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Reproductive Failure:
Anatomy & Physiology

Animal Breeding

Pensacola Jr College

Common Aspects of Reproductive Failure

w Development problems

w Reproductive tract injuries

w Cysts

w No cycling

w Disease (next lecture)

Development Problems

w Freemartin

w Infantile reproductive system

w Incomplete or blocked structures

w Hermaphroditism

w Cryptorchidism

1.  Freemartin

w The female of male-female twins (esp. in cattle)

•   Embryonic membranes of twins fuse before reproductive organs develop

•   Cell mixing brings some Y chromosomes into female

•   Oviducts, uterus, and cervix do not form correctly

•   Always sterile

Cause of Freemartin

2. Infantile reproductive system

w Failure to develop to maturity

w Most often seen in underfed female animals

w Generally reversible

3. Incomplete or blocked structures

w In females: permanent defects in oviducts, uterus, cervix, or vagina (still cycle)

w In males: permanent defects in vas deferens or urethra

w Genetic cause (inbreeding)

w Usually sterile

4. Hermaphroditism

w Presence of anatomical structures of both sexes

w True hermaphrodite:

•   Has both male & female gonads (separate or as ovotestes)

•   Genetic defect (XXY or XO)

4. Hermaphroditism (cont’d)

w Pseudohermaphrodite

•   Has either testes or ovaries (determines sex classification)

•   Has combination of other male and female reproductive tract structures

•   Caused by hormone or enzyme deficiencies

Ovotestis in true hermaphrodite

 

w Pseudo-hermaphrodite

w male cat

Male dog pseudohermaphrodite

5.  Cryptorchidism

w Testes fail to descend into scrotum through inguinal canal

w Genetic defect

w Unilateral cryptorchid

•   only one testis descends, reduced fertility

w Bilateral cryptorchid

•   Neither testis descends, sterile

Cryptorchid dog tumor (top)

Reproductive Tract Injuries

w Uterine or vaginal tears

w Prolapsed uterus

w Broken penis

1. Uterine or Vaginal Tears

w Usually occurs during either assisted delivery or manual removal of retained placenta

w Small tears in normal delivery do not usually block reproduction

w May require surgical correction

2. Prolapsed Uterus

w Uterus moves partway or completely through vaginal canal

w Generally occurs following parturition due to:

•   Dystocia

•   Retained placenta

•   High estrogen pasture/grazing

Prolapsed Uterus – cow

Prolapsed Uterus - bitch

3. Broken Penis

w Penis bent and blood vessels ruptured during copulation at a sharp angle

w Most common in species with fibroelastic penis (less erectile tissue to provide resistance to breakage)

we.g. see hematoma on page

Cystic Ovaries

w Ovaries form abnormal fluid-filled sacs

•   Caused by ovulatory failure

w Follicular cysts:

•   Thin-walled cysts

•   Produce estrogen

•   May cause chronic heat

•   Rupture w/hormone treatments

Follicular cyst

Cystic Ovaries (cont’d)

w Luteinized follicles:

•   Thick-walled cysts

•   Produce progesterone

•   May develop FROM follicular cysts

•   Cause anestrus

•   Regress with hormone treatments

Ultrasound – luteinized follicle

Lack of Cycling

w Anestrus = absence of estrus

w Most common cause = pregnancy!!!

w Other common causes:

•   Postpartum anestrus

•   Lactation

•   Seasonal anestrus

Anestrus as Reproductive Failure

w Physical problem

w Disease problem

w Poor nutrition (especially low calorie intake)