scholarly journals Gonadotropin-releasing hormone increased pregnancy risk in suckled beef cows not detected in estrus and subjected to a split-time artificial insemination program12

2016 ◽  
Vol 94 (9) ◽  
pp. 3722-3728 ◽  
Author(s):  
S. L. Hill ◽  
D. M. Grieger ◽  
K. C. Olson ◽  
J. R. Jaeger ◽  
C. R. Dahlen ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Beef Cows ◽  
Gonadotropin Releasing Hormone ◽  
Pregnancy Risk ◽  
Releasing Hormone ◽  
Split Time

1110 GnRH increased pregnancy risk in suckled beef cows that did not display estrus when subjected to a split-time artificial insemination program

2016 ◽  
Vol 94 (suppl_5) ◽  
pp. 532-532
Author(s):  
S. L. Hill ◽  
D. M. Grieger ◽  
K. C. Olson ◽  
J. R. Jaeger ◽  
C. R. Dahlen ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Beef Cows ◽  
Pregnancy Risk ◽  
Split Time

scholarly journals Evaluation of the 7 and 7 synch protocol for control of the estrous cycle among beef cows prior to fixed-time artificial insemination with sex-sorted or conventional semen

2021 ◽  
Author(s):  
◽  
Carson M. Andersen
Keyword(s):  
Artificial Insemination ◽  
Fixed Time ◽  
Beef Cows ◽  
Gonadotropin Releasing Hormone ◽  
Pregnancy Rates ◽  
Releasing Hormone ◽  
Prostaglandin F2 Alpha ◽  
Estrus Detection ◽  
To Receive ◽  
Activation Status

Experiment 1 was conducted to compare 7 and 7 Synch and the 7-day CO-Synch + controlled internal drug release (CIDR[copyright]) protocols prior to fixed-time artificial insemination (FTAI) of beef cows with conventional or sex-sorted semen. Cows (n = 1,538) were blocked based on age and days postpartum (DPP) and randomly assigned to protocol and semen type. Cows assigned to 7-day CO-Synch + CIDR (n = 769) received administration of gonadotropin-releasing hormone (GnRH) and insertion of an intravaginal progesterone-releasing insert (CIDR) on Day -10, and administration of prostaglandin F2[alpha] (PG) coincident with CIDR removal on Day -3. Cows assigned to 7 and 7 Synch (n = 769) received PG and insertion of CIDR on Day -17, GnRH on Day -10, and PG coincident with CIDR removal on Day -3. Estrus detection aids were applied to all cows. Cows received FTAI 66 h after CIDR removal with conventional (20 x 106 cells per unit) or sex-sorted (4 x 106 cells per unit) semen. Estrus expression was affected by protocol (P = 0.01) by protocol x DPP (P = 0.0004), with 7 and 7 Synch (82 percent; 629/769) resulting in a greater proportion of cows expressing estrus (82 percent [629/769] versus 64 percent [492/769]), especially among cows with greater DPP. Pregnancy rates to FTAI were reduced (P < 0.0001) when using sex-sorted semen but greater among cows treated with 7 and 7 Synch (conventional semen: 72 percent [280/389]; sex-sorted semen: 52 percent [199/380]) compared with 7-day CO-Synch + CIDR (conventional semen: 61 percent [233/383]; sex-sorted semen: 44 percent [171/386]). Experiment 2 was designed to evaluate later timing of fixed-time artificial insemination (FTAI) with sex-sorted semen among postpartum beef cows following the 7 and 7 Synch protocol, with the hypothesis that later timing would result in increased pregnancy rates (P/AI) among cows that expressed estrus prior to FTAI. Beef cows (n=414) were blocked based on age and days postpartum (DPP) and randomly assigned to receive FTAI at 66 or 72 h after administration of prostaglandin F2[alpha] (PG). Estrus was synchrized using the 7 and 7 Synch protocol, which consists of administration of PG (500 [mu]g cloprostenol) and insertion of an intravaginal progesterone-releasing insert (CIDR; 1.38 g progesterone) on Day 0, gonadotropin-releasing hormone (GnRH; 100 [mu]g gonadorelin) on Day 7, and PG coincident with CIDR removal on Day 14. Estrus detection aids (EstrotectTM) were applied to all cows on Day 14, and activation status was recorded at fixed-time artificial insemination (FTAI) on Day 17. All cows that expressed estrus prior to FTAI received sex-sorted semen (4 x 106 cells per unit; SexedULTRA 4MTM). The proportion of cows expressing estrus prior to FTAI did not differ between treatments at this power of test (66 h: 71 percent [146/205]; 72 h: 76 percent [158/209]). Additionally, P/AI of estrous cows inseminated with sex-sorted semen did not differ between treatments (66 h: 45 percent [68/146]; 72 h: 40 percent [63/158]). In conclusion, later timing of FTAI following the 7 and 7 Synch protocol failed to improve P/AI of estrous cows inseminated h sex-sorted semen.

PSXII-15 Evaluation of later timing of fixed-time artificial insemination for beef cows when using sex-sorted semen following the 7 & 7 Synch protocol

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 423-424
Author(s):  
Carson M Andersen ◽  
Emily G Smith ◽  
Genna M VanWye ◽  
Jordan M Thomas
Keyword(s):  
Artificial Insemination ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Beef Cows ◽  
Gonadotropin Releasing Hormone ◽  
Power Of Test ◽  
Releasing Hormone ◽  
Estrus Detection ◽  
To Receive ◽  
Activation Status

Abstract An experiment was designed to evaluate later timing of fixed-time artificial insemination (FTAI) with sex-sorted semen among postpartum beef cows following the 7 & 7 Synch protocol, with the hypothesis that later timing would result in increased pregnancy rates (P/AI) among cows that expressed estrus prior to FTAI. Beef cows (n = 414) were blocked based on age and days postpartum (DPP) and randomly assigned to receive FTAI at 66 or 72 h after administration of prostaglandin F2α (PG). Estrus was synchronized using the 7 & 7 Synch protocol, which consists of administration of PG (500 μg cloprostenol) and insertion of an intravaginal progesterone-releasing insert (CIDR; 1.38 g progesterone) on Day 0, gonadotropin-releasing hormone (GnRH; 100 μg gonadorelin) on Day 7, and PG coincident with CIDR removal on Day 14. Estrus detection aids (EstrotectTM) were applied to all cows on Day 14, and activation status was recorded at fixed-time artificial insemination (FTAI) on Day 17. All cows that expressed estrus prior to FTAI received sex-sorted semen (4 × 106 cells per unit; SexedULTRA 4MTM). The proportion of cows expressing estrus prior to FTAI did not differ between treatments at this power of test [66 h: 71% (146/205); 72 h: 76% (158/209)]. Additionally, P/AI of estrous cows inseminated with sex-sorted semen did not differ between treatments [66 h: 44% (90/205); 72 h: 39% (82/209)]. In conclusion, later timing of FTAI following the 7 & 7 Synch protocol failed to improve P/AI of estrous cows inseminated with sex-sorted semen.

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