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Estrus synchronization in cattle

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protocol of estrus synchronization

protocol of estrus synchronization

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  • Estrous synchronization is a useful part of an artificial insemination program because checking for estrus in breeding animals, particularly under range conditions, is time consuming.and expensive.
  • Estrous synchronization is a useful part of an artificial insemination program because checking for estrus in breeding animals, particularly under range conditions, is time consuming.and expensive.
  • Without estrus synchronization about 1/3 of the cycling animals come in heat during the first week of the breeding period. Only 65 to 70% of them conceive to a given insemination. Thus, after a week of breeding to natural heats, only 21% of the eligible animals could possibly be pregnant (33% in heat x 65% conception). Because many animals may not have resumed normal cycling activity, the actual pregnancy rate during the first week of the breeding period will likely be considerably less. Many estrus synchronization protocols can induce 75 to 90% of the cycling animals to display estrus within a 5 day period. Additionally, many protocols can induce a fertile heat in as much as 50% of the anestrous cows. Thus, it is typical for many of these synchronization protocols to result in 45 to 55% of the animals being pregnant by the end of the first week of the breeding period (Figure 1). Several fixed-time AI options can result in 40 to 50% of the cows pregnant following one single day of breeding with zero hours spent for heat detection. Cows that display estrus during the first week of the breeding period will have 3 opportunities to conceive during the first 45 days while those who don’t will have 2 or less. Also, cows that do not respond to estrus synchronization may be problem animals. Early identification of problem cows allows appropriate veterinary therapy to be administered in a timely fashion and reduces the potential for excessive days open.
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    • 1. Estrus Synchronization in Cattle Abstract
    • 2. Keep in mind that,Neither success nor failure is ever final. Roger W Babson 3
    • 3. Estrus is the period during which animal stand and accept the advances of male for mating. The series of event that occur between two successive estrus is called estrus cycle. These events are: Day O: Female in heat & have dominant follicle on one of her ovaries. E2 Day 1: Rupture of dominant follicle (~28hr) & rupture follicles start to luteinize . E2 P4Illustration of estrus cycle of a cow Day 5: Functional CL. P4 4
    • 4. Gonadotropin releasing hormone(GnRh), luteinizing hormone (LH)and follicle stimulating hormone(FSH) allow final maturation of newfollicles on the ovaries.Estrogen results in +ve feedbackmechanism.Progesterone blocks this mechanism. Fig: Hormonal regulation of reproduction in cattle Source: Intervet 5
    • 5. Estrus Synchronization involves inmanipulating the estrous cycle within aherd to express estrus approximately atthe same time.A labor saving breeding managementtool effective in artificial inseminationand embryo transfer program.Success depend upon a producersunderstanding of how it works.
    • 6. 1. Shorten the AI breeding season.  Cows or heifers are in estrus during a predictable interval that facilitates AI.  Reduce time and labor required to detect estrus.2. Result in more cows and heifers becoming pregnant early during the breeding season.  Progestin-based programs can induce estrous cyclicity in anestrous cows and prepubertal heifers. 7
    • 7. Basic approach is to control the timing of the onset of estrusis by controlling the length of the estrous cycle. Variousapproaches for controlling estrus cycle length are:1. Administration of prostaglandin to regress the corpus luteum of the animal before the time of natural luteolysis.2. Administration of progesterone or synthetic progestins to temporarily suppress the ovarian activity.3. Using gonadotropin releasing hormone (GnRH)which causes ovulation of a large follicle. This help in synchronizing estrous cycle in anoestrous female.
    • 8. One Shot ProstaglandinInject all females with prostaglandin on Day 0 Check for estrus & breed all females in standingand check for estrus & breed 12 hours after estrus for the 1st 5 days of the breeding season.standing estrus. Inject all females with prostaglandin not75% of the cycling females would be expected previously bred at the end of day 5 and breedto display estrus during the next 2 to 5 days. after 12hr of standing heat.Anestrous cows, will not respond to this Cyclic cow display estrus within 2 to 5 days afterprostaglandin protocol because they do not the prostaglandin injection.have a CL present on the ovary Result >90% of cyclic females being inseminated during the first 10 days of the breeding season. 9
    • 9. Two Shot ProstaglandinInject prostaglandin to all cows . Two injections of prostaglandin are given 10-12days apart.75% of the cyclic females come to heat after one Detection of estrus is not required before or betweeninjection within next 5 days and inseminate after injections.12hrs. All cyclic cows should respond to the second injectionsThe females not detected in heat and bred after the regardless of what stage of the estrous cycle they were infirst injection should receive a second prostaglandin when the first injection was administered.injection 11 or 14 days later and be bred 12 hours after Second injection 14 days after the first injection hasthey display standing estrus. resulted in more females exhibiting estrus. 10
