Animal Science 1011 Exam 2

Front 1

What does the scrotum do?

Back 1

-it protects the testes
-regulates temperature, usually 4-5 degrees below body temp.
-when warm the wall of the scrotum thickens and when cold the testes move closer to the body

Front 2

What do the testes do?

Back 2

-produce sperm cells from the seminiferous tubules
-produce testosterone from the leydig cells

Front 3

What is the penis and what does the sigmoid flexure of the penis do?

Back 3

The penis is the organ of copulation in the males. The sigmoid flexure of the penis of bulls, boars, and rams permit retraction by the retractor penis muscles. It is also s shaped. The penis of stallions contains erectile tissue.

Front 4

What is the glans penis?

Back 4

The glans penis is anatomically specialized to aid in copulation, note the corkscrew of the boar and the filiform appendage of the ram.

Front 5

What is the epididymis?

Back 5

The epididymis is the storage site for sperm and the site of sperm maturation.

Front 6

What is the function of the vas deferons?

Back 6

The vas deferons transport sperm cells between the epidiymis and urethra.

Front 7

What is the ampulla and what is its function?

Back 7

The ampulla is the muscular enlargement of the vas deferens that functions in sperm transport at ejaculation.

Front 8

What is the function of the urethra?

Back 8

The urethra is the transport for semen and urine, it is the site of mixing of sperm with fluids from the accessory glands.

Front 9

What do the vesicular/seminal vesicles do?

Back 9

They provide buffers and nutrients for sperm cells.

Front 10

What does the prostate gland do?

Back 10

It adds fluid volume to the semen, particularly in boars.

Front 11

What do the eulbourethral gland or cowper's glands do?

Back 11

-provide fluid to flush urine from the urethra before ejaculation in the bull
-provide the gel plug in the ejaculate of the boar

Front 12

What is castration?

Back 12

-removal or rendering nonfunctional of the testicles
-results in loss of secondary sexual characteristics (aggressiveness and odor)
-reduces muscling, leaness, and efficiency of growth

Front 13

What are cryptorchids?

Back 13

-one of both testicles are retained in the body cavity
-failure to descend into the scrotum
-not fertile
-temp. differential not maintained
-retain secondary sexual characteristics

Front 14

Uterine body

Back 14

-area of fusion of the uterine horns
-site of development of embryos and fetuses in the mare

Front 15

Uterine horns

Back 15

-embryos and fetuses develop in the uterine horns of the cow, sow, and ewe

Front 16

Ovary

Back 16

-produces ova or eggs
-secretes the steroid hormones estrogen and progesterone

Front 17

Oviduct

Back 17

-a differentiated tube which transports ova from the ovary to the uterus
-the oviduct is from the ovary to the uterus and is divided into the infundibulum, the ampulla, and the isthmus
-site of fertilization

Front 18

Part of the oviduct- utero-tubal junction

Back 18

-the site of a sperm reservoir

Front 19

Part of the oviduct- fimbria

Back 19

-sack like end of the oviduct that encompasses the ovary to capture ova at ovulation

Front 20

Part of the oviduct- infundibulum

Back 20

-funnels the ova into the oviduct

Front 21

Part of the oviduct- ampulla

Back 21

-next segment of the oviduct transports ova

Front 22

Part of the oviduct- Isthmus

Back 22

-moves sperm cells to the site of fertilization (ampullary-isthmus junction) and ova or embryos to the uterine horn

Front 23

Cervix

Back 23

-canal connecting the uterus and vagina
-composed primarily of connective tissue
-cervix closes between period of estrus and during pregnancy
-cervix is relaxed during estrus to permit sperm transport (except in the sow) and also relaxed at parturition

Front 24

Vagina

Back 24

-the dual passageway of the urinary and reproductive systems
-the vagina serves as the organ of copulation and as the birth canal
-secretes mucus at estrus to facilitate mating

Front 25

Vulva

Back 25

-outer opening to the vagina
-a reddened vulva is an indicator of estrus

Front 26

Clitoris

Back 26

-the homologue of the penis
-massage of the clitoris may enhance success of artificial insemination

Front 27

Estrogen

Back 27

-female reproductive hormone
-source: large follicles on the ovary
-function: stimulates female mating behavior

Front 28

Progesteron

Back 28

-female reproductive hormone
-source: corpora lutea on the ovary
-function: maintenance of pregnancy

Front 29

Luteinizing hormone (LH)

Back 29

-female reproductive hormone
-source: anterior pituitary
-function: ovulation (follicle rupture), corpus luteum formation

Front 30

FSH

Back 30

-female reproductive hormone
-source: anterior pituitary
-function: development of follicle

Front 31

Follicle

Back 31

-produces estrogen
-promotes ovulation caused by LH serge
-holds the egg
-corpus luteum: source of progesterone

Front 32

Heifer or cow's reproductive cycle

Back 32

-length of estrous cycle: 21 days
-length of estrus: 12-18 hrs
-time of ovulation: 30 hrs after beginning of estrus

Front 33

Ewe's reproductive cycle

Back 33

-estrous cycle: 17 days
-length of estrus: 30 hrs
-time of ovulation: 26 hrs after beginning of estrus
-most breeds of sheep are short day seasonal breeders (breed in the fall)

Front 34

Gilt or sow's reproductive cycle

Back 34

-estrous cycle: 21 days
-length of estrus: 2-3 days
-time of ovulation: 38 hrs after beginning of estrus

Front 35

Mare's reproductive cycle

Back 35

-estrous cycle: 21 days
-length of estrus: 6 days
-time of ovulation: 1 day before end of estrus
-mares are long day seasonal breeders (breed in the spring)

