2: BSE in M - general and canine Flashcards
where do testes originate before descent?
what do they pass through?
where do they end?
abdomen
thru inguinal ring - inguinal canal and superficial inguinal ring to rest in scrotum
how do testes descend?
what structure is key and how does it work?
gubernaculum mediates descent
it shortens and swells to pull testes into and through canal
shrinks and remnant is left in srcotum
what structure does gubernaculum become in adult M?
lig of tail of epididymis
descent of testes in species: ca fe eq bo, ov, cap, por
ca: 14 days old - 6 mos
fe: at birth
eq: 10 days old - 9 mos old
bo/ov/cap/por: birth - rest are culled so latest descent not known
what is required for puberty to occur?
- beh to allow successful courtship, intromisssion and copulation [erection and protrusion]
- ejaculate contains min # spermatozoa req’d to achieve preg [do not have to be high quality to be succesful]
age of puberty depends on what factors?
- season of birth (if seasonal breeder)
- breed
- size of litter
- BCS / plane of nutrition
- housing and stocking density
why does poor BCS inhibit puberty?
suppresses LH levels so dec stim of leydig cells so dec testosterone is produced
age at puberty: ca fe eq bo ov cap por llama/alpaca
ca: 9 mo - 5-12
fe: 9 mo - 8-10
eq: 12 mos - 10-24 or 2nd spring of his life
bo: 11 mos - 7-18
ov: 7 mos - 6-9
cap: 5 mos - 3-8
por: 7 mos - 5-8
llama/alpaca - 2-3 yrs
endocrinology of puberty:
in young animals, what sex has surge center?
in adults?
young: M and FM
adult: FM
implications of surge center or lack of surge center in each sex adult?
M - no surge - frequent pulses of LH throughout day - subsequent pulses of Testosterone (T)
FM - surge center - surge of LH occurs during estrus
loc of surge center?
hypothalamus (hypo)
hormone sec by hypo?
GnRH
GnRH stim what brain structure? what hormones are produced?
ant pit gland
FSH and LH
what does FSH stim in M?
sertoli cells to sec T
what does LH stim in M?
Leydig cells to prod spermatazoa
composition of testes?
seminiferous epithelium and interstitium
what is present in seminiferous epithelium?
germinal epithelium
sertoli cells
what do sertoli cells prod?
inhibin
e2
dihydrotestosterone (DHT)
what is present in interstitium of testes?
leydig cells
what do leydig cells prod?
T
estron sulfate
what species seasonal breeders?
long day?
short day?
what effects on reproductive fxn during off season?
feline - long day - dec sperm count in winter
ov - short day - dec libido, dec scrotal circumferenct, dec semen quality in off season
cap - short day - dec libido, buck odor, scrotal circumference, semen quality in off season
equine - long day - dec sperm count during winter
general terms: what does M need in order to successfully breed?
- coordination and control [hypo, pit]
- prod of gametes [seminiferous tubules of testes, spermatic cord, scrotum]
- storage of gametes [epididymis]
- prepare gametes for FM tract [accessory sex glands]
- deliver gametes to FM tract [ductus deferens, urethra, penis/prepuce]
- support [musculoskeletal, ocular, GIT]
fxn of testes?
- sperm prod in semiferious tubules
- endo gland in interstitum
where in testes does sperm prod occur?
sertoli cells - adluminal compartment specifically
where are mature sperm shed in testes?
shed from seminiferous tubule into the lumen
why is BM of blood testis barrier important?
b/c sperm need immuno protection b/c immune cells will view as ‘not self’ and will attack sperm
epitopes on developing germ cells would be recognized as foreign
what layer and what structures w/in that layer are important for immune protection of sperm?
peritubular layer
junctional complexes btwn Sertoli cells
what compartment of seminiferous tubule is immunologically privileged?
adluminal compartment
across species, what is avg time for sperm production cycle to complete?
about 2 months
feline a little shorter
clin relevant: if poor semen quality, re test in 2 months
what temp must testes be maintained at and why?
