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Reproductive Management in Beef Cattle Estrous Synchronization and AI

Reproductive Management in Beef Cattle Estrous Synchronization and AI. Richard F. Randle, DVM, MS Beef Extension Veterinarian University of Nebraska, Lincoln. U.S. Beef Cattle Inventory 2007 Census of Agriculture. The U.S. Beef Herd. 69% of cow-calf enterprises are secondary income sources

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Reproductive Management in Beef Cattle Estrous Synchronization and AI

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  1. Reproductive Management in Beef CattleEstrous Synchronization and AI Richard F. Randle, DVM, MS Beef Extension Veterinarian University of Nebraska, Lincoln

  2. U.S. Beef Cattle Inventory2007 Census of Agriculture

  3. The U.S. Beef Herd • 69% of cow-calf enterprises are secondary income sources • 50% of producers report an established breeding season of specific duration • 34% of beef herds are routinely pregnancy checked • 10% of beef cattle enterprises utilize AI From NAHMS Survey, 1998

  4. Reasons for not Using Reproductive Procedures From NAHMS Survey, 1998

  5. Meeting the Demand? Having the correct genetics is becoming highly important to meeting industry demands Correct genetics imperative to achieving premium dollars and enhancing returns on investment

  6. A changing market structure that recognizes and rewards quality . . . • AI allows beef producers to use high accuracy proven sires … • BW and calving ease • Weaning and yearling growth • Carcass traits • Replacement females

  7. AI provides the opportunity to make genetic progress andadd value faster

  8. Effective Estrus Synchronization Programs • 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 • More cows and heifers becoming pregnant early during the breeding season • Result in older and heavier calves at weaning • Beneficial effects on the next breeding season • More days postpartum at the next breeding season • Replacement heifers will be older

  9. Improvements in methods to synchronize estrus create the opportunity to significantly expand the use of AI in the U.S. cowherd...

  10. Estrous Cycle • Length of the estrous cycle • Average 21 days (range 18 to 24 days) • Estrus (standing heat) • 12 to 18 hours (range 8 to 30 hours) • Ovulation • Approximately 30 hours after the beginning of standing heat.

  11. LH surge onset of heat LH level Estradiol Progesterone Day of cycle 2 4 6 8 10 12 14 16 18 20 2 4 6 8 10 12 14 16 18 20 2 20/0 Follicular Luteal Follicular Luteal *Two full cycles and start of a third

  12. LH surge onset of heat CL LH level Progesterone Day of cycle 2 4 6 8 10 12 14 16 18 20 2 4 6 8 10 12 14 16 18 20 2 20/0 *Two full cycles and start of a third Estradiol Follicular Luteal Follicular Luteal

  13. Corpus Luteum (CL)Growth and Regression Ovulation Growth Regression Estrus Estrus 0 2 4 6 8 10 12 14 16 18 20 0 Day of the Estrous Cycle

  14. Estrus Estrus 0 2 4 6 8 10 12 14 16 18 20 0 NO NO Prostaglandin F2 PG regresses CL YES Day of the Estrous Cycle

  15. Follicle DevelopmentFollicular Wave Regression Dominance Growth Selection Next Recruitment Recruitment Follicle development occurs as a wave-like pattern consisting of “Recruitment”, “Selection”, “Growth”, “Dominance”, and “Regression” phases. Usually 2 to 4 follicular waves occur during the estrous cycle in cattle

  16. Typical Pattern of Follicular Growth in Lactating Dairy Cows

  17. 0 2 4 6 8 10 12 14 16 18 20 0 Follicle Development During the Estrous CycleExample for 2 Follicular Waves Ovulation Ovulation Estrus Estrus Day of the Estrous Cycle Length of the estrous cycle in cattle with 2 follicular waves is typically 18 to 20 days, slightly shorter than the estrous cycle with 3 follicular waves

  18. LH surge onset of heat LH level Progesterone Day of cycle 2 4 6 8 10 12 14 16 18 20 2 4 6 8 10 12 14 16 18 20 2 20/0 *Two full cycles and start of a third Estradiol Follicular Luteal Follicular Luteal

  19. GnRH • Induces ovulation • Synchronizes follicular waves • Induces formation of a CL

  20. How Does GnRH Induce Ovulation?GnRH, LH surge, and Ovulation GnRH Injection Ovulation LH Surge 2 to 4 24 to 30 0 GnRH induces LH surge within 2 to 4 hours If cattle have large, healthy follicles, ovulation will be induced approximately 24 to 30 hours after GnRH injection without estrous behavior Hours after GnRH injection

