CLASS NOTES - SMALL ANIMAL THERIOGENOLOGY

TABLE OF CONTENTS                                      Back to home page

ENDOCRINOLOGY REVIEW AND STUDY GUIDE    
     
EMBRYOLOGY / PLACENTATION REVIEW AND STUDY GUIDE    
     
CANINE - FEMALE    
  Anatomy    
  Techniques    
    Vaginal cytology  
    Vaginal culture  
    Vaginoscopy  
    Hormone assay  
  Estrous cycle    
    Puberty  
    Stages - Cytology, behavior, endocrinology
      Proestrus  
      Estrus
      Diestrus
      Anestrus
    Breeding management  
    Ovulation timing
    Breeding timing
  Estrus suppression    
  Pregnancy termination    
  Pregnancy / Pregnancy diagnosis  
  Parturition / Dystocia    
  Abnormalities of ...    
    Puerperium  
    Eclampsia
    Metritis
    Mastitis
    Subinvolution of placental sites (SIPS)
    Ovaries  
    Ovarian cysts
    Ovarian neoplasia
    Uterus  
    Metritis
    Subinvolution of placental sites (SIPS)
    Cystic endometrial hyperplasia (CEH) / Pyometra
    Vagina  
    Vaginitis
    Vaginal prolapse
    Vaginal neoplasia
    Mammary glands  
    False pregnancy
    Mastitis
    Agalactia
    Mammary neoplasia
CANINE - MALE      
  Anatomy    
  Techniques    
    Semen collection / Semen evaluation
    Prostatic palpation and massage  
  Abnormalities of ...    
    Penis / Prepuce  
    Congenital defects
    Balanoposthitis
    Phimosis / Paraphimosis
    Penile neoplasia
    Testes / Epididymes  
    Cryptorchidism
    Orchitis / Epididymitis
    Testicular neoplasia
    Prostate  
    Benign prostatic hypertrophy (BPH)
    Prostatitis
    Prostatic neoplasia
CANINE - GENERAL    
  Artificial insemination    
  Brucellosis    
  Early spay/neuter    
FELINE - FEMALE    
  Anatomy    
  Estrous cycle    
    Puberty  
    Stages  
    Induced ovulation  
FELINE - MALE      
  Anatomy    
FELINE - GENERAL    
  Breeding / Artificial insemination  
  Pregnancy / Parturition    
  Abnormalities of ...    
    Sexual differentiation  
    Male calico and tortoiseshell cats
    Female cats  
    Ovarian remnant syndrome
    Mammary hypertrophy
    Mammary neoplasia
    Pyometra
    Male cats  
    Cryptorchidism

 

CANINE - FEMALE

Anatomy

Techniques

Estrous cycle

  1. Proestrus

    Length = 9 days average, range 0 to 17 days

    Physical changes and behavior = The vulva is enlarged and firm. Vulvar discharge ranging in character from serous to serosanguinous is present. Male dogs will be attracted to the bitch but she does not stand for breeding, and often tucks her tail under tightly, sits down, or turns on the male dog.

    Endocrinology = This is the follicular stage of the cycle. Estrogen concentrations rise during proestrus and peak at the end of this stage. Serum progesterone and luteinizing hormone (LH) concentrations are low.

    Vaginal cytology = RBCs may be present throughout the stage. PMNs are present early in this stage but disappear as estrus nears and the vaginal epithelium thickens. The vaginal epithelial cell population gradually changes from completely non-cornified to completely cornified. Cornification will be complete about 2 days before estrogen peaks, about 4 days before standing heat begins.
    To view an image of early proestrous vaginal cytology, click here.
    To view an image of late proestrous vaginal cytology, click here.

    To view a chart detailing endocrine changes during the estrous cycle of the dog, click here.

  2. Estrus

    Length = 9 days average, range 3 to 21 days

    Physical changes and behavior = The vulva may become less turgid as the bitch enters standing heat. The vulvar discharge may become straw-colored but can range from serous to serosanguinous in a normal bitch. Estrus, or standing heat, is defined by the behavior of the bitch; standing = remaining motionless as the male investigates her hindquarters, flagging = deflection of the tail laterally and muscular elevation of the vulva.

    Endocrinology = Estrogen concentrations fall at the beginning of estrus. This decrease in estrogen, along with a preovulatory rise in progesterone, is necessary for appearance of breeding behaviors in the bitch, and presumably elicits the LH surge. A surge of LH is released from the pituitary on or about the first day of estrus, and causes ovulation of a primary oocyte 2 days later. Great variation in time of ovulation exists in the normal dog. After ovulation, CLs form and progesterone production begins. Measurement of serum LH is not routinely performed. However, measurement of serum progesterone concentrations easily can be performed and this data used to optimize breeding management.

    Vaginal cytology = The vaginal epithelial cell population is completely cornified, with greater than 50% of the cells anuclear squames. No PMNs or debris are present. Intra- and extracellular bacteria are commonly present. RBCs may or may not be present. Vaginal cytology cannot be used to predict ovulation time prospectively; however, vaginal cytology changes abruptly as the bitch enters the next stage of the cycle, diestrus, with this change consistently occurring 6 days after ovulation.
    To view an image of estrous vaginal cytology, click here.

  3. Diestrus

    Length = 60 days average, range 50 to 80 days

    Physical changes and behavior = There are no characteristic physical changes or behaviors in diestrus. Small amounts of mucoid vulvar discharge may be present. Some bitches still stand to be bred early in this stage.

    Endocrinology = Bitches maintain the CL for about 60 days whether they were bred or not at that cycle. Progesterone concentrations are high throughout. Diestrus ends with a decline in serum progesterone to less than 2 ng/ml. This is associated with whelping if bitch is pregnant, false pregnancy or no outward signs if she is not. The CL is the sole source of progesterone during pregnancy in the bitch.

    Vaginal cytology = On the first day of diestrus, the vaginal epithelial cell population abruptly shifts to complete non-cornification. There may be a large number of PMNs present, and metestrum cells (non-cornified cells containing leukocytes) and/or foam cells (non-cornified cells containing vacuoles) may be present.

    To view an image of diestrous vaginal cytology, click here.

  4. Anestrus

    Length = About 4.5 months average, so counting the approximately 2.5 months of proestrus, estrus and diestrus, the overall interestrous interval averages 7 months. This is a period of reproductive quiescence with no characteristic physical, behavioral or endocrinologic changes. Vaginal cytology reveals only scant numbers of non-cornified epithelial cells at this stage.
    To view an image of anestrous vaginal cytology, click here.

