffuse fibrosis or inflammation with glandular atrophy and little or no normal endometrium remaining. The grade correlates with the likelihood of carrying a foal to term, with Grade I and IIA mares having a good prognosis, Grade IIB mares a guarded prognosis, and Grade III mares a poor prognosis.

The biopsy should be interpreted in the context of the mare's age, reproductive history, and the stage of the estrous cycle. The endometrium undergoes normal cyclic changes, and a biopsy taken during estrus will show more edema and fewer glands than one taken during diestrus. The pathologist should be provided with the mare's cycle stage and the date of her last ovulation.

Uterine Culture and Biopsy Decision Framework

The decision to perform culture, biopsy, or both depends on the clinical presentation and the stage of the examination. The following table summarizes the indications and the information each test provides.

A mare with positive cytology and a positive culture is treated based on the culture and sensitivity results. A mare with positive cytology and a negative culture may have fungal endometritis or a non-infectious inflammatory condition. A mare with negative cytology and a positive culture is likely contaminated, and the culture should be repeated during estrus. A mare with negative cytology and negative culture but a history of infertility should proceed to biopsy.

Uterine Lavage and Therapy Planning

When endometritis is diagnosed, uterine lavage with sterile saline is the first-line treatment. Lavage physically removes inflammatory debris, bacteria, and accumulated fluid, and it stimulates uterine contractility. The decision to lavage is based on the presence of intrauterine fluid on ultrasound, positive cytology, or a history of persistent post-breeding inflammation. Lavage is performed with a sterile uterine catheter or a Foley catheter with a 30 to 60 mL balloon. Two to three liters of sterile saline are infused slowly, the uterus is massaged per rectum, and the fluid is allowed to drain by gravity or is siphoned off. The procedure is repeated until the returned fluid is clear.

The choice between lavage alone and lavage followed by ecbolic therapy depends on the mare's response. Mares with poor uterine clearance, evidenced by retained fluid after breeding or after lavage, benefit from oxytocin or prostaglandin administration. The response to lavage is assessed by ultrasound 12 to 24 hours after the procedure. If fluid persists, the mare may require additional lavage or a different therapeutic approach.

Antimicrobial therapy is selected based on culture and sensitivity results. Systemic therapy is appropriate for mares with uterine infections caused by organizms that are also found systemically, such as Streptococcus equi subspecies zooepidemicus. Intrauterine therapy is reserved for mares with infections confined to the endometrium. The choice of antimicrobial agent depends on the organizm, the route of administration, and the availability of a suitable intrauterine preparation. Current formulary and label references must be consulted for approved products and doses.

Documentation and Reporting

The breeding soundness examination is documented in a structured format that allows comparison across examinations and between mares. The record includes the mare's signalment, reproductive history, physical examination findings, perineal conformation score, ultrasonographic findings, cytology and culture results, and biopsy grade. Each finding is recorded with the date and the stage of the estrous cycle. The final report states the mare's suitability for breeding, the recommended breeding management, and any treatments or further diagnostics that are indicated.

The report should distinguish between findings that affect the mare's ability to conceive and findings that affect her ability to carry a foal to term. A mare with a normal examination and a Grade I biopsy has an excellent prognosis. A mare with a Grade IIB biopsy may conceive but is at increased risk of pregnancy loss. A mare with a Grade III biopsy has a poor prognosis for carrying a foal to term, and the owner should be counseled accordingly. The prognosis is always stated in relative terms, because individual mares may exceed or fall short of the expected outcome.

Recognized Complications and Early Detection

The principal complications encountered during mare breeding soundness examination relate to diagnostic sampling, patient safety, and interpretation of findings. Uterine culture and cytology collection carry a small risk of endometrial trauma, hemorrhage, or introduction of contaminants, particularly in maiden mares or those with narrow cervical anatomy. The guarded swab or double-guarded culture instrument should pass through the cervix without force, resistance warrants reassessment of technique instead of increased pressure. Cytobrush sampling may induce transient endometrial bleeding that can obscure cytological interpretation if the sample is collected after the brush has contacted the cervix or vagina.

Endometrial biopsy carries the highest risk of the sampling procedures. Complications include hemorrhage, uterine perforation, and peritonitis. Perforation is more likely in mares with a thin, atrophic uterus or when the biopsy forceps is advanced without transrectal guidance. Early detection of perforation relies on the operator recognizing a sudden loss of resistance during forceps advancement, followed by the inability to visualize the instrument within the uterine lumen on ultrasound. Mares with suspected perforation should be monitored for signs of peritonitis, including fever, depression, and abdominal pain, and should receive appropriate systemic therapy.

Post-procedural endometritis is a recognized sequel to any uterine instrumentation. Mares with compromised uterine clearance, such as aged mares or those with poor lymphatic drainage, are at increased risk. Early detection depends on serial transrectal ultrasonography to identify intrauterine fluid accumulation in the days following sampling. The presence of echogenic fluid with suspended particles suggests an inflammatory response that may require intervention.

