Ovulation and pregnancy outcomes in response to human chorionic gonadotropin before resynchronized ovulation in dairy cattle

Buttrey, B.S.; Burns, Matthew; Stevenson, Jeffrey S.

doi:10.1016/j.theriogenology.2009.09.027

Cited by 18 publications

(9 citation statements)

References 29 publications

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“…This lesser response to hCG was independent of pregnancy status but related to greater endogenous progesterone concentrations in cows with more pretreatment CL, which agrees with our previous observations in cows treated with hCG at later stages of pregnancy (d 26 to 71; Stevenson et al, 2008). In nonpregnant cows that were treated with hCG or GnRH as part of a resynchronization program, incidence of new luteal structure formation was affected by treatment, pretreatment progesterone status by treatment interaction, and number of pretreatment CL (Buttrey et al, 2010). Use of GnRH was more effective than hCG in cows with reduced (<1 ng/mL) progesterone concentrations, whereas hCG (1,000 IU) was more effective than GnRH in cows with progesterone concentrations ≥1 ng/mL (Buttrey et al, 2010).…”

Section: Discussionsupporting

confidence: 90%

“…One of the objectives of the present study was to determine characteristics of luteal structures (size, number, and stayability) formed in response to hCG administered on d 7 after AI (first service) in lactating dairy cows. Previous studies in dairy cows have reported similar frequencies of newly formed post-AI luteal structures when hCG was administered at doses ranging from 1,000 to 3,300 IU Stevenson et al, 2007;Buttrey et al, 2010). When administered on d 5 after estrus or between d 5 and 9 after AI, formation of new luteal structures in response to hCG ranged from 60 to 75% Stevenson et al, 2007).…”

Section: Discussionmentioning

confidence: 67%

“…In nonpregnant cows that were treated with hCG or GnRH as part of a resynchronization program, incidence of new luteal structure formation was affected by treatment, pretreatment progesterone status by treatment interaction, and number of pretreatment CL (Buttrey et al, 2010). Use of GnRH was more effective than hCG in cows with reduced (<1 ng/mL) progesterone concentrations, whereas hCG (1,000 IU) was more effective than GnRH in cows with progesterone concentrations ≥1 ng/mL (Buttrey et al, 2010).…”

Section: Discussionmentioning

confidence: 95%

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Characteristics and retention of luteal structures, extended postinsemination cycle, progesterone, and pregnancy-specific protein B in serum after human chorionic gonadotropin treatment of dairy cows

Stevenson

Pulley

2012

Journal of Dairy Science

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Our objectives were to determine characteristics (size, number, and stayability) of luteal structures formed in response to human chorionic gonadotropin (hCG) administered on d 7 after timed artificial insemination (AI) and the influence of hCG on returns to estrus and pregnancy outcome. Holstein cows (n=328), milked 3 times daily, previously inseminated at first service were assigned randomly to a completely randomized design consisting of 2 treatments when at least 1 corpus luteum (CL) was detected on d 7 after AI. Treatment consisted of 1,000 IU hCG or 1 mL of saline (control) administered i.m. Blood was collected and luteal structures were mapped and sized by transrectal ultrasonography on d 7, 14, 21, 28, and 32 after AI. Blood also was collected on d 60 in all pregnant cows. Treatment with hCG induced new luteal structures in 70% of cows, regardless of pregnancy status or number of pretreatment CL. Cows producing greater than the median 46 kg of energy-corrected milk per day were less likely to respond to hCG. The number of total luteal structures per cow, original CL volume, and total luteal volume (original CL + new luteal structures) were increased by hCG. Progesterone concentration was greater in pregnant than nonpregnant cows on d 14 unless cows responded to hCG by forming new luteal structures. Concentrations of progesterone were greatest in pregnant, hCG-treated cows. Pregnancy per AI at d 32 or 60 after first AI was less in hCG- than saline-treated cows because pregnancy outcome for hCG cows that had only 1 pretreatment CL and failed to respond to hCG was only 55 to 61% of that observed in controls. Proportions of cows returning to estrus from 18 to 25 d after AI were less in hCG than control cows but greater for cows returning >25 d. Regardless of treatment, 25% of cows in both treatments retained at least 1 original CL to d 28 after AI and were not pregnant on d 32. Progesterone concentrations in these nonpregnant cows with retained CL between d 14 and 28 after AI were intermediate between nonpregnant cows that returned to estrus by d 25 and all pregnant cows. Concentrations of pregnancy-specific protein B were elevated in some of these nonpregnant, CL-retained cows, indicating early pregnancy loss. Retention of original luteal tissue in nonpregnant cows to d 28 after AI indicated that pregnancy had been initiated but failed, as verified by concentrations of progesterone and pregnancy-specific protein B.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 67%