    Return to Table of Contents

Breeding management

  1. Ovulation timing
  1. Breeding timing

    Sperm must undergo capacitation within the female tract; this requires about 7 hours. Normal sperm can remain viable in a normal female tract for up to 7 to 9 days. The ovulated oocyte is a primary oocyte which must undergo 2 meiotic divisions before fertilization can occur. This maturation process takes about 2 days.

    Best conception rate occurs when the bitch is bred from 4 days before to 3 days after ovulation; best litter size is achieved when the bitch is bred 2 days after ovulation.

    There are 2 possible breeding strategies:
    * Breed every other day while the bitch stands
    To view an image of normal canine breeding behavior, click here.
    * Breed once, 2 days after ovulation

    To view an image of a client handout describing breeding management, click here.

    Return to Table of Contents

Estrus suppression

Pregnancy termination
     
In general, methods that terminate pregnancy prior to day 40 of gestation result in absorption of fetuses while those after day 40 result in expulsion of fluid or tissues. Puppies passed after about day 55 of pregnancy may be alive and should be euthanized when passed.

Pregnancy

Parturition / Dystocia

  1. Endocrine induction of parturition

    The fetus induces parturition. The hypothesized scheme is : Fetal ACTH causes release of fetal and maternal cortisol with subsequent decrease in progesterone secretion and increase in production and release of estrogen and prostaglandin. Dead or abnormal fetuses, or small litter size, may be insufficient to initiate labor.

    Progesterone is thermogenic. As the serum progesterone concentration declines at the time of parturition, you will see a transient decrease in body temperature until other thermoregulatory systems take over. Most bitches begin labor within 24 hours of a rectal temperature drop to less than 99 degrees F.

  2. Normal parturition

    * Stage I = cervical dilation. This occurs secondary to increased estrogen and prostaglandins, and decreased progesterone, uterine contractions and the pressure of the fetus at the cervix. Contractions are not visible. The bitch is restless, pants and may vomit. Signs should increase in frequency and severity.

    * Stage II = expulsion of fetuses. The cervix should be fully dilated. The length of this stage is variable, 6 to 12 hours on average. Abdominal contractions are strong and coordinated. The chorioallantoic sac may be seen first, then the pup with or without the covering of the amniotic sac. Puppies may present cranially or caudally. You ordinarily see passage of a neonate every 30 to 60 minutes. You should see passing of the first pup within 4 hours of labor onset, and the bitch should deliver pups at least every 2 hours thereafter. The bitch should tear away the amniotic sac and lick the neonate to stimulate respiration. If the bitch ignores the pup, tear away the sac and rub briskly with a towel. You may need to aspirate fluid from the pup's respiratory tract.

    * Stage III = expulsion of placentas. Placentas usually pass 5 to 15 minutes after each pup is born. The bitch may eat them; they have no known physiological value, and may cause vomiting and diarrhea.

  3. Post-partum period

    * Uterine involution
    Normal uterine involution takes 4 to 5 weeks. Administration of oxytocin to promote uterine contraction post-partum is only necessary if the pups are stillborn or not nursing.

    * Lochia
    Lochia = normal vaginal discharge present for up to 3 weeks after whelping. Lochia should be sero-mucoid and odorless, ranging in color from pale brown to pale green. Lochia may be slightly hemorrhagic.

    * Rectal temperature
    Slight elevation in body temperature is normal for the several days following parturition.

    * Care of the neonates
         Warmth - Leave with bitch or provide an external heat source. Pups are incapable of thermoregulation until 2 to 3 weeks of age. Be careful with heating pads or heating lamps; pups are easily burned.
         Colostrum - All pups should nurse within the first 12 hours of life. Pups receive 75 to 80% of maternally derived antibodies from colostrum.
         Weight - The pups should double their birth weight by 10 to 14 days of age.
         Tails and dewclaws

    Return to Table of Contents
  1. Causes

         Maternal
              * Obstruction of passage
                   - Pelvis - congenital or acquired
                   - Vagina - hypertrophy, neoplasia, developmental
                   - Vulva - "infantile"
              * Abnormality of uterine function
                   - Obese, debilitated, poorly exercised
                   - Primary inertia = no second stage of labor seen, requires C-section
                   - Secondary inertia = second stage starts but does not progress as uterine muscle fatigues. May be obstructive so be cautious with ecbolic agents.
              * Abnormality of pregnancy
                   - Fetal fluid disorder
                   - Herniation or torsion of uterus

         Fetal
              * Obstruction of passage
                   - Relative oversize = birth canal too small
                   - Absolute oversize = pup too big, birth canal normal
              * Developmental abnormality
                   - e.g. fetal monster, hydrocephalus
              * Abnormal presentation, position, posture
                   - Presentation = relation of long axis of pup to birth canal. Cranial and caudal are normal.
                   - Position = relation of fetal vertebral column to birth canal
                   - Posture = disposition of head and limbs

  2. Determination of dystocia

          Questions to ask:

    * Obvious malpresentation?
    * First stage > 12 hours, second stage weak and intermittent > 2 to 3 hours, second stage hard > 30 minutes, > 2 hours between pups?
    * Abnormal vulvar discharge? Pus, frank hemorrhage, green fluid (denotes placental separation)
    * Rectal temperature decline > 24 hours ago?
    * Signs of labor not progressing?
    * Systemic illness in bitch?
    * Prolonged gestation?
    * High risk pregnancy? (Previous pelvic trauma or dystocia)

          Presentation:

    * History

    - Previous disease or trauma
    - Breeding dates
    - History of previous whelpings
    - Pups and progress at this whelping
    - Temperature drop data
    - Treatment thus far

    * Physical examination

    - General examination
    - Abdominal palpation
    - Digital vaginal examination
    - Lateral abdominal radiographs
    - Uterine monitors (WhelpWise)

Treatment of dystocia

     Manipulative
          * Feathering
          * Digital manipulation
          * Instruments

     Pharmacologic agents
          * Oxytocin - Oxytocin acts as an ecbolic (causes uterine contraction). It may cause premature placental separation and should not be used in obstructive dystocia. Dose = 2 to 5 IU at 20 to 30 minute intervals, for no more than 3 to 4 doses if not effective.
          * Calcium
          * Glucose

       Cesarean section - Anesthesia for C-section


Return to Table of Contents

Abnormalities of...

