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texasdairymatters.org       Strategies to Improve Reproduction        during Heat Stress in Dairy Cattle                  ...
Heat Stress in the U.S.                                                     New York losses ~$20 million                  ...
Effect of milk yield on seasonal variation                     in pregnancy rate in lactating dairy cows:                 ...
Fertilization Rate in Lactating Dairy Cows Exposed           or Not Exposed to Heat Stress                                ...
Heat Stress and Embryo Development  Susceptibility to HS Single         4-cell   Morula      Early                  Expand...
Day 15 – 19 Bovine Uterus                                                   PGF2α                 CL                      ...
Embryo Loss for Different THI    14                                                                           12    12    ...
Strategies to Reduce the Negative Effects              of Heat Stress                 •Bull Breeding vs. Timed AI         ...
NATURAL SERVICE VS. TIMED AI
Semen Quality Before, During and After               Heat Stress Breed                    Initial Motility                ...
Motile Sperm Before, During and        After Heat Stress                        Meyerhoeffer et al., 1985
Economic Comparison of NS vs AI                                  (Overton, 2005)•   60% of the time AI was more profitable...
Conclusion: Natural Service vs. AI• Reduced Genetic Progress and Profitability• Dangerous, cause lameness and injury• Bull...
SYNCHRONIZATION AND TIMED AI
Timed AI vs. Bred on Estrus during                       Summer    120      P < 0.01               100    100             ...
Timed AI vs. Bred on Estrus during                    Summer       100        P < 0.05                   P < 0.01         ...
Using TAI to Enhance Summer     Cumulative Pregnancy Rates    70         *P<.05; † P<.06                                  ...
INDUCED OVULATION WITH    GNRH AT ESTRUS
Daily Progesterone during Spring and      Summer in Holstein Cows                          No Heat Stress                 ...
Progesterone Concentration and Embryo Production of                         Interferon-τ                            12    ...
Effects of GnRH at Estrus on Fertility in                                 Dairy Cows during Summer                      60...
INDUCED ACCESSORY CL AFTER AI
Estrous Cycle                                                                               Ovulation                     ...
Effect of GnRH Agonist and hCG on Progesterone                                      Concentration in Dairy Heifers        ...
Effect of hCG/GnRH on d 4 or 5 post AI during        Summer on Conception Rates                                           ...
Effect of GnRH on d 5 or 11-15 post AI during        Summer on Conception Rates                                  P < 0.08 ...
Effect of GnRH on d 0 and d 12 post AI during        Summer on Conception Rates                                           ...
EMBRYO MANIPULATION AND       TRANSFER
Heat Stress and Embryo Development                                                    Embryo Susceptibility to HS         ...
Effectiveness of ET vs. AI in Summer                              Putney et al., 1989                                    4...
EFFICACY OF EMBRYO TRANSFER IN LACTATING DAIRYCOWS DURING SUMMER USING FRESH AND VITRIFIED,       SEXED IN-VITRO PRODUCED ...
IVF Embryo Production           Oocytes collected and graded           (Only grades 1 and 2 fertilized)                   ...
EXPERIMENTAL PROCEDURES FOR   EMBRYO TRANSFER AND AI
Experimental Design• Two commercial freestall dairies in Central Texas (~3000 milking)   – July to October 2009.• Primi- a...
Synchronization and Treatment Protocol                                   Ovsynch           Heat                           ...
Plasma Progesterone Concentration• Plasma P4 concentration was used to determine  conformation of a synchronized estrus  –...
RESULTS
Percentage of Cows Pregnant at d 40            All Cows          Synchronized Cows TRT - P < 0.01         TRT - P < 0.01  ...
Percentage of Cows Pregnant at d 97      All Cows           Synchronized Cows                                 Stewart et a...
Total Births (%) and Live Births (%)Treatment                   Total Births (%)               Live Births (%)            ...
Total Heifers (%) and Live Heifers (%)Treatment             Total Heifers (%)                  Live Heifers (%)           ...
Take Home MessagesTo Improve Fertility During Summer….•Aggressive heat detection   – Two heat detection aids are better th...
Take Home MessagesTo Improve Fertility During Summer….•GnRH or hCG on and(or) after AI may improve summer fertility   – Re...
texasdairymatters.org                        Thank You!                                 Todd R. Bilby, Ph.D.              ...
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Strategies to Improve Reproduction During Summer Heat Stress- Todd Bilby

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Dr. Todd Bilby presented this information on March 5th, 2012 as part of DAIReXNET's Spring 2012 Heat Stress Webinar Series.

