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62 Cards in this Set
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- Back
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What are the 2 phases of the estrous cycle?
The 4 stages? |
Follicular phase (proestrus + estrus)
Luteal phase (metestrus + diestrus) |
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How long is the normal bovine estrous cycle?
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21d
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The follicular phase is dominated by___________ while the luteal phase is dominated by _____________.
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follicular = estrogen
luteal = progesterone |
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How long (average) is estrus in a cow?
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15 hours (6-24h)
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How long (average) after the beginning of estrus does ovultation occur?
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24 - 32h
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Put the following in the correct order in the bovine estrous cycle:
LH peak FSH peak Ovulation Estrogen peak |
Estrogen peak
FSH peak LH peak Ovulation |
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How long after ovulation does the CL normally form in the cow?
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Usually 3-5 days; mature by day 7
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What are some advantages to estrus synchronization in beef cattle?
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AI efficiency
Labor effeciency More uniform offspring crop Can shorten breeding season |
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What are advantages for estrous synchronization in dairy cattle?
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Reduce need for heat detection
Circumvents cystic ovarian disease May induce fertile ovulation in anestrous cows |
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What are the three hormone classes available to use in estrus synchronization?
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Prostaglandins
Gonadotropins Progestins |
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Which drugs are used to control the luteal phase? What is the mechanism for each?
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Progestins (MGA or CIDR) prolong the luteal phase.
PGF2a (Lutalyse, Estrumate) shorten the luteal phase and induce luteolysis. |
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How long after PGF2a administration should ovulation occur? This only occurs if what is extant?
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Ovulation occurs in 2-5 days ONLY if a CL is already there!
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Which drug is administered to initiate a new follicular wave?
a) LH b) GnRH c) FSH d) Estrogen |
b) GnRH is the only DRUG that is administered (yeah it will stimulate FSH)
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After PGF2a is released (or administered), how quickly should the CL regress?
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Within 2 days
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Describe the drugs used and timing of the Ovsynch protocol.
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day 0 - GnRH
day 7 - PGF2a day 9 - GnRH breed or AI 16 hrs |
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Describe the two methods using only PGF2a for estrus synchronization?
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d0 - PGF2a; d5 heat check/AI
d0 - PGF2a; d5 heat check/AI; d14 - PGF2a; heat check d16-19 |
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Which drugs control ovulation time?
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GnRH
hCG |
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Approximately what percentage of cows should show estrus after PGF2a injection? How long should this take?
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75% of CYCLING cows should show estrus in 2-5 days
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At what point in the cycle should Ovsynch be started for maximum efficacy? How can this be ensured?
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Start Ovsynch at day 5-10.
Ensure with Presynch; using PGF2a at days 0 and 14, then starting Ovsynch at day 26. |
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Describe the hormones administered and administration times for the Co-synch program.
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d0 - GnRH
d7 - PGF2a d9 - GnRH + timed AI |
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How can Cosynch pregnancy rates be increased by 9%?
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separate calves from dam when PGF2a is given
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Why do post-parturient beef cows typically have a short cycle?
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No progesterone priming
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Which synch protocol is best used on heifers?
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Melengesterol Acetate (MGA) synch
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How long should MGA be fed to heifers? When should they be bred?
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Feed 14-18d
Breed d35 - 37 (after giving PGF2a on d33) |
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What does CIDR stand for? What does it contain?
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Controlled Intravaginal Drug Release; contains progesterone
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What is the best synch protocol to get them heifers bred!?
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5-day CIDR synch gives 58.3% preg rate
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T or F:
AI is the method of choice for the beef and dairy industry. |
False!
60% AI in dairy; 6% in beef |
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What are 6 factors that are required when breeding via AI?
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Efficient record system
Well designed facilities Good nutrition Good general health program Accurate heat detect/synch Well-trained AI tech |
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What are the positive signs of pregnancy perceivable via transrectal palpation? When should each be felt?