  21. NO NO NO > 10 mm How Does GnRH Induce Ovulation?Relationship between Follicular Waves and GnRH YES YES YES GnRH injection can induce ovulation in large, healthy follicles more than 10 mm in diameter Diameter of follicles are based on the data from ultrasonographic examination GnRH injection cannot induce ovulation in smaller follicles, less than 10 mm in diameter (premature) and regressing follicles (aged and not healthy)

  22. LH surge onset of heat LH level Progesterone Day of cycle 2 4 6 8 10 12 14 16 18 20 2 4 6 8 10 12 14 16 18 20 2 20/0 *Two full cycles and start of a third Estradiol Follicular Luteal Follicular Luteal

  23. Effect of a Progestin

  24. Effective Synchronization • Physiology and Biology • Synchronization of follicular waves • Induction of ovulation • Management of the CL lifespan • Initiation of estrous cyclicity

  25. Effective Synchronization • Effective Products Available • GnRH • Cystorelin®, Factrel®, Fertagyl®, OvaCyst®, GonaBreed® • Prostaglandin • Estrumate®, In-Synch®, Lutalyse®, Prostamate® • Progestogens • MGA®, Eazi-Breed CIDR®

  26. Resurgence in Research on Estrus Synchronization

  27. Resurgence in Research on Estrus Synchronization Ultimate goal is fixed-time AI with acceptable pregnancy rate!

  28. Applied Reproductive Strategies in Beef Cattle Beef Reproduction Task Force http://beefrepro.unl.edu

  29. Beef Reproduction Task Force • Review of the literature • Comparison of protocols • Beef Heifers • Heat detection protocols • Heat detection + timed AI protocols • Fixed-time AI protocols • Beef Cows • Heat detection protocols • Heat detection + timed AI protocols • Fixed-time AI protocols

  30. Comparison of ProtocolsCows

  31. Comparison of ProtocolsHeifers

  32. Synchronization and Natural Service Use a protocol that uses heat detection Use smaller breeding pastures or lots to reduce travel Use young mature bulls that are active known breeders Make sure pecking order is established Use bull to female ratio of 1:15 to 1:25

  33. Synchronization and Natural Service Bulls in PG 1 Shot- PG 0 5 45 Natural Service Treatment day Larson DM, Musgrave JA, Funston RN, University of Nebraska

  34. Estrus Synchronization:Planning for Success

  35. Plan the work. Work the plan! Expectations for synchronization protocol. Is the herd suited for synchronization protocol? Labor needs . Number of time through the chute. Synchronization costs. Handling facility capabilities. Impact on calving distribution. Record system.

  36. Synchronization Expectations • Survey of recent results from today’s mainstay protocols • 10 trials with 2,970 females from 34 different experimental groups • Average Synch preg. rate = 50.5% (8 to 66%) • 26% of groups > 60% synch preg. rate • 50% of groups 40% to 60% synch preg.rate • 24% of groups < 40% synch preg. rate

  37. Synchronization Expectations Don’t expect great miracles. Do expect variation. • Survey of recent results from today’s mainstay protocols • 10 trials with 2,970 females from 34 different experimental groups • Average Synch preg. rate = 50.5% (8 to 66%) • 26% of groups > 60% synch preg. rate • 50% of groups 40% to 60% synch preg.rate • 24% of groups < 40% synch preg. rate

  38. Conception Rate Formula (Cow fertility) X (Heat detection) X (Semen fertility) X (AI technique) Fail at any one of these and kiss success goodbye!!

  39. Heat Detection Protocols

  40. Standing Estrus Perry, GA: South Dakota State University

  41. Estrous Detection

  42. Estrous Detection • Detection aides • Kmars • Chinball markers • Gomer bulls • Tail chalk • HeatWatch

  43. Synchronization is an Investment • Labor • Facilities • Management • Dollars • In round numbers • Budgeted costs for synch programs can range from $20 to $40 per synchronized female

  44. Is the Herd a Good Candidate? • Fertility rate • Calving distribution • Cow age • Body condition • Calving success • Replacement management

  45. Replacement Management Age Target Weight Reproductive tract scores Breed 20 days prior to cows

  46. Cow AgeHeifers take 20 days longer to cycle… Johnson and Stevenson, KSU

  47. Calving Distribution

  48. Body Condition Score CS = 4 CS = 6 Daryl Strohbehn, Iowa Beef Center

  49. Body Condition Score A Barometer of the Nutrition Program CS = 4 CS = 6 Major Influence on Start of Cyclicity Daryl Strohbehn, Iowa Beef Center

  50. Effect of BCS at Breeding on % Cycling CS <3.5 25% CS 4-4.5 40-48% CS 5-5.5 58-72% CS 6 80% or more Daryl Strohbehn, Iowa Beef Center

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