  1. Eclampsia
    = Puerperal tetany = hypocalcemia. This is seen primarily in small breed dogs nursing large litters during the first 2 to 4 weeks of lactation, when the bitch is under the heaviest metabolic stress due to lactation. It may also be seen at or near parturition.
    Serum calcium concentrations fall to about 4 to 7 mg/dl (normal 9 to 11 mg/dl). The initial presentation is trembling and weakness. As the condition progresses, dilation of the pupils, elevated pulse rate, elevated body temperature and eventually convulsions occur.
    Treatment includes removal of pups from the bitch for 12 to 24 hours, administration of 5 to 10 ml 10% calcium gluconate solution slowly IV while ausculting the heart (give to effect - too rapid infusion can cause bradycardia, cardiac arrhythmias and/or cardiac arrest). Follow-up therapy includes administration of 5 to 10 ml 10% calcium gluconate SQ, and discharge of the dog with 1 - 3 gm calcium lactate or calcium gluconate to be given PO SID with 10,000 to 25,000 IU Vit D. Oral calcium gels also exist. Recurrence in the same or a subsequent lactation is common. Wean pups only if more than one clinical episode occurs within a lactation.
    Some people feel that post-parturient hysteria (savaging of pups) may be a manifestation of eclampsia. Insure the bitch is on a well-balanced ration.

    Return to Table of Contents

  2. Metritis (see Uterine disorders)
  3. Mastitis (see Mammary gland disorders)
  4. Subinvolution of placental sites (SIPS)(see Uterine disorders)
  1. Cysts
    Bitches present with a history of irregular cycles or, more commonly, with a history of prolonged proestrus and/or estrus. Ascertain whether the bitch is truly in a prolonged heat cycle. You may need to perform serial vaginal cytology and progesterone assays over 2 to 3 weeks to verify this.
    Diagnosis is based on a true history of persistent estrus, and physical examination and vaginal cytology signs indicative of estrogen secretion (swollen vulva, cornified vaginal epithelial cells). Similar signs may occur secondary to functional ovarian tumors. Differentiate by abdominal palpation, abdominal radiography or ultrasound, exploratory laparotomy, and response to treatment.
    Treat with induction of ovulation using gonadotropin releasing hormone (GnRH; 50 mcg IM) or human chorionic gonadotropin (hCG; 1000 IU, half IV, half IM). The bitch should be monitored for signs of uterine disease, as she may develop cystic endometrial hyperplasia / pyometra after ovulation induction. For bitches not intended for breeding, and for those bitches that do not respond to medical treatment in 7 to 10 days, OHE is the treatment of choice.

    Return to Table of Contents

  2. Neoplasia
    Primary ovarian neoplasia is uncommon in the dog. Some may be productive tumors, with excessive and/or persistent levels of progesterone and estrogen causing paraneoplastic syndromes referable to actions of the hormone present.
    Most ovarian tumors are palpable as masses in the mid- to cranial abdomen. Radiographs verify tissue location of the mass and are used to assess for metastasis.
    i) Sex cord/Stromal tumor = Granulosa cell tumor. This is the most common primary ovarian neoplasm in the dog. These usually occur in older bitches, and may be more prevalent in nulliparous bitches. Clinical presentation includes a history of progressive abdominal distension. Functional granulosa cell tumors may produce estrogen causing vulvar enlargement, serosanguinous vulvar discharge, persistent estrus and occasionally pancytopenia, progesterone causing CEH/pyometra, or both. Eighty percent of these tumors do not metastasize so surgical removal usually is curative.
    ii) Germ cell tumors = teratoma (benign) and dysgerminoma (malignant)
    Treatment - Complete OHE. Tumors are often bilateral, direct extension to the uterus may occur, and older bitches with ovarian disease may be even more predisposed to uterine disease.

    Return to Table of Contents
  1. Metritis
    Metritis does not equal pyometra!
    Metritis occurs postpartum. It is caused by ascending infection following normal parturition or abortion, fetal infection, dystocia, and/or retention of placentas. Clinical presentation includes fever, anorexia, depression, neglect of pups and exudation of foul-smelling purulent vulvar discharge.
    Diagnose by demonstration of leukocytosis with left shift on CBC, demonstration of purulence of vulvar discharge by cytology, and/or culture of bacteria from vulvar discharge. Abdominal radiographs and/or ultrasound can be used to diagnose retention of placentas and/or feti.
    Treat by promoting evacuation of uterine contents with oxytocin at a dose of 1 IU/kg IM or PGF-2a at a dose of 0.25 mg/kg SQ, and treatment of infection with an antibiotic chosen via culture and sensitivity. While awaiting culture results, start on a broad spectrum antibiotic; as metritis is most commonly caused by Gram negative enterobacters, ampicillin is a common choice (20 mg/kg PO TID). As long as the bitch does not show evidence of toxemia, pups can be allowed to nurse.

    Return to Table of Contents

  2. Subinvolution of placental sites (SIPS)
    This is a disorder that most commonly occurs in young bitches after whelping their first litter. They will present with excessive or prolonged sanguinous vulvar discharge postpartum (remember the normal exudation of lochia for 3 weeks post-whelping). The discharge is cytologically non-purulent and the bitch is normal in all other respects.
    Diagnostic tests to be run include cytology and culture of vaginal discharge (to assess for presence of infection), careful abdominal palpation +/- radiography and/or ultrasound (to rule out metritis, retained placentas or feti), CBC (to rule out metritis and monitor PCV in bitch with chronic hemorrhage), and testing for brucellosis. Definitive diagnosis rarely is performed as it requires histologic examination of placental sites; on gross examination, affected sites are larger than involuted sites and contain nodular protrusions of endometrium. Histologically, these nodules are made up of eosinophilic tissue with necrosis and hemorrhage. The persistent hemorrhage is due to failure of the normal thrombosis and occlusion of endometrial blood vessels which occurs as part of the involution process.
    Treat by OHE in bitches not intended for breeding in the future, and supportive care for those left intact. Monitor the PCV and transfuse if necessary, and give antibiotics if secondary reproductive tract infection develops.

    Return to Table of Contents

  3. Cystic endometrial hyperplasia (CEH) / Pyometra
    Pyometra does not equal metritis!
    The initial insult is development of CEH. CEH develops due to repeated prolonged exposure of the estrogen-primed uterus to progesterone (estrogen increases the number of progesterone receptors in the endometrium). Bitches are prone to uterine disease due to the unique nature of cycling in the dog. Most bitches older than 5 to 6 years of age have some degree of CEH. Exogenously administered estrogens and progestogens can induce CEH and subsequent pyometra. Pyometra develops when ascending infection overlies CEH. E coli is the organism most commonly isolated.
    To view a gross pathologic image of CEH, click here.
    Presenting history is of a bitch usually older than 5 to 6 years of age who was in heat 1 to 12 weeks ago, and who is currently exhibiting anorexia, depression, PU/PD, abdominal distension, and possibly purulent vulvar discharge (variable, depending on patency of cervix). Signs of septic shock, vomiting and diarrhea may also be present, especially late in the course of the disease. On physical examination, vulvar discharge may or may not be present and the uterus will be palpably enlarged. Be cautious with abdominal palpation; overly aggressive palpation of the friable, distended uterus may induce uterine rupture.
    Diagnosis involves demonstration of uterine enlargement and non-pregnancy (remember, we're in diestrus) by radiography and/or ultrasound. Immature neutrophilia will be present, with higher WBC number if the cervix is closed. Changes on a serum chemistry profile include increased BUN and increased total plasma protein (globulins). Urine will be normal to dilute and proteinuria may or may not be present. The vaginal discharge will be cytologically purulent.
    To view an image of CEH on ultrasound, click here.
    To view an image of purulent vaginal discharge cytology, click here.

