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62 Cards in this Set

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  • Back
What are the 2 phases of the estrous cycle?
The 4 stages?
Follicular phase (proestrus + estrus)
Luteal phase (metestrus + diestrus)
How long is the normal bovine estrous cycle?
The follicular phase is dominated by___________ while the luteal phase is dominated by _____________.
follicular = estrogen
luteal = progesterone
How long (average) is estrus in a cow?
15 hours (6-24h)
How long (average) after the beginning of estrus does ovultation occur?
24 - 32h
Put the following in the correct order in the bovine estrous cycle:
LH peak
FSH peak
Estrogen peak
Estrogen peak
FSH peak
LH peak
How long after ovulation does the CL normally form in the cow?
Usually 3-5 days; mature by day 7
What are some advantages to estrus synchronization in beef cattle?
AI efficiency
Labor effeciency
More uniform offspring crop
Can shorten breeding season
What are advantages for estrous synchronization in dairy cattle?
Reduce need for heat detection
Circumvents cystic ovarian disease
May induce fertile ovulation in anestrous cows
What are the three hormone classes available to use in estrus synchronization?
Which drugs are used to control the luteal phase? What is the mechanism for each?
Progestins (MGA or CIDR) prolong the luteal phase.
PGF2a (Lutalyse, Estrumate) shorten the luteal phase and induce luteolysis.
How long after PGF2a administration should ovulation occur? This only occurs if what is extant?
Ovulation occurs in 2-5 days ONLY if a CL is already there!
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)
After PGF2a is released (or administered), how quickly should the CL regress?
Within 2 days
Describe the drugs used and timing of the Ovsynch protocol.
day 0 - GnRH
day 7 - PGF2a
day 9 - GnRH
breed or AI 16 hrs
Describe the two methods using only PGF2a for estrus synchronization?
d0 - PGF2a; d5 heat check/AI

d0 - PGF2a; d5 heat check/AI; d14 - PGF2a; heat check d16-19
Which drugs control ovulation time?
Approximately what percentage of cows should show estrus after PGF2a injection? How long should this take?
75% of CYCLING cows should show estrus in 2-5 days
At what point in the cycle should Ovsynch be started for maximum efficacy? How can this be ensured?
Start Ovsynch at day 5-10.
Ensure with Presynch; using PGF2a at days 0 and 14, then starting Ovsynch at day 26.
Describe the hormones administered and administration times for the Co-synch program.
d0 - GnRH
d7 - PGF2a
d9 - GnRH + timed AI
How can Cosynch pregnancy rates be increased by 9%?
separate calves from dam when PGF2a is given
Why do post-parturient beef cows typically have a short cycle?
No progesterone priming
Which synch protocol is best used on heifers?
Melengesterol Acetate (MGA) synch
How long should MGA be fed to heifers? When should they be bred?
Feed 14-18d
Breed d35 - 37 (after giving PGF2a on d33)
What does CIDR stand for? What does it contain?
Controlled Intravaginal Drug Release; contains progesterone
What is the best synch protocol to get them heifers bred!?
5-day CIDR synch gives 58.3% preg rate
T or F:
AI is the method of choice for the beef and dairy industry.
60% AI in dairy; 6% in beef
What are 6 factors that are required when breeding via AI?
Efficient record system
Well designed facilities
Good nutrition
Good general health program
Accurate heat detect/synch
Well-trained AI tech
What are the positive signs of pregnancy perceivable via transrectal palpation? When should each be felt?
Amniotic vesicle (35-60d)
Fetal membrane slip (30-35d)
Fetus (60 - 65d)
Placentomes (80-90d)
Fremitus (120-150d)
What are the major methods of pregnancy determination in cattle?
Transrectal palpation
Hormonal tests
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
What are examples of hormonal tests for bovine pregnancy?
Estrone sulfate
Pregnancy specific hormone B
BioPRYN test
Milk/serum progesterone (nonpregnancy)
When should ballotement be positive for pregnancy?
6 mos
What is the ultimate earliest that pregnancy can be detected by ultrasonography? How about realistically?
9 day earliest
24 d realistically (heartbeat)
Fetal cortisol stimulates the release or increase of which maternal hormones?
How long should each stage of labor last?
Stage 1 - 2 - 6 hrs
Stage 2 - < 2hrs (30-60min)
Stage 3 - 2 - 8 (maybe 12) hrs
What is the Ferguson reflex?
Pressure on cervix causes oxytocin release
How can abortion be induced before day 150? After 150?
<150 (use PGF)
>150 (use PGF + corticosteroid)
Every abortion should be regarded as a potential ____________.
What is the cutoff between EED, abortion, and stillbirth?
<42d = EED
>260d = stillbirth
abortion in between
What is the typical abortion rate on a dairy? Stillbirth rate?
Abortion = 10%
Stillbirth = 4-6%
What is probably the most important tissue in determining abortion etiology?
chorioallantois and cotyledons
Paired sera tests are useful when investigating which abortive agent?
What is the #1 bacterial agent for abortions in cattle?
Arcanobacterium pyogenes
(Bacillus spp. a close second)
What is the #1 viral agent for cattle abortions?
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
A cow that loses her fetus via EED and shows post-coital pyometra is likely infected with...
Segmental aplasia is more common in...
...all-white shorthorned breed
T or F:
Vaginal prolapse is almost always pre-partum.
What is the common signalment for vaginal prolapse in the cow? How is this fixed?
Pre-partum, fat, polled hereford in the cold
Fixed with the Buhner technique
Cervicovaginal prolapse is common in...
...Santa Gertrudis and Beefmasters
What is the definition of a cystic follicle?
A dominant follicle, >17mm, that fails to ovulate and persists.
How can a luteal cyst be differentiated from a cystic CL via transrectal palpation?
Ovulation papilla in the cystic CL.
What is the treatment for hypoplastic ovaries in cows?
eat 'em (the cows not the ovaries)
What is the endocrinological hallmark of a granulosa cell tumor in the cow?
High levels of inhibin
What are the signs of cystic ovarian disease?
Masculinization (in chronic cases)
What is the incidence of cystic ovarian disease? How is it treated?
Treat with GnRH or hCG, PGF, Ovsynch, CIDR, or combo
How is pyometra treated?
Get rid of the CL
Choose hydrallantois or hydramnios...
...more common
Hydrallantois (90%)
Choose hydrallantois or hydramnios...
...occurs rapidly.
Choose hydrallantois or hydramnios...
...fetus doesn't or can't swallow amniotic fluid.
One of the most life threatening emergencies to the cow is..