NAVLE Theriogenology: Reproduction and Infertility Essentials

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

Key Takeaways

• The hypothalamic-pituitary-gonadal axis relies on pulsatile GnRH release to stimulate FSH and LH from the pituitary, driving follicular development and ovulation; understanding this cascade is crucial for interpreting endocrine data and designing ovulation induction protocols.
• Estrous cycle phases (proestrus, estrus, metestrus/diestrus, anestrus) and species-specific variations in cycle length, ovulation timing (spontaneous vs. induced), and luteal phase duration (e.g., prolonged in bitches/queens) dictate breeding management and infertility workup strategies.
• Semen evaluation requires assessment of motility, morphology, and concentration, with a single poor ejaculate necessitating repeat collection and interpretation in context of age, health, and environmental factors due to the 2-6 week lag time for effects of insults on spermatogenesis.
• Pregnancy diagnosis utilizes species-appropriate methods including ultrasound (transrectal/transabdominal), palpation, and hormone assays (progesterone, relaxin), with method selection dependent on gestation stage and available resources.
• Infertility workups follow a logical sequence: confirm cyclicity/ovulation, verify correct breeding/insemination timing, assess semen quality, confirm fertilization/implantation, and investigate pregnancy loss, prioritizing management factors before advanced diagnostics.
• Hormonal therapies like prostaglandin F2 alpha for luteolysis and progesterone/progestins for cycle synchronization or pregnancy maintenance are key, alongside surgical interventions for conditions like pyometra or cryptorchidism, with treatment decisions driven by specific diagnoses.

This article reviews the reproductive physiology, breeding management, and common infertility presentations that appear on the North American Veterinary Licensing Examination (NAVLE). It is written for veterinary students preparing for board examination and for clinicians seeking a structured refresher in theriogenology. The content spans domestic species, including dogs, cats, horses, cattle, sheep, goats, and swine, with attention to species differences that commonly generate examination questions.

The NAVLE assesses clinical reasoning across the major veterinary disciplines, and theriogenology questions typically test your ability to integrate endocrine pathways, breeding schedules, and diagnostic findings into a coherent infertility workup. The official examination structure and content areas are published by the International Council for Veterinary Assessment, and candidates should review that material to understand how reproduction topics are weighted within the overall examination blueprint ICVA NAVLE candidate information. This article emphasizes the decision frameworks and physiological principles that recur across species, instead of memorized facts alone.

The scope here covers reproductive physiology, breeding management, and infertility evaluation. Obstetric emergencies, dystocia management, and neonatal care are excluded, as those topics require separate treatment. The goal is to give you a portable mental model for approaching reproduction questions, whether they involve a seasonally anestrous mare, a bitch with silent estrus, or a bull with poor semen quality.

At a Glance

Reproductive Physiology Foundations

The Hypothalamic-Pituitary-Gonadal Axis

The reproductive axis operates through a cascade of hormonal signals. The hypothalamus secretes gonadotropin-releasing hormone (GnRH) in a pulsatile fashion. GnRH stimulates the anterior pituitary to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH drives follicular growth and estrogen production, while LH triggers ovulation and supports luteal function. The gonads produce steroid hormones, primarily estrogen, progesterone, and testosterone, which exert negative and positive feedback on the hypothalamus and pituitary.

Pulsatility is the critical variable. Continuous GnRH exposure downregulates pituitary receptors, which is the basis for using GnRH agonists to suppress reproductive function. In contrast, the preovulatory LH surge requires a sustained elevation of estrogen that shifts feedback from negative to positive. Understanding this switch is essential for interpreting endocrine data and for designing ovulation induction protocols.

The Estrous Cycle

The estrous cycle is divided into four phases: proestrus, estrus, metestrus (diestrus in the bitch), and anestrus. Proestrus is characterized by follicular development and rising estrogen. Estrus is the period of sexual receptivity and coincides with peak estrogen and, in spontaneous ovulators, the LH surge. Metestrus or diestrus follows ovulation and is dominated by progesterone from the corpus luteum. Anestrus is the period of reproductive quiescence.