35* C - is optimal for sperm production and survival
function and structure of tunica dartos?
heat retention
smooth M loc inside scrotum - constricts scrotal skin to move and maintain testes near body
long term heat -
what 2 structures are important for heat retention in testes?
tunica dartos
creamaster M
what is structure / fxn of cremaster M
striated M
imp for short lived retraction of testes closer to body
3 structures imp for heat dissipation of testes?
scrotal skin [thin]
countercurrent heat exchange mech
tunica tardos relaxation
describe counter current heat exchange mechanism?
pampiniform plexus is testicular V returning from bottom of testis
testicular A is torturous and interdigitated btwn pampiniform plexus vessels
heat moves down hill gradient from testicular A and into testicular V => cools blood as it moves into bottom of scrotum so sperm are NOT exposed to 37* C blood
structure and fxn of epididymis?
single coiled duct
consists of: head, body, tail
fxns: sperm maturation - acquisition of motility, plasma mem alteration, gain fertilization competence
sperm storage until ejaculation
what is testicular orientation in dog, stallion, boar and bull/ram/buck?
dog - long axis oriented parallel to ground - head and body of epididymis are dorsal and tail towards tail of dog
stallion same as dog
boar - slight rotation so tail points up a little bit
bull/ram/buck - long axis vertical, head at top, body medial and tail at ventral pole
fxn of accessory sex glands?
what is their development and maintenance dependent on?
secrete components of seminal plasma, facilitating delivery of sperm
coag substance to minimize sperm loss from FMs in stallion and boar
depend on T
t/f - semen and ejaculate are not exactly the same thing
true - semen is a sample and an ejaculate is a complete physiologic sample
canine acc sex glands?
prostate
only one therefore common site for pathology
feline acc sex glands?
bulbourethral glands
prostate
equine acc sex glands?
MC pathology loc? ***
bulbourethral glands
prostate
vsicular glands
ampullae ***
bovine acc sex glands?
ovine and caprine same!
bulbourethral glands
prostate
vesicular glands (**MC path in cattle)
ampullae
porcine acc sex glands:
bulbourethral glands
prostate
vesicular glands
structure of prostate?
bi lobed gland, symmetrical
2 types of penis?
fibroelastic (w sigmoid flexure)
- narrow, rigid penis that extends length to penetrate
musculocavernous penis
- cavernous cavities that fill w blood
fxn of penis?
to deliver gametes to variable loc in FM tract (dep on species)
fxn of spines on tom penis?
to induce ovulation in queen
belling of stallion penis fxn?
stretches cervix of mare - promote evacuation of uterus following breeding (plunger/suction effect)
what species have a fibroelastic penis?
bull ram buck boar macho
structure of fibroelastic penis?
firm outer tunica albugenica that px significant inc in diameter, only stiffening as cavernous spaces fill
- straightening achieved w sigmoid flexure
structure of musculocavernous penis?
blood engorgement of cavernous spaces (cavernosum and spongiosum) inc diameter substnatially during erection
species with musculocavernous penis?
stallion
dog
what structure does dog penis have to help w intromission?
os penis
what is BSE? breeding soundness evaluation
complement of exams and evals that allow us to formulate an OPINION as to whether or not a M is capable of breeding and successfully impretnating a given # of FM under prevailing industry mgmt conditions
t/f - BSE is a guarantee of fertility
false
Breeding soundness does NOT guarantee fertility
poor performance on a BSE does not necessarily mean that a M is sterile/infertile, just sub fertile
general goals of BSE?
- select genetically superior individuals to promote cont genetic improvement across a group/breed/species
- discriminate against heritable dzz
- provision of reasonable assurance that M is capable of achieving x % preg rate with exposed to x # FM for breeding season of x # days
indications for BSE?
- select breeding stock
- pre sale, pre purchase
- prior to use [bulls for the season, dogs for a breeding arrangement w bitch]
- sub fertility (infertility)
general components to BSE:
- hx - general and esp as it pertains to reproduction
- permanent ID of animal
- general PE
- exam external genialia
- semen collection and eval
maybe: - direct exam of internal genitalia / accessory sex glands
- eval of libido, breeding beh and serving capacity
- testing for presence of infectious / genetic dz
- collect data and pronounce classification of M
limitations of BSE?
- results valid for day of exam and for conditions under which it was performed
- manner in which exam is performed does NOT usually permit eval of libido, mating ability or serving capacity
- fertility is multi factorial and difficult to eval
indications for BSE of stud dog?
