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  • 147 Simplification of the follicle-stimulating hormone protocol for superovulation of the first follicular wave in sheep
    Reproduction Fertility and Development, 2021
    Co-Authors: C. Brochado, B. J. Duran, Alejo Menchaca, J. D. Kieffer, J. C. L. Motta, A. Pinczak, A. Garcia-guerra
    Abstract:

    The objective of the present study was to evaluate the effect of length of the FSH superstimulatory treatment on ovarian response and embryo production in sheep. Poll Dorset ewes (n = 63) 3.2 ± 0.2 years old weighing 58.5 ± 1.5 kg and with a body condition score of 2.7 ± 0.1 (0 = emaciated; 5 = obese) were used during the transition from the breeding to the non-breeding season. All ewes received an ovarian superstimulatory treatment during the first follicular wave (Day 0 protocol). On Day −9 all ewes received a 0.3-g progesterone intravaginal device (CIDR, Zoetis) for 6 days. On Day −3, the CIDR was removed and all ewes were administered 125 μg of cloprostenol sodium intramuscularly (IM) (PGF, estroPLAN, Parnell) and 200 IU of equine chorionic gonadotrophin (eCG) + 100 IU of human chorionic gonadotrophin (hCG) IM (P.G. 600, Merck). Thirty-six hours after CIDR removal (Day −1.5) ewes were administered 100 μg of Gonadorelin Acetate IM (gonadotrophin-releasing hormone, GnRH; Gonabreed, Parnell). Superstimulatory treatments were initiated on Day 0 (84 h after CIDR removal) with a total of 240 mg of NIH-FSH-P1 (12 mL, Folltropin, Vetoquinol), and a new CIDR was used from the first to the last FSH dose (6-dose = 3 days; 8-dose = 4 days). Ewes were randomised to receive the total dose of FSH distributed in eight decreasing doses (8-dose group, n = 33) or six decreasing doses (6-dose group, n = 30) twice daily 12 h apart. Two doses of PGF were administered with the last two doses of FSH, and GnRH was administered 12 h after the last FSH administration. Intrauterine AI with fresh semen was performed by laparoscopy 16 h after GnRH administration. Ovarian response was determined by laparoscopy 6 days after AI and ova/embryos were collected surgically in ewes with >2 corpora lutea (CL). Data were analysed using generalized linear mixed models (SAS 9.4; SAS Institute Inc.) and presented as mean ± s.e.m. in Table 1. The percentage of responding donors (>2 CL) was 93.3% (28/30) and 78.8% (26/33; P = 0.5) for the 6-dose and 8-dose groups, respectively. The number of CL tended (P = 0.06) to be lesser in ewes in the 6-dose than the 8-dose group. However, no differences (P > 0.10) were found in total ova/embryo, fertilized ova, transferable embryos, or freezable embryos. In conclusion, despite a tendency for a greater ovarian response in ewes treated with 8 doses of FSH, embryo yield did not appear to differ after either 6 or 8 doses of FSH administered during the first follicular wave in sheep. Table 1. Ovulatory response and embryo production in responding ewes (>2 corpora lutea) superstimulated with either 6 or 8 doses of FSH during the first follicular wave Outcome Treatment P-value 6-dose 8-dose Number of ewes 28 26 Corpora lutea (n) 14.2 ± 1.7 20.3 ± 2.8 0.06 Total ova/embryos (n) 9.0 ± 1.3 10.9 ± 1.8 0.38 Fertilized ova (n) 8.1 ± 1.4 10.2 ± 1.9 0.34 Fertilized ova (% per ewe) 89.0 ± 5.0 81.7 ± 7.0 0.40 Degenerate embryos 1.3 ± 0.4 2.0 ± 0.8 0.89 Transferable embryos (Grade 1–3) 6.8 ± 1.2 8.2 ± 1.8 0.52 Transferable embryos (% per ewe) 85.7 ± 4.4 75.4 ± 8.4 0.46 Freezable embryos (Grade 1–2) 6.6 ± 1.1 8.2 ± 1.8 0.43 Freezable embryos (% per ewe) 80.5 ± 5.6 75.4 ± 8.4 0.61

  • 7 Pregnancy rates in suckled beef cows synchronized with a shortened progesterone/oestradiol-based protocol (J-synch) and inseminated with conventional or sexed-sorted semen
    Reproduction Fertility and Development, 2019
    Co-Authors: E. E. Huguenine, J. J. De La Mata, R. L. R. De Carneiro, Alejo Menchaca
    Abstract:

    An experiment was designed to evaluate pregnancy rates (P/AI) in suckled beef cows synchronized with a progesterone (P4)/oestradiol-based protocol (J-Synch) and inseminated (AI) with sexed or nonsexed (conventional) semen. Angus or Angus crossbred cows (n = 877), 60 to 90 days postpartum, with a body condition score of 2.5 to 3.5 (scale of 1 to 5) and a corpus luteum or a follicle >8 mm in diameter detected by ultrasonography, were randomly allocated to be AI with sexed-sorted or nonsexed (conventional) semen. The experiment was performed in 4 farms, and the sexed-sorted (SexedUltra™ 4 M, with 4 million sperm; ST Genetics, Navasota, TX, USA) and conventional (25 million sperm) semen were from split ejaculates from 5 Angus bulls. All cows received a P4 device (DIB 0.5, Zoetis, Villa Adelina, Argentina) and 2 mg of oestradiol benzoate (Gonadiol, Zoetis) on Day 0. On Day 6, cows received 400 IU of eCG (Novormon 5000, Zoetis) and 500 µg of cloprostenol (Ciclase DL, Zoetis) and DIB was removed. All cows were also tail painted and observed for signs of oestrus (i.e. >30% of the tail paint rubbed off) at 60, 72, and 84 h after DIB removal. Cows with the tail paint rubbed off by 60 or 72 h after DIB removal were artificially inseminated at 72 h with either sexed or conventional semen. Those not showing oestrus by 72 h received 100 µg of Gonadorelin Acetate (Gonasyn GDR, Zoetis) at that time and were artificially inseminated with either sexed-sorted or conventional semen 12 h later (i.e. 84 h). Pregnancy was diagnosed by ultrasonography 30 days after AI. Data were analysed by general linear model for binary data with a logit link. Overall, 76.4% (678/877) of cows showed oestrus 60 to 84 h after DIB removal, and there were differences in P/AI between sexed-sorted and conventional semen (P 

  • Improvement of pregnancy rate by using the 6-days J-synch protocol in recipient cows transferred with in vitro produced embryos
    Animal reproduction, 2015
    Co-Authors: Alejo Menchaca, S. Dutra, J. M. Carrau, F. Sapriza, J. Salazar, J. De La Mata
    Abstract:

    Proestrus length affects the ability of the follicle to growth and achieve ovulation, so pregnancy rate could be improved if proestrus is prolonged. Taking this into account, a new protocol for FTAI using estradiol and progesterone has been proposed named as J-Synch. In this new treatment the removal of the device is advanced to Day 6 instead Day 7 or 8, and GnRH is given 72 h later to induce ovulation instead of ECP at device removal. The objective of this study was to determine pregnancy rate in recipient females obtained with the conventional 7 d vs. the new 6 d progesterone treatment. The experiment was performed in five replicates using 945 cycling Hereford crossbreed recipients with body condition score >2.5 (1 to 5 scale). All the females received an intravaginal device (0.5 g progesterone, DIB, Syntex, Argentina) plus 2 mg EB i.m. (Syntex) (Day 0). In the 7-day progesterone + ECP treatment group (n=481) the DIB was removed on Day 7 in the morning and 500 µg cloprostenol (Ciclase DL, Syntex), 400 IU eCG (Novormon, Syntex), and 0.5 mg ECP (Cipiosyn, Syntex) was administrated i.m.. In the experimental J-Synch group (n=464), DIB was removed on Day 6 at time of cloprostenol and eCG was given i.m.. For this group the females received one dose of GnRH analogue (100 µg Gonadorelin Acetate, Gonasyn Gdr, Syntex) given 72 h after device removal. Fixed time embryo transfer (FTET) was performed on Day 16 and 17 with blastocysts produced by in vitro fertilization using sexed semen. Pregnancy rate was determined by ultrasonography 40-45 days after embryo transfer. Data were analyzed using logistic regression. Pregnancy rate was higher for the 6- days treatment (49.3%, 229/464) than conventional treatment (40.9%, 197/481; P