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Strategies to Improve Reproduction During Summer Heat Stress- Todd Bilby

  1. 1. texasdairymatters.org Strategies to Improve Reproduction during Heat Stress in Dairy Cattle Dairy Heat Stress Roadshow Todd R. Bilby, Ph.D. Associate Professor and Extension Dairy Specialist
  2. 2. Heat Stress in the U.S. New York losses ~$20 million annually Heat Wave in 2006 cost ~$1 billion in milk and animalsAnnual loss to American Dairy Industry is $897 MILLION! St-Pierre et al., 2003 J. Dairy Sci. E52-E77. July 11 and 12, 1995, ~3700 cattle deaths 2 day heat wave in 1999 lost ~$20 million in cattle deaths and performances losses
  3. 3. Effect of milk yield on seasonal variation in pregnancy rate in lactating dairy cows: Florida & Georgia 100 <4536 kg 90 4536-9072 kg >9072 kg 80Pregnancy rate (%) 70 60 50 40 30 20 10 0 J F M A M J J A S O N D Month Al-Katanani et al., 1999
  4. 4. Fertilization Rate in Lactating Dairy Cows Exposed or Not Exposed to Heat Stress 80 70 88 Fertilization Rate (%) 60 50 40 55 30 20 10 0 Heat Stress Non - Heat Stress Sartori et a., 2002 2010 Sartori et al.,
  5. 5. Heat Stress and Embryo Development Susceptibility to HS Single 4-cell Morula Early Expanded Blastocyst cell embryo Blastocyst BlastocystDay 1 Day 1-2 Day 5 Day 6 Day 7 Day 7-9 Oviduct Uterus
  6. 6. Day 15 – 19 Bovine Uterus PGF2α CL ) Embryo IFN-τOvary Heat Stress: Decreased weights of embryos on d 17 (Biggers et Progesterone and PGF2α Up to 40 % of total embryonic losses occur between Days 8 and 17 of Non-Pregnant uterus Pregnant uterus al., 1987) pregnancy (Thatcher et al., 1994, 1995). D17 → post-estrus D17 failures in maintenance of CL ?71 % post-estrusDecreased IFN-τ by (Putney et al., 1988b) Increased endometrial secretion of PGF2α (Putney et al., 1988b) Day
  7. 7. Embryo Loss for Different THI 14 12 12 10 Summer vs. Winter: 8 8 3.7 times more likely to lose embryo 6 5.4 times more likely to lose embryo if twins 4 (Lopez-Gatius et al., 2004)%onpeagycsr)( 2l 2 1 0 0 <55 55-59 60-64 65-69 >69 Max THI Adapted from Garcia-Ispierto et al., 2006
  8. 8. Strategies to Reduce the Negative Effects of Heat Stress •Bull Breeding vs. Timed AI •Synchronization and Timed AI •Induction of Accessory CL •Embryo Manipulation and Transfer
  9. 9. NATURAL SERVICE VS. TIMED AI
  10. 10. Semen Quality Before, During and After Heat Stress Breed Initial Motility Abnormal Spermatozoan Spermatozoa Concentration Period % % Initial % % Initial 106 ml-1 % InitialHolstein 3 wk prior to HS 53 100 9 100 1194 100 1 wk of HS 45 85 13 144 1303 112 1-3 wk after HS 34 64 53 589 537 48 7-9 wk after HS 42 79 29 467 460 39 Ambient Temperatures above 27 °C (80 °F) for 6 h per day can reduce semen quality in bulls! Johnston et al., 1963
  11. 11. Motile Sperm Before, During and After Heat Stress Meyerhoeffer et al., 1985
  12. 12. Economic Comparison of NS vs AI (Overton, 2005)• 60% of the time AI was more profitable than natural service• Predicted NM$ Gain/Milking Herd = $ 37,480• In average, use of NS resulted in loss of $ 10.27/cow/year compared with AI
  13. 13. Conclusion: Natural Service vs. AI• Reduced Genetic Progress and Profitability• Dangerous, cause lameness and injury• Bull Breeding during Heat Stress – Heat stress decreases sperm concentration, motility, and increases % of abnormal sperm – Does not return to normal for 2 months!!• IF YOU ARE GOING TO USE BULLS YOU MUST MANAGE THEM – Rotate, BSE scores, vaccinations, etc.. By-pass negative effects by using A.I.
