Repro2- Ovsynch

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Repro2- Ovsynch
2015-10-07 10:44:00
vetmed repro ovsynch

vetmed repro
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  1. Advantages of manipulation of the estrous cycle. (4)
    improves efficiency of heat detection, facilitates use of AI, allows use of fixed time AI, improves overall repro efficiency
  2. Disadvantages of manipulation of the estrus cycle. (2)
    variable response to treatment, concentration of AI and parturition
  3. The cow is receptive for a _______ period during estrus.
  4. In cattle, day 0 of the cycle is...
    the day estrus is detected.
  5. The onset of estrus coincides with the _______.
    LH surge
  6. When is the refractory period of the CL? What is the significance of this period?
    first 5 lays after ovulation; will not respond to PGF2α shot
  7. Estrus occurs ______ days after ________.
    2-5; luteolysis
  8. Dose for Dinoprost (Lutalyse).
    25mg IM
  9. Dose for Cloprostenol (Estrumate).
    500μg IM
  10. After PG shot, which is given in the _________ phase, there is a rapid decrease in _________ and an increase in ________.
    mid-luteal; progesterone; gonadotropin
  11. How do prostaglandin shots work?
    CL produces progesterone, which blocks heat and ovulation; PG causes premature luteolysis, allowing cycle to continue
  12. The time to response to a PGF2α shot depends on ___________.
    stage of follicular wave
  13. Describe a one PG injection system.
    give all cows PG--> heat check and AI in the next 2-5 days--> day 6, give PG to all cows that did not get AI--> heat check and AI in next 2-5 days--> repeat
  14. Describe a two PG injection system.
    [palpation] PG shot to all cows with CL--> heat check and AI in 2-5 days--> PG shots to all cows who did not get 1st PG shot in 11-14 days--> heat check and AI cows who got 2nd shot in next 2-5 days--> preg check and repeat
  15. At the onset of estrus behavior, there is a(n) __________, which is brought on by a(n) __________.
    LH surge; spike in GnRH from the hypothalamus
  16. Describe the series of events that occur when you give GnRH to a cow with a pre-ovulatory follice in estrus.
    follice has LH receptors--> GnRH causes LH surge--> ovulation
  17. Describe the series of events that occur when you give GnRH to a cow with a pre-ovulatory follice in diestrus.
    there is increase progesterone, which usually prevents ovulation--> GnRH causes lutinization of follice and onset of a new follicular wave--> NO FERTILE FOLLICLE TO OVULATE
  18. When progesterone is high, during _________, giving GnRH causes... (3)
    diestrus; follicle to ovulate but it is not fertile, reseting of follicular wave, start of Co-synch.
  19. When progesterone is low, during _________, giving GnRH will cause... (2)
    proestrus; fertile ovulation, success with timed AI.
  20. Describe the ovsynch protocol.
    GnRH shot (causes ovulation or lutinization depending on stage of cycle-reset follicular wave)--(7 days)--> PGF shot (lutinization of 5-7 day CL)--(2 days)--> GnRH (ovulate fertile follicle)--(16hr)--> timed AI
  21. With the ovsynch protocol, a fertile follicle should be ovulated within _______ of the _______ injection.
    28hrs; second GnRH
  22. What is the diference b/w cosynch and ovsynch?
    Cosynch- inseminate at same time as second GnRH shot; Ovsynch- inseminated 16-18hrs after second GnRH shot
  23. What are the results of long term progesterone treatment? {14-16 days} (4)
    prevention of LH surge, persistent (old) follicle, changes in uterine environment, reduced fertility until next cycle
  24. What are the results of short-term progesterone treatment? {7 days} (3)
    natural CL may outlast the treatment, inadequate control of cycle, acceptable fertility
  25. What is the method of choice for cycle control of heifers?
    short-term progesterone txt (CIDR) and PGF injection
  26. How do progestins work? (2)
    progesterone from a progestin source blocks heat and ovulation, progestin blocks estrus (even in cows who naturally regress their CL)
  27. CIDR use and caveat?
    induces estrous cycle in non-cycling cows; caveat- may be showing heat on a persistent/reduced fertility follicle
  28. The _________ in a persistent follicle is infertile; avoiding breeding cows that have been on more than ________ of ________ treatment.
    oocyte; 8 days; progestin (progesterone)
  29. What is the preferred protocol for cows/heifers that are not cycling?
    7 days of pregestin treatment--> PGF injection (lyse CL)
  30. What is the CIDR protocol that excludes use of GnRH?
    CIDR--(7 days)--> PGF shot--> heat check and AI cows in heat within 5 days of PGF
  31. What is the CIDR protocol that include GnRH injections?
    GnRH (ovulate follicle) + place CIDR--(7 days)--> PGF shot--> heat check and AI cows in heat within 3 days --> second GnRH shot and fixed time AI in 72 hours for cows not already bred
  32. Synthetic progesterone that is given as an oral supplement for 14 days; often used for heifers.
    melengestrol acetate (MGA)
  33. High _______ inhibits ovarian activity; therefore, in some beef herds, they do __________ to decrease _________ and induce _________.
    prolactin; 48hr weaning of 1-2month old calves; prolactin; estrous cycle in beef cows