  • 7 pregnancy rates in beef heifers synchronized with a shortened oestradiol based treatment that provides for a prolonged proestrus
    Reproduction Fertility and Development, 2015
    Co-Authors: Alejo Menchaca, R Nunezolivera, F. Cuadro
    Abstract:

    An oestradiol-based protocol (named J-Synch) has been developed recently with the aim of providing for a longer proestrus, enhancing the development of the dominant follicle before ovulation, and increasing pregnancy rates following fixed-time AI (FTAI) in heifers (de la Matta and Bo 2012 Taurus 55, 17–23). Two experiments were performed in Uruguay with 1953 Angus × Hereford crossbred heifers to compare pregnancy rates obtained with the J-Synch protocol with the conventional 7-day oestradiol-based protocol. A secondary objective was to determine the effects of the time of FTAI and the addition of eCG at the time progestin device removal on pregnancy rates. In Experiment 1, 966 heifers received a DIB device (0.5 g of progesterone, Syntex, Buenos Aires, Argentina) plus 2 mg of oestradiol benzoate IM (Syntex) on Day 0. Heifers in the conventional treatment group (n = 485) received cloprostenol (500 μg, Ciclase DL, Syntex) and oestradiol cypionate (0.5 mg, Cipiosyn, Syntex) IM and had their DIB removed on Day 7 a.m. Heifers in this group were then subdivided to be FTAI on Day 9 a.m. or p.m. (i.e. 48 or 56 h after DIB removal). Heifers in the J-Synch treatment group (n = 481) received cloprostenol IM and DIB removal on Day 6 p.m. and received gonadotropin-releasing hormone (100 μg Gonadorelin Acetate, Gonasyn Gdr, Syntex) on Day 9 a.m.; heifers were then FTAI on Day 9 a.m. or p.m. (i.e. 60 or 72 h after DIB removal). All heifers in this experiment were also treated with 300 IU of eCG (Novormon, Syntex) at DIB removal. In Experiment 2, 987 heifers were treated with the J-Synch protocol as described in Experiment 1. At device removal (Day 6 p.m.), heifers were divided to receive (n = 488) or not (n = 499) 300 IU of eCG IM at that time and were further subdivided to receive gonadotropin-releasing hormone and FTAI on Day 9 a.m. or p.m. (i.e. 60 or 72 h after DIB removal). Pregnancy rates were determined by ultrasonography 30 days after FTAI. Data were analysed using logistic regression, and results are shown in Table 1. J-Synch-treated heifers tended (P < 0.1) to have higher pregnancy rates following FTAI, whereas time of FTAI only affected pregnancy rates following the conventional 7-day treatment (P < 0.05). However, removal of eCG from the J-Synch protocol in Experiment 2 resulted in reduced pregnancy rates when inseminations were done on Day 9 p.m. (P < 0.05). In summary, the addition of eCG to the J-Synch protocol provided for a wider window of insemination times facilitating FTAI in large groups of beef heifers. Table 1.Effect of length of progestin insertion, time of insemination and eCG treatment on pregnancy rates in beef heifers

  • 7 PREGNANCY RATES IN BEEF HEIFERS SYNCHRONIZED WITH A SHORTENED OESTRADIOL-BASED TREATMENT THAT PROVIDES FOR A PROLONGED PROESTRUS
    Reproduction Fertility and Development, 2015
    Co-Authors: Alejo Menchaca, R. Núñez-olivera, F. Cuadro
    Abstract:

    An oestradiol-based protocol (named J-Synch) has been developed recently with the aim of providing for a longer proestrus, enhancing the development of the dominant follicle before ovulation, and increasing pregnancy rates following fixed-time AI (FTAI) in heifers (de la Matta and Bo 2012 Taurus 55, 17–23). Two experiments were performed in Uruguay with 1953 Angus × Hereford crossbred heifers to compare pregnancy rates obtained with the J-Synch protocol with the conventional 7-day oestradiol-based protocol. A secondary objective was to determine the effects of the time of FTAI and the addition of eCG at the time progestin device removal on pregnancy rates. In Experiment 1, 966 heifers received a DIB device (0.5 g of progesterone, Syntex, Buenos Aires, Argentina) plus 2 mg of oestradiol benzoate IM (Syntex) on Day 0. Heifers in the conventional treatment group (n = 485) received cloprostenol (500 μg, Ciclase DL, Syntex) and oestradiol cypionate (0.5 mg, Cipiosyn, Syntex) IM and had their DIB removed on Day 7 a.m. Heifers in this group were then subdivided to be FTAI on Day 9 a.m. or p.m. (i.e. 48 or 56 h after DIB removal). Heifers in the J-Synch treatment group (n = 481) received cloprostenol IM and DIB removal on Day 6 p.m. and received gonadotropin-releasing hormone (100 μg Gonadorelin Acetate, Gonasyn Gdr, Syntex) on Day 9 a.m.; heifers were then FTAI on Day 9 a.m. or p.m. (i.e. 60 or 72 h after DIB removal). All heifers in this experiment were also treated with 300 IU of eCG (Novormon, Syntex) at DIB removal. In Experiment 2, 987 heifers were treated with the J-Synch protocol as described in Experiment 1. At device removal (Day 6 p.m.), heifers were divided to receive (n = 488) or not (n = 499) 300 IU of eCG IM at that time and were further subdivided to receive gonadotropin-releasing hormone and FTAI on Day 9 a.m. or p.m. (i.e. 60 or 72 h after DIB removal). Pregnancy rates were determined by ultrasonography 30 days after FTAI. Data were analysed using logistic regression, and results are shown in Table 1. J-Synch-treated heifers tended (P 

A. Garcia-guerra - One of the best experts on this subject based on the ideXlab platform.

  • 109 Pre-synchronization and reutilization of progesterone devices during a 6-day CO-Synch protocol for fixed-time artificial insemination in beef heifers
    Reproduction Fertility and Development, 2021
    Co-Authors: E. R. Canadas, B. J. Duran, G. Machado, A. Nall, S. E. Battista, M. L. Mussard, P. S. Baruselli, A. Garcia-guerra
    Abstract:

    Ovulatory response to the initial gonadotrophin-releasing hormone (GnRH) of the CO-Synch protocol is affected by circulating progesterone (P4) and follicle size. In addition, heifers that ovulate to the initial GnRH treatment have greater fertility after AI. Thus, this study determined the effect of (1) presynchronization (Presynch) before a 6-day CO-Synch protocol and (2) circulating [RCE1] (P4) on ovulatory response, oestrus expression, and pregnancies per AI (P/AI) in beef heifers. Yearling beef heifers (n = 233) at three locations were randomly assigned in a 2 × 2 factorial design to the following treatments: (1) Presynch + 6-day CO-Synch with a new P4 device; (2) Presynch + 6-day CO-Synch with a once-used P4 device; (3) 6-day CO-Synch with a new P4 device; and (4) 6-day CO-Synch with a once-used P4 device. Presynch consisted of insertion of a new P4 intravaginal device (1.38 g of P4) on Day −17 and removal of P4 device on Day −11 concurrently with 500 µg of cloprostenol sodium (PGF). On Day −9, all heifers received either a new (New) or once-used (Used) CIDR and 100 µg of Gonadorelin Acetate (GnRH). Six days later (Day −3), CIDRs were removed, 1000 µg of PGF was administered and an oestrous detection patch applied (Estrotect). At 72 h after CIDR removal, AI was performed concurrently with administration of 100 µg of GnRH. Pregnancy was determined by transrectal ultrasonography 31 days after AI. A subset of heifers (n = 155) was examined on Day −9 and Day −3 by ultrasonography to determine ovulation to Day −9 GnRH. Data were analysed using generalized linear mixed models (SAS 9.4; SAS Institute Inc.). Presynch heifers had larger follicle diameter on Day −9 (12.7 ± 0.3 vs. 10.1 ± 0.3 mm; P 

