Module 8 - Reproductive System Disorders

Testes

• Primary reproductive organs located in the scrotum 

• Produce sperm (spermatogenesis) 

• Secrete testosterone and other androgens 

• Optimal function requires temperature lower than body temperature 

Scrotum

• External sac that houses the testes 

• Provides temperature regulation for sperm production 

• Contains muscles that can raise or lower testes for thermoregulation 

Epididymis

• Coiled tubular structure attached to each testis 

• Provides site for sperm maturation and storage 

• Connects testes to vas deferens 

Vas Deferens

• Muscular tubes that transport sperm from epididymis to urethra 

• Forms part of the spermatic cord 

Prostate Gland

• Primary accessory sex gland in male dogs and cats 

• Produces seminal fluid components that nourish and transport sperm 

• Surrounds the urethra at the neck of the bladder 

Urethra

• Conducts both urine and semen 

• Extends from bladder through the prostate and penis 

Penis

• Male copulatory organ 

• Contains erectile tissue for breeding 

• In dogs, includes the os penis (bone) and bulbus glandis (for "locking" during breeding) 

Prepuce

• Protective fold of skin covering the penis when not erect 

Ovaries

• Paired primary reproductive organs 

• Produce oocytes (eggs) 

• Secrete hormones including estrogen and progesterone 

• Control reproductive cycles 

Oviducts

• Paired tubes extending from ovaries to uterine horns 

• Site of fertilization 

• Transport ova/embryos to uterus 

Uterus

• Bicornuate structure (two horns, one body) in dogs and cats 

• Receives, implants, and nourishes developing embryos 

• Expels fetuses during parturition 

• Undergoes cyclic changes in response to hormones 

Cervix

• Connects uterus to vagina 

• Controls entry into uterus 

• Creates barrier between uterus and vaginal environment 

• Dilates during estrus and parturition 

Vagina

• Tubular structure extending from cervix to vulva 

• Receives penis during copulation 

• Serves as birth canal during parturition 

Vulva

• External genitalia including the vestibule, labia, and clitoris 

• Provides protection for internal reproductive structures 

• Changes appearance during different reproductive stages 

Mammary glands

• Modified skin glands arranged in two parallel rows 

• Produce milk for nourishment of offspring 

• Respond to reproductive hormones 

• Dogs typically have 5 pairs; cats typically have 4 pairs 

Pregnancy

Cats can typically be diagnosed with pregnancy earlier (21-28 days after breeding) compared to dogs (25-36 days). Ultrasonography can detect pregnancy in both species around 20 days post-breeding, while radiography becomes useful after 45 days when fetal skeletal mineralization occurs. 

Dystocia

Causes:

• Fetal factors

  • oversized fetuses

  • fetal abnormalities (anasarca, hydrocephalus)

  • abnormal positioning

  • breech position is normal in dogs and cats

• Maternal factors

  • narrowed birth canal (development or trauma-related)

  • primary uterine intertia (lack of coordinated contractions)

  • secondary uterine intertia (exhaustion from prolonged labor)

Dystocia clinical signs

• Labor lasting longer than 4 hours without producing a fetus 

• Green vaginal discharge during parturition

• More than 1 hour elapsed between births 

• Straining without productive delivery 

• Maternal distress 

Dystocia diagnosis

• Physical examination with digital vaginal palpation 

• Radiography to evaluate:  

  • Fetal position 

  • Fetal size 

  • Number of remaining fetuses 

• Ultrasonography to assess:  

  • Fetal viability 

  • Signs of fetal distress 

Dystocia treatment

manual manipulation

• carefully dislodge fetus lodged in vaginal canal

medical management

• oxytocin administration

• calcium supplementation if hypocalcemia is present

surgical intervention

• cesarean delivery if medical treatment fails

• can be combined with OVH in non-breeding animals

dystocia client education

• Appropriate breeding practices (avoiding extremely disparate size matings) 

• Prepare a whelping box and accustom the animal to it before delivery 

• Ensure proper nutrition both before, during and after pregnancy 

• Supervise birthing but avoid creating stress

• Recognize when veterinary intervention is needed 

• Special care may be needed for neonates after cesarean delivery 

Eclampsia (Puerperal Tetany)

Cause

• Hypocalcemia due to:  

  • Heavy lactation demands 

  • Calcium-deficient diet 

  • Insufficient calcium mobilization from bones 

• Most common 2-3 weeks after whelping 

• More common in small breed dogs with large litters 

• Rare in cats compared to dogs 

Clinical signs of eclampsia

• Nervousness and restlessness 

• Salivation 

• Stiff gait progressing to ataxia 

• Muscle tremors 

• Hyperthermia 

• Tachycardia 

• Seizures in advanced cases 

Eclampsia Diagnosis

• Clinical signs in a lactating female 

• Low serum calcium levels 

• Response to calcium therapy 

• Ruling out other causes of neurological signs 

Eclampsia Treatment and prevention

Emergency treatment

• Slow intravenous administration of 10-20% calcium gluconate 

• Heart rate monitoring during administration 

• Stop infusion if bradycardia or arrhythmias occur 

Follow up care

• Oral calcium supplementation 

• Serum calcium monitoring throughout lactation 

• Weaning puppies/kittens or supplemental feeding if severe 

Prevention

• Adequate prenatal nutrition 

• Calcium supplementation during late pregnancy and lactation 

• Limit litter size in susceptible animals 

Eclampsia Client Education

• Eclampsia tends to recur in subsequent pregnancies 

• Affected animals may not be suitable for breeding 

• Importance of proper nutrition during pregnancy and lactation 

• Recognition of early signs requiring immediate veterinary attention

• Proper calcium supplementation protocols 

• Monitoring nursing frequency and duration 

Pyometra Causes

Progressive uterine disease related to hormonal influences

• repeated exposure to progesterone during estrous cycles

• cystic endometrial hyperplasia progressing to fluid accumulation

Secondary bacterial infection (most commonly E. Coli)