    Treatment is dependent on cervical patency. Students often ask about placing drains through the cervix to bypass the problem of cervical patency. There are few such reports in the literature, with most using catheters as a path by which intrauterine fluid can drain along the catheters rather than through them. Success has been variable and most reports have included medical therapy (prostaglandin) along with the catheter placement for success. I have not tried these techniques nor do I know of anyone who considers them a likely alternative for the treatments listed below.

    * Closed cervix
    - OHE + fluids + antibiotics
    1) Correct fluid deficit
    2) Culture cranial vagina, start bitch on
    ampicillin (20 mg/kg PO TID)
    3) OHE as soon as stable

    * Open cervix
    - OHE + fluids + antibiotics
    As above - OHE is always the best treatment
    since the bitch with pyometra has underlying
    CEH which will probably always be present.

    Pyometra is an acute manifestation of a
    chronic disease process.
    - PGF-2a
    Four criteria required for medical treatment of pyometra are an open cervix (evidenced by vulvar discharge), the bitch is still of breeding age (generally less than about 6 years of age) and is valuable in a breeding program and the bitch is not azotemic.
    1) Determine uterine size (to follow progress)
    2) Culture and sensitivity of vaginal discharge
    3) Start bitch on ampicillin (20 mg/kg PO TID).
    Change antibiotic if necessary based
    on sensitivity. Continue antibiotic for
    1 month.
    4) PGF-2a (Lutalyse - Upjohn) at dose of
    250 mcg/kg SQ SID x 2 to 7 days,
    until uterine size nears normal. If the
    bitch is still in diestrus, administer BID
    to lyse CL and decrease progesterone.
    5) Recheck bitch 2 to 4 weeks after therapy is
    concluded. Vulvar discharge may
    persist for up to 1 month. If vulvar
    discharge is increasing in volume or
    uterine size has increased, consider
    repeat of PGF-2a therapy or OHE.
    6) At next proestrus, collect an anterior vaginal
    culture and treat with an appropriate
    antibiotic for 3 weeks. Breed at that
    season. If she does not conceive,
    consider luteolysis with PGF-2a to de-
    crease progesterone effect and
    recurrence of pyometra. OHE as
    soon as breeding life over!

    Return to Table of Contents
  1. Vaginitis

    * Prepuberal = puppy vaginitis. This appears prior to the first estrus. The dog presents with a history of small amounts of clear to cloudy sticky vulvar discharge with occasional vulvar licking, and rarely presents with systemic signs.

    * Adult vaginitis. This appears after the first estrus and in spayed females. Signs are similar to those above. Vulvar discharge may be copious and the bitch may attract male dogs.

    Physical examination findings are all normal except in the genital system. Assess for uterine enlargement and perform a digital vaginal examination to assess for presence of anatomic abnormalities predisposing to infection.
    Diagnose by anterior vaginal culture and sensitivity (remember that the vagina is not a sterile environment). Perform vaginal cytology; vulvar discharge may be a normal indication of estrus in an intact dog. Check for brucellosis. Make sure to differentiate from urinary tract disease.
    Treatment - Puppy vaginitis often resolves spontaneously, and may be more likely to resolve spontaneously if the bitch is allowed to go through one estrous cycle. Treat with a 4 week course of a specific antibiotic only after ruling out or treating all underlying problems (e.g. vaginal strictures, urinary incontinence, pyometra). Some dogs may respond to topical therapy with triple-antibiotic ophthalmic ointment. Spayed dogs may benefit from low-dose estrogen therapy. Veterinarians at Colorado State University recommend a therapeutic trial with phenylpropanolamine as used for urinary incontinence in bitches with idiopathic vaginitis, assuming subclinical urine leakage into the vaginal vault through an incompetent urethral sphincter.

    Return to Table of Contents

  2. Vaginal prolapse
    Signalment - This occurs in intact, young, large breed dogs. It almost always occurs during proestrus or estrus, occasionally at parturition. Estrogen stimulus causes edematous enlargement of the vagina with subsequent protrusion of the vaginal mucosa through the vulvar lips.
    Three stages: Stage I = perineal swelling, Stage II = eversion of vaginal floor (hyperplastic change originates just cranial to urethral papilla), Stage III = eversion of entire vaginal circumference.
    To view an image of stage II vaginal prolapse, click here.
    To view an image of stage III vaginal prolapse, click here.
    Treatment - If the bitch can be spayed, OHE! If the bitch is to be left intact, treat with topical soothing lubricants and an Elizabethan collar and consider administration of GnRH to induce ovulation. Surgical resection may be necessary. Recurrence is common in dogs without surgical resection (2/3), but may even recur after surgery. Purse-string sutures and pexy- procedures are not recommended as secondary infection may occur.

    * Differentiation of vaginal prolapse and vaginal neoplasia *

    Vaginal prolapse
    Vaginal neoplasia
    Young dogs Older dogs
    Arises from vaginal floor cranial to urethral papilla Arises anywhere in vagina
    Appearance and progression vary with estrous cycle Appearance and progression do not vary with estrous cycle