  • 109 Pre-synchronization and reutilization of progesterone devices during a 6-day CO-Synch protocol for fixed-time artificial insemination in beef heifers
    Reproduction Fertility and Development, 2021
    Co-Authors: E. R. Canadas, B. J. Duran, G. Machado, A. Nall, S. E. Battista, M. L. Mussard, P. S. Baruselli, A. Garcia-guerra
    Abstract:

    Ovulatory response to the initial gonadotrophin-releasing hormone (GnRH) of the CO-Synch protocol is affected by circulating progesterone (P4) and follicle size. In addition, heifers that ovulate to the initial GnRH treatment have greater fertility after AI. Thus, this study determined the effect of (1) presynchronization (Presynch) before a 6-day CO-Synch protocol and (2) circulating [RCE1] (P4) on ovulatory response, oestrus expression, and pregnancies per AI (P/AI) in beef heifers. Yearling beef heifers (n=233) at three locations were randomly assigned in a 2×2 factorial design to the following treatments: (1) Presynch+6-day CO-Synch with a new P4 device; (2) Presynch+6-day CO-Synch with a once-used P4 device; (3) 6-day CO-Synch with a new P4 device; and (4) 6-day CO-Synch with a once-used P4 device. Presynch consisted of insertion of a new P4 intravaginal device (1.38g of P4) on Day −17 and removal of P4 device on Day −11 concurrently with 500µg of cloprostenol sodium (PGF). On Day −9, all heifers received either a new (New) or once-used (Used) CIDR and 100µg of Gonadorelin Acetate (GnRH). Six days later (Day −3), CIDRs were removed, 1000µg of PGF was administered and an oestrous detection patch applied (Estrotect). At 72h after CIDR removal, AI was performed concurrently with administration of 100µg of GnRH. Pregnancy was determined by transrectal ultrasonography 31 days after AI. A subset of heifers (n=155) was examined on Day −9 and Day −3 by ultrasonography to determine ovulation to Day −9 GnRH. Data were analysed using generalized linear mixed models (SAS 9.4; SAS Institute Inc.). Presynch heifers had larger follicle diameter on Day −9 (12.7±0.3 vs. 10.1±0.3 mm; P&lt;0.001), greater ovulatory response to Day −9 GnRH (82.5%; 66/80 vs. 56%; 42/75; P&lt;0.001), greater expression of oestrus (90.6%; 106/117 vs. 78.4%; 91/116; P&lt;0.02), and earlier oestrus (49.8±1 vs. 53.1±1 h; P&lt;0.01) compared with controls. There was a treatment×CIDR interaction on oestrous expression, such that a lesser (P&lt;0.05) percentage of control heifers with new CIDR expressed oestrus compared with all other groups (Table 1). Heifers with a used CIDR during the 6-day CO-Synch tended (P=0.08) to have greater P/AI (52.1%; 61/117) than those with a new CIDR (40.5%; 47/116). In conclusion, presynchronization before initiation of a 6-day CO-Synch increased follicle diameter, enhanced ovulatory response and oestrous expression, but did not affect fertility. The earlier onset of oestrus in presynchronized heifers suggests that the timing of AI may need to be modified. Table 1. Oestrous expression and pregnancy per AI (P/AI) in beef heifers with or without presynchronization and treated with a new or used CIDR during a 6-day CO-Synch Treatment CIDR Oestrus (%; n/n) Time of oestrus (h) P/AI (%; n/n) Control New 67.8a (40/59) 53.7±1.5a 33.9 (20/59) Used 89.5b (51/57) 52.7±1.6a 50.9 (29/57) Presynch New 94.7b (54/57) 50.9±1.4b 47.4 (27/57) Used 86.7b (52/60) 48.7±1.3b 53.3 (32/60) P-value Treatment 0.03 0.01 0.21 CIDR 0.62 0.19 0.08 Interaction 0.003 0.75 0.38 a,bValues with different superscripts differ (P&lt;0.05).

  • 115 Presynchronization and reutilization of progesterone devices during a 6-day CO-Synch protocol for fixed-time artificial insemination in beef heifers
    Reproduction Fertility and Development, 2021
    Co-Authors: E. R. Canadas, G. Machado, A. Nall, S. E. Battista, M. L. Mussard, P. S. Baruselli, B. Duran, A. Garcia-guerra
    Abstract:

    Ovulatory response to the initial gonadotrophin-releasing hormone (GnRH) of the CO-Synch protocol is affected by circulating progesterone (P4) and follicle size. In addition, heifers that ovulate to initial GnRH treatment have greater fertility after AI. Thus, the aim of this study was to assess the effect of (1) presynchronization (Presynch) before a 6-day CO-Synch protocol and (2) P4 device reuse (new vs. second use) on ovulatory response, oestrous expression, and pregnancy per AI (P/AI) in beef heifers. Yearling beef heifers (n=233) were randomly assigned in a 2×2 factorial design to the following treatments: (1) Treatment (Presynch): (1a) Presynch+6-day CO-Synch with new P4 device; (1b) Presynch+6-days CO-Synch with a once-used P4 device; (2) Control (no Presynch): (2a) 6-day CO-Synch with new P4 device; (2b) 6-day CO-synch with once-used P4 device. Presynch consisted of insertion of a new P4 intravaginal device (CIDR, 1.38g of P4; Zoetis) on Day −17 and removal of the CIDR on Day −11 concurrently with 500µg of cloprostenol sodium. On Day −9, all heifers received either a new or once-used (used) CIDR and 100µg of Gonadorelin Acetate (GnRH, Parnell Inc.). Six days later (Day −3) CIDRs were removed, 1000µg of PGF was administered, and an oestrous detection patch applied (Estrotect, Rockway Inc.). At 72h after CIDR removal, 100µg of GnRH and AI using 3 different sires was performed. Pregnancy was determined by ultrasonography 31 days after AI. A subset of heifers (n=151) were examined on Day −9 and Day −3 by ultrasonography to assess ovulation to Day −9 GnRH. Data were analysed using GLIMMIX (SAS 9.4; SAS Institute Inc.). Presynch heifers had larger follicle diameter on Day −9 (12.7±0.3 vs. 10.4±0.3 mm; P&lt;0.0001), greater ovulatory response (84.6%; 66/78 vs. 52.05%; 38/73; P&lt;0.0001), greater oestrus expression (90.6%; 106/117 vs. 78.4%; 91/116; P=0.03), and expressed oestrus earlier (49.8±1.0 vs. 53.1±1.1 h; P=0.01) compared with controls. There was an interaction for treatment and CIDR on oestrous expression, whereas a lesser (P=0.003) percentage of control heifers with new CIDR showed oestrus compared with all other groups (Table 1). Heifers treated with a used P4 device tended (P=0.08) to have greater P/AI (52.1%; 61/117) than those with a new CIDR (40.5%; 47/116). In conclusion, presynchronization before initiation of a 6-day CO-Synch increased follicle diameter, ovulatory response, and oestrous expression, but did not affect fertility. The earlier onset of oestrus in Presynch heifers warrants further study on timing of AI. Table 1. Oestrous expression and pregnancy per AI (P/AI) in beef heifers with or without presynchronization and treated with a new or used CIDR Treatment CIDR Oestrus (%; n/n) Time of oestrus (h) P/AI (%; n/n) Control New 67.8a (40/59) 53.7±1.5a 33.9 (20/59) Used 89.5b (51/57) 52.7±1.6a 50.9 (29/57) Presynch New 94.7b (54/57) 50.9±1.4b 47.4 (27/57) Used 86.7b (52/60) 48.7±1.3b 53.3 (32/60) P-value Treatment 0.03 0.01 0.21 CIDR 0.62 0.18 0.08 Interaction 0.003 0.78 0.38 a,bValues with different superscripts differ (P &lt; 0.05).

