Evaluation of split-time artificial insemination following administration of a long or short-term progestin-based estrus synchronization protocol in beef heifers

2019 ◽  
Vol 133 ◽  
pp. 179-186 ◽  
Author(s):  
E.R. Knickmeyer ◽  
J.M. Thomas ◽  
J.W.C. Locke ◽  
R.C. Bonacker ◽  
M.R. Ellersieck ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Estrus Synchronization ◽  
Beef Heifers ◽  
Short Term ◽  
Split Time ◽  
Synchronization Protocol

scholarly journals PSXIII-12 Evaluation of split-time artificial insemination following administration of the 7-d CO-Synch + CIDR® estrus synchronization protocol in beef heifers

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 374-374
Author(s):  
Emma R Knickmeyer ◽  
Jordan M Thomas ◽  
James William C Locke ◽  
Rachael C Bonacker ◽  
Mark R Ellersieck ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Reproductive Tract ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Estrus Synchronization ◽  
Beef Heifers ◽  
Estrus Detection ◽  
Delayed Time ◽  
Split Time ◽  
Synchronization Protocol

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 < 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.

scholarly journals PSXIII-11 Altering length of the presynchronization period in a long-term progestin-based estrus synchronization protocol for timed artificial insemination of beef heifers

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 375-376
Author(s):  
Emma R Knickmeyer ◽  
Jordan M Thomas ◽  
James William C Locke ◽  
Rachael C Bonacker ◽  
Lauren Ciernia ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Reproductive Tract ◽  
Prostaglandin F2α ◽  
Estrus Synchronization ◽  
Dominant Follicle ◽  
Estrus Detection ◽  
Timed Artificial Insemination ◽  
Split Time ◽  
Synchronization Protocol

Abstract An experiment was designed to evaluate the effect of extending the presynchronization period in a progestin-based estrus synchronization protocol. Heifers were assigned to an 18 d or 14 d CIDR® treatment (1.38 g progesterone), with prostaglandin F2α (PG; 250 mg im) 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 weight. Estrus detection aids (Estrotect®) were applied at PG and split-time artificial insemination (STAI) was performed based on estrus expression at 66 h. Heifers that expressed estrus at 66 h were inseminated and heifers that did not express estrus were inseminated at 90 h. Only heifers that failed to express estrus by 90 h received gonadotropin-releasing hormone (GnRH; 100 µg im) at AI. At location one, blood samples were collected at PG and AI (66 h or 90 h) from all heifers to determine E2 concentrations, 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 by 66 h (60%) or in total by 90 h (84%) after PG did not differ between treatments. 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). There were no differences between treatments in mean diameter of the dominant follicle at PG (P = 0.6) or STAI (P = 0.3), nor were any differences observed between treatments in E2 concentrations at PG (P = 0.8) or STAI (P = 0.6). These data suggest that CIDR® treatment can be extended from 14 to 18 d, providing flexibility in scheduling without compromising reproductive outcomes.

scholarly journals Altering duration of the presynchronization period in a long-term progestin-based estrus synchronization protocol for timed artificial insemination of beef heifers

2019 ◽  
Vol 136 ◽  
pp. 66-71 ◽  
Author(s):  
E.R. Knickmeyer ◽  
J.M. Thomas ◽  
J.W.C. Locke ◽  
R.C. Bonacker ◽  
L.A. Ciernia ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Estrus Synchronization ◽  
Beef Heifers ◽  
Timed Artificial Insemination ◽  
Synchronization Protocol

scholarly journals Short-term progestin estrus synchronization with timed insemination for beef heifers: CIDR vs. MGA

2004 ◽  
pp. 11-12
Author(s):  
A.W. Thompson ◽  
D.R. Eborn ◽  
L.D. Keenan ◽  
David M. Grieger
Keyword(s):  
Estrus Synchronization ◽  
Beef Heifers ◽  
Short Term

Evaluation of later timepoints for split-time artificial insemination when using sex-sorted semen among beef heifers following the 14-d CIDR®-PG protocol

2021 ◽  
Vol 224 ◽  
pp. 106649
Author(s):  
J.N. Ketchum ◽  
R.C. Bonacker ◽  
C.M. Andersen ◽  
E.G. Smith ◽  
K.S. Stoecklein ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Beef Heifers ◽  
Split Time

510 Impact of estrus synchronization and fixed-time artificial insemination on calving distribution in Bos indicus influenced beef heifers

2017 ◽  
Vol 95 (suppl_4) ◽  
pp. 249-249
Author(s):  
N. Oosthuizen ◽  
P. L. P. Fontes ◽  
C. D. Sanford ◽  
F. M. Ciriaco ◽  
D. D. Henry ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Bos Indicus ◽  
Fixed Time ◽  
Estrus Synchronization ◽  
Beef Heifers
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