    Return to Table of Contents

  3. Neoplasia
    Leiomyoma and TVT most common.
    Patients with vaginal neoplasia present with clinical signs of bulging of the perineal region, dysuria or pollakiuria, and/or bulging of tumor tissue through the vulva. Diagnose by exfoliative cytology or histopath after core or excision biopsy. Treatment of vaginal tumors consists of surgical removal.
    To view an image of a vaginal leiomyoma, click here.
    TVT = transmissible venereal tumor = naturally occurring neoplasm with unique chromosome complement (2n = 59), transmitted by transplantation to external genitalia at mating. It appears as single or multiple nodules or pedunculated cauliflower-like friable masses on the genitalia. Transplantation to nasal mucosa and other tissues can occur. Tumor behavior varies depending on host's immune status. Treat with vincristine +/- surgical debulking.
    To view an image of a vaginal TVT, click here.
  1. False pregnancy
    This is a normal phenomenon in which the dog exhibits nesting behavior, lactation and possibly maternal protection of inanimate objects as a response to the normal decline in serum progesterone at the end of diestrus. This can be mimicked by withdrawal of exogenous progestogen therapy or OHE during diestrus.
    No other reproductive tract condition predisposes a bitch to false pregnancy or vice versa. Belgian researchers have some evidence that false pregnancy may be associated with mammary neoplasia, presumably secondary to distension of the mammae with milk and subsequent hypoxia and free radical formation.
    Treatment - Spontaneous remission - Light sedation with hot and/or cold compresses of mammary glands may help very uncomfortable animals. Do not treat with phenothiazine tranquilizers (e.g. acepromazine), which may inhibit dopamine and potentiate prolactin secretion. Mibolerone at 18 mcg/LB PO x 5 days is reported to alleviate signs of false pregnancy (not approved). Testosterone cypionate (0.5 to 1.0 mg/kg IM once) decreases milk production in dogs (not approved). Pseudopregnancy can also be treated with prolactin inhibitors (bromocriptine, cabergoline). Do not use progestogens; the dog will relapse after therapy is discontinued. OHE is not curative.

    Return to Table of Contents

  2. Mastitis
    Mastitis is most commonly due to ascending or hematogenous infection with coliforms, Staph or Strep sp. in the first week of lactation.
    Infected mammary glands are enlarged, hot and painful. The bitch exhibits pyrexia and neglect of pups. The CBC shows immature neutrophilia. Abscessation and gangrene of mammary tissue may be present.
    Treatment - Start on broad spectrum antibiotics until culture and sensitivity results are back. If abscessation or necrotic tissues are present, the areas should be surgically drained and debrided, leaving them open to heal by second intention. Warm soaks or hot packing may be beneficial. Aspirin can be given for its antipyretic and analgesic effects. Pups need not be weaned unless abscessation is present.

    Return to Table of Contents

  3. Agalactia
    Agalactia is poorly documented in the bitch. Treat with oxytocin therapy (Syntocinon). Oxytocin aids in milk letdown only, not in milk production. Acupuncture also can be used to stimulate lactation in bitches as can treatment with the dopamine antagonist, metoclopramide (0.1 - 0.2 mg/kg BID to TID - watch for behavior changes; causes depression in women) or domperidone (2.2 mg/kg per os BID).

  4. Mammary neoplasia - Need a review of oncology terminology?
    This is the most common neoplasm in female dogs.
    Signalment - Mammary neoplasia is most common in bitches over 6 years of age, those left intact (bitches spayed before 2.5 years of age or 4 estrous cycles have decreased risk of developing mammary neoplasia with greatest benefit if spayed before puberal estrus), and in purebreds (compared to crossbreds) with tumors most often arising in the caudal pair of mammae.
    Many types of tumors may arise in mammary tissue with many patterns of metastasis possible. In the dog, 50% of mammary tumors are benign fibroadenomas (=mixed mammary tumor) and 50% are malignant adenocarcinomas. The most common sites of metastasis for adenocarcinoma are the regional lymph nodes (axillary LN drain 3 cranial mammae, superficial inguinal LN drain 2 caudal mammae) and lungs. Many of these tumors contain receptors for estrogen and progesterone. The mammary gland of dogs is more sensitive to neoplastic transformation due to progesterone than is mammary tissue in other species. This effect may be mediated by growth hormone.
    Diagnose by palpation of masses in 1 or more glands. More than one mass is present in the majority of cases. Systemic signs vary with pattern of metastasis. Needle aspirate, scraping of ulcerated lesions or cytology of fluid from affected glands may yield useful information in diagnosis of malignancy, but lack of neoplastic cells does not imply that malignancy is not present. Definitive diagnosis requires histopath on an excision biopsy sample.
    Treatment - Surgical removal +/- OHE - If OHE is performed at the same time as tumor removal, do the OHE first to prevent seeding of the abdomen with neoplastic cells.
    * Lumpectomy = removal of mass only
    * Simple mastectomy = removal of gland containing mass
    * En bloc dissection = removal of mass, gland, intervening lymphatics, and regional LN
    * Unilateral mastectomy = removal of entire chain of glands +/- regional LN
    No definitive studies have been done that determine which technique is associated with best survival time. In women, studies suggest that more radical therapy is not necessarily correlated with improved survival time. Chemotherapy, radiation therapy, and immunotherapy are possible, but are not well characterized in the dog.
    Prognosis - Prognosis is very good with benign masses, and poor to good with malignant masses with poorest prognosis associated with tumors greater than 2 to 3 cm is diameter or the presence of metastasis (75% survive < 2 years after surgical removal of primary tumor).

    Return to Table of Contents

CANINE - MALE

Anatomy and physiology

Techniques

  1. Semen collection

    i) Equipment - Teaser bitch (may increase number of sperm in ejaculate), collection vessel (AV, syringe case, cup or plastic bag)
    To view an image of semen collection equipment, click here.

    ii) Technique
    The dog is manually stimulated through the prepuce. As erection begins, the prepuce is pushed caudal to the bulbus glandis and the artificial vagina (AV) introduced. The fingers encircle the penis caudal to the bulbus glandis tightly, simulating contraction of the constrictor vestibulae muscles during the copulatory lock (=tie). Three fractions of semen are ejaculated; the clear pre-sperm, cloudy sperm-rich (thrusting behavior) and clear prostatic fluid fractions (rhythmic anal contractions and urethral pulsations). When you are done collecting semen, release the grip caudal to the bulbus and gently peel off the AV. Ensure detumescence and replacement of penis within the prepuce prior to kenneling the dog.
    To view an image of semen collection in the dog, click here.

    Return to Table of Contents

  2. Semen evaluation

    i) Color - Normal = milky, red or brown = blood, yellow = urine, green = pus

    ii) Volume (ml/ejaculate) - Normal = 1 to 30 ml, extremely variable

    iii) pH - prostatic fraction only. Normal 6.5 to 7.0 - pH may be used to direct antibiotic therapy in prostatic disease (see Prostatitis).

    iv) Progressive motility - Look at one drop of semen on a warmed glass slide with or without extender. Normal = > 70%

    v) Concentration (sperm/ml) - Hemacytometer and WBC Unopette system. Count center square to get number of million sperm per milliliter. The normal number is variable as it is dependent on the volume of prostatic fluid collected.

    vi) Total sperm number (sperm/ejaculate) = volume x concentration. Normal = 300 to 2000 million. Larger dogs make more sperm as they possess a larger mass of spermatogenic tissue.

    vii) Morphology - Stain with eosin-nigrosin (SFT Morphology stain) or DiffQuik stains. Normal = > 80% morphologically normal sperm. Examine at least 100 individual sperm under the oil immersion objective. Correlation of defects with fertility is unknown in the dog.
    To view an image of canine spermatozoa on phase contrast microscopy, click here.
    To view an image of canine spermatozoa stained with DiffQuik,click here.
    To view an image of canine spermatozoa stained with eosin-nigrosin (SFT) stain, click here.