  • 147 Simplification of the follicle-stimulating hormone protocol for superovulation of the first follicular wave in sheep
    Reproduction Fertility and Development, 2021
    Co-Authors: C. Brochado, B. J. Duran, Alejo Menchaca, J. D. Kieffer, J. C. L. Motta, A. Pinczak, A. Garcia-guerra
    Abstract:

    The objective of the present study was to evaluate the effect of length of the FSH superstimulatory treatment on ovarian response and embryo production in sheep. Poll Dorset ewes (n = 63) 3.2 ± 0.2 years old weighing 58.5 ± 1.5 kg and with a body condition score of 2.7 ± 0.1 (0 = emaciated; 5 = obese) were used during the transition from the breeding to the non-breeding season. All ewes received an ovarian superstimulatory treatment during the first follicular wave (Day 0 protocol). On Day −9 all ewes received a 0.3-g progesterone intravaginal device (CIDR, Zoetis) for 6 days. On Day −3, the CIDR was removed and all ewes were administered 125 μg of cloprostenol sodium intramuscularly (IM) (PGF, estroPLAN, Parnell) and 200 IU of equine chorionic gonadotrophin (eCG) + 100 IU of human chorionic gonadotrophin (hCG) IM (P.G. 600, Merck). Thirty-six hours after CIDR removal (Day −1.5) ewes were administered 100 μg of Gonadorelin Acetate IM (gonadotrophin-releasing hormone, GnRH; Gonabreed, Parnell). Superstimulatory treatments were initiated on Day 0 (84 h after CIDR removal) with a total of 240 mg of NIH-FSH-P1 (12 mL, Folltropin, Vetoquinol), and a new CIDR was used from the first to the last FSH dose (6-dose = 3 days; 8-dose = 4 days). Ewes were randomised to receive the total dose of FSH distributed in eight decreasing doses (8-dose group, n = 33) or six decreasing doses (6-dose group, n = 30) twice daily 12 h apart. Two doses of PGF were administered with the last two doses of FSH, and GnRH was administered 12 h after the last FSH administration. Intrauterine AI with fresh semen was performed by laparoscopy 16 h after GnRH administration. Ovarian response was determined by laparoscopy 6 days after AI and ova/embryos were collected surgically in ewes with >2 corpora lutea (CL). Data were analysed using generalized linear mixed models (SAS 9.4; SAS Institute Inc.) and presented as mean ± s.e.m. in Table 1. The percentage of responding donors (>2 CL) was 93.3% (28/30) and 78.8% (26/33; P = 0.5) for the 6-dose and 8-dose groups, respectively. The number of CL tended (P = 0.06) to be lesser in ewes in the 6-dose than the 8-dose group. However, no differences (P > 0.10) were found in total ova/embryo, fertilized ova, transferable embryos, or freezable embryos. In conclusion, despite a tendency for a greater ovarian response in ewes treated with 8 doses of FSH, embryo yield did not appear to differ after either 6 or 8 doses of FSH administered during the first follicular wave in sheep. Table 1. Ovulatory response and embryo production in responding ewes (>2 corpora lutea) superstimulated with either 6 or 8 doses of FSH during the first follicular wave Outcome Treatment P-value 6-dose 8-dose Number of ewes 28 26 Corpora lutea (n) 14.2 ± 1.7 20.3 ± 2.8 0.06 Total ova/embryos (n) 9.0 ± 1.3 10.9 ± 1.8 0.38 Fertilized ova (n) 8.1 ± 1.4 10.2 ± 1.9 0.34 Fertilized ova (% per ewe) 89.0 ± 5.0 81.7 ± 7.0 0.40 Degenerate embryos 1.3 ± 0.4 2.0 ± 0.8 0.89 Transferable embryos (Grade 1–3) 6.8 ± 1.2 8.2 ± 1.8 0.52 Transferable embryos (% per ewe) 85.7 ± 4.4 75.4 ± 8.4 0.46 Freezable embryos (Grade 1–2) 6.6 ± 1.1 8.2 ± 1.8 0.43 Freezable embryos (% per ewe) 80.5 ± 5.6 75.4 ± 8.4 0.61

  • 163 Treatment with gonadotrophin-releasing hormone at the time of AI in beef heifers that fail to express oestrus after an estradiol-based synchronisation protocol improves pregnancies per AI
    Reproduction Fertility and Development, 2020
    Co-Authors: A. Butler, H. Butler, G. Cesaroni, R. Alberio, S. Perez Wallace, A. Garcia-guerra
    Abstract:

    Oestrus expression between progesterone (P4) withdrawal and fixed-time AI (FTAI) has been shown to improve pregnancies per AI (P/AI) by 27% in beef cattle. As a result, cattle that do not express oestrus after P4 withdrawal present a challenge to the efficiency of FTAI. The present study was designed to test the hypothesis that administration of gonadotrophin-releasing hormone (GnRH) at the time of AI in heifers that do not express oestrus can improve fertility. Two-year-old Angus heifers (n = 1032) with a condition score of 2.75 to 3.5 at two locations in Argentina were used. On Day 0, heifers received an intravaginal device containing 0.5 g of P4 (Cronipres, Biogenesis) and 2 mg of oestradiol benzoate intramuscularly (Bioestrogen, Biogenesis). On Day 8, devices were removed and heifers received 150 µg of d-cloprostenol intramuscularly (Enzaprost, Biogenesis), 0.5 mg of oestradiol cipionate intramuscularly (Croni-Cip, Biogenesis), and an oestrus detection patch (Estrotect, Rockway Inc.). On Day 10, AI was performed in all heifers 50 to 54 h after device removal. Heifers were categorised based on oestrus expression, and those that did not express oestrus were randomised to receive 100 µg of Gonadorelin Acetate intramuscularly (Gonasyn, Syntex; n = 158) concurrent with AI or remain as untreated controls (n = 151). Pregnancy was determined using ultrasonography at Days 38 and 111 after AI. Differences in fertility were evaluated using generalised linear mixed models, and the results are shown in Table 1. Oestrus expression between device removal and FTAI was 70.1% (723/1032). Pregnancies per AI at Days 38 and 111 were different between groups (P 

Marcelo H. Ratto - One of the best experts on this subject based on the ideXlab platform.

