Jeffrey S. Stevenson, Ph.D .

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Department of Animal Sciences and Industry. Ontario Association of Bovine Practitioners Reproductive Symposium. Improving Pregnancy Rates. Jeffrey S. Stevenson, Ph.D. Objective. Maximize number of pregnancies achieved each week! PR = S ubmission R ate C onception R ate Example: - PowerPoint PPT Presentation


<ul><li><p>Jeffrey S. Stevenson, Ph.D.Improving Pregnancy RatesOntario Association ofBovine PractitionersReproductive Symposium</p></li><li><p>ObjectiveMaximize number of pregnancies achieved each week!</p><p>PR = Submission Rate Conception RateExample:Herd #1: PR = 50% SR 30% CR = 15%</p><p>Herd #2: PR = 70% SR 30% CR = 21%</p></li><li><p>Pregnancy Rate FactorsSubmission ratesHeat detectionTAI programs for first servicesFrequency of open checksResynchrony of repeat servicesConception ratesProper handling and placement of semenDry matter intakeCycling statusEnergy balanceFeed supplementsUse of rbSTUse of PresynchLength of VWPHerd health programsSire fertility</p></li><li><p>Increasing Submission RatesHeat detectionTAI programs for first servicesFrequency of open checksResynchrony of repeat servicesIncreasing submission rates . . .</p></li><li><p>+20+40Fertile egg lifeOvulationStanding heat027 h2040Secondary heat signsNormal fertile sperm lifeCorrect Timing of AIAIIncreasing submission rates . . . </p></li><li><p>Standing Activity is a Function of the Number of Cows in EstrusMore mounted cows (90%) are in estrus than mounting ones (79%)Standing events ranged from 1 to 179Inclination to mount is stage-of-cycle dependentIncreasing submission rates . . . Hurnik et al., 1975</p><p>Source: Hurnik et al. (1975) Appl. Anim. Ethol. 2:55</p></li><li><p>Stage of Cycle and Mounting ActivityIncreasing submission rates . . . </p><p>Source: Helmer and Britt (1985) JDS 68:1290</p><p>Stage of cycle</p><p>% of</p><p>heifers</p><p>( attempted mounts</p><p>% attempted mounts</p><p>Luteal</p><p>Preestrual</p><p>Estrual</p><p>Postestrual</p><p>48.3</p><p>15.4</p><p>8.8</p><p>27.5</p><p>56</p><p>203</p><p>717</p><p>96</p><p>5.2</p><p>18.9</p><p>66.9</p><p>9.0</p><p>Total</p><p>100.0</p><p>1072</p><p>100.0</p></li><li><p>Housing and FootingMaximize the number of nonpregnant cows housed together to increase heat detection efficiencyDuring estrus cows prefer to spend 73% of their time on dirt than on concreteMounting activity increases 3-15 fold when cows are on dirtDuration of estrus and standing activity is greater for cows on dirtBritt et al., 1986Increasing submission rates . . . </p></li><li><p>Ovsynch ProtocolGnRHPGF27 days48 hGnRHCL(s)regresses0 24 hTAILHsurgeovulatesDominantfollicle24-34 hIncreasing submission rates . . . </p></li><li><p>GnRH + PGF2 + Heat Detection (Control) vs. Ovsynch during SummerIncreasing submission rates . . . Cartmill et al., 2001</p><p>Item</p><p>Control</p><p>Ovsynch</p><p>Cows attempted to A.I. </p><p>218</p><p>207</p><p>A.I. submission rate, %</p><p>58.7</p><p>100</p><p>Conception rate, %</p><p>32.0</p><p>33.3</p><p>Pregnancy rate*, %</p><p>17.9</p><p>33.3</p><p>GnRH = Fertagyl</p></li><li><p>Frequency of Pregnancy Checks*Assumes palpation begins at 35 days and ultrasound at 28 days of pregnancy, respectively.Increasing submission rates . . . </p></li><li><p>Pregnancy CheckGnRHAIPGFM M W Th7 daysGnRHRebreeding OptionsAIConcentrated heat detection 21-25 days after AIApplying Ovsynch to Open CowsIncreasing submission rates . . . </p></li><li><p>Pregnancy CheckGnRHAIPGFM M W Th7 daysGnRHRebreeding OptionsAIStarting Ovsynch 7 days before Preg ChecksConcentrated heat detection 21-25 days after AIIncreasing submission rates . . . </p></li><li><p>Pregnancy diagnosis by ultrasonographyCosynch TAI 0 Day 19 26 28 29 GnRHGnRHTAIPGFResynch before Pregnancy DiagnosisFricke et al., 2003 0 Day 26 33 35 36 0 Day 33 40 42 43 Day 19Day 2642%a (n = 240)34%b (n = 121)Day 3333%b (n = 236)38%b (n = 143)46%a (n = 235)23%a (n = 120)Trt1st TAI2nd TAI(n=711)Increasing submission rates . . .