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118 Cards in this Set
- Front
- Back
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Before puberty GnRH is realsed how?
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Released in a low amplitude, low frequency which is basal level
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After puberty how is GnRH released?
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Tonic center: controls basal level which is higher than prepubertal
Surge center: responsive for prevoulatory surge |
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True or False:
Surge center is absent in males. |
True.
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Testosterone crosses the blood brain barrier and is converted to what?
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Estradiol
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What hormone defeminizes the surge center in the male?
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Estrogen
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In females what does estrogen in circulation bind to to prevent it from cross the blood brain barrier?
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alpha fetoprotein
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What are some factors that affect puberty?
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Genetics (Sire scrotal circumference)
Breed Nutrition Socio-environment/biostimulation Birth season in seasonal breeders Temperature |
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What is the optimal age for calving for heifers?
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2 yrs
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Duration of Bovine:
Proestrus- Estrus- Metestrus- Diestrus- |
Proestrus: 2-5 d
Estrus: 1 d Metestrus: 1-3 d Diestrus: 13-16 d |
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Activity of bovine ovary:
Proestrus- Estrus- Metestrus- Diestrus- |
Proestrus- Follicel forming regressing CL
Estrus- Mature Follicle Metestrus- CL formation Diestrus- CL |
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Bovine Uterus Activity:
Proestrus- Estrus- Metestrus- Diestrus- |
Proestrus- Edema; Inc blood supply
Estrus- inc edema, inc blood supply, inc tone Metestrus- dec tone, dec edema, dec blood supply Diestrus- dec tone, inc glandular development |
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Bovine Hormone Profile
Proestrus- Estrus- Metestrus- Diestrus- |
Proestrus- dec P4, inc FSH, inc E2
Estrus- Peak E2, low P4, LH surge 12-18 hrs after estrus = OV Metestrus- dec E2, inc P4 Diestrus- P4 high until luteolysis |
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Describe the Follicular Phase.
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1)Period from regression of CL to OV.
2)Proestrus and Estrus. 3) Dominant structure follicle. 4) Dominant hormone is E2. |
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What events occur during the follicular phase?
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1) Gonadotropin release from pituitary.
2) Follicular preparation for OV. 3) Sexual receptivity. 4) OV. |
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True or False
Follicular wave emergence stops during pregnancy and anestrus periods. |
False.
Follicular wave emergence CONTINUES in pregnancy and during ansestrus periods. |
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What advantages does the dominant follicle have over subordinate cohort follicles?
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1)Timing- 8 hrs ahead of its sub-ordinate follicle
2)Expressing LH receptors 3) Utilizing both FSH and LH |
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What does the secretion of inhibin and estradiol cause?
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Inhibits further cohort development
Inhibits/timing the emergence of the next wave |
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What happens if there is high P4 and a dominant follice?
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ATRESIA
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Describe the luteal phase.
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Period from OV to regression of CL.
Dominant structure is CL. Dominant hormone is P4. Metestrus and diestrus stages of estrous cycle. |
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What are the events of the luteal phase?
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CL formation
Production of P4 Luteolysis |
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In what species is there a local countercurrent exhange of PGF between the unterine vein and ovarian artery?
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Ruminants
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In what species is there local and systemic PGF?
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swine
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When and how does maternal recognition occur?
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Cow- 15-18 days after OV
bovine interferon tau |
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What does Endometerial PG Synthesis Inhibitor do?
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EPSI interferes with arachidonic acid cascade and down regulates oxytocin receptors
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What type of placenta do ruminants have?
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cotyledonary
epitheliochorial -attachment is well established at 40d |
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Induction abortion/parturition
<150d? 1502-250d? >250d? |
< 150 days – PGF2a
150-250 days – PGF2a and corticosteroids >250 days – PGF2a and/or corticosteroids |
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Hormone VetMed Uses:
GnRH/LH? E2? PGF? Corticosteriods? |
GnRH/ LH– to induce ovulation/lutenization
Estrogen – to induce ovulation (not licensed) GnRH – to synchronize follicular waves by inducing ovulation or atresia Prostaglandin – to induce luteolysis ( to induce estrus/abortion/parturition) Corticosteroids – to induce abortion or parturition |
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What is the goal of estrus synch programs?