  • The effect of seminal plasma β-NGF on follicular fluid hormone concentration and gene expression of steroidogenic enzymes in llama granulosa cells
    Reproductive Biology and Endocrinology, 2019
    Co-Authors: Ximena P. Valderrama, Jose F. Goicochea, Mauricio E. Silva, Marcelo H. Ratto
    Abstract:

    Background Nerve growth factor (β-NGF) from llama seminal plasma has been described as a potent ovulatory and luteotrophic molecule after intramuscular or intrauterine infusion in llamas and alpacas. We tested the hypothesis that systemic administration of purified β-Nerve Growth Factor (β-NGF) during the preovulatory stage will up-regulate steroidogenic enzymes and Vascular Endothelial Growth Factor (VEGF) gene expression in granulosa cells inducing a change in the progesterone/estradiol ratio in the follicular fluid in llamas. Methods Experiment I: Female llamas ( n  = 64) were randomly assigned to receive an intramuscular administration of: a) 50 μg Gonadorelin Acetate (GnRH, Ovalyse, Pfizer Chile SA, Santiago, Chile, n  = 16), b) 1.0 mg of purified llama β-NGF ( n  = 16), or c) 1 ml phosphate buffered saline (PBS, negative control group, n  = 16). An additional group of llamas ( n  = 16) were mated with a fertile male. Follicular fluid and granulosa cells were collected from the preovulatory follicle at 10 or 20 h after treatment (Time 0 = administration of treatment, n  = 8/treatment/time point) to determine progesterone/estradiol concentration and steroidogenic enzymes and VEGF gene expression at both time points. Experiment II: Granulosa cells were collected from preovulatory follicles from llamas ( n  = 24) using ultrasound-guided transvaginal follicle aspiration for in vitro culture to determine mRNA relative expression of Steroidogenic Acute Regulatory Protein (StAR) and VEGF at 10 or 20 h ( n  = 4 replicates) and progesterone secretion at 48 h ( n  = 4 replicates) after LH or β-NGF treatment. Results Experiment I: There was a significant increase in the progesterone/estradiol ratio in mated llamas or treated with GnRH or purified β-NGF. There was a significant downregulation in the mRNA expression of Aromatase (CYP19A1/P450 Arom) for both time points in llamas mated or treated with GnRH or llama purified β-NGF with respect to the control group. All treatments except β-NGF (20 h) significantly up regulated the mRNA expression of 3-beta-hydroxysteroid dehydrogenase (HSD3B) whereas the expression of StAR and Side-Chain cleavage enzyme (CYP11A1/P450scc) where significantly up regulated only by mating (20 h), or β-NGF at 10 or 20 h after treatment. VEGF was up regulated only in those llamas submitted to mating (10 h) or treated with purified β-NGF (10 and 20 h). Experiment II: Only β-NGF treatment induced an increase of mRNA abundance of StAR from llama granulosa cells at 20 h of in vitro culture. There was a significant increase on mRNA abundance of VEGF at 10 and 20 h of in vitro culture from granulosa cells treated with β-NGF whereas LH treatment increases VEGF mRNA abundance only at 20 h of in vitro culture. In addition, there was a significant increase on progesterone secretion from llama granulosa cells 48 h after LH or β-NGF treatment. Conclusions Systemic administration of purified β-NGF from llama seminal fluid induced a rapid shift from estradiol to progesterone production in the preovulatory follicle. Differences in gene expression patterns of steroidogenic enzymes between GnRH and mated or β-NGF-treated llamas suggest local effects of seminal components on the preovulatory follicle.

  • Evaluation of the effect of mating, intrauterine deposition of raw seminal plasma or seminal plasma purified β-NGF on endometrial vascularization in llamas.
    Theriogenology, 2018
    Co-Authors: Felipe Urra, Marcelo H. Ratto, Mauricio Silva
    Abstract:

    The aim of this study was to evaluate the endometrial vascularization area (EVA) of both uterine horns in llamas subjected to different intrauterine treatments resembling physiological conditions after a single mating. Llamas with a growing follicle (≥8 mm) were randomly assigned to: a) single mating with a fertile male (mating; positive control; n = 6); b) intramuscular administration of 50 μg of Gonadorelin Acetate plus an intrauterine infusion of 4 ml of PBS (GnRH; negative control; n = 4); c) intrauterine infusion of 4 ml of raw llama seminal plasma (SP; n = 4) or d) intrauterine infusion of 10 mg of β-NGF purified from llama semen diluted in 4 ml of PBS (spβ-NGF; n = 6). Females in GnRH, SP and NGF group received 50% of treatment volume into each horn by guiding an insemination pipet through the cervix. Ovaries were examined by ultrasonography every 12 h until Day2 (Day 0 = Day of treatment) to determine ovulation. Power-Doppler ultrasonography evaluation of EVA in a cross-section of the middle segment of each horn was conducted at 1 h before and 1, 3, 6, 12 and 24 h (intensive evaluation) and 2, 4, 6 and 8 days (long-term evaluation) after treatment administration. Serial EVA data was analyzed as a 2-by-2 factorial design for repeated measures using the MIXED procedure. The analysis included main effects of treatment (mating, SP, spβ-NGF or GnRH), uterine horn (left vs right), time, and their interactions. According to the 2 by 2 analysis there was no effect of uterine horn on EVA during the first 24 h and from Day 2 to Day 8 after treatment; therefore, data were grouped based on treatment type regardless of uterine horn for both periods of observation. Thus, EVA was affected by time (P 

  • Nerve growth factor from seminal plasma origin (spβ-NGF) increases CL vascularization and level of mRNA expression of steroidogenic enzymes during the early stage of Corpus Luteum development in llamas
    Theriogenology, 2017
    Co-Authors: Mauricio Silva, Cesar Ulloa-leal, Gregg P. Adams, X.p. Valderrama, O.a. Bogle, Marcelo H. Ratto
    Abstract:

    Abstract The objectives of the study were to determine the effect of seminal plasma β-NGF on Corpus Luteum morphology and function and level of mRNA expression of steroidogenic enzymes. Llamas were assigned (n = 12/per group) to receive an intramuscular dose of: (a) 1 ml phosphate buffered saline (PBS), (b) 5 μg Gonadorelin Acetate (GnRH), or (c) 1.0 mg of purified llama spβ-NGF. Ovaries were examined by transrectal B-mode ultrasonography from treatment to ovulation (Day 0 = treatment). B mode/Power Doppler ultrasonography and blood samples collection were performed at Days 4, 8 and 10 (n = 3 llamas per treatment group/per time point) to determine CL diameter, vascularization and plasma progesterone concentration respectively. Plasma progesterone concentration was analyzed in all llamas at Day 0. Then females were submitted to ovariectomy at Days 4, 8 and 10 (n = 3 llamas/treatment/time), CL was removed to determine vascular area, proportion of luteal cells and CYP11A1 /P450scc and STAR expression by RT-PCR. Ovulation was similar between llamas treated with GnRH or spβ-NGF and CL diameter did not differ between GnRH or spβ-NGF groups by Day 4, 8 or 10. Vascularization area of the CL was higher (P  CYP11A1 /P450scc was upregulated 3 folds at day 4 and 10 by spβ-NGF compared to GnRH. STAR transcription was 3 folds higher at day 4 in females treated with spβ-NGF. In conclusion, the luteotrophic effect of spβ-NGF could be related to an increase of vascularization and up regulation of CYP11A1 /P450scc and STAR transcripts enhancing progesterone secretion.

  • A comparative study of the effects of intramuscular administration of Gonadorelin, mating and intrauterine infusion of either raw seminal plasma or seminal plasma purified β-NGF on luteal development in llamas.
    Reproduction in domestic animals = Zuchthygiene, 2017
    Co-Authors: Mauricio Silva, Felipe Urra, Cesar Ulloa-leal, Marcelo H. Ratto
    Abstract:

    Contents The aim of this study was to compare the effect of the intramuscular administration of 50 μg of Gonadorelin Acetate versus natural mating, intrauterine infusion (i.u.) of a physiological relevant dose of either raw llama seminal plasma (SP) or purified beta-nerve growth factor from seminal origin (spβ-NGF) on ovulation rate and corpus luteum (CL) development and function in llamas. Females with a follicle (≥8 mm) were assigned to groups: (i) i.m. administration of 50 μg of Gonadorelin Acetate (GnRH; positive control; n = 4); (ii) single mating (mating; n = 6); (iii) i.u. infusion of 4 ml of llama SP (SP; n = 4); or (iv) i.u. infusion of 10 mg of spβ-NGF contained in 4 ml of PBS (phosphate-buffered saline) (spβ-NGF; n = 6). Ovaries were examined by power Doppler ultrasonography at 0, 1, 3, 6, 12 and 24 hr after treatment to determine preovulatory follicle vascularization area (VA), and additionally every 12 hr until Day 2 (Day of treatment = Day 0) to determine ovulation. Afterwards, ovaries were examined every other day until Day 8 to evaluate CL diameter and VA. Blood samples were collected on Days 0, 2, 4, 6 and 8 to determine plasma progesterone (P4) concentration. Ovulation rate did not differ (p = .7) among groups, but treatment affected (p 