  14. 14. SYNCHRONIZATION AND TIMED AI
  15. 15. Timed AI vs. Bred on Estrus during Summer 120 P < 0.01 100 100 TAI 80 BOE% 60 P < 0.01 P < 0.05 40 23 27 18 17 20 13 0 Insemination Rate Conception Rate 120 d PP De la Sota et a., 1998
  16. 16. Timed AI vs. Bred on Estrus during Summer 100 P < 0.05 P < 0.01 90 91 90 TAI 80 78 BOE 70 59 60 50Days 40 30 20 10 0 Days Open for Cows Conceiving Interval to First Service De la Sota et a., 1998
  17. 17. Using TAI to Enhance Summer Cumulative Pregnancy Rates 70 *P<.05; † P<.06 BOE-1 60 50 * TAI-1 BOE-2 40 TAI-2 30 †%nPeagrt 20 10 * 0 1st AI 90-d PP 120-d PP Aréchiga et al., 1998
  18. 18. INDUCED OVULATION WITH GNRH AT ESTRUS
  19. 19. Daily Progesterone during Spring and Summer in Holstein Cows No Heat Stress Heat Stress Howell et al., 1994
  20. 20. Progesterone Concentration and Embryo Production of Interferon-τ 12 20000 Interferon-t (units per uterus) Progesterone (ng.ml-1) 9 15000 6 10000 3 5000 ** 0 0 0 2 4 6 8 10 12 14 16 Large Small Day of cycle embryo embryo Day 16 **P<0.01Adapted from Mann et al. (1999) interferon
  21. 21. Effects of GnRH at Estrus on Fertility in Dairy Cows during Summer 60 P < 0.05 GnRH 52 50 ControlConception Rate (%) P < 0.05 40 35 29 31 30 21 20 18 10 0 Kaim et al., 2003 Ullah et al., 1996 Lopez-Gatius et al., 2006
  22. 22. INDUCED ACCESSORY CL AFTER AI
  23. 23. Estrous Cycle Ovulation hCG PGF2a E2 GnRH OvulationHormone Concentration CL Progesterone Estrus 5 10 15 Estrus Courtesy of W. W. Thatcher
  24. 24. Effect of GnRH Agonist and hCG on Progesterone Concentration in Dairy Heifers 18.0 25 Progesterone (ng/mL) 20 hCG 15 CON 10 hCG 25 5 9.7 0 11.7Progesterone (ng/mL) 20 10 14 16 12 0 2 4 6 8 15 GnRH CON Days of the estrous cycle 10 GnRH 5 8.5 0 12 14 16 10 0 2 4 6 8 Days of the estrous cycle Adapted from Schmitt et al. (1996)
  25. 25. Effect of hCG/GnRH on d 4 or 5 post AI during Summer on Conception Rates hCG or GnRH40 38 P < 0.01 Control35 3230 P < 0.05 2625 24 24 24 2320 19151050 C. Fischer- Karami et al. (2010) Schmitt et al. Gandy et al. (2002) Tenhagen et al. (1996) (2010)
  26. 26. Effect of GnRH on d 5 or 11-15 post AI during Summer on Conception Rates P < 0.08 Control40 d5 3535 32 d 11 - 153025 20 20 1920151050 Franco et al. (2006) Willard et al. (2003)
  27. 27. Effect of GnRH on d 0 and d 12 post AI during Summer on Conception Rates Control P < 0.0560 d0 52 d 0 and 12 4950 42 b P < 0.0540 b a 35 3130 c 21 b20 a100 Ryan et al., (1991) Lopez-Gatius et al. (2006)
  28. 28. EMBRYO MANIPULATION AND TRANSFER
  29. 29. Heat Stress and Embryo Development Embryo Susceptibility to HS Transfer Single 4-cell Morula Early Expanded Blastocyst cell embryo Blastocyst BlastocystDay 1 Day 1-2 Day 5 Day 6 Day 7 Day 7-9 Oviduct Uterus
  30. 30. Effectiveness of ET vs. AI in Summer Putney et al., 1989 45 Drost et al., 1999 45 Pregnancy rate (%) Pregnancy rate (%) 40 40 35.4% 35 29.2% 35 30 30 24.1% (48) 25 (113) 25 18.8% 20 13.5% 20 (84) 15 15 (48) 10 (524) 10 5 5 0 0 AI MOET fresh AI MOET IVF Frozen 45 45 Ambrose et al., 1999 Al-Katanani et al., 2002Pregnancy rate (%) Pregnancy rate (%) 40 40 35 35 30 30 26.7% 25 17.5% 25 (20) 20 20 15 6.7% 15 6.1% 5.0% 7.4% 10 10 5 5 (39) (46) 0 0 TAI Fresh Frozen TAI Fresh Vitrified TET TET
  31. 31. EFFICACY OF EMBRYO TRANSFER IN LACTATING DAIRYCOWS DURING SUMMER USING FRESH AND VITRIFIED, SEXED IN-VITRO PRODUCED EMBRYOS Stewart et al., 2010
