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define puberty in female swine.
first spontaneous ovulation
a group of females have challenges with health and growth. use a common theory for puberty to explain the likely timing for occurrence of puberty in these females.
accumulation of fat is limiting, below threshold, puberty will be delayed.
indicate the first major goal for reproduction in mammalian livestock. for livestock, describe the typical relationship between puberty and first major goal for reproduction.
age at first parturition. puberty should occur and not limit age of first conception.
for equine indicate the duration of estrous cycle include units of time.
cattle duration of estrus cycle
ovine estrus cycle duration
swine duration estrus cycle
name and define two mechanisms for cellular growth
- hyperplasia- increased number of cells
- hypertrophy- increased size of cells
what cellular growth mechanism does not require synthesis of DNA. EXPLAIN
hypertrophy- increased volume of cytoplasm
concurrent with increased mass of endometrium, concentration of DNA increases. what is the cellular mechanism for growth of endometrium. EXPLAIN
- hyperplasia- concentration of DNA is the same. content of DNA will increase
- Fusion- will increase concentration of DNA per cell/mg of tissue
excluding cellular growth name and provide an example for:
- holistic growth: weight or height
- molecular growth: accumulation/accretion of a protein or a fat
what is the principle for sexual differentiation
all embryos become female unless masculinized
define sexual determination
establish sexual genotype (XX or XY) at fertilization
define freemartin. use no more than 10 words
masculinized female bovine co-twin
start at conception and in sequence describe 4 key events for sexual differentiation in a stallion.
- 1: primordial germ cell migrate to genital ridge (XY to testes)
- 2: sertoli cells produces antimullerian hormone and decreases mullarian ducts
- 3: testosterone to dihydrotestosterone leads to differentiation of penis, scrotum, and sex accessory glands
- 4: hypothalamus masculinized so no LHRH surge.
describe the sequence of cellular differentiation during myogenesis
presumptive myoblasts undergo mitosis-myoblast undergo fusion- myotubules undergo fusion-turn to myofibrils
based on sequence of events in cellular differentiation during myogenesis, explain double muscling in calves
lack of myostatin prolongs mitosis of presumptive myoblasts
assume that "sat-booster" will activate quiescent satellite cells in weaned cattle and pigs. what is the likely effect of "sat-booster" on holistic animal growth.
increase mass of muscle less than/equal to 10% increase. given that satellite cells are incorporated.
based on current knowledge, what hormone, not "sat-booster", would have a direct and positive effect on myogenesis in weaned pigs? EXPLAIN.
IGF-1 assists uptake of amino acids into muscles and retention of nitrogen (anabolic)
in females what are four broad functions of the reproductive system? name tissue/organ that supports each function.
- Gametogenesis: ovary follicle
- mating: vagina
- nutritive support fetus: uterus/placenta
- endocrine: follicle/CL/placenta
within the female reproductive tract, what is the location of fertilization
independant of the season, name all species of livestock that experience seasonal parturition
horses, sheep, goats, beef cattle
defend or refute. in animals that are inseminated and concieve, they progress through all stages of an estrus cycle similar to animals that are not pregnant. EXPLAIN
REFUTE. pregnant animals after conception DO NOT experience postestrus, diestrus continues to gestation.
With attention to the target tissues for estradiol, what is the anatomical basis/evidence that estradiol is present in blood in significant concentrations from day 18 until day 1 postestrus in cows?
- Brain - behavior.
- Exterior genitalia - swelling.
- Cervix - mucus.
- Uterus - hyperplasia. Increase tone, increase edema, increase myometrial activity
during the estrous cycle, describe briefly three effects of estradiol that regulate events during that estrous cycle. name three events and describe the regulatory effects of estradiol in each event.
- embryo transport: oviduct to uterine horn
- regress CL: increased synthesis of prostaglandin F2-α
- follicle growth: mitosis of granulosa cells
define the critical period for maternal recognition of pregnancy (MROP) no species or numbers.
conceptus signals CL before committed to regress
If MROP was 100% successful, what will be the quantitative impact on reproductive success of livestock? Explain.
decreased embryonic death and increased reproductive success, could reduce EM as much as 50-75%
name and describe two basic strategies for MROP. include species that use each strategy.