• other potential organisms: staph, streptococcus, klebsiella, pasteurella, proteus, moraxella

Risk factors:

• Middle aged to older females

• typically occurs within 60 days after estrys

• previous hormonal treatments (estrogen, progestins)

• Nullparity (never having given birth)

Pyometra clinical signs

• Vulvar discharge (open-cervix pyometra)

• May be absent in closed-cervix pyometra 

• Abdominal enlargement 

• Vomiting 

• Lethargy 

• Polyuria/polydipsia 

• Dehydration 

• Azotemia (elevated kidney values) 

• Fever 

Pyometra diagnosis

• Radiography: enlarged fluid-filled uterus 

• Ultrasonography: fluid-filled uterus (differentiates from pregnancy) 

• Laboratory findings:  

  • CBC: leukocytosis, neutrophilia with left shift, dehydration 

  • Possible nonregenerative anemia 

  • Serum chemistry: increased alkaline phosphatase, elevated proteins, increased BUN 

• Vaginal cytology: degenerative neutrophils, endometrial cells, bacteria 

• Bacterial culture and sensitivit

Pyometra client education

• Ovariohysterectomy is the definitive treatment and prevention 

• Early, aggressive treatment is essential 

• Significant mortality rate - even with proper treatment 

• High recurrence rate within 1 year if medical treatment only 

• Medical treatment more successful with open-cervix pyometra 

• Recognition of signs requiring immediate veterinary attention 

• Lifetime risk in intact females increases with age 

Pseudopregnancy in dogs and cats

Pseudopregnancy (also known as false pregnancy) is a physiologic syndrome characterized by signs mimicking those of normal pregnancy in non-pregnant female animals. This condition is fairly common in intact female dogs (bitches) but uncommon in female cats (queens).  

In dogs, pseudopregnancy represents an exaggeration of the normal hormonal changes that occur during the estrous cycle. While all non-pregnant bitches experience some degree of pseudopregnancy physiologically, only some display overt clinical signs.  

Pseudopregnancy causes

Hormonal mechanism:

• Abrupt drop in progesterone levels at the end of diestrus 

• Increased prolactin secretion playing a central role 

• All non-pregnant bitches are physiologically "pseudopregnant" but with variable intensity of signs 

• Can be triggered by ovariohysterectomy or ovariectomy during the luteal phase

Species differences

• Common in dogs, particularly in certain breeds 

• Rare in cats due to differences in reproductive physiology (induced ovulators) 

• More pronounced in nulliparous bitches (female that has never previously given birth)

Contributing factors

• Previous pseudopregnancy episodes increase risk of recurrence 

• Possible genetic predisposition 

• Stress or environmental factors may play a role 

• Individual sensitivity to hormonal fluctuations 

psuedopregnancy clinical signs

behavioral signs

• Restlessness and anxiety 

• Decreased activity 

• Anorexia

• Licking at abdomen 

• Aggression (may be protective) 

• Maternal behaviors:  

  • Nesting behavior 

  • "Mothering" of inanimate objects (carrying toys) 

  • Protective behavior over toys or bedding 

physical signs

• Weight gain

• Mammary gland enlargement 

• Lactation (milk production) 

• Mucoid vaginal discharge 

timing

• Usually develops 6-12 weeks after estrus in dogs 

• Typically lasts 1-3 weeks if untreated 

• Signs are self-limiting in most cases 

species differences

• Dogs typically show more pronounced signs 

• Cats rarely display overt pseudopregnancy symptoms 

pseudopregnancy diagnosis

Based primarily on:

• Compatible clinical signs in a non-pregnant intact female 

• History of recent estrus (approximately 2 months prior) 

• Physical examination findings 

• Ruling out actual pregnancy

Diagnostic approach

-No specific diagnostic tests available 

• Hormonal assays are non-diagnostic 

• Ultrasonography to rule out pregnancy 

• Radiography (after 45 days) can rule out pregnancy

pseudopregnancy treatment

Conservative management

• Most cases resolve without treatment 

• Avoidance of mammary stimulation 

• Mild water restriction 

• Diuretics in some cases 

• Prevention of self-stimulation (Elizabethan collar if necessary) 

Pharmacological intervention

• prolactin-inhibitng drugs

surgical management

• Ovariohysterectomy is the only permanent cure 

• Should be performed during anestrus 

• Surgery during luteal phase can induce pseudopregnancy 

psuedopregnancy client ed

• Explain that pseudopregnancy is a normal physiological process in dogs 

• Reassure that it is typically self-limiting 

• Explain the hormonal basis for the condition 

• Increased risk of mammary tumors in intact females 

• Discuss spaying as a permanent solution for non-breeding animals 

• Explain importance of timing spay surgery during anestrus 

• Review likelihood of recurrence in subsequent cycles 

• When to seek veterinary care:  

  • Severe behavioral changes affecting quality of life 

  • Excessive milk production leading to discomfort 

  • Signs persisting beyond 3 weeks 

  • Any indication of mammary infection