Male Reproduction Flashcards
What are the functions of the testicles?
exocrine: produce sperm cells, endocrine: produce the male steroid Testosterone (also produce estrogen but not as much)
Function of the epididymis?
sperm maturation and storage
Function of the scrotum?
contains and protects testicles
Function of the ductus deferens?
connects epididymis to urethra, transports sperm to the urethra
What is another name for the ductus deferens?
vas deferens
Function of the urethra?
muscular canal extending from the urinary bladder to the length of the penis
What makes up the accessory glands?
seminal vesicles (vesicular glands), prostate, and cowpers glands
Function of the accessory sex glands?
add volume and nutrients for sperm to semen
Function of the penis?
organ of copulation
What are the components of sperm?
head, mid-piece, principle peace, proximal cytoplasmic droplet
Function of the head of sperm?
contains genetic information, haploid cells
What is a haploid cell?
a cell containing a single set of chromosomes
Function of the mid-piece of sperm? What is another name for midpiece?
(mitochondrial helix) energy production for mobility
Function of the principle piece?
(tail) motility
What is the proximal cytoplasmic droplet?
sign sperm did not fully mature in epididymis
What is acrosome?
digestive enzyme that breaks down outer portion of ovum
What is capacitation?
changes that occur to sperm in female tract
When does the acrosome reaction occur?
after capacitation
What are the penile types?
vascular and fibrous
What is a vascular penis?
tremendous blood influx increases length, stiffens, and increases width
What is a fibrous penis?
stiffening of penis and relaxation of contractor muscles
What kind of penis do dogs have?
fibroelastic
What are the 3 parts of the penis?
glans penis (head), shaft (where most of the erection occurs, and root
What 3 things are semen analyzed for?
volume per ejaculate (ml), sperm concentration per ml x 10^6, total sperm per ejaculate x 10^9
Why is boar semen deposited in the cervix?
because they have low sperm concentration
How does the male reproductive organs differ in poultry?
no penis and instead have a rudimentary organ of copulation that transfers sperm to the oviduct of the hen, testis maintained internally inside the body
How is sperm stored in poultry?
It is stored in the oviduct of female and is able to fertilize eggs for 70 days in turkeys and 35 days in chickens
What is the “equivalent of a penis” in poultry?
phallus
What is castration?
removal of the testicles
What is castration called for dogs and cats?
neuter
What is the purpose of castration?
preventing undesired mating and improving meat quality
What is a negative of castration?
decreases feed efficacy and growth rate
What is controlled/limited breeding season?
limiting the time interval animals are allowed to mate
What are the two types of breeding?
artificial and natural
What are examples of natural breeding?
sheep-natural breed in the fall and lamb in the spring-short day breeders
horse-natural breed in late spring and foal the following spring-long day breeders
What is a long day breeder?
breed in spring
What is short day breeder?
breed in fall
What is artificial breeding?
limiting of breeding season by man
What are advantages of controlled breeding season?
easier nutritional management, easier health management, easier to observe and assistance at time of parturition, more uniform animals to market
What are the disadvantages of controlled breeding season?
all animals reach marketing age at the same time
What is estrous synchronization?
getting all livestock to go into heat at same time
Do all sheep/horses/etc follow the breeding season?
Not necessarily because in some places there are not distinct seasons
How does estrous synchronization occur?
induction of corpus luteum regression/ovulation, delaying ovulation, or a combination
What does regressing the corpus luteum do?
allow estrous to peak
What does estrous synchronization use?
AI or embryo transfer, greater supervision of animals at parturition
Benefits of estrous synchronization?
more efficient use of labor and facilities, animals bred on 1 day will give birth in at approximately the same time, out of season breeding
What is artificial insemination?
semen is deposited in female reproductive tract by artificial techniques rather than natural mating
When was AI first documented? In what animal?
1779, dogs
What animals have AI techniques been developed in?
cattle, horses, sheep, goats, swine, poultry, and lab animals
What are advantages of AI?