  • 183 EFFECTS OF LONG-TERM NUTRITIONAL RESTRICTION ON PREOVULATORY LUTEINIZING HORMONE SURGE, LEPTIN, AND LUTEAL PHASE IN LLAMAS (LAMA GLAMA)
    Reproduction Fertility and Development, 2013
    Co-Authors: M.c. Norambuena, Mauricio Silva, Felipe Urra, C. Ulloa-leal, C. Letelier, A. Fernández, Gregg P. Adams, Marcelo H. Ratto
    Abstract:

    The aim of the study was to determine the effect of long-term energy restriction on preovulatory LH surge and luteal phase in llamas. Mature nonlactating, nonpregnant, female llamas (n = 16) were assigned randomly to the following groups: (1) llamas received Ballica sp. hay ad libitum and 300 g d–1 of commercial concentrate (control group, n = 8, BCS = 3.9) or (2) llamas were fed the same feed but the amount was progressively reduced from 70% to 40% of their maintenance energy requirement (MER) for a period of 87 days, until the final BCS was 2.5 (restricted group, n = 8). After 2 months and 21 days of 40% MER diet, ovarian follicular wave emergence was synchronized by transvaginal ultrasound-guided ablation of follicles ≥5 mm in diameter using a 17-ga needle attached to a 5-MHz convex-array transducer. Ten days after follicle ablation (Day 0), llamas were given an i.m. dose of 50 µg of Gonadorelin Acetate to induce ovulation. Frequent blood samples were taken every 30 min for 6 h and every 15 min for 1 h for plasma LH and leptin concentration measurements, respectively, immediately after treatment. Llamas were examined daily by transrectal ultrasonography for 20 days to record serial changes in the CL diameter. In addition, blood samples were taken every 2 days from Day 0 to 16 to determine plasma concentrations of leptin and progesterone. Discrete dependent variables were compared between groups by Student t-tests and continuous dependent variables were analysed by analyses of variance with repeated-measures. There was an effect of time on plasma LH concentration (P ≤ 0.001), but not an effect of group (P = 0.1) or interaction (P = 0.6) after Gonadorelin Acetate treatment. Plasma leptin concentration was lower in llamas from the restricted than that of the control group after Gonadorelin treatment [effect of time, group (P ≤ 0.01), and interaction (P ≤ 0.01)]. The maximum diameter of the CL and plasma progesterone concentration were lower in the restricted than in the control group, and both variables were affected by group (P ≤ 0.01, P ≤ 0.02), and day (P ≤ 0.001, P ≤ 0.001, respectively). Plasma leptin concentration was lower in the restricted than that of the control group during the entire experiment. In conclusion, long-term nutritional restriction affected negatively CL diameter, progesterone secretion, and leptin plasma concentration in llamas. The differential response of leptin to Gonadorelin Acetate treatment could reflect a subfertlity-nutritional induced problem related with steroidogenesis, oocyte quality, ovulation, and early embryo development processes. Research supported by Postdoctoral Fondecyt N° 3110095.

J. J. De La Mata - One of the best experts on this subject based on the ideXlab platform.

  • 7 Pregnancy rates in suckled beef cows synchronized with a shortened progesterone/oestradiol-based protocol (J-synch) and inseminated with conventional or sexed-sorted semen
    Reproduction Fertility and Development, 2019
    Co-Authors: E. E. Huguenine, J. J. De La Mata, R. L. R. De Carneiro, Alejo Menchaca
    Abstract:

    An experiment was designed to evaluate pregnancy rates (P/AI) in suckled beef cows synchronized with a progesterone (P4)/oestradiol-based protocol (J-Synch) and inseminated (AI) with sexed or nonsexed (conventional) semen. Angus or Angus crossbred cows (n = 877), 60 to 90 days postpartum, with a body condition score of 2.5 to 3.5 (scale of 1 to 5) and a corpus luteum or a follicle >8 mm in diameter detected by ultrasonography, were randomly allocated to be AI with sexed-sorted or nonsexed (conventional) semen. The experiment was performed in 4 farms, and the sexed-sorted (SexedUltra™ 4 M, with 4 million sperm; ST Genetics, Navasota, TX, USA) and conventional (25 million sperm) semen were from split ejaculates from 5 Angus bulls. All cows received a P4 device (DIB 0.5, Zoetis, Villa Adelina, Argentina) and 2 mg of oestradiol benzoate (Gonadiol, Zoetis) on Day 0. On Day 6, cows received 400 IU of eCG (Novormon 5000, Zoetis) and 500 µg of cloprostenol (Ciclase DL, Zoetis) and DIB was removed. All cows were also tail painted and observed for signs of oestrus (i.e. >30% of the tail paint rubbed off) at 60, 72, and 84 h after DIB removal. Cows with the tail paint rubbed off by 60 or 72 h after DIB removal were artificially inseminated at 72 h with either sexed or conventional semen. Those not showing oestrus by 72 h received 100 µg of Gonadorelin Acetate (Gonasyn GDR, Zoetis) at that time and were artificially inseminated with either sexed-sorted or conventional semen 12 h later (i.e. 84 h). Pregnancy was diagnosed by ultrasonography 30 days after AI. Data were analysed by general linear model for binary data with a logit link. Overall, 76.4% (678/877) of cows showed oestrus 60 to 84 h after DIB removal, and there were differences in P/AI between sexed-sorted and conventional semen (P 

  • 8 combination of oestrus detection and fixed time artificial insemination in beef heifers following a shortened oestradiol based protocol that provides for a lengthened proestrus
    Reproduction Fertility and Development, 2015
    Co-Authors: J. J. De La Mata
    Abstract:

    Studies have shown that gonadotropin-releasing hormone-based protocols that reduce the period of progestin insertion and prolong the period from progestin removal to gonadotropin-releasing hormone and fixed-time AI (FTAI; named 5-day Co-Synch) results in similar or higher pregnancy rates than the conventional 7-day Co-Synch protocol in beef cows and heifers (Bridges et al. 2008 Theriogenology 69, 843–851). Similar findings have been reported following the use of an oestradiol-based protocol that also provides for a longer period of proestrus (named J-Synch; de la Mata and Bo 2012 Taurus 55, 17–23). An experiment was designed to compare the J-Synch protocol for synchronization of ovulation that allows for a prolonged proestrus with a conventional 7-day oestradiol-based protocol for FTAI in heifers. Cycling 18-month old Angus and Hereford heifers (n = 208) with a body condition score of 6 to 7 (scale of 1 to 9) were randomly allocated to 1 of 2 treatment groups. Heifers in the 7-day EB group (n = 105) received a progesterone (P4) device (DIB 0.5 g of P4, Syntex SA, Buenos Aires, Argentina) and 2 mg of oestradiol benzoate (EB, Syntex SA) on Day 0 and 500 μg of cloprostenol (PGF; Ciclase DL, Syntex SA) and 0.5 mg oestradiol cypionate (Cipiosyn, Syntex SA) on the day of DIB removal (Day 7). Heifers were also tail painted at the time of DIB removal and observed for signs of oestrus (i.e. tail paint rubbed off). Those with the tail paint rubbed off by 36 h after DIB removal were inseminated 12 h later, whereas those not showing oestrus by 36 h were FTAI at 54 h. Heifers in the J-Synch group (n = 103) received DIB and 2 mg of EB on Day 0 and PGF on the day of DIB removal (Day 6). Heifers in this group were also tail painted at DIB removal, and those with their tail paint rubbed off by 48 h were inseminated 12 h later; those not showing oestrus by 60 h received 100 μg of Gonadorelin Acetate (gonadotropin-releasing hormone, Gonasyn gdr, Syntex SA) and were FTAI at 72 h after DIB removal. Pregnancy was diagnosed by ultrasonography at 55 days after FTAI (Honda 101V, 5.0-MHz transducer). Data were analysed by logistic regression. Oestrus detection rate and pregnancy rate to FTAI did not differ (P > 0.1) between groups (38.8%, 40/103 and 60.3%, 38/ 63 for heifers in the J-Synch group v. 28.5%, 30/105 and 45.3%, 34/75 for those in the 7-day EB group). However, pregnancy rates to observed oestrus tended (P < 0.09) to be higher and the overall pregnancy rate was significantly higher (P < 0.01) in heifers in the J-Synch group (80.0%, 32/40 and 67.9%, 70 /103) compared with those in 7-day EB group (50%, 15/30 and 46.6%, 49/105). Furthermore, heifers within the J-Synch group that had their tail paint rubbed off by 48 h after DIB removal and were AI 12 h later (i.e. 60 h) had higher (P < 0.05) pregnancy rate than those in the same group that were FTAI. In conclusion, reducing the time of progestin device insertion and lengthening the proestrus period, as in the J-Synch protocol, results in higher pregnancy rates than with the conventional oestradiol-based protocol. Furthermore, the combination of oestrus detection and FTAI would appear to improve the pregnancy outcome even more.

