ANSC 1401 Exam #4

reproductive efficiency

# live offspring born in a period of time

importance of repro efficiency

more born --> more to sell-->stability of operation

repro efficiency effect on maintenance cost/unit

more babies--> lower cost/unit

repro efficiency effect on selection process

more babies--> greater oppurtunity for genetic improvement

species differences

know what environment, management, and goal is best for each animal

physiology influence on repro efficiency

does animal have physical ability to reproduce

genetic potential influence on repro efficiency

does animal have gene for multiples

nutrition influence on repro efficiency

too fat or too thin

season influence on repro efficiency

spring long days = best to repro

other factors influence on repro efficiency

heat+humidity not good for repro

Testes

primary sex organ in males

Gamete (sperm) function

in testicle, sperm is produced by seminiferous tubules

endocrine function

within testicle, testosterone is produced by interstitial cells

epididymis

long tube attached to side of testicle - functions as area for sperm maturation and storage - sperm must be mature before active

Vas Deferens

tube that transports sperm from epididymis to urethra

Ampulla

a reservoir in animals that ejaculate rapidly (bulls, stallions, ram, and buck)
- found where urethra meets vas deferens
- temporary storage depot for sperm

prostate gland

nourish and stimulate activity of sperm
-opens into urethra close to opening to bladder

vesicular gland (seminal vesicles)

neutralize urine residues and stimulate activity of sperm

bulbourethral glands (cowpers glands)

neutralize urine residues, add volume to ejaculate, form gel in boar semen that plugs cervix in sow
-opens into urethra

urethra

large muscular canal from bladder through full length of penis for sperm and urine

penis

passageway for sperm and urine

glans penis

free end of the penis

fibroelastic cavernosum tissue
sigmoid flexor

when s curve streightens to make erection
- in bulls, boar, ram

cavernosum tissue

spongy tissue that fills with blood making the penis rigid and erect in preparation for mating

vascular cavernosum tissue
no sigmoid flexor

stallion, dog

retractor muscle

bends urethra when not erect

boar shape

curved to fit in cervix

ram shape

has extention of urethra

scrotum

contains and protects testicle as well as regulates temperature

cremaster muscle

regulates temperature

castration effects

no secondary sex characteristics
grow slower
fatten quickly
higher meat quality
fewer behavior problems

gonadotropin releasing hormone (GnRH)

produced in hypothalamus in brain
- stimulates LH and FSH release

gonadotropic

- produced by the anterior pituitary gland

Follicle Stimulating Hormone in male (FSH)

stimulates development of sperm in seminiferous tubes

Luteinizing hormone in males (LH)

stimulates secretion of testosterone in testes

ovary

primary sex organ in female
-produces ova (egg) and hormones

Follicle

filled with fluid
-Graafian Follicle - mature follicle

Ovulation

follicle ruptures and releases egg

corpus hemorrhagicum

site formerly occupied by the ovum is filled with blood

corpus luteum (yellow body)

if pregnant, the corpus hemorrhagicum is filled with cells and produces a corpus luteum to secrete progestrone to maintain pregnancy

corpus albicans (white body)

if pregnancy does not occur the corpus luteum regresses to form a corpus albicans

Oviducts (Fallopian Tubes)

site of fertilization

infundibulum

funnel to pick up ovulated egg

Ampulla

carries egg to sperm for fertilization

Isthmus

carries sperm to egg for fertilization

Uterus (womb)

site of placental, embryonic, and fetal development

Uterine horns

2 parts

uterine body

looks different in species where placenta attaches

Cervix

connects uterus to vagina
open during estrus
sealed during pregnancy

Vagina

copulatory organ for the female,
birth canal and bladder also open in vagina

Clitoris

highly sensitice organ at lower tip of vagina
stimulation during AI may increase conception

Vulva

external genitalia
same as scrotum in male

Gonadotropin Releasing Hormone (GnRH) in females

produced in hypothalamus
stimulates LH and FSH release

Follicle Stimulating Hormone (FSH) in female

produced by anterior pituitary gland
stimulates growth of follicles on ovaries

Luteinizing Hormones (LH) in females

produced in anterior pituitary
causes Graafian Follicle to rupture (ovulation) and corpus luteum to form

Prolactin

produced in anterior pituitary
initiates and maintains lactation
can stop repro in some animals

Oxytocin

produced in pituitary
stimulates uterine contraction and letdown of milk in mammals - can be stimulates by sound or feeling of calf

Estrogen

made in follicle in ovary
responsible for development of secondary sex charasteristics and general appearance
duct growth in mammory glands, estrus or heat period when female is receptive to mating, prep uterus to pregnancy,

Progesterone

produced by corpus luteum
prevents ovulation and maintains pregnancy, completes uterine growth started by estrogen
increase milk production tissues

Relaxin

produced in ovaries or placenta
causes relaxation of cartlidge and ligaments to assist in birth

placenta attachements

transmission of nutrients from mother to young, transmission of wastes from young to mother, protection from shock, prevention of transmission of bacteria and secretion of hormones

age at puberty

age when repro starts

Estrous cycle days

days from one ovulation to another

Estrus

the heat period for an animal to breed

time when ovulation occurs

when ovulation happens during heat, usually want to repro on last day of heat

mare age at puberty

15-24 months

mare Estrous cycle (days)

19-21 months

mare estrus (heat)

96-216 hours

mare gestation

340 days
11 months

mare # offspring

1

mare ovulation time v estrus hours

24-48 hours before end

cow age at puberty

10-18 months

cow estrous cycle

19-21 days

cow estrus

12-24 hours

cow gestation

283 days
9 months

cow offspring #

1

cow ovulation time v estrus time

12-24 hours after end

sow age at puberty

7-10 months

sow estrous cycle

19-21 days

sow estrus

24-72 hours

sow gestation

114 days

sow offspring #

8-12

sow ovulation time v estrus time

35-45 hours from beginning

ewe age at puberty

7-10 months

ewe estrous cycle

15-17 days

ewe estrus

24-36 hours

ewe gestation

148 days
5 months

ewe offspring #

1-3

ewe ovulation time v estrus hr.

24-36 hours from beginning

Advantages of AI

widespread use of outstanding sire genes
greater availability of sires
overcomes incompatibilities of males and females
lessens dangers of males to humans or females
reduces repro diseases
rapid proof of sire possible
more uniform crop of offspring

Disadvantages of AI

widespread use of poor sire is possible
inbreeding can happen with fewer sires in use
training is required
spread of genetic defects
more checking and confinement to females
too much use of unproven show or race winner

Artificial Vagina

semen collection technique - best way on any animal - only way for horse
must train male to a dummy

Mechanical Manipulation

semen collection technique - uses gloved hand- mostly on boars

electrical stimulation

semen collection technique - mainly for checking semen before collecting

concentration of sperm

more is better

motility of sperm

more is better - move foreward streight

Morphology of sperm

less abnormality is better

Extension (dilusion) of sperm

diluted to use multiple times
diluted with egg yolk, milk, fruit and veggie juices, glycerol - if freezing

straws

used to package semen one end crimped and one end has cotton in it

ampules

not used anymore to package semen