- semen can be diluted multiple matings from one ejaculation
- semen can be frozen and stored for later use
- use sires after death
- limit possible spread of disease
- mate animals which are a large distance apart
What are disadvantages of AI?
additional skills required
When does AI have to occur?
as close to ovulation as possible
Where does AI occur?
semen is deposited beyond the vagina and past the cervix into the uterine body ensure more likely to get pregnant and sperm cells reach ovum
What is necessary for successful AI?
accurate detection of estrus
How is estrus detected in cattle?
cow in estrus will stand to be ridden by other cows, sterilized bull will aid in detection of estrus
How is estrus detected in sheep/goats?
animals in estrus will stand to be mated by male, sterilized males must be used to detect estrus
How is estrus detected in horses?
mare elevates tail, contracts vulva (winking), and braces in the presence of stallion
How is estrus detected in swine?
assume a rigid stance with ears erect when pressure is applied to back, presence of boar will enhance response, lordosis
What is lordosis?
sow will arch back when pressure applied
Why is AI used in almost all livestock turkeys?
they are bred too big to breed naturally
What is cryopreservation?
preservation of sperm/eggs so that there are genetic resources to use in the future
What are the two parts of the epididymus?
caput and cauda
What is the function of the caput epididymis?
sperm maturition
What is the function of the cauda epididymus?
sperm storage
What is the function of the ampulla?
adds fructose to the sperm to nourish it
What is the sigmoid flexure?
in fibrous penis, the rest of the length
What is the gubernaculum?
structure that pulls testes from the abdominal region into the scrotum through the inguinal canal
Why are the testes outside the body for most animals?
the testes need to be cooler for semen production, 2-3 degrees cooler
What is the retractor penis muscle?
what moves the penis in and out of sheath (relaxed=in and contracted=out)
How is semen collected?
using a live animal or a dummy, electroejaculation
Do probes lead to more semen ejaculation?
no
What is semen evaluated for?
sperm morphology, life to death ratio, sperm concentration
What are the ingredients in semen extension?
isotonic media, nutrient, cryopreservation, antibiotic
Why is isotonic media added to semen?
it has the same osmolarity
Why are nutrients added to semen?
“feeds” the sperm (like calcium etc)
Why are antibiotics added to semen?
so it doesn’t grow bacteria that can destroy sperm cells
How is semen stored?
frozen gradually through a computer controlled process. Tubes containing semen are stores inside canes which are stores inside a canister with liquid nitrogen
How long can preserved semen last?
over 50 years
What are the ways pregnancy is diagnosed?
breeding marks, palpation, blood test, ultrasound, bagging
What are breeding marks? What do they do?
male marks female at mating; earliest possible indication of conception
What are breeding marks for cattle?
chin ball marker, K-mar patches
What are breeding marks for sheep and goats?
marking harness, painted brisket
what are animals with breeding marks presumed to be?
pregnant, non-marked are presumed to be open
What is the problem with breeding marks?
marks can wash off, marker wears out and no mark at mating, mating does not guarantee pregnancy
What animals is palpation used in?
cattle and horses
What is palpation?
trained individuals feel for developing calf or foal
What do blood tests look for in cattle?
elevated levels of progesterone levels and PSPB (pregnancy specific protein B)
What is PSPB produced by?
the uterus
What do blood tests look for in dogs?
Relaxin protein
What do blood tests look for in humans?
HCG, human chorionic hormone
What are the types of ultrasound?
external transducer, real time external, real time transrectal
What is an external transducer ultrasound?
a hand-held machine which indicates pregnancy by beeping
What can result in a false positive for external transducer ultrasounds?
full bladder
What animals are external transducer ultrasounds used on?
sheep, goats, pigs
What is a real time external ultrasound?
machine which allows you to visualize the developing fetus on a screen; allows you to count fetuses
What animals are real time external ultrasounds used on?
sheep, goats, pigs
What is a real time transrectal ultrasound?
same machine as real time external but a probe goes in the rectum
Which ultrasound can detect pregnancy the earliest? How early?
real times transrectal; 18 days
What animals are real time transrectal ultrasounds used on?
sheep, goats, pigs, horses, and cows
What is bagging?
examination of udder to check for development
When can bagging be used?
1 month before parturition
What is embryo transfer?
removal of the embryo early in its development from its own mother’s (donor’s) uterus and transfer to another female’s (recipient’s) uterus
Is the recipient or donor “better”?
the donor
What animals were embryo transfer developed in?
sheep, goats, swine, cattle, and horses
What animal is embryo transfer used commercially in?
purebred cattle
What are the steps of embryo transfer in cattle?
- donors are superovulated (induced to ovulate multiple eggs) and bred
- embryos are removed non-surgically
- embryos are removed and transferred to recipients or frozen and stored for later use
What is in vitro fertilization?
fertilization in a test tube (outside the body)
How does in vitro fertilization occur?
eggs are collected from donor female, mature and fertilized in a lab, then frozen or transferred to a recipient
At what stage are eggs collected for in vitro fertilization?
any stage
