Animal Reproduction

Question 1

reproductive cyclicity

Answer 1

provides females with repeated opportunities to become pregnant

Question 2

estrous cycle

Answer 2

physiological events that occur between periods of sexual receptivity (heat) and/or ovulations
the full cycle

Question 3

estrus

Answer 3

period of sexual receptivity

Question 4

anestrus

Answer 4

condition when females do not exhibit regular estrous cycle

Question 5

polyestrous

Answer 5

uniform distribution of estrous cycles occurring regularly throughout the year (cow, sow)

Question 6

seasonal polyestrous

Answer 6

“periods” of estrous cycles occurring only during certain seasons of the year (sheep, goats, deer, mare)

Question 7

monoestrous

Answer 7

only one cycle per year, often lasting several days (dogs, wolves, fox, bear)

Question 8

estrogen

Answer 8

Source— ovarian follicle and the placenta
Targets— uterus, hypothalamus, mammary tissue
Functions—mating behavior, uterine growth, secondary sex characteristics(why females look like females promotes GnRH —gonadotropin releasing hormone)

Question 9

luteinizing hormone (LH)

Answer 9

Source— anterior pituitary
Targets— ovary (luteal cells in females), testis (interstitial cells in males)
Functions—ovulation, corpus luteum formation, progesterone production, testosterone production

Question 10

follicle stimulating hormone (FSH)

Answer 10

source: anterior pituitary
targets: ovary (grandulosa cells) and testis (sertoli cells)
functions: follicular development, estrogen synthesis, sperm production

Question 11

progesterone

Answer 11

source: corpus luteum (CL) and placenta
targets: uterus, mammary tissue, hypothalamus
functions: inhibits GnRH release, maintenance of pregnancy, mammary development
pregnancy hormone; pro gestation

Question 12

testosterone

Answer 12

source: interstitial cells of testis
target: skeletal muscle, male reproductive tract
functions: anabolic growth, sperm production, secondary sex characteristics

Question 13

gonadotropin releasing hormone (GnRH)

Answer 13

source: hypothalamus
target: anterior pituitary
functions: release LH and FSH

Question 14

gestation

Answer 14

the period of fetal development, beginning wth fertilization and ending with parturition
fertilization takes place in the oviduct
the zygote migrates to the uterus
membranes form and attachment takes place between 20 and 30 days in cattle and horses, 14-21 in swine

Question 15

cleavage

Answer 15

fertilization through zona pellucida (the thick transparent membrane surrounding a mammalian ovum before implantation) disintegration

Question 16

differentiation

Answer 16

placentation

Question 17

growth

Answer 17

shifts to fetus from embryo, ends in parturition

Question 18

cow gestation length

Answer 18

285 days; 9 months

Question 19

ewe gestation length

Answer 19

147 days; 5 months

Question 20

mare gestation length

Answer 20

336 days; 11 months

Question 21

sow gestation length

Answer 21

114 days; 3 months 3 weeks 3 days

Question 22

stages of parturition

Answer 22

stage 1: preparatory stage involving cervical dilation and positioning of the fetus in the birth canal via myometrial contractions
stage 2: time of hard labor and expulsion of fetus
stage 3: expulsion of the placental membranes and subsequent uterine involution

Question 23

initiation of parturition

Answer 23

initiated by the hormone cortisol released from the fetus; fetus under stress

Question 24

dystocia

Answer 24

difficult birth, major cause of calf loss

Question 25

relative dystocia

Answer 25

normal sized calf and small birth canal, often first time moms

Question 26

absolute dystocia

Answer 26

abnormally large calf and a normal sized birth canal, most common cause of dystocia is from an oversized calf

Question 27

hiplock

Answer 27

shoulders of the calf "lock" onto the bones of the pelvis during delivery, results in the calf getting stuck in the birth canal

Question 28

artificial insemenation

Answer 28

advantages: genetic improvement through increased use of superior sires, disease control, improved record keeping, eliminates need for keeping bull disadvantages: time required to detect estrus, percent of cows in estrus during the breeding, trained personnel required, overuse of inferior sires

