Chapter 3 Outline-Animal reproduction Flashcards
What are the three parts to the male reproductive system
- Testicles
- secondary sex glands and organs
- external copulatory organ
What is needed in order to measure reproductive efficiency
- litter size
- calving rate
- days open: 3 months open for a cow to get pregnant
- eggs hatched
What are the two vital functions of the testicles
- production of male reproductive cells, spermatozoa or sperm.
- production of male hormone: testosterone
What is the function of the testicles
To transport the spermatozoa from the site of formation to be deposited into the female tract
What does the testes consist of
- epididymis
- vas deferens
- secondary sex glands(3 glands)
What are the four functions of the epididymis
- transport
- maturation
- storage
- concentrates sperm: 4 billion per mL
What is the function of the vas deferens
Transport
What is the function if then glands and what are the three different glands
Glands produce bulk of fluid
- seminal vesicles
- Cowper’s glands
- prostate gland
What is the process that the external copulation organ goes through
-during excitation
Sigmoid flexure: must straighten to mate female, S shaped curve of the penis
-following copulation
Retractor penis muscle: takes penis back in for protection
Where do the testes need to be at the right temperature
The scrotum
What happens in the scrotum
-spermatogenesis: process of taking a round cell to a sperm, takes 6-8 weeks, required cooler temperature
What is the function of the Inguinal canal
Small opening in the body cavity where the testes descend through to reach the scrotum
What is cryptorchidism.
This is when 1 or both testes don't descend into scrotum and it is a genetically tied trait.
-One testes- unilateral
Reproductively impaired
-two testes- bilateral
SterileWhen do the female and male reproductive systems become functional
They do not become functional until puberty- age at sexual maturity
How is puberty defined in the male
- the ability to produce viable sperm and a desire to mate
- influenced by the hormone, testosterone
What does follicle stimulating hormone (FSH) function and where does it come from
- released by the anterior pituitary
- required for spermatogenesis(sperm production)
What does luteinizing hormone (LH) do and where does it come from
- released by the anterior pituitary
- stimulates the production of testosterone by the testes
Explain puberty in females
- 1 month of age: follicles start to appear on the ovaries
- estrous cycle: 5 to 14 months of age( depends on species)
- age at which puberty occurs varies with the species and breed
What happens at first estrus
-first estrus sometimes produces no egg
-estrus is caused by the hormone estrogen and influenced by:
Weight, age, and body fat
-acceptance of the male
-occurrence of ovulation
What is the percent body weight in which puberty occurs for dairy cattle, beef cattle, and sheep
- Dairy cattle- 30 to 40% of adult weight
- Beef cattle- 45 to 55% of adult weight
- Sheep- 40 to 50% of adult weight
What is the function of the ovaries
- produce ovum or egg
- produce hormones( estrogen and progesterone)
What are the ovaries homologous with
- the male testes
- they remain in the body cavity near the kidneys and do not descend
What does monotocous mean and give some examples
It means to give birth to one young at each gestation period
- one ovum is produced each estrous cycle
Ex: cow, mare, and ewe
What does polytocous mean and give an example
-litter bearing animals
The sow:
the female produces 10 to 25 ova in each cycle and gives birth to several young each gestation period
What tissue produces the ovum and where is it located
- The functional layer is the parenchyma
- it contains the ovarian follicles and the cells that produce the ovarian hormones
- near the surface of the ovary
What happens to the follicle following different stages of puberty
-the follicle becomes the mature ovum (Graafian follicle)
Follicle has fluid and contains ova: looks like blister
-produces estrogen which must be elevated to show heat
What is the Graafian Follicle
- looks like a blister on the ovary
- is caused by follicle stimulating hormone (FHS) from the anterior pituitary gland
- FHS causes follicle to enlarge
What hormone does the pituitary produce and what is it’s function
It produces LH which causes a rupture (ovulation) of this follicle and a release of an ovum (egg)
What happens immediately after ovulation
The cavity left by the vacated ovum now becomes the corpus luteum (CL)
What hormone does the corpus luteum produce and what is it’s function
It produces progesterone
- suppresses further heats(estruses) - important for maintaining a pregnancy
What happens if fertilization does not occur
Prostaglandin (PGF2alpha) will be released from the uterus causing a regression of the CL
If fertilization occurs where does the fertilized egg go
It travels to the Fallopian tube that functions as a passageway and fertilization
What are the three parts of the Fallopian tube and it’s functions
- Infundibulum- picks up ovum
- Ampulla- place of fertilization
- Isthmus- joins with the uterine horns
What are the functions of the uterus
- passage way for the sperm cells
- incubator
- nutrients
What is the structure of the uterus
- two horns and one body
- broad ligament
- caruncles
- cotyledons
- placentomes
What is the function of the braid ligament
Supports the uterus and reproductive system. Attached to the pelvic girdle and uterus. Can herniate when stretches with several offspring
What are caruncles and where do they come from
They are projections off the uterus in: cattle, goats, and sheep.