Front 36

Spermatogenesis

Back 36

-sperm production in the testicles and seminiferous tubules of the male
-occurs throughout the lifetime of a male
-billions of sperm cells are produced

Front 37

Steps of Spermatogenesis

Back 37

-spermatogonium: undiffrentiated diploid germ cell
-primary spermatocyte: diploid chromosomes duplicate the cell and the cell divides (meiosis)
-secondary spermatocyte: each contains on duplicated chromosome from each pair and the cell divides
-spermatid: haploid cell which undergoes differentiation (spermiogenesis) to form a motile sperm cell

Front 38

Oogenesis

Back 38

-initiated in the fetal ovary
-a limited supply of ova result
-the second meiotic division of oogenesis is completed only after fertilization

Front 39

Steps of Oogenesis

Back 39

-oogonim: undifferentiated diploid germ cell
-primary oocyte: diploid chromosomes duplicate and then the cell divides unevenly into a secondary oocyte and a polar body
-secondary oocyte- each contains one (duplicated) chromosome from each pair
-the cell divides unevenly into an ootid and polar body after fertilization

Front 40

Gestation

Back 40

-time during which female carries developing young within the uterus
-young receives nutrients from yolk and uterine secretions until maternal/ fetal contact made

Front 41

Stage of Gestation- Clevage

Back 41

-period of cell divison without increase in cytoplasm
-fertilization to hatched blastocyst
-takes place in the oviducts and uterus
-completed by day 11 in the ewe, day 13 in the cow, and day 6 in the sow

Front 42

Stage of Gestation- Differentiation

Back 42

-period of development of organs and placental membranes and attachment to the uterus
-true embryo
-completed by day 28 in the sow, day 45 in the ewe, and by day 45 in the cow

Front 43

Stage of Gestation- Fetal Growth

Back 43

-period of growth of the developed fetus
-weight of a fetal calf increases (40g-40kg)
-completed at paturition day 114 in the sow, day 145 in the ewe, and day 282 in the cow

Front 44

Gestation length

Back 44

-cow: 279-290 days
-sow: 112- 115 days
-ewe: 144-151 days
-mare: 330-337 days

Front 45

Placentation

Back 45

-the placenta functions to transfer nutrients from the dam to the fetus and waste from the fetus to the dam
-there is no direct contact

Front 46

Types of Placenta

Back 46

-sow and mare: diffuse
-cow and ewe: cotiledonary
-contact and certain points on the uterus rather than over entire surface

Front 47

Placental Attachment

Back 47

-occurs during the period of differentiation
-day 12-20 for sow, day 18-20 for ewe, and day 30-35 for cow

Front 48

Placental Membrane- Chorion

Back 48

-outermost layer
-contacts the endometrium of the uterus

Front 49

Placental Membrane- Allantois

Back 49

-second layer
-contains fetal waste

Front 50

Placental Membrane- Amnion

Back 50

-innermost layer
-fluid filled, cushions the fetus from shocks

Front 51

Hormonal events at parturition

Back 51

-ACTH from the fetal pituitary thought to initiate parturition which stimulates prostoglandin
-prostoglandin from the uterus destroys the CL which lowers progesterone
-relaxin from the uterus relaxes pelvic ligaments (birth canal)
-estrogen from the placenta and oxytocin from the hypothalamus stimulate uterine contractions
-prolactin from anterior pituitary stimulates milk secretion

Front 52

Reproductive Management

Back 52

-measures of reproductive efficiency
-percent calf crop/lamb crop= # of calves or lambs born divided by the # of cows or ewes exposed times 100
-pigs per sow per year= # of progeny born in a year divided by the # of sows in the herd
-non-return rate= amt of cows that received 1st insemination- amt of cows who receive 2nd insemination divided by 1st insemination x 100 (measure of breeding success)

Front 53

Artificial Insemination

Back 53

-marketed by feed and specialized companies and cooperatives
-extent of utilization: turkeys nearly 100%, swine more than 90%, dairy cattle 65%, and beef cattle 5-8%

Front 54

AI Advantages

Back 54

-doesn't expose healthy sire to diseases
-use of superior sires
-wider choice of sires
-early detection of fertility problems
-semen is regularly tested

Front 55

AI Disadvantages

Back 55

-disseminate desirable genetic traits
*increase frequency of detrimental recessive allele
-requires special training, equipment
-more labor intensive

Front 56

Extending semen

Back 56

-increase volume of ejaculate
-increase number of inseminations
-species differences in sperm concentration
-ram: high concentration
-boar: lower concentration
-maintain longetivity
-protection from contaminants

Front 57

Semen testing

Back 57

-appearance: milky white, viscous
-sperm #
-motility:
1= no progressive motility
5=excellent motility
-morphology
-dead alive stain=
dead accept stain, alive do not
-ph

Front 58

AI procedure

Back 58

-semen is collected from the male usually by training him to ejaculate into an artificial vagina
-semen can be successfully frozen in cattle, but success is low in other species
-fresh or thawed diluted semen is introduced into the cervix or through the cervix into the uterus via a specialized catheter

Front 59

Estrous detection in cattle

Back 59

-cows are observed twice per day for extra activity and mounting or standing to be mounted

Front 60

Estrous detection in swine

Back 60

-sows are exposed to a boar and will display lordosis (immobility), back pressure test

Front 61

Estrous detection in sheep

Back 61

-ewes are penned with a vasectomized ram which has had it's breast painted with pigmented grease and ewes are observed daily for marks from mounting

Front 62

Estrous detection in horses

Back 62

-mares are exposed across a fence from a stallion and are observed for urination and winking