    To view a chart of morphologic abnormalities in the dog, click here.

    viii) Cytology - Examine the sample for abnormal cells, bacteria, and/or inflammatory cells.

    ix) Microbial culture - Aerobes, anaerobes, Mycoplasma. Perform a quantitative culture with > 10,000 bacteria (CFU) per ml indicative of significant overgrowth of an organism.
    The correlation between inflammatory cytology and presence of infection is not 100%. Perform a culture even if the cytology is normal if you are suspicious of reproductive tract infection (e.g. recurrent prostatitis or cystitis, infertility).

Abnormalities of ...

  1. Congenital defects

  2. Balanoposthitis
    = inflammation of penile and preputial mucosa. The condition is usually caused by opportunistic invasion of normal flora. Affected dogs may show preputial discharge and/or excessive licking. Diagnose by physicalsigns and culture; treat with local and systemic specific antibiotic therapy.

  3. Phimosis / Paraphimosis

    Phimosis = inability to extrude penis. This may be due to congenital or induced stenosis of the preputial orifice.

    Paraphimosis = extruded penis cannot be withdrawn into prepuce. Paraphimosis may follow normal copulation or may be due to presence of a hair ring decreasing vascular outflow or physical movement of the penis. Treat by lubrication. If recurrent, this condition may respond to therapy with progestogens (megestrol acetate 0.5 mg/kg once daily per os for a maximum of 30 days) or may require surgical enlargement of the preputial orifice.

  4. Neoplasia
    TVT, skin tumors

    Return to Table of Contents
  1. Cryptorchidism
    = lack of descent of one or both testicles into the scrotum by 6 months of age. The retained testicle(s) may be found at the inguinal ring, in the inguinal canal, or in the abdomen
    .
    Normal testicular descent - The testes develop initially caudal to the kidneys, attached to the superficial inguinal ring by the gubernaculum testis. The gubernaculum grows, pulling the testicle through the abdomen and inguinal canal, and then shrinks, pulling the testicle into the scrotum. The process is dependent on physical presence of the testis. Testosterone is important only late in descent. Factors controlling gubernacular outgrowth are unknown.

    Cryptorchidism is due to hormonal, genetic and/or physical-environmental factors altering gubernacular outgrowth and movement of the testis. In rats, cryptorchidism is associated wtih decreased androgen secretion, decreased smooth muscle content in the gubernaculum or decreased sympathetic tone in the gubernaculum. Canine cryptorchidism is believed to be a sex-limited hereditary trait with transmission due to a single autosomal recessive gene. The genetic predisposition may be carried by males or females, although it will only be manifested in males.

    Incidence - This is a common disorder with purebred dogs more susceptible than crossbreds (perhaps due to inbreeding), with toy breeds predisposed, and unilateral cryptorchidism more common than bilateral with the right side more commonly retained.

    The risk of testicular neoplasia and torsion is increased in retained testicles.

    The unilateral cryptorchid is fertile. Retained testicles are incapable of spermatogenesis due to elevated abdominal temperature destroying spermatogenic tissues, but are capable of steroidogenesis.

    Breeding of unilateral cryptorchids should be discouraged. Neuter them! This condition is hereditary, and the dog is at increased risk of testicular torsion and neoplasia. Cryptorchid dogs cannot be shown in AKC sanctioned dog shows.

    Return to Table of Contents

  2. Orchitis/Epididymitis
    = inflammation of the testicular and/or epididymal tissue due to bacterial infection after penetrating injury or hematogenous introduction of bacteria, traumatic, or autoimmune causes. Brucellosis is associated with epididymitis in dogs. The dog will be painful, the scrotum reddened and the testicles palpably enlarged. Diagnose by physical examination findings, needle aspirate of the affected testicle, CBC (immature neutrophilia) and/or serology for brucellosis. Treat with specific antibiotics and/or castration. Prognosis for future fertility is guarded as inflammation = increased temperature within the scrotum = decreased spermatogenesis.

  3. Neoplasia
    Testicular neoplasia is the second most common type of neoplasia in male dogs (skin #1).
    Three types exist; all are equally common in scrotal testicles. Incidence of testicular neoplasia is increased in animals over age 8. It may be uni- or bilateral and more than 1 tumor type may be present. Bilateral castration is the treatment of choice for all types.

    * Sertoli cell tumor - Arises from Sertoli cells - Large - This is the type most likely to produce a paraneoplastic syndrome due to production of estrogen, with gynecomastia, attraction of male dogs, pendulous penile sheath, alopecia and blood dyscrasias. The non-neoplastic testicle atrophies due to increased scrotal temperature and negative feedback of excessive gonadal steroids from the neoplastic testicle. Sertoli cell tumors are the most common type in abdominally retained testicles.

    * Seminoma - Arises from germ cells. Paraneoplastic syndromes are uncommon. These are the most common type in inguinally retained testicles.

    * Interstitial cell tumor - Arises from interstitial (Leydig) cells - Small - These occasionally produce paraneoplastic syndromes.
    Treatment = castration. You can do a unilateral orchiectomy in a valuable breeding dog but be aware that fertility may be reduced due to atrophy or undetected neoplasia in the testicle left behind. Signs of paraneoplastic syndromes regress with tumor removal. Prognosis is good; while the occurrence of metastasis varies greatly, it is generally <10%. Prognosis is worse if pancytopenia is present.

    Return to Table of Contents
  1. Benign prostatic hypertrophy (BPH)
    = enlargement of the prostate, unassociated with infection

    BPH occurs in intact dogs. It occurs to some degree in all intact dogs > 5 years of age. The aging prostate in dogs and man secretes increasing amounts of estradiol which increases prostatic receptors for a testosterone metabolite, 5-a-dihydrotestosterone, which increases prostatic size.

    The dog may be asymptomatic or show clinical signs consisting of dripping bloody fluid from the penis unassociated with urination, blood in the semen, or hematuria. No systemic signs are usually present..
    Palpation - The prostate is symmetrically enlarged and non-painful.