  • 8 COMBINATION OF OESTRUS DETECTION AND FIXED-TIME ARTIFICIAL INSEMINATION IN BEEF HEIFERS FOLLOWING A SHORTENED OESTRADIOL-BASED PROTOCOL THAT PROVIDES FOR A LENGTHENED PROESTRUS
    Reproduction Fertility and Development, 2015
    Co-Authors: J. J. De La Mata
    Abstract:

    Studies have shown that gonadotropin-releasing hormone-based protocols that reduce the period of progestin insertion and prolong the period from progestin removal to gonadotropin-releasing hormone and fixed-time AI (FTAI; named 5-day Co-Synch) results in similar or higher pregnancy rates than the conventional 7-day Co-Synch protocol in beef cows and heifers (Bridges et al. 2008 Theriogenology 69, 843–851). Similar findings have been reported following the use of an oestradiol-based protocol that also provides for a longer period of proestrus (named J-Synch; de la Mata and Bo 2012 Taurus 55, 17–23). An experiment was designed to compare the J-Synch protocol for synchronization of ovulation that allows for a prolonged proestrus with a conventional 7-day oestradiol-based protocol for FTAI in heifers. Cycling 18-month old Angus and Hereford heifers (n = 208) with a body condition score of 6 to 7 (scale of 1 to 9) were randomly allocated to 1 of 2 treatment groups. Heifers in the 7-day EB group (n = 105) received a progesterone (P4) device (DIB 0.5 g of P4, Syntex SA, Buenos Aires, Argentina) and 2 mg of oestradiol benzoate (EB, Syntex SA) on Day 0 and 500 μg of cloprostenol (PGF; Ciclase DL, Syntex SA) and 0.5 mg oestradiol cypionate (Cipiosyn, Syntex SA) on the day of DIB removal (Day 7). Heifers were also tail painted at the time of DIB removal and observed for signs of oestrus (i.e. tail paint rubbed off). Those with the tail paint rubbed off by 36 h after DIB removal were inseminated 12 h later, whereas those not showing oestrus by 36 h were FTAI at 54 h. Heifers in the J-Synch group (n = 103) received DIB and 2 mg of EB on Day 0 and PGF on the day of DIB removal (Day 6). Heifers in this group were also tail painted at DIB removal, and those with their tail paint rubbed off by 48 h were inseminated 12 h later; those not showing oestrus by 60 h received 100 μg of Gonadorelin Acetate (gonadotropin-releasing hormone, Gonasyn gdr, Syntex SA) and were FTAI at 72 h after DIB removal. Pregnancy was diagnosed by ultrasonography at 55 days after FTAI (Honda 101V, 5.0-MHz transducer). Data were analysed by logistic regression. Oestrus detection rate and pregnancy rate to FTAI did not differ (P > 0.1) between groups (38.8%, 40/103 and 60.3%, 38/ 63 for heifers in the J-Synch group v. 28.5%, 30/105 and 45.3%, 34/75 for those in the 7-day EB group). However, pregnancy rates to observed oestrus tended (P 

Jordan M Thomas - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of later timepoints for split-time artificial insemination when using sex-sorted semen among beef heifers following the 14-d CIDR®-PG protocol
    Animal reproduction science, 2020
    Co-Authors: Jaclyn N Ketchum, R.c. Bonacker, C.m. Spinka, C. M. Andersen, E. G. Smith, K. S. Stoecklein, Jordan M Thomas
    Abstract:

    Abstract An experiment was designed to evaluate later timepoints for Split-Time AI (STAI), with the hypothesis that delaying AI may improve estrous response and pregnancy per AI when using sex-sorted semen. Timing of estrus was synchronized among 794 heifers using the 14-d CIDR®-PG protocol (1.38 g progesterone intravaginal insert from Day 0–14, followed by 25 mg dinoprost tromethamine on Day 30) with STAI performed based on estrous status. Heifers were blocked based on breed, source, sire, reproductive tract score (RTS), and BW and assigned within block to one of two approaches. In Approach 66, heifers that were estrual by 66 h after PG administration were inseminated at 66 h, and remaining heifers were inseminated 24 h later (90 h). In Approach 72, heifers that were estrual by 72 h were inseminated at 72 h, and remaining heifers were inseminated 24 h later (96 h). With both approaches, heifers that were non-estrual by the final timepoint were administered 100 μg Gonadorelin Acetate (GnRH). Within approach, heifers were pre-assigned to receive SexedULTRA 4M™ sex-sorted or conventional semen. The proportion of heifers estrual by the first timepoint was greater (P

  • Comparison of the 7 & 7 Synch protocol and the 7-day CO-Synch + CIDR protocol among recipient beef cows in an embryo transfer program
    Theriogenology, 2020
    Co-Authors: R.c. Bonacker, K. R. Gray, C. A. Breiner, J. M. Anderson, D. J. Patterson, C.m. Spinka, Jordan M Thomas
    Abstract:

    Abstract An experiment was designed to evaluate the effectiveness of the recently developed 7 & 7 Synch protocol to synchronize estrus among recipients prior to embryo transfer (ET). Postpartum beef cows (n = 1358) across thirteen locations were assigned to either the 7-d CO-Synch + CIDR protocol or the 7 & 7 Synch protocol prior to ET. Cows were preassigned to balanced treatments within location based on age and days postpartum, with body condition score recorded at ET. Cows assigned to the 7-d CO-Synch + CIDR protocol were administered gonadotropin-releasing hormone (GnRH; 100 μg Gonadorelin Acetate) on Day 7, an intravaginal controlled internal drug release (CIDR; 1.38 g progesterone) from Day 7 to Day 14, and prostaglandin F2α (PGF2α; 25 mg dinoprost tromethamine) coincident with CIDR removal on Day 14. Cows assigned to the 7 & 7 Synch protocol were administered PGF2α (25 mg dinoprost tromethamine) coincident with CIDR insertion on Day 0, GnRH (100 μg Gonadorelin Acetate) on Day 7, and PGF2α (25 mg dinoprost tromethamine) coincident with CIDR removal on Day 14. Cows were observed for visible signs of estrus, with GnRH (100 μg Gonadorelin Acetate) administered to cows failing to express estrus during the detection period. Embryo transfer was performed approximately seven days after estrus or GnRH administration. Presence of corpora lutea (CL) was determined via transrectal palpation by a single veterinarian blinded to treatment, and embryos were transferred only to cows with palpable CL. Embryo transfer was performed using either fresh or frozen embryos, with embryo stage and grade recorded for each recipient. The proportion of cows expressing estrus was increased (P