Common Errors and Corrective Action

Less experienced clinicians frequently misinterpret endometrial cytology by over-reading background debris or epithelial cells as inflammatory cells. Neutrophils must be identified by their multilobed nuclei and granular cytoplasm, a finding of fewer than two neutrophils per high-power field in a representative area is generally considered within normal limits, whereas higher numbers indicate active inflammation. Novice evaluators also tend to overinterpret the significance of a single positive culture result. A positive culture in the absence of cytological inflammation and without ultrasonographic evidence of fluid may represent transient contamination or commensal growth, and treatment decisions should not rest on culture alone.

A second common error is performing the examination without regard to the stage of the oestrous cycle. The endometrium undergoes substantial changes in echogenicity and edema across the cycle, and the cervix relaxes under oestrogen influence. Evaluating uterine tone or cervical patency during dioestrus can produce misleading results. The examination should be scheduled during oestrus whenever possible, and the cycle stage should be confirmed by ultrasonographic assessment of follicular and luteal structures.

A third error involves the interpretation of endometrial biopsy samples. The Kenney and Doig classification system assigns prognostic categories based on the severity of endometrial pathology, but clinicians sometimes apply the classification without considering the mare's age, parity, and intended use. A Grade IIB biopsy in a 20-year-old broodmare with a valuable pedigree carries different management implications than the same grade in a 5-year-old maiden. The biopsy result must be interpreted in the context of the complete examination.

Limitations of Current Evidence

The evidence base for mare breeding soundness examination is constrained by the difficulty of establishing true fertility endpoints. Pregnancy rates per cycle are influenced by stallion fertility, management practices, and seasonal factors, making it difficult to attribute outcomes to specific mare findings. The Society for Theriogenology provides professional resources on breeding soundness evaluation, but formal consensus standards for the mare examination are less developed than those for the bull or stallion Society for Theriogenology resources. Expert opinion differs on the predictive value of endometrial biopsy grades, with some clinicians placing greater weight on histopathology than on cytology or culture, while others argue that the dynamic nature of endometrial inflammation makes single-time-point sampling unreliable.

Doppler ultrasonography has been investigated as an adjunct to conventional reproductive assessment, with studies in domestic species demonstrating relationships between uterine and ovarian blood flow and reproductive function New Approaches to Assess Fertility in Domestic Animals. However, the clinical application of Doppler parameters in the mare breeding soundness examination remains an area of active investigation instead of established practice, and reference values for clinically meaningful thresholds are not yet standardized.

Referral and Regulatory Considerations

Referral to a theriogenology specialist is warranted when the examination reveals findings that exceed the general practitioner's diagnostic or therapeutic capacity. These include suspected uterine neoplasia, recurrent pregnancy loss with an undetermined cause, or persistent endometritis that has failed to respond to standard therapy. Specialist referral is also appropriate when advanced imaging, such as hysteroscopy, is required to evaluate intraluminal lesions that cannot be characterized by transrectal ultrasonography.

Laboratory involvement is indicated for endometrial biopsy histopathology, which requires a pathologist experienced in equine reproductive tissues. Cytological interpretation can be performed in-house, but referral laboratories may offer additional value through standardized staining and interpretation protocols. Culture and sensitivity testing should be performed by a laboratory with experience in equine uterine pathogens, particularly for the isolation of beta-hemolytic streptococci and other fastidious organizms.

Regulatory reporting obligations vary by jurisdiction. The WOAH terrestrial animal health standards address notifiable reproductive diseases that may be encountered during examination, and the AVMA practice resources provide guidance on professional obligations. Clinicians should be familiar with the reporting requirements in their region for conditions such as contagious equine metritis, equine viral arteritis, and other diseases with trade implications. The MSD Veterinary Manual offers a general reference for infectious reproductive diseases and their clinical presentation.

Frequently Asked Questions

How should I proceed when transrectal ultrasonography is unavailable for a breeding soundness examination?

Transrectal palpation alone can identify uterine tone, cervical tone, ovarian structures, and gross uterine enlargement, but it cannot detect intraluminal fluid, endometrial edema patterns, or early pregnancy. Palpation findings should be interpreted conservatively and paired with vaginal speculum examination and cytology. If the mare is being examined for breeding management instead of purchase, consider whether the examination can be deferred until ultrasound access is secured. When ultrasound is truly unavailable, endometrial cytology and culture become proportionally more important for detecting inflammation. Document the equipment limitation explicitly in the report so the referring veterinarian understands the reduced sensitivity of the examination. Professional resources on reproductive health management can guide interpretation of palpation findings in this context Society for Theriogenology resources.

What is the minimum database if the owner declines endometrial biopsy?