    Diagnosis - This list of diagnostic tests is applicable for all prostatic
    disease conditions.
    * Cytology and culture of prostatic fluid, collected by ejaculate or prostatic massage
    * Survey radiographs of the caudal abdomen
    * Retrograde cystourethrography
    * Prostatic ultrasound
    * Prostatic aspirate or biopsy
    In BPH, no significant changes besides prostatic enlargement are noted. The diagnosis can be verified by prostatic biopsy or aspirate but these tests only define the condition in the part of the prostate that was sampled.
    Treatment:
          * Surgical = castration
         * Medical - In breeding dogs, you may treat with progestogens (e.g. Ovaban at 1 mg/lb for up to 2 weeks) or 5-alpha reductase inhibitors (Finasteride [Proscar™] at 0.1 - 0.5 mg/kg/day). Progestogens act by exerting negative feedback to the pituitary, decreasing release of LH and testostesterone and have not been demonstrated to be detrimental to spermatogenesis. Finasteride causes a decrease in prostate size within one month of therapy and does not appear to affect semen quality or libido. Other treatments used in men (e.g. nutritional supplements, doxazosin mesylate [Cardura™]) have not been evaluated in the dog. Herbal therapy (saw palmetto) has been shown not to be efficacious in dogs with BPH. If the male with BPH is to continue breeding, you may see adequate reproductive performance, even with blood in the semen. Monitor with quantitative semen cultures every 4 to 6 months to catch early onset of prostatitis, which will decrease fertility. The long range plan = castration as soon as the dog's breeding life is over.

    Return to Table of Contents

  2. Prostatitis
    = prostatic inflammation associated with infection

    Prostatitis occurs in intact dogs. Ascending infection is often superimposed on BPH. The clinical presentation varies. In acute prostatitis, the dog is painful, with a stilted gait in the rear limbs, fever and anorexia. He may be painful when ejaculating. In chronic prostatitis, the dog may be asymptomatic or show intermittent signs of urinary tract disease.

    Palpation - The prostate may be asymmetrical. If cysts or abscesses are present, the prostate may be greatly enlarged.

    Diagnosis - See the list of diagnostic tests under BPH. Cytology of prostatic fluid will be inflammatory, and cultures of prostatic fluid positive (> 10,000 CFU per ml, most common organisms E. coli, Staph and Strep sp.). On retrograde cystourethrography, the contrast medium will move out into the honeycomb of prostatic tissue and may fill cystic spaces. On ultrasound, the prostatic tissue may appear mottled. If an abscess is present, it will be visible as a round, fluid-filled structure within the parenchyma. Prostatic biopsy is contraindicated if infection is present.

    Treatment - Appropriate antibiotic therapy is the treatment of choice. The antibiotic used must diffuse into prostatic tissue. You can base your antibiotic choice on pH; if the prostatic fluid is acidic, weak bases should be trapped within the prostatic tissue. Trimethoprim sulfa, chloramphenicol, and Baytril are known to diffuse well into prostatic tissue. Treat for 3 to 4 weeks, recheck cultures at 7 weeks and 3 to 4 weeks post-treatment if necessary. Castration will decrease prostatic size and increase the chance of clearing prostatitis but do not perform castration in the presence of uncontrolled reproductive tract infection. Treatment of prostatic abscesses may involve surgical resection of the abscess (some research suggests marsupialization of the abscess or packing of the cavity with omentum hastens recovery and decreases recurrence) or ultrasound-guided aspiration of purulent material. Appropriate antibiotic therapy is paramount prior to these procedures.

    Return to Table of Contents

  3. Neoplasia
    The most common prostatic neoplasm is malignant adenocarcinoma.
    Prostatic neoplasia occurs in intact or neutered dogs. One study suggested that neutered dogs may have 2X more risk of developing this tumor than intact dogs. There is no known hormonal influence. It is most common in older dogs. Dogs may present with a wide array of clinical signs, varying with the pattern of metastasis. These include stilted gait, tenesmus, dysuria, emaciation, rear limb weakness, and lumbar pain. Metastasis occurs most often in iliac LN, lungs, urinary bladder, periprostatic tissue, rectum, bone, and kidney.

    Palpation - The neoplastic prostate is usually enlarged, firm and nodular and may be asymmetrical. You may be able to palpate enlarged sublumbar LN.

    Diagnosis - See the list of diagnostic tests under BPH. You may see exfoliated neoplastic cells on cytology. Retrograde cystourethrography reveals prostatic enlargement, disruption of the smooth mural surface of the urethra, and/or excessive movement of contrast medium into the gland. On ultrasound, the gland will appear mottled with hyperechoic areas suggestive of calcification. Definitive diagnosis is based on cytologic samples of prostatic fluid, or biopsy or aspirate samples of prostatic parenchyma. Cytologic examination of prostatic fluid is less invasive and should be performed first.

    Treatment - Prostatectomy is not the treatment of choice. No hormonal therapy is known to be effective. The prognosis is grave as metastasis usually already has occurred when the dog is diagnosed.

    Return to Table of Contents

CANINE - GENERAL

Artificial insemination

Brucellosis

The etiologic agent is Brucella canis. Canine brucellosis is a zoonotic disease.
Transmission occurs primarily via ingestion, secondarily by venereal or congenital routes. The prepatent period is 1 to 3 months. Bacteremia with no fever may persist for 6 to 12 months. This bacterium eludes the immune system by persisting inside macrophages and PMNs.

Clinical history:
Both genders: Asymptomatic, occasional cause of vertebral discospondylitis
Females: Abortion late in gestation, persistent vaginal discharge, infertility
Males: Orchitis, epididymitis, scrotal irritation, poor semen quality, infertility

Diagnosis:
- Serologic tests - Dog must be off antibiotics for 4 weeks prior to testing
* Rapid slide agglutination test (RSAT) - This test is sensitive but not specific. False positives are due to cross-reaction with Bordetella, Pseudomonas, Staph sp., etc. The RSAT becomes positive earliest of all serologic tests in a true infection. All positives should be rechecked!
* Tube agglutination test (TAT) - Gives a titre instead of just a yes/no answer. The same problem with false positives exists as described above.
* Agar gel immunodiffusion test (AGID) - This test is performed at Cornell University. It identifies cytoplasmic antigens (very specific) and cell wall antigens (less specific). This test remains positive longer after the animal becomes abacteremic.
Chronically infected animals are intermittently bacteremic, and show an intermittent decrease in titres. Chronically infected animals may therefore test negative falsely with any test. If you are unsure, 3 negative tests at monthly intervals are required to call a suspicious animal truly negative.
- Culture - This is definitive but difficult. Consider blood, LN aspirates, and obvious samples such as aborted tissues and vaginal or preputial discharge for culture.

Treatment: OHE or castration should be performed as gonadectomized animals shed fewer organisms. Consider euthanasia, especially in kennel situations. Antibiotic therapy may decrease titres but is not curative.