Species differ in cycle length, ovulation timing, and seasonality. The cow has a 21 day cycle with estrus lasting 12 to 18 hours and ovulation occurring 10 to 12 hours after the end of estrus. The mare has a 21 to 22 day cycle with estrus lasting 5 to 7 days and ovulation occurring 24 to 48 hours before the end of estrus. The ewe cycles every 17 days during the breeding season, which is triggered by decreasing day length. The sow cycles every 21 days with estrus lasting 2 to 3 days. The queen is seasonally polyestrous and an induced ovulator, requiring vaginal stimulation to release LH. The bitch is monoestrous, cycling once or twice per year with a prolonged anestrus of 4 to 6 months.

The Role of Progesterone

Progesterone is the hormone of pregnancy maintenance. It is produced by the corpus luteum in all domestic species, with the placenta assuming primary production in the mare after approximately 100 days of gestation. Progesterone suppresses further follicular development, maintains endometrial gland secretion, and reduces myometrial contractility. In the nonpregnant animal, luteolysis occurs through prostaglandin F2 alpha released from the endometrium, which terminates the luteal phase and allows a new cycle to begin.

The corpus luteum lifespan varies by species. In the cow, ewe, sow, and mare, luteolysis occurs at a predictable interval after ovulation. In the bitch and queen, the luteal phase is prolonged even in nonpregnant animals, lasting 60 to 70 days in the bitch and 30 to 40 days in the queen. This distinction has practical consequences for managing pseudopregnancy and for timing diagnostic procedures.

Breeding Management Principles

Timing of Breeding and Insemination

Optimal breeding timing depends on the relationship between estrus onset, ovulation, and sperm survival in the female reproductive tract. Spermatozoa survive 24 to 48 hours in most species, while the oocyte remains fertilizable for 12 to 24 hours after ovulation. The goal is to have viable sperm present at the time of ovulation.

For natural service, the male should be introduced at the first sign of standing estrus and bred every 24 to 48 hours until estrus ends. For artificial insemination with chilled or frozen semen, timing becomes more critical because sperm survival is reduced. Frozen semen should be deposited closer to ovulation, typically 12 to 24 hours before the expected time of ovulation. The specific recommendations vary by species and are detailed in the MSD Veterinary Manual reproduction sections.

Semen Collection and Evaluation

A complete breeding soundness examination includes physical examination, genital examination, and semen evaluation. Semen is evaluated for volume, concentration, total sperm number, progressive motility, morphology, and the percentage of normal spermatozoa. Thresholds for satisfactory classification are species-specific and are published by professional organizations such as the Society for Theriogenology.

A single poor ejaculate should never be used to condemn a male. Repeat collection after 48 to 72 hours, and interpret results in light of the male's age, body condition, recent illness, and environmental temperature. Heat stress, fever, and certain medications can transiently depress sperm quality, with effects appearing 2 to 6 weeks after the insult due to the duration of spermatogenesis and epididymal transit.

Pregnancy Diagnosis

Early and accurate pregnancy diagnosis is central to reproductive management. Transrectal ultrasonography is the method of choice in cattle and horses, allowing detection as early as day 25 to 30 in the cow and day 12 to 14 in the mare. Transabdominal ultrasound is used in small ruminants, swine, dogs, and cats. Hormonal assays include progesterone measurement, which confirms luteal activity but cannot distinguish pregnancy from a persistent corpus luteum, and relaxin, which is pregnancy-specific in the bitch and queen.

The choice of diagnostic method depends on the stage of gestation, the species, and the available equipment. The WOAH terrestrial animal health standards address reproductive disease surveillance and trade-related testing requirements that may influence pregnancy diagnosis protocols in production settings.