- luteotropic- Human
- antibuteolytic- cattle and sheep
- combination- swine
for swine describe when and how MROP occurs
PGF exocrine, estrone sulfate less potent than estrodiol. increase LH secretion, estrodiol luteotropic (increased progesterone secretion)
for horses describe when and how MROP occurs.
increased contacts between emryo and endometrium (pinball) increased estrone sulfate.
from conception to death when does adipose tissue experience mitosis?
up to or just after puberty
what determines extent of hypertrophy that occurs in adipocytes
if dietary energy exceeds total net energy
defend or refute. like muscle cells, adipocytes are not endocrine. EXPLAIN.
REFUTE. adipose secretes leptin making it an endocrine tissue.
name a compound that is used as a repartitioning agent. justify the title/label.
- β-Agonists-(paylean, optiflex) redirect energy from fat to muscle or milk.
- GH- (posilac) increases secretion of triiodothyronine/thyroxine which increases fat metabolism
consider diestrus in a species of livestock that is not a mare. what ovarian structures are present and prominent?
CL prominent. periodic follicles
consider diestrus in a species of livestock that is not a mare. what is the function and structural status of the uterus?
- endometrium: secretory
- myometrium: quiescent
consider diestrus in a species of livestock that is not a mare. what is the predominant hormone in the blood?
- steroid (if any): progesterone, transient estrodiol
- protein or non steroid (if any): PGF 2-α in late diestrus
in cattle horses and swine when does diestrus occur? use a specific range of days and include descriptive units for time.
4-18 days postestrus
what are the phases of growth?
pre-natal (fetal), pre-weaning (birth to weaning), post-weaning (wean to market)
describe uterine capacity as it pertains to growth. provide an example.
- increase uterine capacity- increase birth weight
- swine: increase litter size- decrease birth weight.
for cattle, horses, and sheep, what is the effect of gender on growth?
male > castrated male > female
consider the effects of diet on growth of a fetus. use versus cattle to discuss homeorhesis.
- underfed pregnant cows: no effect on fetus growth
- underfed pregnant ewes: decreased fetal growth, ewes have lower homeorhesis priority for pregnancy/fetal growth
consider dairy cattle from birth to first parturition, describe, with attention to age and units, the growth. also after first parturition describe the calving interval and lengths associated with pregnancy and lactation.
- wean: 1.5 months
- puberty: 9-12 months
- conception: 15 months
- first parturition: 24 months
- non pregnant: 82 days
- pregnant: 283 days
- lactation: 305 days
- dry period: 60 days
- calving interval goal one per year
consider horses, from birth to first parturition, describe, with attention to age and units, the growth. also after first parturition describe the calving interval and lengths associated with pregnancy and lactation.
- wean: 3-4 months
- puberty: 18 months
- conception: 36 months
- first foal: 47-48 months
- conception at second foal estrus: 30 days post parturition
- pregnant: 335 days
- lactation: 2-4 months
- dry period: 8-10 months
- foaling interval one per year
describe spermatogenesis in males.
- 1: proliferation- of stem cell pool MITOSIS
- 2: Differentiation- meiosis I= DNA replication normal DNA but haploid chromosome number. meiosis II= no DNA replication DNA reduced 50% in new cells. Metamorphosis= spermiogenesis shape change from cuboidal to teardrop
what is the first cell that does not have a complete set of chromosomes?
describe the effect of heat on fertility in males
this leads to infertility due to sensitivity of meiotic steps to heat, infertility can occur immediatly or several weeks after hyperthermia of testes. (duration can vary widely)
describe spermatogenic wave
different stages of the spermatogenic cycle distributed along length of a seminiferous tubule
what is the significance of spermatogenic waves?
allows for continual production of spermatozoa
describe the path of sperm out of the testes.
start in seminiferous tubules, to rete testis, to ductus efferens, to capa epidiymis, to corpus epidiymis, to cauda epididymus, to vas deferens.
what is the effect of ACTIVIN on spermatogenesis
it is mitogenic and increases DNA synthesis
what is the effect of INHIBIN βA on spermatogenesis?
decreased DNA synthesis
what is the effect of TGF-β1 on spermatogenesis?
increased DNA synthesis
what event must take place in the environment of the female vagina that allows for a sperm cell to fertilize an oocyte.
define sexual differentiation using no more than 10 words
process that creates sexual phenotype
define freemartin using no more than 10 words
phenotypically masculinizing a genotypic female co-twin
schedules for artificial insemination are based on fundamental biological issues. excluding seasonality and type of ovulator, describe four fundamental issues that determine schedule for AI in virtually all mammals.
