Reproduction Flashcards
most important part of livestock operation
REPRODUCTION
reproduction influenced by (4)
body condition, stress, external environments, disease
3 roles of male reproductive system
- produce lots of spermatozoa
- deliver sperm to proper place at proper time
- provide 50% of genetic makeup and determine gender
functions of testicles
primary make sex organ, produces sperm cells, produces testosterone
scrotum function
sack which contains balls, regulates ball temp
inguinal canal
prevents balls from going back in body and guts from coming down into scrotum
cryptorchid
absence of at least 1 testicle from scrotum
unilateral and bilateral cryptorchid
- 1 up, 1 down
- both up (sterile)
abdominal testicle problems
still produces sex hormones which can lead to bad behavior
seminiferous tubules
tubular structure in crown jewels where sperm cells develop
Leydig cells
adjacent to seminiferous tubules, produces testosterone, under control of pituitary gland
epididymis function
coiled tube in each testis, storage and maturation site for sperm
Vas Deferens
long structure that transports sperm from epididymis to urethra
seminal vesicles [vesicular gland]
produce urine neutralizing fluid to add volume
prostate gland
provides sperm nutrients
Cowpers [bulbourethral] gland
makes gel for cervical plug [in boars]
urethra function
tube which runs through penis and is exit hole
penis definition
organ of copulation
3 parts of sperm cell
head, midpiece, tail (flagellum)
breeding soundness evaluation (6)
body condition score, general physical exam, palpation of internal genitalia, palpation of testes, scrotal measurement, evaluation of semen
evaluation of semen
volume, motility, sperm count, abnormal sperm
best practices of castration
timing (young, no flies), clean equipment, trained personnel, accepted techniques, pain control
why castrate? (5)
stop male hormone production, prevent unplanned mating, decrease aggression, produce consistent quality meat, decrease management costs
term for castrated sheep, cattle, pig, horse, chicken
wether, steer, barrow, gelding, capon
stag
male castrated after sexual maturity
vasectomy
portion of vas deferens removed = infertile but still has sex drive and male characteristics
methods of physical castration
knife (surgical), burdizzo, elastrator
elastrator
elastic band castration technique, stops blood flow, low failure rate
burdizzo
crushes spermatic cord carrying blood to testicle, high failure rate
role of female in reproduction (3)
supply 50% of genetic material, nourishes fetus in uterus, nourished offspring via milk
vulva
exterior part of female repro tract
vestibule
general passageway to urinary and reproductive tracts, has glands for lubrication, produces pheromones
vagina
female organ of copulation and birth canal, between vestibule and cervix
cervix
opening into uterus, protects fetus by staying tightly closed, connective tissue with muscles and glands
uterus contents
body and two uterine horns
fallopian tube / oviduct
tube between ovaries and uterus, egg travels down tube from uterus to uterine cavity
oviduct function
transports sperm into infundibulum, fluids secreted for stable fertilized ovum environment until it reaches uterus
infundibulum
site of fertilization
ovary
primary female sex organ, source of eggs, source of estrogen
functions of uterus
site of embryo implantation, place for fetus to grow, provides nourishment, passageway for sperm going from vagina to fallopian tubes
at birth, the ovary contains all of the __
follicles (eggs). Stays dormant until sexually mature
mature follicles are called __, which secrete __
Graafian or tertiary follicles, estrogen
smallest to largest age of puberty: cattle, sheep, horses, pigs
pigs, sheep, cattle, horses
estrous vs estrus
- describes all things related to cycle
- period of time they are in heat
monoestrus vs polyestrus
one cycle per year vs many
induced ovulators
don’t follow a cycle, ovulate on copulation
4 phases of estrous cycle
estrus, metestrus, diestrus (pregnancy prolongs diestrus), proestrus
estrus
step 1, heat, period when female is receptive to breeding, max estrogen production
metestrus
step 2, after estrus, corpus luteum is formed, which secretes progesterone to prep for embryo and reduces estrogen levels
diestrus
step 3, luteal phase with corpus luteum max size, non-sexual receptivity, detects pregnancy if any
proestrus
step 4, egg growth and rising estrogen levels, wall of vag thickens, internals become soft for sperm transport
estrous cycle controlled by __, follicles stimulated to grow by __
anterior pituitary gland, follicle stimulating hormone (FSH)
how heat happens
follicle grows via instructions from FSH, grows and produces more estrogen, when estrogen levels reach a certain point heat occurs, luteinizing hormones released from pituitary, which causes wall of follicle to rupture and release egg
functions of estrogen (4)
induction of estrus, dilation of cervix, makes cervical mucus, mammary gland development
corpus luteum development
new tissue grows in crater where follicle ruptures (ovulated) develops into CL and secretes progesterone
progesterone functions (6)
hormone of pregnancy, preps of arrival of embryo from fallopian tube, prevents ovulation, maintains pregnancy, increases uterine blood supply, mammary gland development
what happens when not pregnant?
CL regresses due to prostaglandins. Decrease in progesterone production signals pituitary to release more FSH to stimulate new follicle growth
lifespan of ovum
about 1 day after ovulation
zona pellucida
(mammals) sperm must pass through to join with nucleus of ovum, only allows a single sperm through
zygote is __ and divides __
sperm + egg, mitotically
before implantation embryo is nourished with:
uterine milk (secretions)
3 sets of membranes that develop around embryo
amnion, chorion, allantois
chorion
outermost layer of embryo, contacts endometrium of uterus
amnion
fluid-filled sac around embryo, protects it from shock, connected via umbilical cord
allantois
extension of urinary system, webbed with blood vessels, deals with liquid waste, gas membrane, nutrition
placenta formation and function
formed by fusion of chorion and uterine mucosa, transmits nutrients and waste, protects fetus, prevents infection, secretes hormones
diffuse, zonary and cotyledonary placenta attachment
- entire surface of membranes involves in placenta formation (horses/pigs)
- complete or incomplete band around fetus (dogs/cats)
- multiple areas of attachment (ruminants)
free martin
infertile female twin, with other twin being male. Twins may share blood and Y-chromosome causes infertility
4 ways to detect pregnancy
- rectal palpation, can detect uterine enlargement, day 45
- biological tests, measure progesterone in blood, urine or milk, day 21
- ultrasound, visualize embryos, day 30
- doppler, detects fetal heartbeat and placental attachment, small animals only
terms for poopin out babies for sheep, pigs, goats, cattle, horses
lambing, farrowing, kidding, calving, foaling
5 birth hormones
ACTH, prostaglandin, estrogen, oxytocin, relaxin
avian male reproductive tract
paired internal testes, transfer semen to cloaca same as mammals, no weenie, use floor of cloaca for “cloaca kiss”
site of fertilization
fallopian tube