Infertility in the Female

Failure to Cycle

Anestrus is the most common presenting complaint in female infertility. The diagnostic approach begins with confirming the animal is not pregnant, then assessing age, body condition, nutrition, season, and social environment. In seasonally breeding species, the photoperiod is the dominant factor. In the mare, the transition from winter anestrus to cyclic activity can be hastened with artificial lighting. In the ewe and doe, the breeding season is initiated by decreasing day length, and out-of-season breeding requires hormonal manipulation.

Nutritional status exerts a powerful influence on cyclicity. Thin animals may fail to cycle due to insufficient energy reserves, while obese animals may cycle irregularly due to excess adiposity and altered steroid metabolism. Body condition scoring systems are species-specific, and the target score for breeding varies by production system and breed.

Silent Estrus and Poor Detection

Silent estrus refers to ovulation without detectable behavioral signs. It is common in cattle, particularly in postpartum animals, and in mares with a foal at foot. The diagnosis is confirmed by serial progesterone measurements or by transrectal ultrasonography documenting ovulation. Management focuses on improving estrus detection, using estrus synchronization protocols, or employing ovulation induction agents.

Early Embryonic Loss

Pregnancy loss before day 42 in the cow, or the equivalent stage in other species, is termed early embryonic loss. Causes include chromosomal abnormalities, uterine infection, luteal insufficiency, heat stress, and nutritional deficiencies. Diagnosis is challenging because many losses occur before the animal is confirmed pregnant. Serial progesterone monitoring and ultrasonography can identify some cases, but the etiology often remains unknown.

Infertility in the Male

Breeding Soundness Examination

The male infertility workup follows a structured format. The history includes prior fertility, libido, mating ability, and any recent illness or injury. The physical examination assesses body condition, testicular size and consistency, scrotal circumference, and the accessory sex glands. Semen collection and evaluation complete the examination.

Testicular hypoplasia, degeneration, and neoplasia are the primary testicular causes of infertility. Testicular degeneration is often secondary to fever, trauma, or toxins and may be reversible if the insult is removed. Scrotal circumference correlates with sperm production and is a standard component of bull breeding soundness evaluations.

Libido and Mating Ability

A male may have excellent semen quality but still fail to breed due to poor libido, musculoskeletal disease, or behavioral problems. Libido is influenced by age, social dominance, and prior experience.

Diagnostic Approach to Infertility

Infertility investigation begins with a complete history and a problem-oriented physical examination. The history should include breeding dates, observed estrous behavior, previous pregnancy outcomes, vaccination status, and any treatments administered. A common error is proceeding to advanced diagnostics before confirming that breeding management was correct. For example, a female presented for apparent infertility may simply have been bred at the wrong time relative to ovulation, a problem that no laboratory test will resolve.

The diagnostic sequence follows a logical progression. First, confirm the animal is cycling and ovulating. Second, confirm that mating or insemination occurred at the correct time. Third, confirm that semen quality was adequate. Fourth, confirm that fertilization and implantation occurred. Fifth, investigate causes of pregnancy loss. This sequence prevents wasted expense on advanced imaging or endocrine testing when the problem lies in management.

History and Signalment

Signalment provides the first diagnostic clues. Age is critical. A young animal that has never cycled suggests a congenital or developmental problem, while an older animal with previously normal reproduction may have acquired disease. Breed predispositions matter. For example, certain dog breeds have higher rates of dystocia and some cattle breeds have higher rates of cystic ovarian disease. Species and production system determine what is economically feasible. A companion animal owner may pursue advanced reproductive technologies, while a commercial cow-calf operation requires a cost-effective approach.

The history should establish the expected reproductive cycle for the species. The table below summarizes key cycle parameters across common domestic species.

These values represent population norms. Individual variation is substantial, and the clinician should use them as starting points instead of absolute rules. The MSD Veterinary Manual provides species-specific reproductive physiology details that should be consulted when cycle parameters are unclear.

Diagnostic Testing and Interpretation

Hormonal assays provide objective data when history and physical examination are inconclusive. Progesterone measurement is the most widely used endocrine test in reproduction. In the bitch, serial progesterone concentrations identify the optimal breeding window. In the cow and mare, progesterone confirms luteal function and helps stage the cycle. A single progesterone sample has limited value. Serial sampling at 48 to 72 hour intervals provides far more information about cycle progression.