- usually have perceived problem:
does not like bitch uninterested in bitch - "gay dog?" missed his last bitch problem pooping or peeing abnormal discharge/blood coming from penis
OR owner wants ‘guarantee’ before committing to breeding
- scheduling and transporting animals is expensive and involved process
dog BSE components:
- sig and hx
- ID
- general PE
- exam of external genitalia
- maybe exam internal genitalia
- semen collection and eval
- maybe libido assessment
- additional dx if necessay
signalment info of dog for BSE?
- age - pubertal vs mature vs senile
- breed - heritable defects, size of gene pool considerations
- use - show, hunting, performance, working, breeding only
what considerations for working/show dog under chronic stress?
chronic physiologic stress down regulates LH and T
hard working or very lean dogs may experience this
hx of dog for BSE?
- has dog bred before?
- by what methods?
- outcomes? preg rate and litter size
- has semen been collected / evaluated before?
- tested for aby against Brucella canis?
- other repro problems occurring?
- general health and care of dog - preventative care, meds, vacc, etc
litter size depends on M or FM?
FM - number of oocytes ovulated
expected preg rate of dog?
natural service 75%
AI 50-90%
ways to ID dog
microchip tattoo registered number - AKC, UKC, field dog stud book, etc DNA number color images
general PE of dog?
- general health: BCS, skin, look for endocrinopathy
- heritable defects
- musculoskeletal defects that interfere w ability to breed?
although not part of BSE, where can you refer for certifications regarding dog breeding/genetics?
OFA
CERF
cardiac
dog PE BSE - general considerations:
- eyes, adnexa
- dentition
- cryptorchidism
- hernias
- musculoskeletal conformation
- exercise induced collapse
- degenerative myelopathy
considerations when examining scrotum and contents:
- integument: smooth, thin, free of lesions/dermatitis
- scrotal contents: spermatic cord, epididymis, testes
- symmetric
- owner should do this often
if epididymides are asymmetrical, what might that indicate?
epididymitis or segmental aplasia
if blood epididymis barrier is broken, what will likely form in epididymis?
sperm granuloma - foreign body attack
how should testes appear in scrotum?
- IN the scrotum
- symmetrical but one may sit slightly cranial
- freely movable
testes size considerations?
should correlate with NORMAL body weight for breed/age [consider of stud is obese]
what consistency should testes have?
what if too soft?
what if too firm?
firm but vibrant - spring back when pushed
- too soft: hypoplasia or degeneration
- too firm: neoplasia, terminal degeneration (fibrosis)
how can semen collection be elicited out of M?
- estrus teaser
- non estrus bitch
- secretions from estrus bitch
- no stimulus - some do this often, are trained, and know the drill when they go into vet/for breeding
equipment for semen collection?
- semen collection apparatus: rubber cone w vial at end, funnel w collection vial, warm water bath
- lubricant
- exam gloves
process of stimulating M and collecting semen?
- stim bulbus glands thru prepuce
- retract prepuce proximally to exteriorize bulb prior to full engorgement
- clamp prox non-erectile portion of penis circumferentially
- retroflex penis and allow M to ‘tie’ => clamp to simulate FM tying
how many fractions are there to semen?
what is in each fraction?
1st - pre sperm = clear
2nd - sperm ritch = opaque
3rd - prostatic = clear
how to assess libido in M dog?
use teaser bitch
what to look for on perputial orifice of M dog?
- exteriorize penis - how narrow is it?
- congenital malformation
- acquired stricture (phimosis)
- excessive smegma -> balanitis or balanoposthitis
- hair rings?
what to look for on penis of M dog?
- congenital abnormalities: hypoplasia
- acquired conditions: urethral prolapse, os penis fracture, mass lesions
overall semen eval?
- color and opacity
- volume
- progressive motility
- morphology
- concentration
- total sperm count (more imp than volume)
how to eval motility of sperm?
PM = progressive motility
PMS = progressively motile sperm
- instruments and disposables warm (35* C)
- canine sperm should swim fwd in STRAIGHT line
- estimate % PM, % abnormally motile and % dead
what % PM is normal for dog?
over 80% PMS
what can be used to dilute semen sample?
physiologic saline
semen extender
prostatic fluid
what direction do dog sperm swim and why?
fwd direction
b/c neck attaches to head axially
how to eval morphology of semen?