Section: Discussionmentioning

confidence: 95%

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Characteristics and retention of luteal structures, extended postinsemination cycle, progesterone, and pregnancy-specific protein B in serum after human chorionic gonadotropin treatment of dairy cows

Stevenson

Pulley

2012

Journal of Dairy Science

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“…Surprisingly, the increase in P/AI due to presynchronization with GnRH (and, consequently, with high P4 at G1) was not related to an increase in ovulatory response to G1. The suppressive effect of circulating P4 on GnRH-induced LH secretion has been reported (Buttrey et al, 2010;Giordano et al, 2012b), and the mechanism seems to involve the negative feedback of high P4 on pituitary release of LH in both lactating dairy cows (Giordano et al, 2012b) and beef heifers (Dias et al, 2010).…”

Section: Ovulatory Response To G1 and Luteal Regression After Pgfmentioning

confidence: 99%

Effect of timing of initiation of resynchronization and presynchronization with gonadotropin-releasing hormone on fertility of resynchronized inseminations in lactating dairy cows

Lopes

Giordano

Valenza

et al. 2013

Journal of Dairy Science

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Lactating Holstein cows (n=1,456) were randomized in a 2×2 factorial design to compare the main effects of day of initiation of resynchronization after artificial insemination (AI; 32 vs. 39 d) and presynchronization with GnRH 7d before initiation of resynchronization on fertility to timed AI (TAI). This design resulted in the following 4 resynchronization treatments: (1) resynchronization (GnRH treatment, PGF2α treatment 7d later, GnRH treatment 56 h later, and TAI 16 h later), initiated 32 ± 3 d after AI; (2) presynchronization with 100 µg of GnRH 25 ± 3 d after AI and resynchronization initiated 32 ± 3 d after AI at nonpregnancy diagnosis; (3) resynchronization initiated 39 ± 3 d after AI (GPG39); and (4) presynchronization with 100 µg of GnRH 32 ± 3 d after AI at nonpregnancy diagnosis and resynchronization initiated 39 ± 3 d after AI. Overall, 344 cows were inseminated at estrus between enrollment (25 ± 3 d after AI) and TAI of the resynchronization treatments, and 1,112 cows received TAI. Progesterone (P4) was analyzed in blood samples collected from all cows at the first GnRH injection of the resynchronization protocols (G1), and ovarian structures were evaluated and blood samples were collected at G1, at the PGF2α injection, and at the TAI of the resynchronization protocols in a subgroup of cows (n=417). When analyzed as main effects, cows presynchronized with GnRH had more pregnancies per AI (P/AI) than nonpresynchronized cows (38.9 vs. 33.8%), whereas timing of initiation of resynchronization did not affect P/AI. Although cows with high P4 at G1 had greater P/AI than cows with low P4 (38.7 vs. 31.8%), presynchronization with GnRH did not increase the proportion of cows with high P4 (>1.0 ng/mL) at G1 but moved cows from a low-P4 environment to an intermediate-P4 level. Presynchronization with GnRH also decreased the percentage of cows with low P4 at the PGF2α injection, thereby increasing synchrony to the protocol. Cows with high P4 at G1 had a decreased ovulatory response to G1 compared with cows with low P4 (40.9 vs. 69.1%), and cows that ovulated to G1 had decreased luteal regression after PGF2α compared with cows that did not ovulate (78.5 vs. 87.3%). We conclude that presynchronization with GnRH 7d before initiation of resynchronization increased fertility in dairy cows, whereas timing of initiation of resynchronization did not.