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manipulate the estrous cycle sothat all females ovulate during a short, predefined period w/ normal fertility
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How do you determine pregnancy rate?
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pregnancy rate = number pregnant/ number treated for synchronization
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What are uses for PGF2a?
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Pyometra
Luteal Cysts Unobserved Estrus Mummified fetus Controlled breeding |
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What factors need to be considered when selecting a synch protocol?
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Cost
Efficacy of protocol objective available labor facilities body condition of cows postpartum interval of cows econocmics of input |
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How long is estrus in cattle? What are signs of estrus?
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3-18 hrs (9hrs)
walking bellowing dec milk production restlessness frequent urination mucus discharge |
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What is the definition of pregnancy rate?
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the % of cows eligible to become pregnant, in a given ttime frame, that actually do become pregnant
PR = HDR xCR |
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What factors affect estrus signs?
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breed
season lameness ovarian pathology |
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What are some different types of automated systems for estrus?
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walking- pedometry
mouting-pressure sensors temperature- milk and core body sensors progesterone profiles odors & pheromones Tissue or mucus impedance |
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Describe the tail stripe system.
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2 colors. Place crayon stripe from point of back to slope of tail. apply or reapply to every cow every day. If rubbed off = heat.
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What are advantages of the tail stripe system?
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high efficiency
inexpensive requires you to look at each cow |
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Disadvantages of tail stripe.
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AI cows not in Heat
Cows remaked dialy if needed |
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At what time do you inseminate cows?
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Insemination should occur in relation to ovulation
OV in dairy cows is 28+/- 5 hrs after onset of estrus. Better to inseminate early than late. |
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Define dystocia.
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prolongation of the first and/or second stages of parturition such that completion becomes difficult or impossible for the dam alone.
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Define eutocia
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safe, easy, natural parturition
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At what size should heifers be at breeding and calving?
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To have an adquate birth canal heifers should be at 60% mature BW at breeding and 85-95% mature weight at calving
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How much should a heifer weigh the day prior to calving?
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85-90% + 100lbs
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What is a culling tool you can use to increase birth canal size?
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measure pelvic area pre-breeding
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How can you decrease calf size to decrease dystocia?
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1) use of breeds or strains with smaller brith weights
2) Use of calving ease sires |
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Explain EPD
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Expected Progeny Difference
Compare bulls for any measurable trait Data from pedigree, performance, progeny |
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What is presentation when discussing a dystocia?
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1)Relation of the spinal axis of the fetus to that of the dam
2) Portion of the fetus that is approaching or entering the pelvic cavity |
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What is position?
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The relation of the dorsum of the fetus in longitudinal presentation, or the head in transverse position, to the quadrants of the maternal pelvis.
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What are the quardrants of the maternal pelvis?
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sacrum
right ilium left ilium pubis |
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What does posture denote in dystocia
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The relation of the extremities to the body of the fetus.
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How can ultrasound be used in bovine practice?
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Accurate identification of ovarian sturcture
Diagnose uterine/ovarian pathology early pregnancy diagnosis/fetal loss fetal sexing research/commerical applications bull infertility |
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True or false.
Fetal sexing is based on identification of gential tubercle. |
True
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When is the optimal time for fetal sexing in cows?
in heifers? |
cows - 60-75 days
heifers - 60-90 days |
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What are indications for transvaginal ultrasound?
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Transvaginal ovum pick-up
cyst aspiration twin reduction uterin wall abcess lacing |
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When can you diagnose a pregnancy by U/S?
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28 days
Important economically.. costs $6/d for each day open |
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How can U/S be used in bulls?