  32. 32. IVF Embryo Production Oocytes collected and graded (Only grades 1 and 2 fertilized) Maturation of oocytes (21-24 h, 38.5° C + 5 % CO2) Fertilization 8hPercoll (IVF-TALP)Gradient Sex-Sorted Culture Semen (BBH-7) % Cleaved at d 3 Expanded Blastocyst d 7 Embryo Transfer
  33. 33. EXPERIMENTAL PROCEDURES FOR EMBRYO TRANSFER AND AI
  34. 34. Experimental Design• Two commercial freestall dairies in Central Texas (~3000 milking) – July to October 2009.• Primi- and multiparous (n = 722) lactating Holstein dairy cows – Assigned randomly by lactation number, number of previous AI, and projected 305 d milk yield• 1 of 3 treatment groups following a synchronized estrus (study d 0) • AI (Control): AI with conventional semen on d 0 (n = 227) • ET-V: Embryo transfer-vitrified on d 7 (n = 279) • ET-F: Embryo transfer-fresh on d 7 (n = 216) Stewart et al., 2010
  35. 35. Synchronization and Treatment Protocol Ovsynch Heat GnRH or Pregnancy GnRH PGF Estrus AI+BS US diagnose Detection AI Heat GnRH or Pregnancy Detection GnRH PGF Estrus BS VIT+US diagnoseET-V Heat GnRH or Pregnancy GnRH PGF BS FR+US diagnose Detection EstrusET-FExperiment Day -10 -3 -1 0 7 40 ± 7 97±7
  36. 36. Plasma Progesterone Concentration• Plasma P4 concentration was used to determine conformation of a synchronized estrus –Synchronized • if P4 was < 1 ng/mL on d 0 and presence of CL on d7 Stewart et al., 2010
  37. 37. RESULTS
  38. 38. Percentage of Cows Pregnant at d 40 All Cows Synchronized Cows TRT - P < 0.01 TRT - P < 0.01 a, b a,b,c - P < 0.01 - P < 0.01 x, y– P = 0.10 Stewart et al., 2010
  39. 39. Percentage of Cows Pregnant at d 97 All Cows Synchronized Cows Stewart et al., 2010
  40. 40. Total Births (%) and Live Births (%)Treatment Total Births (%) Live Births (%) All cows Synch cows All cows Synch cows (n = 550) (n = 460) (n = 550) (n = 460)AI 14.6a 17.9a 14.6a 17.9aET-V 20.1a 20.9a 17.1a 18.1aET-F 31.2b 33.9b 27.5b 29.9ba, b Values within column with different superscripts differ (P < 0.05)x, y Values within column tend to differ (P ≤ 0.10) Stewart et al., 2010
  41. 41. Total Heifers (%) and Live Heifers (%)Treatment Total Heifers (%) Live Heifers (%) All cows Synch cows All cows Synch cows (n = 113) (n = 107) (n = 113) (n = 107)AI 50.0a 53.9a 50.0a,x 53.9a,xET-V 80.0b 79.0b 72.5y 73.7yET-F 88.4b 88.4b 79.1b 79.1ba, b Values within column with different superscripts differ (P < 0.05)x, y Values within column tend to differ (P ≤ 0.10) Stewart et al., 2010
  42. 42. Take Home MessagesTo Improve Fertility During Summer….•Aggressive heat detection – Two heat detection aids are better than one•Robust synchronization and timed AI programs can improvefertility vs. heat detection – Watch lock up times and compliance•AI can improve fertility and genetic gain compared to bulls – Bulls can achieve acceptable pregnancy rates but must be aggressively managed
  43. 43. Take Home MessagesTo Improve Fertility During Summer….•GnRH or hCG on and(or) after AI may improve summer fertility – Results are inconsistent•Embryo transfer can improve fertility and number of heifersborn – Large scale implementation can be difficult – Need to improve fertility from frozen embryos
  44. 44. texasdairymatters.org Thank You! Todd R. Bilby, Ph.D. Associate Professor Dairy Extension Specialist Texas AgriLife Research and Extension trbilby@ag.tamu.edu This project was supported by Agriculture and Food Research Initiative Competitive Grant no. 2010-85122-20623 from the USDA National Institute of Food and Agriculture.

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