What are cotyledons and where do they come from
Attaches to caruncles. Form snap over caruncles
What are placentomes.
They are between caruncles and cotyledons. Where blood vessels feed dam and fetus, makes umbilical cord.
What is the function of the cervix
- passageway for sperm cells
- seals off the uterus
During pregnancy:
- mucus plug
- dilates when she gets ready to give birth mucus plug liquified, cervix will dilate and mucus plug releases
What is the function of the vagina
- copulatory organ of the female
- mucus secretion
What is the vulva and the function of the vulva
It is the external opening of the reproductive tract
Functions:
- passage of urine
- opening for mating
- terminal portion of the birth canal
What is the difference between estrous and estrus
- Estrous is the time between one heat to the next
- estrus is the time that the animal is in heat
What is the estrus cycle for a cow, mare, ewe, and sow
Cow- 12 to 18 hours
Mare- 2 to 12 days
Ewe- 24 to 36 hours
Sow- 48 to 72 hours
What is the estrous cycle for a cow, mare, ewe, sow, and doe
Cow- 21 days Mare- 18 to 25 days Ewe- 16 to 17 days Sow- 20 to 21 days Doe- 17 days
What are some visual signs of pre-estrus
- swelling and redness of vulva
- restlessness
- standing for the male
What is gestation and what is it for a cow, ewe/doe, mare, and sow
The period of pregnancy Cow- 9 months Ewe/doe- 5 months, 5 days Mare- 11 months Sow- 3 months, 3 weeks, 3 days
What does diagnosing pregnancy early allow for
Managing nutritional demands of gestation and lactation, as well as for rebreeding
What is the most common method for pregnancy diagnosis
Rectal palpating for large animals only
- palpating is done by inserting the arm into the rectum and feeling the reproductive tract for pregnancy
What are pregnancy diagnosing tools for small farm animals
- x-rays, however, much too costly
- Ultrasound
- Hormones: milk, blood, urine, and perhaps saliva
What is the first stage of birth
Dilation of the cervix and the positioning of the fetus in the birth canal
How long does the first stage take for a cow and ewe, mare, and sow
Cow and ewe- 2 to 6 hours
Mare- 1 to 4 hours
Sow- up to 12 hours
What is the second stage of parturition
Expulsion of the fetus which is usually very quick
How long does the second stage take for cows and ewes and mares
Cows and ewes- less than 2 hours
Mares- 15 to 20 minutes
What is the third stage of parturition
Expulsion of the placenta
What are signs of parturition
- udder development
- relaxation of the pelvis
- distention of the teats
- mucus discharge from the vulva
What does the hormone, relaxin, do during parturition
It comes from the corpus luteum and placenta
- dilation of cervix - relaxation of pelvis
What does the hormone, estrogen, do during parturition
Estrogen comes from the placenta
- opens birth canal
- starts early uterine contractions
What does the hormone oxytocin do during parturition
Oxytocin is stored in the posterior pituitary
- begins bigger uterine contractions
- milk let down( must stimulate teats)
What are some early labor signs
- uneasy
- restless
- separates from herd
- only assist if animal is weak
What is normal calf presentation
- front feet first with head between legs
- hoof pointing downward
- amniotic fluid used as lubricant
What is abnormal calf presentation
- beach birth
- abnormally large calf
Explain care of the newborn
- cleaned by the dam
- dip in the navel cord
- colostrum: first milk the is yellow and thick
- gives antibodies
- gives energy
- minerals and vitamins(vitamin A)
What is artificial insemination
The introduction of sperm into the female reproductive tract by other than natural methods
How is semen collected
- artificial vagina
- electroejaculator
Where is semen stored
- In ampoules or plastic straws
- In liquid nitrogen
What are advantages of AI
- eliminates cost of buying bulls
- use of outstanding sires for a reasonable price
- more accurate evaluation of AI bull’s breeding ability
- better heard health: prevents disease from transferring from bull to cow
What are disadvantages of AI
- increased labor cost
- conception rates may be lower compared to live mating
- skilled inseminators
What are fertility testing in bulls
-bulls should be sound and not have any critical defects
How should a bull’s semen be
- motility
- concentration
- percent of live semen
- structural normality
What is estrus synchronization
-hormone therapy so that all animals come into heat at the same time
What are they reasons for synchronization
- AI is more practical
- breeding season is reduced
- calf drop is more uniform
- calving season is shorter
- reduced number of bulls