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Diagnosis of testicular masses/enlargement
-Tumor -firotic foci -hydrocele -epididymitis Penile/Prepucal masses -Abscess Hematoma Foreign body |
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How long does it take for ova to reach the uterin horn in small ruminants?
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2-4 days
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how many cervical rings do small ruminants have and what does that mean?
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6-8 cervical rings that point caudally
impacts AI; ewes must be AI laproscopically |
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Age at puberty for sheep and goats?
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5-7 months
meeting 2/3 mature body weight |
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Length of estrous cycle in small ruminants?
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sheep: 17days
goats: 21 days |
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Duration of estrus in small ruminants?
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sheep: 36 hrs
goats: 30-40 hts |
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Estrus behavior in ewe?
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seeks ram
swollen vulva |
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Estrus behavior in doe?
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Wags tail
Bleats buck jar swollen vulva clear-cloudy-cheesy white mucus |
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When are sheep ovulatory?
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August to January - ish
short day breeders |
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When are sheep anovulatory?
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January-May
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When are sheep transitional?
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June-August
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Which breed has the longest breeding season?
the shortest? |
Dorset
Suffolk |
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What breed of goat has the longest season? the shortest?
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Boer- longest
Alpine - shortest |
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What are the advantages of synchronization of estrous in the breeding season?
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Shorten breeding and lambing season
timely pregnancy diagnosis health and nutritional managment can meet the market demands more efficient use of labor/facilities supervision of ewes abd lambs better ram management |
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Synch programs for small ruminants?
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Prostagladins
Progesterone/progestagen |
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How do you PGF to synch small ruminants?
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Ewes/does must be cycling
Single PGF2a = 60-70% Double PGF2a = 100% Sheep - 24-36 hrs Goats- 36-40 hrs; within 2 days |
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How do you use P4 to synch small ruminants?
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MGA .22mg/hd/d plus PG600
Prolongs luteal phase virtually all ewes enter estrus cause an LH surge upon removal and OV |
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How do can light be used to induce estrus in sheep?
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16 hrs of light Dec - late Jan
8 hrs of light 6 more wks requires total confiment 40-70% will cycle in march include male |
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Light induced estrus in goats?
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16 hrs of light mid-Jan for 70 days
8 hrs of light for 70 days 60-70% does will start cycling Include bucks |
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Describe the "Ram Effect".
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1 teaser/40-50 ewes
introduce abruptly and in 48 hrs full effect inc in LH leads to OV ewes will be in heat in 18d rest of ewes will come in in 25d b/c of OV at introduction |
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Describe the "Dormitory Effect"
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Introduction of ewe in estrus
25% will respond remaining 80% will respond within few weeks |
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What is FecB?
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Booroola fecundity gene
single autosmal gene additive effect on ovulation rate |
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Describe 3 in 2 breeding management.
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3 lambings in 2 yrs
1 production cycle = 8 mo 2 mangement flocks 2 lambing perids/yr Breeding season <30d lambing & lactation 75-80d |
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Describe Cornell Star Breeding Management.
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5 lambings in 3 yrs
1 production cycle = 7.2 mo 3 managment flocks 5 lambings periods/yr Breeding <30 d Lambing and lactation 66d |
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What are selction criteria for ewes?
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extended ovulatory period
small size maternal ability milking ability prolificacy early onset of puberty |
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What are selection criteria for rams?
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carcass quality
growth efficiency feed efficiency |
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When is pregnancy recognition in ewes and does?
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Ewe: 12-13d
ovine trophoderm-interferon-t Doe: 16d interferon-t |
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How can you diagnose pregnancy in small ruminants?
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marker male
abdominal ballottement hormonal analysis Ultrasonography |
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When can you use U/S to diagonse preg in small ruminants?
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By trans-rectal/transabdominal
24days 45 days see fetus & placentomes diagnose twins around 45 days |
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What are factors causing poor pregnancy rates?
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Ram fertility
Ram:ewe ratio phytoestrogens environmental factors nutrition ewe factors chromosomal anomalies |
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Length of pregnancy in ovine?
caprine? |
ovine: 5mo
caprine: 5 mo |
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P4 source in preg for ovine and caprine preg?