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Amniotic vesicle (35-60d)
Fetal membrane slip (30-35d) Fetus (60 - 65d) Placentomes (80-90d) Fremitus (120-150d) |
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What are the major methods of pregnancy determination in cattle?
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Transrectal palpation
Ultrasonography Hormonal tests |
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How big is the bovine fetus at:
2 mos 3 mos 4 mos 5 mos 6 mos |
2 mos - mouse
3 mos - rat 4 mos - small cat 5 mos - fat cat 6 mos - beagle |
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What are examples of hormonal tests for bovine pregnancy?
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Estrone sulfate
Pregnancy specific hormone B BioPRYN test Milk/serum progesterone (nonpregnancy) |
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When should ballotement be positive for pregnancy?
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6 mos
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What is the ultimate earliest that pregnancy can be detected by ultrasonography? How about realistically?
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9 day earliest
24 d realistically (heartbeat) |
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Fetal cortisol stimulates the release or increase of which maternal hormones?
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Estrogen
PGF2a Oxytocin Relaxin |
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How long should each stage of labor last?
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Stage 1 - 2 - 6 hrs
Stage 2 - < 2hrs (30-60min) Stage 3 - 2 - 8 (maybe 12) hrs |
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What is the Ferguson reflex?
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Pressure on cervix causes oxytocin release
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How can abortion be induced before day 150? After 150?
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<150 (use PGF)
>150 (use PGF + corticosteroid) |
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Every abortion should be regarded as a potential ____________.
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EPIDEMIC
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What is the cutoff between EED, abortion, and stillbirth?
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<42d = EED
>260d = stillbirth abortion in between |
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What is the typical abortion rate on a dairy? Stillbirth rate?
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Abortion = 10%
Stillbirth = 4-6% |
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What is probably the most important tissue in determining abortion etiology?
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chorioallantois and cotyledons
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Paired sera tests are useful when investigating which abortive agent?
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lepto!
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What is the #1 bacterial agent for abortions in cattle?
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Arcanobacterium pyogenes
(Bacillus spp. a close second) |
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What is the #1 viral agent for cattle abortions?
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BHV-1 (IBR)
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T or F:
Dam infection with BVD post 170 d gestation can result in cerebellar hypoplasia, birth defects, and stunted growth. |
False! This describes >100d infection.
>170 d = normal calf + titer |
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A cow that loses her fetus via EED and shows post-coital pyometra is likely infected with...
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...trichomoniasis
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Segmental aplasia is more common in...
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...all-white shorthorned breed
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T or F:
Vaginal prolapse is almost always pre-partum. |
True!
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What is the common signalment for vaginal prolapse in the cow? How is this fixed?
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Pre-partum, fat, polled hereford in the cold
Fixed with the Buhner technique |
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Cervicovaginal prolapse is common in...
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...Santa Gertrudis and Beefmasters
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What is the definition of a cystic follicle?
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A dominant follicle, >17mm, that fails to ovulate and persists.
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How can a luteal cyst be differentiated from a cystic CL via transrectal palpation?
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Ovulation papilla in the cystic CL.
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What is the treatment for hypoplastic ovaries in cows?
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eat 'em (the cows not the ovaries)
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What is the endocrinological hallmark of a granulosa cell tumor in the cow?
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High levels of inhibin
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What are the signs of cystic ovarian disease?
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Anestrus
Nymphomania Masculinization (in chronic cases) |
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What is the incidence of cystic ovarian disease? How is it treated?
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12%;
Treat with GnRH or hCG, PGF, Ovsynch, CIDR, or combo |
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How is pyometra treated?
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Get rid of the CL
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Choose hydrallantois or hydramnios...
...more common |
Hydrallantois (90%)
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Choose hydrallantois or hydramnios...
...occurs rapidly. |
Hydrallantois
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Choose hydrallantois or hydramnios...
...fetus doesn't or can't swallow amniotic fluid. |
Hydramnios
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One of the most life threatening emergencies to the cow is..
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...UTERINE PROLAPSE
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