  • 166 Comparison of the 7 and 7 Synch protocol and the 7-day CO-Synch + controlled internal drug release protocol among recipient beef cows in an embryo transfer programme
    Reproduction Fertility and Development, 2020
    Co-Authors: R.c. Bonacker, K. R. Gray, C. A. Breiner, J. M. Anderson, D. J. Patterson, Jordan M Thomas
    Abstract:

    An experiment was designed to evaluate the effectiveness of the recently developed 7 and 7 Synch protocol to synchronise oestrus and ovulation among recipients before embryo transfer (ET). Postpartum beef cows (n = 1358) across 13 locations were assigned to either the 7-day CO-Synch + controlled internal drug release (CIDR) protocol or the 7 and 7 Synch protocol before oestrus detection and subsequent ET. Cows were pre-assigned to balanced treatments within location based on age and days postpartum, and body condition score was recorded at ET. Cows assigned to the 7-day CO-Synch + CIDR protocol were administered gonadotrophin-releasing hormone (GnRH; 100 µg of Gonadorelin Acetate) on Day 0, an intravaginal CIDR insert (1.38 g of progesterone) from Day 0 to 7, and prostaglandin F2α (PG; 25 mg of dinoprost tromethamine) coincident with CIDR removal on Day 7. Cows assigned to the 7 and 7 Synch protocol were administered PG (25 mg of dinoprost tromethamine) coincident with CIDR insertion on Day −7, GnRH (100 µg of Gonadorelin Acetate) on Day 0, and PG (25 mg of dinoprost tromethamine) coincident with CIDR removal on Day 7. The 7 and 7 Synch protocol was hypothesised to enhance response to GnRH administration on Day 0 among mixed groups of oestrous cycling and anestrous cows, ultimately resulting in improved oestrous response and synchrony of oestrus before ET. Cows were observed for visible signs of oestrus following oestrus synchronisation, with GnRH (100 µg of Gonadorelin Acetate) administered to cows failing to express oestrus during the detection period. Length of the detection period varied among locations but was consistent across treatments within location. Embryo transfer was performed approximately 7 days after oestrus or GnRH administration. Presence of corpora lutea (CL) was determined via transrectal palpation by a single veterinarian blinded to treatment, and embryos were transferred only to cows with palpable CL. Embryo transfer was performed using fresh or frozen embryos staged and graded according to IETS recommended guidelines, with embryo information recorded for each recipient. Data were analysed using the PROC GLIMMIX procedure of SAS (SAS Institute Inc.). Proportion of cows expressing oestrus was improved (P 

  • PSXIII-12 Evaluation of split-time artificial insemination following administration of the 7-d CO-Synch + CIDR® estrus synchronization protocol in beef heifers
    Journal of Animal Science, 2019
    Co-Authors: E Knickmeyer, R.c. Bonacker, Jordan M Thomas, J.w.c. Locke, Mark R. Ellersieck, Scott E. Poock, Michael F. Smith, David J. Patterson
    Abstract:

    Abstract Estrous response and pregnancy rates resulting from fixed-time (FTAI) or split-time (STAI) artificial insemination were compared among heifers following treatment with the 7-d CO-Synch + CIDR® (controlled internal drug release;1.38g progesterone) protocol. Heifers (n = 456) were assigned to balanced treatments based on weight and reproductive tract score (RTS; Scale 1–5). Gonadotropin-releasing hormone (GnRH; 100 µg Gonadorelin Acetate) was administered coincident with CIDR® insertion. Progesterone inserts were removed after 7 d, and PG (250 mg im cloprostenol sodium) was administered at CIDR® removal. Estrus detection aids (Estrotect®) were applied at the time PG was administered. Estrous status was recorded at FTAI or STAI, and estrus was defined as removal of ≥ 50% of the grey coating from the Estrotect® patch. Heifers assigned to the FTAI treatment received GnRH and were artificially inseminated 54 h after PG administration. In the STAI treatment, only heifers that expressed estrus prior to 54 h were artificially inseminated at that time. For heifers failing to express estrus, AI was postponed 24 h and only those heifers that failed to exhibit estrus by the delayed time (78 h) received GnRH concurrent with AI. Estrous response prior to the standard time of FTAI did not differ between treatments (P = 0.3). Total estrous response was increased (P &lt; 0.001) among heifers assigned to STAI (74%, STAI; 47%, FTAI); however, pregnancy rates resulting from AI were similar between treatments (48%, STAI; 46%, FTAI; P = 0.4), as were pregnancy rates at the end of a 60 d breeding season (P = 0.6). In summary, STAI resulted in a greater estrous response following treatment with the 7-d CO-Synch + CIDR® protocol; however, this did not result in an increase in pregnancy rate compared to heifers that received FTAI.

  • Altering duration of the presynchronization period in a long-term progestin-based estrus synchronization protocol for timed artificial insemination of beef heifers
    Theriogenology, 2019
    Co-Authors: E Knickmeyer, R.c. Bonacker, Jordan M Thomas, Jaclyn N Ketchum, J.w.c. Locke, Mark R. Ellersieck, Scott E. Poock, Michael F. Smith, Lauren A Ciernia, D. J. Patterson
    Abstract:

    Abstract An experiment was designed to evaluate the effect of extending duration of the presynchronization treatment in a long-term progestin-based estrus synchronization protocol. Heifers were assigned to either an 18 d (Day 0–18) or 14 d (Day 4 to Day 18) CIDR® treatment (1.38 g progesterone controlled internal drug release insert; Zoetis, Madison, NJ), with prostaglandin F2α (PG; 250 μg im cloprostenol sodium) administered 16 d after CIDR® removal (Day 34). Heifers at two locations (location one, n = 193; location two, n = 649) were assigned to treatment based on reproductive tract score (RTS; Scale 1–5) and body weight. Heifers that were assigned RTS 1 were not retained for the trial (n = 6). Estrus detection aids (Estrotect®) were applied at PG. Split-time artificial insemination (STAI) was utilized and AI performed based on expression of estrus at 66 h. Expression of estrus was defined as removal of ≥50% of the grey coating from the Estrotect® patch. Heifers that expressed estrus at 66 h were inseminated then and heifers that had not expressed estrus were inseminated at 90 h. Only heifers that failed to express estrus by 90 h received gonadotropin-releasing hormone (GnRH; 100 μg im Gonadorelin Acetate) at the time of AI. At location one, blood samples were collected at PG and AI (66 h or 90 h) from all heifers to determine E2 concentration by radioimmunoassay, and transrectal ovarian ultrasound was performed to detail ovarian structures on a subset of heifers (n = 73) at both time points. The proportion of heifers expressing estrus did not differ between treatments, either by 66 h (60%) or in total by 90 h (84%) after PG. Pregnancy rate to STAI did not differ between treatments (P = 0.3; 52%, 14-d CIDR®-PG; 50%, 18-d CIDR®-PG), or at the end of the 60 d breeding season (P = 0.2; 86%, 14-d CIDR®-PG; 82%, 18-d CIDR®-PG). No differences were detected in mean diameter of the dominant follicle at PG (P = 0.6; 10.9 ± 0.4 mm, 14-d CIDR®-PG; 11.0 ± 0.4 mm, 18-d CIDR®-PG) or at STAI (P = 0.3; 12.6 ± 0.4 mm, 14-d CIDR®-PG; 13.2 ± 0.4 mm, 18-d CIDR®-PG), nor were any differences observed between treatments in concentrations of E2 at PG (P = 0.8; 1.1 ± 0.19 pg/ml, 14-d CIDR®-PG; 1.1 ± 0.19 pg/ml, 18-d CIDR®-PG) or STAI (P = 0.6; 3.8 ± 0.19 pg/ml, 14-d CIDR®-PG; 3.6 ± 0.19 pg/ml, 18-d CIDR®-PG). These data indicate that duration of CIDR® treatment can be extended from 14 to 18 d, thus providing flexibility in scheduling without compromising reproductive outcomes.