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ovine: <50d CL; >50d placenta
caprine: CL whole |
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What are advantages of induction of parturtion in small ruminants? What do you use?
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Advantages:
concentrated lambing improves lamb survival Glucocorticoids - ewe prostagladings - doe |
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What disease creates "donut shaped" lesions in the fetal liver?
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campylobacter
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What do you do when a small ruminant abortion occurs?
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1) assume cause is infectious
2)ID dam that aborted & isolate 3)remove aborted fetus & afterbirth 4)remove potentially infected bedding 5) wear gloves/wash 6)start on LA -200 7) take fetus & afterbirth to lab |
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What do you submit to the lab in a small ruminant abortion case?
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Fetus and Placenta
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What are some causes of early abortions?
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Malformations
Sheep & Goat hybrids (GHEEPS!!) Toxo Border Disease Nutritional Factors |
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Why do you restrict medicinals in the first 35 days of gestation in small ruminants? What are examples?
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Cause malformations
Albendazole, Cambendazole, xylazine, ace, diazepam |
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What are nutritional factors that cause early abortions?
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Cu and I deficiency
Energy and protein deficiency |
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What are causes of late abortions?
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Enzootic Abortion of Ewes
Toxo Campylobacter Salmonella Border Disease Leptospirosis Listeriosis Prolapsed vagina Pregnancy toxemia |
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How doe ewes get Chlamydophila abortus?
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ingestion of contaminated food and water
exposure to uterine discharg and fluids |
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How long is the incubation period for Clamydophila abortus in gestation?
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50-90 days
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True or False.
Chlamydophila has veneral transmission. |
False
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What is a vector for campylobacter?
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birds
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What is the source of infection for campylobacter?
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contaminated food and water
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what is the incubation period for campylobacter?
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7-60 days
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When are abortions with campylobacter infections?
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abortions last 3rd of pregnancy or stillbirth
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What organism caues Q fever? Where does it cause disease?
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Coxiella burnetti
predilection for trophblast cells in ovine placenta |
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Describe the zoonotic form of Q fever.
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flu like symptoms with penumonia and cardiac lesions
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Since the outcome of a Toxo infection depends on the stage of gestation what will you see at:
early? Mid? Late? |
Early: fetal death and resorption
Mid: Infection established in placenta- if <70d fetus resistance depends on immune system development; if fetus surives compromised placenta leads to abortion Late- viable healthy lambs |
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What is the major manifestation of Brucella ovis?
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Epididymitis
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True or False.
Brucella ovis is not zoonotic. |
True
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What happens in a congenital infection by Border Diease?
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<65d embryonic death and abortion
65-85d PI > 85d immunity |
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What is the repro management goal in beef cows?
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An early calf every year
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What must happen for cows to become pregnant early in the breeding season?
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Calve early this year
Cycle soon after calving High conceptin rate |
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What are the 6 factors that influence the initation of estrous activity?
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Time of calving
Age of cow BCS at calving Suckling Presence of a bull Use of exogenous hormones |
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What are the major advantages of getting a cow to calve earlier in the season?
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calf will be older thus heavier
more uniform calf ages to more effectively apply management practices more size uniform group |
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How can you achieve a shorter season in a herd with prolong calving?
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1) moving cows back
2) letting cows drift forward by extending the calving to breeding interval 3) culling |
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How can you overcome the inhibtion suckling has on estrus?
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Remove calves from cows for 48 hrs at begining of breeding season.
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What two hormones can stimulate cycling postpartum?
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GnRH
P4 |
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What are the 3 major factors known to influence fertility in beef herds?
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Time of Calving
Weight gain or loss at time of breeding Bull Factors |
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True or False
Gaining or maintaining cows have high conception rates than cows losing weight at breeding. |
True
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What two adverse effects does endophyte infected fescue have?
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screws up vascular function
decreases prolactin |