Ultrasonography is the primary imaging modality for reproductive assessment. Transrectal ultrasound in large animals allows visualization of ovarian follicles, corpora lutea, and uterine contents. In small animals, transabdominal ultrasound is used for pregnancy diagnosis and fetal viability assessment. Ultrasound findings must be interpreted in context. A corpus luteum confirms ovulation occurred but does not confirm that the oocyte was fertilized or that the embryo survived.

Vaginal cytology is useful in the bitch and queen to stage the estrous cycle. Superficial cell percentage correlates with estrogen effect. In the bitch, cytology confirms proestrus and estrus but does not predict ovulation timing. In cattle, vaginoscopy and cytology have limited diagnostic value compared to palpation or ultrasound.

When to Refer or Reassess

Referral to a theriogenology specialist is appropriate when the diagnostic workup exceeds the general practitioner's equipment or expertise. Examples include advanced semen evaluation, embryo transfer, or management of complex endocrine disorders. The American Veterinary Medical Association practice resources provide guidance on scope of practice and referral expectations.

A diagnostic plan should include a timeline for reassessment. If a female fails to conceive after two or three properly timed breedings with confirmed semen quality, further investigation is warranted. If the workup reveals a treatable condition, a specific treatment trial with defined endpoints should be planned. If the workup reveals a poor-prognosis condition, the owner should receive an honest prognosis and options for alternative approaches such as artificial insemination with donor semen or embryo transfer.

Diagnostic Imaging in Reproduction

Ultrasonography is the central element of reproductive imaging. The choice of transducer frequency and placement depends on the species and the target structure. High-frequency linear transducers provide excellent resolution for superficial structures such as the canine prostate or the equine uterus. Lower-frequency convex transducers penetrate deeper for transabdominal imaging in large patients.

Ovarian and Uterine Assessment

In the mare, transrectal ultrasound is used to track follicular development, identify ovulation, and diagnose twins. Follicles appear as anechoic spherical structures. A corpus luteum appears as a more echogenic structure with a distinct border. Uterine edema increases during estrus and decreases after ovulation, providing a useful indicator of cycle stage.

In the cow, transrectal ultrasound is used to confirm pregnancy as early as day 28 and to assess fetal viability. The presence of a heartbeat confirms a live fetus. Uterine pathology such as pyometra or mucometra appears as fluid accumulation within the uterine lumen. The character of the fluid, whether anechoic or echogenic, provides diagnostic information.

In the bitch, transabdominal ultrasound is the standard method for pregnancy diagnosis after day 21 to 25. Fetal heartbeats are visible by day 25 to 28. Ultrasound is also used to diagnose ovarian remnants in spayed females presenting with signs of estrus.

Advanced Imaging Modalities

Radiography has limited application in reproductive diagnosis. It is useful for fetal counting in late pregnancy in small animals and for diagnosing fetal death when gas is present within the uterus. Contrast studies such as vaginography have largely been replaced by ultrasound and endoscopy.

Computed tomography and magnetic resonance imaging are rarely indicated for reproductive diagnosis in general practice. They may be useful for evaluating adrenal disease or pituitary masses that cause reproductive dysfunction, but these cases are typically referred to specialty centers.

Therapeutic Decision Making

Treatment decisions follow directly from the diagnostic findings. Anovulation requires different therapy than early embryonic loss. The clinician should establish a specific diagnosis before initiating treatment. Empiric therapy without a diagnosis wastes time and money and may mask underlying disease.

Hormonal Therapy

Prostaglandin F2 alpha and its analogues are used to lyse a functional corpus luteum in cattle, horses, and swine. The indication is to synchronize estrus or to terminate a nonviable pregnancy. The response depends on the presence of a responsive corpus luteum, which requires that at least 5 to 7 days have passed since ovulation.