- sample prep / stain / oil
- count at least 100 sperm
what % must have normal morphology?
over 70%
70-80% expected
abnormal sperm defect classification?
primary
secondary
tertiary
what % of sperm can have 1* or 2* defects to be considered sound?
1*: less than 10%
2*: less than 20%
morphology classification considerations:
what is compensatory vs non compensatory?
implications for fertility?
compensatory: abnormal sperm unable to reach uterine tube or can reach uterine tube but NOT penetrate oocyte
- inc sperm count may compensate for defects
non compensatory: sperm capable of reaching and penetrating oocyte, but embryo dev fails
- inc sperm count cannot compensate
morphology classification as major or minor?
major: 1* a functional defect of acrosome, head and mid piece
minor: defects of the head, mid piece and tail believed NOT to be so deleterious to fertility
primary vs secondary vs tertiary morphology defects?
- classification depends on organ of origin
primary: occurred in seminiferous tubules of testes - defect in production
secondary: occurred in epididymis - abnormality in latter stages of maturation or while in storage
tertiary: post ejaculatory / iatrogenic - difficult to distinguish from secondary
structure of normal canine sperm:
head: acrosome, equitorial region, post acrosomal region
slightly narrowed neck - axial attachment
mid piece
tail
primary defects MC affect what part of sperm?
head
secondary defects MC affect what part of sperm?
mid piece and tail
examples of primary defects of sperm?
- knobbed (lipped) acrosome
- macrocephalic
- pyriform head
- diadem defect
- double sperm
- deatched abnormal heads
- dag defect
- tightly coiled tail
what type of defect is retained cytoplasmic droplets?
is this bad for dog fertility?
primary defect
NOT a problem with dog [problem for bull…]
examples of secondary defects to sperm:
terminally coiled tail
distal midpiece reflex w retained distal cytoplasmic droplet
less common: bent tail, detached normal head
what is hemospermia?
what does it indicate?
erythrocyte (RBC) contamination
- urethral or cavernosal rent
- iatrogenic
- benign prostatic hypertrophy
what is leukospermia?
what might it indicate?
- pyospermia
- leukocyte (WBC) contamination
- balanoposthitis
- orthicis / epididymitis
- prostatitis
- can be from sheath so exteriorize penis before collection so sample is not contaminated
how to eval concentration of semen?
number of millions of sperm per mL of sample
prepare sample: 1:100 dilution in buffered formyl saline
- number of sperm in the counting chamber equals number of sperm in millions per mL
total sperm count =
???
concentration (million sperm / mL)
x
volume (mL)
what is minimum total sperm count across all dog breeds - required for dog to pass BSE?
300 million
although: this is low standard for large breed dogs (such as great dane)
what is azoospermia?
no sperm
what is oligospermia?
less than 200 million
more common than azoospermia
what to do if NO sperm in semen sample?
- determine if dog ejaculated fluid from epididymal tails or not…
- also bring teaser bitch for next ejaculation
how to determine if fluid in sample is from epididymal tails or not? what do you measure? what does high/low value mean?
conc of alkaline phosphatase in sample
high alk phos: epididymal fluid, so dog dig ejaculate
low alk phos: no epididymal fluid so dog did not ejaculate
what is implication of high alk phos (over 5k) and no sperm in semen sample of dog?
he ejaculated but there are not sperm - bad news bears
what is implication of low alk phos (less than 5) and no sperm in semen sample of dog?
blocked epididymal ducts - b;c no epididymal fluid
sperm may be there but cannot get out
how to test for infectious dzz in dogs?
- genital and semen cultures
what is major infectious dz that is tested for?
brucella canis
what type of test is brucella canis test?
serologic test: rapid card agglutination test
screening test
what does positive and negative brucella test mean?
positive: false pos common bc of cross reactivity w aby to cell wall Ag of commonly encountered canine pathogens
add 2-ME to card test to eliminate cross reactivity - very effective to determine if positive is false or true
confirm positive serologic results via: AGID (agar gell immunodiffusion) test or blood culture (MO)
negative test is negative
one of most important indicators in dog is?
total sperm count
if total sperm count in dog is low, what is an option?
re eval in 60 days - allow sperm prod cycle to carry out for a full cycle
if dog has compromised fertility, what are chances he will return to normal fertility?
LOW
re evaluate 2 mos later and 6 mos later - if still poor, he will very likely NEVER get better