Endometrial biopsy provides prognostic information that cytology and culture cannot, particularly regarding fibrosis and chronic degenerative changes. If the owner declines biopsy, the minimum acceptable database consists of transrectal palpation, ultrasonography, endometrial cytology, and aerobic culture with sensitivity. The clinician should explain that the examination can identify current inflammation and infection but will not reliably predict the mare's ability to carry a pregnancy to term. A normal cytology and culture result in a mare with good perineal conformation and no historical reproductive loss supports a guarded to favorable prognosis, but the confidence interval is narrower than with biopsy. Record the owner's refusal and the rationale for proceeding without biopsy in the medical record.

How do I interpret a positive endometrial culture in a mare with no cytologic evidence of inflammation?

A positive culture with negative cytology suggests either contamination during sampling, low-grade colonization without active inflammation, or a fastidious organizm present in numbers below the threshold for cytologic detection. Repeat sampling using a guarded swab or double-guarded culture instrument before initiating therapy. If the same organizm is isolated on repeat culture and the mare has a history of persistent infection or pregnancy loss, treatment is warranted even without cytologic inflammation. If the isolate is a common contaminant such as a non-hemolytic Streptococcus species and the mare is clinically normal, many clinicians defer treatment and recheck at the next estrus. The distinction matters because unnecessary antibiotic therapy disrupts the normal uterine flora and may select for resistant organizms.

What are the practical limits of Doppler ultrasonography in routine mare breeding soundness examination?

Doppler evaluation of uterine and ovarian blood flow has been investigated as a tool for assessing reproductive function, and research in domestic species supports its value for evaluating perfusion of reproductive organs Doppler assessment of reproductive organ irrigation. However, routine clinical application in mares remains limited by equipment cost, operator experience, and the absence of standardized reference values that predict fertility outcomes. Color Doppler can document luteal blood flow and uterine perfusion patterns, but these findings rarely change management decisions in a mare with otherwise normal examination findings. Reserve Doppler for research settings or for problem mares where vascular compromise is suspected, such as mares with previous uterine torsion or severe endometrial fibrosis. The evidence base for prognostic value in mares specifically is less developed than in other species.

How should I structure the written report for a breeding soundness examination?

Organize the report by body system with findings, interpretation, and recommendations in each section. Include signalment, examination date, reproductive history, and the specific question the owner asked. State the stage of the estrous cycle and how cycle stage influenced interpretation of findings. Separate objective findings from subjective impressions, and list any samples submitted for cytology, culture, or histopathology with the laboratory name and submission date. Provide a final assessment that classifies the mare as satisfactory, satisfactory with reservations, or unsatisfactory for breeding, and specify the basis for that classification. Include a follow-up plan with recheck intervals and any recommended therapies. The MSD Veterinary Manual provides guidance on reproductive examination documentation standards.

How do I counsel an owner when the examination identifies a poor prognostic finding?

Present the finding directly with the supporting evidence, then place it in the context of the mare's age, reproductive history, and intended use. For example, a mare with moderate endometrial fibrosis may still carry a foal if managed aggressively, but the likelihood of success and the expected cost of repeated cycles should be stated plainly. Offer the owner time to consider the information and a second opinion if they request one. Avoid language that guarantees either success or failure, and document the discussion in the medical record. The owner's decision may reasonably differ from the clinician's recommendation depending on the mare's sentimental or economic value, and the clinician's role is to provide accurate prognostic information without steering the decision. Professional practice resources can support communication strategies for difficult conversations AVMA practice resources.

Related Clinical & Scientific Guides

• Diagnostic Approach to Canine Infertility in the Bitch
• Canine Neonatal Resuscitation: Protocol and Monitoring
• Equine Breeding Soundness Examination of the Stallion

References and Further Reading

• New Approaches to Assess Fertility in Domestic Animals: Relationship between Arterial Blood Flow to the Testicles and Seminal Quality.. 2020.
• Advances in applications of color Doppler ultrasonography in the andrological assessment of domestic animals: A review.. 2021.
• Flow cytometric and microscopic evaluation and effect on fertility of abnormal chromatin condensation in bovine sperm nuclei.. 1994.
• Canine reproductive ultrasound examination for predicting future sperm quality.. 2017.
• Capacitation, acrosome function and chromatin structure in stallion sperm.. 2005.
• The deleterious effect of postpartum pyometra on the reproductive indices, the metabolic profile, and oxidant/antioxidant parameters of dairy cows.. 2021.
• Society for Theriogenology Resources. Society for Theriogenology.
• MSD Veterinary Manual, Professional Edition. MSD Veterinary Manual.
• American Veterinary Medical Association Practice Resources. American Veterinary Medical Association.

Related Articles

• Equine Breeding Soundness Examination of the Stallion
• Breeding Soundness Examination of the Canine Male
• Breeding Soundness Examination of Bulls: Standards and Interpretation
• Equine Brucellosis: Diagnosis and Management
• Dystocia in Mares: Diagnosis and Management

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.