Progesterone and progestins are used to suppress estrus, to maintain pregnancy in cases of luteal insufficiency, and to synchronize cycles. In the bitch, progestins are used to delay estrus. In cattle, progestin-releasing devices are used in synchronization protocols. The MSD Veterinary Manual provides detailed protocols for these applications.

Gonadotropins such as equine chorionic gonadotropin and human chorionic gonadotropin are used to stimulate follicular development and induce ovulation. Their use requires careful monitoring because ovarian hyperstimulation is a real risk.

Surgical and Non-Hormonal Therapy

Surgical intervention is indicated for specific conditions. Ovariohysterectomy is the treatment of choice for pyometra in companion animals when the owner does not intend to breed. Cesarean section is indicated for dystocia that cannot be managed medically. Cryptorchidectomy is indicated for retained testicles due to the risk of neoplasia.

Non-hormonal therapy includes antibiotics for bacterial endometritis, anti-inflammatory drugs for uterine inflammation, and supportive care for systemic illness. The choice of antibiotic should be based on culture and sensitivity results whenever possible. Empiric antibiotic use is discouraged because it promotes resistance and may not address the underlying cause.

Documentation and Monitoring

Accurate records are essential for reproductive management. Each breeding should be documented with dates, method of insemination, semen source, and any treatments administered. Serial hormone values should be plotted over time to visualize trends. Ultrasound findings should be recorded with images when possible.

Monitoring parameters depend on the clinical situation. In a bitch being bred, progesterone is measured every 2 to 3 days until ovulation is confirmed. In a mare being bred, follicular size and uterine edema are assessed daily. In a cow being synchronized, the response to each protocol step is assessed to confirm the animal is progressing as expected.

The International Council for Veterinary Assessment describes the examination structure and content areas that include reproduction. Candidates should be prepared to interpret reproductive data, select appropriate diagnostic tests, and recommend treatment based on findings. The Association of American Veterinary Medical Colleges provides curriculum resources that emphasize competency in reproductive medicine across species.

Recognized Complications and Failure Modes

Reproductive case management fails through predictable pathways. Early detection depends on knowing which parameter to monitor and when.

Anestrus misclassification. A female presented as "not cycling" may be cycling silently, cycling but not detected, or truly acyclic. The discriminating check is serial progesterone measurement. Two samples 7 to 10 days apart that remain below 1 ng/mL confirm absence of luteal activity. A single elevated sample indicates ovulation has occurred and the problem is detection, not cyclicity.

Ovarian remnant syndrome. Post-ovariohysterectomy females showing estrous behavior may have residual ovarian tissue. Basal serum luteinising hormone is elevated in ovariectomised females but suppressed in the presence of functional ovarian tissue. Anti-Müllerian hormone measurement provides a more reliable indicator of remnant tissue, as it is produced by granulosa cells regardless of cycle stage.

Persistent corpus luteum. Prolonged diestrus with sustained progesterone elevation suggests either pregnancy, pyometra, or a persistent luteal structure. Ultrasonography differentiates these: the gravid uterus shows fluid-filled uterine horns and embryonic vesicles, while pyometra shows echogenic intraluminal fluid without embryonic structures.

Sperm retrieval failure. Azoospermia on collection may reflect testicular failure, epididymal obstruction, retrograde ejaculation, or collection technique error. Repeat collection after sexual rest and evaluate the post-ejaculatory urine sediment for spermatozoa to distinguish retrograde flow from true azoospermia.

Misinterpreted pregnancy diagnosis. Early ultrasonography before day 21 in the bitch frequently produces false negatives. Equine transrectal palpation before day 14 cannot reliably distinguish embryonic vesicles from uterine tone. Repeat examination at the appropriate interval for the species is the standard safeguard.

Common Errors and Corrective Actions

Over-reliance on a single diagnostic test. Students and new clinicians frequently diagnose pregnancy, infertility, or cyclicity status from one sample or one ultrasound image. Reproductive diagnoses are time-sensitive and dynamic. Serial sampling and repeat imaging are the corrective standard.