- timing of ovulation
- fertile life of oocyte
- time required for capacitation and transport of spermatazoa
- fertile life and adequate number of spermatazoa
what issue is the most important for scheduling of AI? EXPLAIN.
- fertile life of oocyte, it is the shortest interval
- time of ovulation, if not calculated correctly, can miss it with AI too late and capacitation takes too long= no fertilization.
what is the weakness of the am pm rule in AI for farm animals?
am pm rule only works properly given that detection of estrus is accurate. if detect estrus too late with am pm rule AI will be too late to fertilize the oocyte before it becomes in-viable
what is the fertilization area within the reproduction tract?
defend or refute, the two major reproductive goals of beef cattle and dairy cattle are different. EXPLAIN.
REFUTE. the two major goals are identicle, age at first parturition ~ 2yrs of age and calving interval ~ 365 days long
use narrative and numbers to state the two major reproductive goals in horse females
- first parturition at ~4 yrs of age
- successive foaling at 12 months
use narrative and numbers to state the two major reproductive goals in swine females
- first parturition at ~12 months of age
- successive farrowing at 150 days
defend or refute. Estradiol exerts a direct and indirect regulatory effect on function and life span of a corpus luteum in most mammalian livestock females. EXLPAIN
- direct effect- decrease activity of 3-β hydroxysteroid dehydrogenase so less pregnenelone. decrease progesterone.
- indirect- increase prostoglandin F2α from endometrium which decreases progesterone
define functional genomics
method to screen activity of entire genome--active vs. not
as a researcher why might you choose to use functional genomics as a tool?
investigate interactions among genes per physiological group
what is a knock out?
eliminate activity/expression of a gene
what is a common objective for using "knock-outs"?
to determine all effects of specific gene
during an estrous cycle, when does diapedesis occur?
including cause describe/define diapedesis.
leaky capillary due to decreased estradiol
define recruitment of follicles. what factor(s) regulate recruitment.
primordial follicles change to primary follicles. species and age determine when this will happen
describe a dominant follicle
largest, most granulosa cells, highest estradiol production
including numbers and time, describe A non-ovulatory follicular wave in mares.
- overall duration~~ 7-10 days
- ~~20 follicles become primary, 1 becomes dominant; 19 atretic.
consider diestrus in a non-pregnant species of livestock that is not a mare. what ovarian structures are present and prominent?
- dominant follicle- intermittent
name and describe the strategies for MROP in horses.
name and describe the strategies for MROP in sheep
name and describe the strategies for MROP in swine
anti-luteolytic and luteotropic
name and describe the strategies for MROP in cattle
what is a repartitioning agent in use for swine
what is a repartitioning agent in use for cattle
describe features of a beef cow that will almost certainly experience prolonged postpartum an-ovulation. use cryptic descriptive phrases, not complete sentences.
- calf suckles aggressively
- uterine infection
- low NE in diet postpartum
describe foal heat
estrus and ovulation 7-10 days after parturition
why do cattle and swine not experience an equal version of foal heat?
suckling delays estrus/ovulation
name three major events (not lactation or welfare) prepartum that must occur for successive parturition, include key regulatory hormone for each.
- decreased inhibin to myometrium-decreased progesterone
- increased expulsive forces-increase prostaglandin F2 α
- dilate or soften cervix-relaxin
provide the duration of gestation and the percentage of gestation that is dependant on CL for horses
- duration: 330 days
- percent: 50-175 days so 15-53%
provide the duration of gestation and the percentage of gestation that is dependant on CL for swine
- duration: 114 days
- percent: 114 days so 100%
provide the duration of gestation and the percentage of gestation that is dependant on CL for sheep
- duration: 145 days
- percentage: 55 days so ~~33%