Question 29

artificial vagina

Answer 29

sire ejaculates into a man-made apparatus that mimics the feel of breeding a female by natural service mimics by: temperature, pressure, lubrication, and position/angle

Question 30

electroejaculation

Answer 30

an electrical probe is inserted into the rectum to stimulate ejaculation via slight electrical stimulus to the accessory sex glands

Question 31

semen evaluation

Answer 31

after it is evaluated for volume, sperm concentration (hemacytometer or spectrophotometer), motility of sperm, morphology of sperm (abnormalities)

Question 32

estrus detection

Answer 32

visual inspection: 30 minutes in the morning and evening, standing to be mounted (lordosis), mounting of other cows, swollen vulva, mucus other tools: teaser animals, marker aids, heatwatch estrus detection system

Question 33

rectocervical AI

Answer 33

manipulation of the cervix over the insemenation gun via the rectum (cows) if cow is in heat in the morning, breed her in the evening

Question 34

speculum

Answer 34

tube-like instrument that spans the vulva and posterior vagina allowing visual inspection of the cervix (deer and goats)

Question 35

laparascopy

Answer 35

surgical introduction of semen directly into the uterine horns (sheep)

Question 36

cervical

Answer 36

introduction of spirette with a counter clockwise rotation into the cervix gilts- inseminate 12 hours after detection of estrus sows- inseminate 24 hours after detection of estrus

Question 37

vaginocervical

Answer 37

introduction of the insemenation gun into the cervix via the vagina (equine) insemenation time is based on presence of a 35mm follicle, open cervix, and detection of estrus

Question 38

dairy cattle AI

Answer 38

80-90% of the cows are bred artificially 21.2 million units of dairy semen sold domestically

Question 39

beef cattle AI

Answer 39

about 13% of beef cows are inseminated, semen from angus and simmental bulls is most extensively, 1.3 million units of beef semen sold domestically

Question 40

swine AI

Answer 40

about 80% of all pigs born in US are conceived via AI

Question 41

horse AI

Answer 41

limited due to the rules of some breed associations, challenges associated with freezing equine semen

Question 42

sheep and goat AI

Answer 42

limited because herds and flocks are dispersed over wide areas, cost per unit semen is high

Question 43

estrous synchronization

Answer 43

a management technique that makes use of hormones to control or reschedule the estrous cycle: LH, FSH, Progesterone, Estrogen, Prostaglandin advantages: decrease labor involved with heat detection, makes AI possible for extensive operations, may be economically advantages, may promote earlier conception, critical to embryo transfer programs

Question 44

synchronization products

Answer 44

GnRH PGF2a (prostaglandin-gets rid of CL/progesterone) MGA (melengestrol acetate-progesterone, feed compund that keeps them out of heat until prostaglandin injection) EAZI-BREED CIDR (progesterone based, similar to IUD?)

Question 45

purpose of embryo transfer

Answer 45

increase productivity of genetically superior donors maximize use of valuable semen transport genetics across long distances production of identical offspring by embryo splitting

Question 46

embryo transfer

Answer 46

1. synchronization of recipients with donor 2. superovulation of donor female--produces many follicles 3.inseminate donor with semen from genetically superior bull 4. recovery and identification of viable embryos 5. transfer of viable embryos into synchronized recipients

Question 47

reproductive technologies

Answer 47

In vitro fertilization nuclear transfer cloning intra cytoplasmic sperm injection gamete intrafollopian transfer semen sexing embryo sexing preimplantation genetic diagnosis

Question 48

in vitro fertilization

Answer 48

in vitro=in glass, in dish involves placing sperm and matured oocyte together in a dish keep embryo in vitro for up to 7 days- in vitro culture (IVC)

Question 49

sperm sexing

Answer 49

works only because of the 3.5% difference in DNA quantity of X or Y bearing sperm lasers are able to detect this 3.5% difference selection method is called flow cytometry some decrease in conception rates

Question 49

sperm sexing

Answer 49

works only because of the 3.5% difference in DNA quantity of X or Y bearing sperm lasers are able to detect this 3.5% difference selection method is called flow cytometry some decrease in conception rates