Ignoring male factors in female infertility. When a bitch or mare fails to conceive, the male is often assumed fertile because he "breeds readily." Semen evaluation must accompany female workup in every breeding failure investigation.

Misreading vaginal cytology. Superficial cell percentage varies with collection technique and staining. Cornification indices above 80% support estrus but do not predict ovulation timing. Combine cytology with progesterone and clinical signs instead of relying on cytology alone.

Incorrect timing of progesterone sampling. A single progesterone sample taken at an unknown cycle stage cannot guide breeding timing. Samples must be interpreted relative to the observed onset of proestrus or estrus and repeated every 2 to 3 days until the preovulatory rise is documented.

Failure to distinguish uterine from ovarian pathology. Transrectal or transabdominal ultrasonography that identifies uterine fluid may be attributed to pyometra when the true problem is vaginal or cervical pathology. Complete reproductive tract imaging, including the cervix and vagina, prevents this error.

Evidence Limitations and Divergent Expert Opinion

The theriogenology evidence base contains genuine gaps. Controlled trials comparing breeding management protocols are sparse for many companion and production species. Much of what is taught rests on clinical experience and extrapolation across species.

Progesterone threshold values for ovulation timing vary between laboratories and assay platforms. Published thresholds for the bitch range from 2 to 5 ng/mL depending on the assay. Clinicians should know their laboratory's reference intervals and interpret values accordingly.

Timing of first breeding after prostaglandin administration in mares remains debated. Some experts recommend breeding at a fixed interval, others advocate ovulation detection with serial ultrasonography. Both approaches have published support and neither is universally superior.

The role of uterine lavage in endometritis management differs between species and between experts. Equine practitioners generally support lavage, while its use in cattle is more contested. Regional practice patterns and available evidence should guide decisions.

Anti-Müllerian hormone reference ranges for ovarian reserve assessment are not standardized across laboratories or breeds. Results should be interpreted cautiously and in combination with other findings.

Referral, Consultation, and Reporting

Referral to a theriogenology specialist is appropriate when routine diagnostic testing fails to identify a cause, when advanced imaging or assisted reproductive techniques are required, or when the economic value of the animal justifies advanced intervention.

Laboratory involvement is required for semen cryopreservation, extended culture, hormonal assay validation, and genetic testing. Confirm the laboratory's species-specific protocols before sample collection.

Regulatory reporting obligations vary by jurisdiction and species. Brucellosis in dogs, contagious equine metritis, and Trichomonas fetus in cattle are reportable in many regions. The WOAH terrestrial animal health standards describe international notification requirements for listed reproductive diseases. Clinicians must also know their local reporting rules through AVMA practice resources and regional veterinary authorities.

Zoonotic risk warrants consultation with public health authorities when Brucella canis or Coxiella burnetii is suspected. The MSD Veterinary Manual provides species-specific guidance on zoonotic reproductive pathogens and their occupational risks.

When to stop. If a breeding program has failed for three or more cycles despite appropriate diagnostic workup, referral is indicated. Continuing the same diagnostic pathway without specialist input wastes time and client resources.

Frequently Asked Questions

How do I manage breeding when access to ultrasound or hormone assays is limited?

Prioritize physical examination, vaginal cytology, and vaginoscopy where applicable, as these require minimal equipment. For timing, use behavioral signs and serial cytology in dogs, while in cattle and horses, rectal palpation of ovarian structures provides usable information when ultrasound is unavailable. Progesterone measurement is the most valuable single assay, and where in-house analyzers are absent, commercial laboratory submission remains an option, though results are delayed. When diagnostic options are constrained, extend breeding windows and use natural service instead of artificial insemination to reduce timing risk. Document every limitation in the record so that subsequent interpretation of pregnancy failure accounts for reduced diagnostic certainty. The MSD Veterinary Manual provides species-specific guidance on physical examination findings that substitute for advanced diagnostics.

What is the minimum semen evaluation I can perform without a microscope?