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“…Ovulation, follicular wave emergence, and corpus luteum (CL) formation result from administration of hCG (Niasari-Naslaji et al, 1996;Diaz et al, 1998). When hCG was administered to beef cows, CL development resulted from follicles <10 mm in diameter (Sheffel et al, 1982) and 6 of 18 Iactating dairy cows treated with hCG having follicles <10 mm in diameter ovulated compared with 0 of 13 treated with GnRH (Buttrey et al, 2010). In addition, beef cows receiving 1,000 IU of hCG tended to have greater concentrations of progesterone (P4) 7 d after treatment than those receiving GnRH (Burns et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Administration of human chorionic gonadotropin to suckled beef cows before ovulation synchronization and fixed-time insemination: Replacement of gonadotropin-releasing hormone with human chorionic gonadotropin1

Marquezini

Dahlen

Bird

et al. 2011

Journal of Animal Science

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Two experiments were conducted to evaluate whether hCG administered 7 d before initiating the CO-Synch + controlled internal drug release (CIDR) ovulation synchronization protocol (Exp. 1 and 2), or replacing GnRH with hCG at the time of AI (Exp. 1), would improve fertility to a fixed-time AI (TAI) in suckled beef cows. In addition, the effects of hCG on follicle dynamics, corpus luteum development, and concentrations of progesterone (P4) were evaluated. In Exp. 1, cows were stratified by days postpartum, age, and parity and assigned randomly to a 2 × 2 factorial arrangement of 4 treatments: 1) cows received 100 µg of GnRH at CIDR insertion (d -7) and 25 mg of PGF(2α) at CIDR removal (d 0), followed in 64 to 68 h by a TAI plus a second injection of GnRH at TAI (CG; n = 29); 2) same as CG but the second injection of GnRH at the time of insemination was replaced by hCG (CH; n = 28); 3) same as CG, but cows received hCG 7 d (d -14) before CIDR insertion (HG; n = 28); and 4) same as HG, but cows received hCG 7 d (d -14) before CIDR insertion (HH; n = 29). Pregnancy rates were 52, 41, 59, and 38% for GG, GH, HG, and HH, respectively. Cows receiving hCG (39%) in place of GnRH at TAI tended (P = 0.06) to have poorer pregnancy rates than those receiving GnRH (56%). Pre-CO-Synch hCG treatment increased (P < 0.05) the percentage of cows with concentrations of P4 >1 ng/mL at d -7, increased (P < 0.02) concentration of P4 on d -7, and decreased (P < 0.001) the size of the dominant follicle on d 0 and 3, compared with cows not treated with hCG on d -14. In Exp. 2, cows were stratified based on days postpartum, BCS, breed type, and calf sex and then assigned to the CG (n = 102) or HG (n = 103) treatments. Overall pregnancy rates were 51%, but no differences in pregnancy rates were detected between treatments. Pre-CO-Synch hCG treatment increased (P < 0.05) the percentage of cows cycling on d -7 and increased (P < 0.05) concentrations of P4 on d -7 compared with pre-CO-Synch controls. Therefore, pretreatment induction of ovulation after hCG injection 7 d before initiation of CO-Synch + CIDR protocol failed to enhance pregnancy rates, but replacing GnRH with hCG at the time of AI may reduce pregnancy rates.

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Ovulation and pregnancy outcomes in response to human chorionic gonadotropin before resynchronized ovulation in dairy cattle

Cited by 18 publications

References 29 publications

Characteristics and retention of luteal structures, extended postinsemination cycle, progesterone, and pregnancy-specific protein B in serum after human chorionic gonadotropin treatment of dairy cows

Characteristics and retention of luteal structures, extended postinsemination cycle, progesterone, and pregnancy-specific protein B in serum after human chorionic gonadotropin treatment of dairy cows

Effect of timing of initiation of resynchronization and presynchronization with gonadotropin-releasing hormone on fertility of resynchronized inseminations in lactating dairy cows

Administration of human chorionic gonadotropin to suckled beef cows before ovulation synchronization and fixed-time insemination: Replacement of gonadotropin-releasing hormone with human chorionic gonadotropin1

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