scholarly journals PSXIII-22 Modeling the optimal time point at which to perform timed artificial insemination

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 371-371
Author(s):  
Jordan M Thomas ◽  
William R Lamberson ◽  
John B Hall
Keyword(s):  
Mathematical Model ◽  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Pregnancy Rates ◽  
Optimal Time ◽  
Estrus Synchronization ◽  
Time Points ◽  
Optimal Time Point ◽  
Split Time ◽  
Time Point

Abstract Timing of artificial insemination (AI) critically impacts likelihood of pregnancy success. In modern timed AI protocols for cattle, AI is performed at a predetermined time point following estrus synchronization. As a result, there may be significant variation among cows or heifers in estrous status and in timing of insemination relative to estrus onset. Recommendations as to when timed AI should be performed are formulated based on research trials evaluating alternative time points. However, available data are limited, as such trials are costly and require large numbers to detect significant differences. As an alternative approach, a mathematical model was developed to predict the anticipated aggregate pregnancy rate to timed AI based on the hour at which timed AI is performed. Previously published distributions of estrus onset were compiled separately for two long-term progestin-based protocols for beef heifers (MGA-PG and 14-d CIDR-PG). Probability of pregnancy was modeled using a regression equation for fertility based on timing of AI in relation to timing of estrus, with heifers grouped in one hour time blocks. Based on a previously published meta-analysis that compiled pregnancy rates when timed AI was performed prior to onset of estrus, a reduced pregnancy rate was assigned to heifers for which timed AI would be performed prior to anticipated estrus expression. Modeled pregnancy rates based on timing of AI were plotted for each protocol. Additionally, use of a split-time AI versus fixed-time AI approach was modeled, as well as predicted impact of varying intervals between the two time points used for split-time AI. Modeled cumulative estrous response and aggregate pregnancy rates were compared to published data for the MGA-PG and 14-d CIDR-PG protocols. Results suggest a mathematical model may be useful to determine the optimal time point at which to perform timed AI following estrus synchronization.

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 PSII-21 Vaginitis incidence and effects on fertility of beef females enrolled on estrus synchronization protocols using a controlled internal drug release (CIDR) device

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 242-242 ◽  
Author(s):  
Nicholas W Dias ◽  
Alvaro Sales ◽  
Claire Timlin ◽  
Stefania Pancini ◽  
John Currin ◽  
...  
Keyword(s):  
Drug Release ◽  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Pregnancy Rates ◽  
Estrus Synchronization ◽  
Pregnancy Status ◽  
Timed Artificial Insemination ◽  
System 1 ◽  
Synchronization Protocol

Abstract Our objectives were to characterize the incidence of vaginitis caused by a controlled internal drug release (CIDR) device and its effects on fertility of beef females enrolled on estrus synchronization followed by timed-artificial insemination (TAI). A total of 1,097 mature cows and 215 heifers from 9 different locations were enrolled in the 7-d CO-Synch + CIDR synchronization protocol. At CIDR insertion, all females were inspected for any previous signs of vaginitis prior to enrollment in the experiment. As evidence of vaginitis, a CIDR score was determined at CIDR removal, and an AI plastic sheath score was also performed at TAI following a 1 to 4 system: 1=clean presenting no secretion; 2=clean presenting clear secretion; 3=presence of purulent secretion; 4=presence of purulent secretion and blood. Pregnancy status was determined by rectal ultrasonography approximately 40 days after TAI. The scores for CIDR and AI plastic sheath did not differ between cows and heifers. Of all females, 6% had a CIDR score of 1, 31% score 2, 56% score 3, and 7% score 4. Plastic sheath score was 1 for 16%, 2 for 62%, 3 for 15%, and 4 for 7% of females. Pregnancy rate to TAI differed between cows and heifers (P < 0.01), among locations (P < 0.001) and ranged from 36 to 66%; however, it was not influenced by CIDR score (P = 0.259) and plastic sheath score (P = 0.785). Pregnancy rate of females by different CIDR scores was 60%, 57%, 52%, and 46% for scores 1, 2, 3, and 4, respectively. Pregnancy rate of females by different AI plastic sheath score was 60%, 55%, 45%, and 48%, for scores 1, 2, 3, and 4, respectively. The presence of vaginitis caused by a CIDR does not influence pregnancy rates of TAI in beef females.

scholarly journals The effect of clitoral stimulation post artificial insemination on pregnancy rates of multiparous Bos indicus beef cows submitted to estradiol/progesterone-based estrus synchronization protocol