A microscope is non-negotiable for assessing sperm motility and morphology, and no alternative reliably substitutes for it. Without one, you can still evaluate ejaculate volume, color, and consistency, and you can assess libido and mating behavior. These gross parameters identify obvious problems such as azoospermia, hemospermia, or urethral contamination, but they miss subfertility caused by poor motility or abnormal morphology. If a microscope is unavailable, advise the client that a complete breeding soundness examination is deferred and that conception rates may be lower than expected. Refer the male to a facility with proper equipment before committing to a breeding season. The ICVA NAVLE candidate information outlines the examination expectations for semen evaluation that candidates must be prepared to apply.

How should I adapt infertility workups between dogs, cats, and production animals?

The fundamental diagnostic framework is shared, but practical constraints differ sharply. In cattle and horses, economic value justifies hormonal assays, ultrasound, and repeated examinations, and the goal is a single seasonal pregnancy. In dogs, the timeline is compressed and progesterone timing is critical, while vaginal cytology adds value that it does not offer in cattle. In cats, queens are induced ovulators, so the entire cycle physiology differs and failure to cycle is rarely the presenting problem. Small ruminants are seasonal breeders, so a workup performed outside the breeding season yields misleading results. Always confirm the species-specific normal values before interpreting any hormone result, because assay interpretation is not transferable across species. The MSD Veterinary Manual organizes these species differences by system and is a reliable reference for normal reproductive parameters.

What records should I keep for a breeding management case, and why do they matter?

Maintain a chronological record that includes signalment, body condition score, vaccination and deworming status, each examination date, findings on palpation or ultrasound, hormone assay results with the laboratory reference range, and the timing of every breeding or insemination. Record semen evaluation data in the male, including volume, concentration, motility, and morphology, with the same technician performing assessments where possible to reduce inter-observer variability. These records allow you to distinguish true infertility from management failure, such as mistimed breeding or poor semen handling. They also support defensible recommendations when a client requests a refund, a repeat breeding, or a second opinion. The AVMA practice resources include guidance on medical record content and professional communication standards that apply to reproduction cases.

How do I explain a poor pregnancy rate to a client without overstating what I know?

Present the pregnancy rate as a range that depends on species, age, and management, and avoid promising a specific outcome. State clearly which diagnostic steps have been completed and which have not, then list the most probable causes in order of likelihood based on the findings so far. Acknowledge that early embryonic loss is often undetectable and that some cases remain unexplained despite a complete workup. Offer a concrete next step, whether that is a hormonal assay, a breeding soundness examination of the male, or a referral, and give the client a realistic timeline for when answers will be available. This approach preserves trust while maintaining professional honesty about diagnostic limits.

When should I refer an infertility case, and what should I send with the patient?

Refer when you have completed a basic workup without a diagnosis, when the case requires advanced imaging such as Doppler ultrasound or computed tomography, when hormonal therapy has failed, or when surgical intervention is contemplated. Refer promptly when the breeding season is time-limited, because delay can cost the client an entire production cycle. Send a complete history, all laboratory results with reference ranges, imaging studies or their reports, and a log of all treatments given with dates and responses. Include the client's breeding goals and any financial constraints that affect the diagnostic plan. The WOAH terrestrial animal health standards also apply when movement of animals or genetic material across borders is part of the breeding plan, and these requirements should be reviewed before referral across jurisdictions.

Related Clinical & Scientific Guides

• Developing a Study Schedule for NAVLE Diagnostic Reasoning
• Veterinary Physiology Concepts Frequently Tested on the NAVLE
• NAVLE Clinical Rotation Preparation: What to Review Before Each Service

References and Further Reading

• ICVA NAVLE Candidate Information. ICVA.
• AAVMC Veterinary Education Resources. AAVMC.
• 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

• NAVLE Anesthesia and Analgesia Review
• NAVLE Study Resources: A Comparative Review
• Veterinary Pharmacology Drug Classes: A NAVLE Review
• Creating Effective Study Notes for NAVLE Review
• NAVLE Anesthesia and Analgesia: Monitoring and Troubleshooting

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.