<~~ BACK to PJC ZooTech

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

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)

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)