</p></li><li><p>2025 33 40 42 43 GnRHGnRHTAIPGFGnRHAIPGFGnRHGnRH+ AIPGFPGFPGFGnRHW W M M ThM M W ThPresynch + OvsynchOvsynchDays after AI*Pregnancy diagnosisM M W ThHeat checksAll cowsOpen cows14 days12 days7 days7 daysetc.3 days7 daysAI Breeding with No Heat Detectionor</p></li><li><p>Increasing Conception RatesProper handling and placement of semenDry matter intakeCycling statusEnergy balanceLength of VWPHerd health programsSire fertility</p></li><li><p>Handling SemenSemen handling: Cold shock?Thaw too many straws at one time?Cleanliness of AI equipmentFatigue: Too many cows to AI at one time?Semen placementIncreasing conception rates . . . </p></li><li><p>Conception Rates after First AIat Various Postpartum IntervalsBritt, 1975 (8 studies)</p></li><li><p>n=262 73-81 DIMn=148 73-81 DIMn=142 73-81 DIM2-yr-oldsOlder cowsMilk yield (lb) at 35 DIMTenhagen et al. (2003)Milk Yield Groups6688Increasing conception rates . . . </p></li><li><p>n = 148 Tenhagen et al. (2003)Low-Producing Cowsn = 153Days in Milk at Ovsynch Timed AI*P &lt; 0.05*Increasing conception rates . . . </p></li><li><p>n = 128 Days in Milk at Ovsynch Timed AITenhagen et al. (2003)High-Producing Cowsn = 142*P &lt; 0.05*Increasing conception rates . . . </p></li><li><p>Sire FertilityEstimated Relative Conception Rate (ERCR)Ranking of sires relative to other sires (herds in midwest, east, and south U.S.)Based on 70-day non-return rateRanges from 5 to +4 for Holsteins and 7 to +4 for Jerseys (May, 2004)Go to Click on Bull Fertility SummaryGenerally accurate ranking of sire fertility</p><p>Increasing conception rates . . .</p></li><li><p>Sire FertilityAgriTech Analytics (5545 Avenida de los Robles, Visalia, CA 93291; tel: 800-532-0900 or 559-738-5300; fax: 559-738-5321)Ranking of sires relative to other sires (herds in western U.S. only). Based on actual pregnancy diagnosesRanges from 9 to +6 for Holsteins (April, 2004). Data for Jerseys are available (5-star system)Most accurate ranking of actual sire fertility Available for a nominal fee to any dairy producerIncreasing conception rates . . .</p></li><li><p>AI4 to 9 dayspost-AIPregnancy diagnosishCG (3.3 mL of Chorulon)GnRH (2 mL of Fertagyl) Control11 to 16 dayspost-AI24 to 47 dayspost-AI38 to 78 dayspost-AICIDRAIAIAIExperimental Design</p></li><li><p>Percentage of Cows with Induced CL (Exp. 1) **Different from control (P &lt; 0.001)*n = 41n = 41n = 40n = 40Stevenson et al. (2006)</p></li><li><p>*n = 190n = 182n = 194n = 187Change in Concentrations of Progesterone in Serum (Exp. 1)*Different from control (P &lt; 0.001)Stevenson et al. (2006)</p></li><li><p>Conception Rates after Post-AI Treatments of P4 (CIDR insert), GnRH, and hCG (Exp. 2)Different from control (P &lt; 0.10; *P &lt; 0.05; **P &lt; 0.01).1A tendency (P = 0.11) for a treatment herd interaction.Stevenson et al. (2006)</p><p>TreatmentHerdControlCIDRGnRHhCG--------------------- % (no. of cows) --------------------131.7 (41)50.1 (40)32.6 (40)38.7 (38)226.0 (158)30.8 (158)28.6 (159)34.0 (158)326.9 (143)40.3** (162)31.3 (153)37.8* (153)433.8 (206)23.4* (204)29.8 (209)33.7 (209)523.8 (160)22.3 (147)20.2 (158)25.6 (156)Total128.3 (708)32.7 (711) 28.1 (719)33.6* (714)</p></li><li><p>n = 36n = 216n = 695n = 843n = 1,017n = 45Conception Rates by Day of Treatment (Exp. 2)Stevenson et al. (2006)</p></li><li><p>The bottom line .. is the number of pregnancies produced per unit of time.How does one measure the success of the AI-breeding program?</p></li><li><p>No. of Services and PregnanciesNumberWeek of yearWeeklyPreg. Goal</p></li><li><p>Thank you!Ontario Association ofBovine PractitionersReproductive Symposium</p><p>582101</p></li></ul>


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