Return to Table of Contents

Early spay/neuter

Definition:
= surgical sterilization of sexually immature animals

Pros:
* Control of pet overpopulation - Animals gonadectomized before placement from humane societies, shelters, pet stores, or breeders
* Surgery quick with minimal bleeding
* No scientific reason exists for traditionally recommended time of gonadectomy
* Studies done to date have not demonstrated negative short-term or long-term side-effects of prepuberal gonadectomy in dogs or cats

Cons:
* Anesthesia/surgery concerns in pediatric animals
To view an image of ovariohysterectomy of a 7-week-old kitten, click here.

Return to Table of Contents

FELINE - FEMALE

Anatomy

Estrous cycle
Cats are seasonally polyestrous. In natural light, queens will cycle from January to mid-October. They can be induced to cycle year-round with artificially increased daylength (14 to 16 hours light daily).

  1. Proestrus
    Rarely observed in cats

  2. Estrus
    Length = 6 to 10 days, range 12 hours to 19 days, +/- effect of breeding
    Clinical appearance - Signs of heat include lordosis, vocalization, increased affection, positive stimulation and allowing the male to mount.
    Vaginal cytology - Vaginal epithelial cells will become cornified, but not to the same degree as in canine samples.
    To view an image of lordosis in a cat, click here.

  3. Postestrus
    = period after an estrus during which the queen was not induced to ovulate. Length = 13 to 18 days.

  4. Diestrus
    = period after an estrus during which the queen was induced to ovulate. The CL persists and progesterone is produced. Length if a fertile mating occurred (= gestation length) is about 65 to 66 days with range of 63 to 71. If a non-fertile mating occurred, pseudopregnancy will follow, with a length of 40 to 50 days.

  5. Anestrus
    Seasonal

FELINE - MALE

Anatomy

Accessory sex glands = prostate and bulbourethral glands
Penis - Penile "spines" = cornified papillae which encircle the penis. These spines appear at puberty and disappear with castration (androgen-dependent).

FELINE - GENERAL

Breeding/Artificial insemination

Pregnancy/Parturition

Abnormalities of ...

  1. Ovarian remnant syndrome
    = presence of functional ovarian tissue in a previously ovariohysterectomized queen

    Causes:
    * Surgeon error - Improper placement of clamps or ligatures, inadvertent deposition of ovarian tissue in abdomen. One study found that < 50% of cases evaluated had been spayed by new graduates :)
    * Congenital anomaly? - Presence of completely or partially separated piece of normal ovary near the main ovary or in the broad ligament
    * Drugs?

    Presentation:
    Post-surgical onset is variable but once cycles are resumed, they assume normal periodicity. The cat exhibits normal signs of estrus and attracts tomcats.

    Diagnosis:
    * Vaginal cytology - Cytology will be cornified when the cat is showing signs of behavioral estrus.
    To view an image of non-cornified feline vaginal cytology, click here.
    To view an image of cornified feline vaginal cytology, click here.
    * Hormone assays
    Resting:
    - Estradiol - Not accurate. Cytology is more accurate as a bioassay.
    - Progesterone - Will be low as cats are induced ovulators
    Challenge:
    - Give GnRH (25 mcg/cat IM) while the cat is in estrus. Recheck progesterone in 2 to 3 weeks. If the serum progesterone concentration is high (> 2 ng/ml), you have proven that luteinized ovarian tissue is present.
    * Exploratory laparotomy

    Treatment:
    * Medical - Estrus-suppressing drugs. None are approved for use in cats, and this would have to be life-long therapy.
    * Surgical - Perform an exploratory laparotomy when the cat is exhibiting signs of estrus (follicular structures on remnant) or after induction of luteinization of tissue (luteal structures on remnant).

    Return to Table of Contents

  2. Mammary hypertrophy
    This condition is usually seen in young intact females following estrus, and in male and female cats receiving long-term therapy with progestogens. It is a progesterone-dependent condition.
    Diffuse or localized non-painful firm swellings of one or more mammary glands will be present. No necrosis or inflammation is present histologically. As hypertrophy mimics mammary neoplasia which is usually malignant, biopsy is indicated.
    Treat by removing the progesterone source, with OHE in diestrus animals and cessation of exogenous progestogen therapy in other animals. The mammary glands usually regress spontaneously if left untreated. Testosterone cypionate (0.5 to 1.0 mg/kg IM once) causes a decrease in milk production and may hasten regression of mammary hypertrophy (not approved).

    Return to Table of Contents

  3. Mammary neoplasia
    This is the third most common tumor of the cat (skin #1, lymphatics #2). Malignant adenocarcinoma is the most common type.
    Presentation - This is seen in older cats. They will present with firm nodular masses in one or more mammae, unrelated to the time of last estrus. Tumor incidence is equally common in all mammary glands.
    To view a gross pathologic image of feline mammary neoplasia, click here.
    Metastasis to regional LN may or may not be palpable. Metastasis to many tissues may occur; the most common cause of death is respiratory dysfunction secondary to pulmonary metastases.
    Due to its highly malignant character, biopsy is always indicated. Needle aspirates may not be diagnostic. It is usually best to submit tissue after surgical excision of the mass. Radical surgery, compared to lumpectomy, has not been shown to increase overall survival time, but will decrease incidence of local recurrence. Prognosis is associated with tumor size; following surgery, the median survival for cats with tumors > 3 cm in diameter is 6 months, for cats with tumors 2 to 3 cm in diameter 2 years, and for cats with tumors < 2 cm in diameter approximately 3 years. Patients with pulmonary metastatic disease rarely survive longer than 2 months after diagnosis.

    Return to Table of Contents

  4. Pyometra
    Pyometra is most common in cats > 6 years of age.
    The underlying lesion is CEH, which develops secondary to repeated exposure of the endometrium to progesterone. Pyometra develops due to ascending infection with normal flora of the vagina (most common are E. coli, b-hemolytic Strep sp.). Pyometra may occur in cats receiving exogenous progestogens.
    Diagnosis - Pyometra is easily diagnosed by identification of an enlarged uterus in a non-pregnant animal. You may or may not see purulent to sanguinous vulvar discharge. Systemic signs (e.g. PU/PD) are less common than in the dog.
    Treatment :
    * OHE + fluids + antibiotics - This is the best option!
    * PGF-2a + fluids + antibiotics. As in the bitch, treatment may not promote endometrial repair to a significant extent. Queens with CEH will always be predisposed to pyometra.

    Return to Table of Contents

Back to home page


The views and opinions expressed in this page are strictly those of the page author.
The contents of this page have not been reviewed or approved by the University of Minnesota.