2020 ◽  
Vol 98 (7) ◽  
Author(s):  
Ramiro V Oliveira Filho ◽  
Reinaldo F Cooke ◽  
Gustavo A de Mello ◽  
Victor M Pereira ◽  
Jose Luiz M Vasconcelos ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Body Condition Score ◽  
Bos Indicus ◽  
Fixed Time ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Estrus Synchronization ◽  
Exit Velocity ◽  
Clitoral Stimulation

Abstract Clitoral stimulation after artificial insemination (AI) in beef cattle is a common practice utilized by AI technicians; however, the effect of clitoral stimulation during fixed-time AI (TAI) is still unknown. The objective of the present experiment was to evaluate the effect of clitoral stimulation on temperament responses and pregnancy rates to TAI in Bos indicus beef cows. A total of 1,186 multiparous Nellore cows across three different locations were assigned to an estradiol/progesterone-based estrus synchronization + TAI protocol (day −11 to 0). Cows were randomly assigned to receive either 3 s of clitoral stimulation (n = 602) or no clitoral stimulation (n = 584) immediately after TAI (day 0). Cow body condition score (BCS) was recorded on day −11. Estrus expression was evaluated based on estrus detection visual aid patch activation on day 0 (estrus, ≥50% activated; no estrus, <50% activated). Temperament was assessed by individual chute score based on a 5-point scale before TAI, and individual exit velocity was measured after clitoral stimulation. Pregnancy diagnosis was performed 30 d after TAI via transrectal ultrasonography. Pregnancy rate to TAI was positively affected by BCS (P < 0.01) and estrus expression (P = 0.03). Pregnancy rates of cows receiving clitoral stimulation did not differ (P = 0.39) from cows non-stimulated (47.5 ± 4.6% vs. 44.3 ± 4.6%, respectively). No interaction of clitoral stimulation and estrus expression was observed (P = 0.26). Chute score was positively correlated to exit velocity (P < 0.01; r = 0.29); however, clitoral stimulation did not affect exit velocity (P = 0.86). In summary, pregnancy rates to TAI are influenced by various factors and multiple strategies have the potential to increase the fertility of beef cows submitted to TAI; however, clitoral stimulation of Bos indicus beef cows did not improve TAI pregnancy rate.

scholarly journals Effect of Insemination Time on Pregnancy Rate and Ovulatory Events of Nili Ravi Buffalo Heifers in 7 Day CIDR Co-Synch

2021 ◽  
Author(s):  
Sajjad Haider ◽  
Ghazanfar Ali Chishti ◽  
Muhammad Usman Mehmood ◽  
Muhammad Ameen Jamal ◽  
Khalid Mehmood ◽  
...  
Keyword(s):  
Growth Rate ◽  
Drug Release ◽  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Pregnancy Rates ◽  
Optimal Time ◽  
Follicular Growth ◽  
Pregnancy Diagnosis ◽  
Timed Artificial Insemination

Abstract The present study aimed to compare the pregnancy rates at the optimal time of artificial insemination in a 7-day CIDR Co-synch in Nili Ravi buffalo heifers. Forty Nili Ravi buffalo heifers were randomly separated into two treatments based on artificial insemination (A.I.) timing (72 vs 84 hours). All heifers were subjected to controlled internal drug release (CIDR), containing 1.38 grams of progesterone for 7 days. On CIDR removal, both treatments received 150 µg of prostaglandin intramuscularly. In 7-day CIDR Co-synch (n = 20), animals were injected 100 µg of GnRH intramuscularly and inseminated concurrently at 72 hours after CIDRs removal. The remaining half (n=20) were injected and inseminated concurrently at 84 hours of CIDRs removal. Pregnancy diagnosis was performed after 40 days of timed artificial insemination (TAI). The follicular growth rate in 7-day CIDR Co-synch was more significant at 84 than 72 hours. The interval from GnRH/A.I. to ovulation in 7-day CIDR Co-synch was significantly (P < 0.05) differ between 72 and 84 hours. Pregnancy rates were considerably higher in buffalo heifers inseminated at 84 hours (65%) than 72 hours (25%) in 7-day CIDR Co-synch treatment. In conclusion, the buffalo heifers treated with CIDR Co-synch based protocols in relation to TAI at 84 hours improves follicular growth rate, interval from GnRH/A.I. to ovulation, and pregnancy rate.

scholarly journals The Effect of A PRID®Delta-Based Estrus Synchronization Protocol On Pregnancy Rates In Cows With No Estrus Symptoms

2022 ◽  
Author(s):  
Murat Can Demir ◽  
Cihan Kaçar ◽  
Umut Çağın Arı ◽  
Semra Kaya ◽  
Oğuz Merhan ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Prostaglandin F2α ◽  
Pregnancy Rates ◽  
Dominant Follicle ◽  
Serum Progesterone ◽  
Blood Samples ◽  
Follicle Diameter ◽  
Follicle Size ◽  
Equine Chorionic Gonadotropin