    • 10. Synchronization of estrus with progestogens maintain high levels ofprogesterone in the female’s system, even after the regression of thecorpus luteum.Synchrony of estrus occurs 2-5 days following progestin removal.Commercial product that fall into this category are MelengesterolAcetate (MGA, oral feeding), Syncro-Mate-B (Ear Implant) and CIDR(Intra-vaginal device).Estrus was synchronized in only 48% of the cows treated on d3, butthe synchronization was 100%when treated on d9 of the estrouscycle.Longer the progestin was administered to cattle, the higher rate ofestrus synchronization, but the lower the fertility of the synchronizedanimals. 11
    • 11.  MGA is fed at .5 mg/head/day for 14 days. Exhibit estrus 2-5 days after withdrawal of the MGA. The estrus that occurs immediately after MGA feeding subfertile so not to breed female. A single injection of prostaglandin is administered 17 (or 19 days) days after the MGA has been removed from the feeding program. Exhibit estrus 48 - 72 hours after the PGF2a injection. Inseminate females 12 hours after standing estrus. Inducing estrous cycles in some non cyclic female. 12
    • 12. CIDR contains 1.38 g progesterone. Day 0: Placing CIDR in vaginaDesigned to maintain elevated blood Day 6: Inject 5ml prostaglandinconcentration of progesterone to at least 2ng/mlfor up to 10days. Day 7: Remove CIDRRemoval CIDR decrease plasma PGF, triggering Days 8 - 11: Detect heat & inseminateestrus within 3-4 days.Detect heat & inseminate from days 8 to 11.The progestin CIDR induce estrous cycles inanestrous cows & advance puberty in heifers.The majority of the females that respond to thisprotocol will exhibit estrus between 25 and 72hours after the prostaglandin injection. 13
    • 13. Recently developed protocolGnRh causes regression or ovulation of Day 1: GnRH used to programthe dominant follicle and initiates the follicle growth in cyclic females and to induceemergence of a new wave of follicular ovulation in anestrousgrowth in avg. 2.5 d following treatment. females.Control time of ovulation more exactly Day 8: PGF used to inducesand allow a single timed insemination regression of CL that arewithout the need for of estrus detection. present to cause a decline in progesterone.Four system for synchronization of estrus Day 10-11: GnRH induces ovulation ofwith GnRH-PG combinations are dominant follicles thatOVSYNCH, COSYNCH, SELECT SYNCH and pre-programmed by theHYBRID SYNCH. first GnRH treatment. 14
    • 14. Day 0: Inject GnRH to program follicle Estrus following GnRH is fertile and cows growth in cyclic females and to induce can be inseminated. ovulation in anestrous females. The prostaglandin injection is not Day 7: Inject PGF used to induces necessary in cows that have already regression of CL Day 6-13: Check for estrus and inseminalte. exhibited estrus and not yet bred, but will not cause any harm, either. Do not inject prostaglandin in females that have been bred after the GnRH injection. Timed insemination is not recommended 15 when using this protocol.
    • 15.  The protocol builds on the basic Day0: Inject GnRH GnRH-PGF format by adding a Day 7: Inject PGF second GnRH injection 48 hours Day 9: Inject GnRH (after 48 hrs.) after the PGF injection. Day 11: Timed insemination 8 – 18 hr after the This second GnRH injection induces 2nd GnRH injection. ovulation of the dominant follicle recruited after the first GnRH injection. All cows are mass inseminated without estrous detection at 8 to18 hours after the second GnRH injection. 16
    • 16. MGA-GnRH-PG protocol: Administered MGA orally for 14 days. Inject GnRH 12 days after the withdrawal of MGA. Inject PGF2a 7d after the GnRH injection. 80% of the cows showed estrus within 48 to 96 hrs after PGF2a injection. 17
    • 17. 1. The most common use of the CIDR with GnRH based systems involves insertion of the CIDR on day 1, and withdrawal of CIDR on day 8.2. An injection of GnRH on day of CIDR insertion.3. The CIDR is kept in Sutu for seven days.4. On the day of CIDR withdrawal, an injection of prostaglandin is given.5. The second GnRH injection is given after two days of prostaglandin injection.6. Time breed 52- 56 hrs after PG 18
    • 18. Advantage of CIDR to GnRH – Based protocol1. Exposure to progesterone during the period between day 1 and day 8, result in normal cycle in previously anestrous cow.2. Withdrawal of a progestin induce on set of cycles in some anestrous females. So, the likelihood of an ovulation is enhanced.3. Early heat inherent to these systems are prevented. The progesterone released by the CIDR will prevent estrus and ovulation between days 1 and 9. 19
    • 19. Females exhibiting regular estrouscycles.Good health and good nutritionprogram.A willingness by producers to learnhow to use the product and program.Accurate and thorough detection ofestrus.Individual identification and accuraterecord keeping system. 20
    • 20. R. Islam. Synchronization of Estrus in Cattle: A Review. Vet World. 2011; 4(3):136-141N. E. David, P. J. timothy and C. W. Gary. 2001. Arthur’s Veterinary Reproductionand Obstetrics. Harcourt (India) Pvt. Ltd. 8th edition.Thatcher W.W, Moreira F, Santos J.E.P, et al: Effects of Hormonal Treatments onReproductive Performance and Embryo Production. Theriogenology 55:75-89,2001.L.E. Mc Donald.1989. Veterinary Endocrinology and Reproduction. Lea &Febiger, Philadelphia, London. 4th edition: 545-547 http://www.jarvm.com/articles/volllssl/LOPEZ.DJVN.htm http://digitalcommons.unl.edu/rangebeefcowsymp/150 http://beef.unl.edu 21
    • 21. 22
    • 22. 1. Does prolong use of hormone have got any adverse effect on the health of animal? Ans: Yes, hormone have got adverse effect on the health of animal if use in high dose for prolong period . Example: if progesterone is use for prolonged period give rise to persistent estrogen secreting follicle , premature resumption of meiosis of ova, etc. 23

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