Abstract The present study aimed to determine the effects of progesterone-based gonadotropin-releasing hormone (GnRH), prostaglandin F2α (PGF2α), and equine chorionic gonadotropin (eCG) injections on progesterone profiles and pregnancy rates in cows with no estrus symptoms within 60 days after parturition. A total of 80 cows were included in the study. All animals had the progesterone-releasing device PRID®Delta placed intravaginally for nine days with an injection of GnRH. On the eighth day, PGF2α was injected, and PRID®Delta was removed from the vagina on day nine. Artificial insemination was carried out 60 hours after PRID®Delta removal. In half of the animals (n = 40), 600 IU of eCG was injected when PRID®Delta was removed on the ninth day before artificial insemination 60 hours later. Blood samples were taken from the tail vein on days 0 and 8 to determine progesterone levels. The pregnancy rate in the group that received eCG was 37.5%, while it was 27.5% in those that did not (P = 0.4). While the dominant follicle diameter was 15.5 mm in cows injected with eCG during timed artificial insemination, the follicle diameter was 12.4 mm in cows with no eCG injection (P <0.001). There were no differences in serum progesterone values in blood samples taken until the time of artificial insemination. However, progesterone values in the blood taken during artificial insemination were 0.94 ng/ml in the eCG- group and 0.72 ng/ml in the eCG+ group (P <0.05). As a result, it was determined that eCG injections, in addition to progesterone-based GnRH and PGF2α applications, increased the pregnancy rates in cows without symptoms of estrus. The dominant follicle diameter was larger in cows treated with eCG during artificial insemination; however, follicle size did not increase the pregnancy rate.

scholarly journals Effect of progesterone, human chorionic gonadotropin and progesterone + human chorionic gonadotropin treatment on conception rates in repeat breeder cows

2020 ◽  
Vol 89 (4) ◽  
pp. 307-315
Author(s):  
Hasan Alkan ◽  
Huseyin Erdem
Keyword(s):  
Pregnancy Rate ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Group 4 ◽  
Prostaglandin F ◽  
Repeat Breeder ◽  
Group 1

The aim of this study was to investigate the effects of hormonal support on the pregnancy rate in repeat breeder cows. Prostaglandin F2α + Ovsynch oestrus synchronization protocol was applied to the cows. Following the fixed time insemination (day 0), the cows were divided into 4 groups. In Group 1 (n = 42), progesterone releasing intravaginal device (PRID) was placed vaginally at 84 h and removed on the 9th day after the artificial insemination. In Group 2 (n = 40), the cows were administered human chorionic gonadotropin (hCG) on the 7th day. Group 3 (n = 45) was applied a combination of progesterone and hCG. Group 4 (n = 42) was not given any treatment. Blood samples were collected from all cows 4 times on days 3.5, 7, 12, and 18 to evaluate progesterone concentrations. The pregnancy rates were 40.47%, 37.50%, 44.44%, and 30.95% in Group 1, 2, 3, and 4, respectively (P > 0.05). In addition, in cows with progesterone concentrations <2 ng/ml on day 3.5, the pregnancy rates were found to be lower than in the cows with progesterone concentrations >2 ng/ml in Group 4 (P < 0.05). Progesterone supplementation in cows with progesterone concentrations < 2 ng/ml appeared to increase pregnancy rates (P < 0.05) in Groups 1 and 3. As a result, post-insemination hormonal applications in the repeat breeder cows did not increase the pregnancy rate. However, it was concluded that determination of progesterone concentrations on day 3.5 following artificial insemination and then hormonal support in the cows with low concentrations would increased the pregnancy rate.

scholarly journals RBC Transfusion Triggers: Is There Anything New?

2020 ◽  
Vol 47 (5) ◽  
pp. 361-369
Author(s):  
Tina Tomic Mahecic ◽  
Martin Dünser ◽  
Jens Meier
Keyword(s):  
Clinical Practice ◽  
Adverse Effects ◽  
Scientific Evidence ◽  
Optimal Time ◽  
Blood Transfusions ◽  
Erythrocyte Concentrates ◽  
Optimal Time Point ◽  
Almost All ◽  
Rbc Transfusion ◽  
Time Point

For many years, in daily clinical practice, the traditional 10/30 rule (hemoglobin 10 g/dL – hematocrit 30%) has been the most commonly used trigger for blood transfusions. Over the years, this approach is believed to have contributed to a countless number of unnecessary transfusions and an unknown number of overtransfusion-related deaths. Recent studies have shown that lower hemoglobin levels can safely be accepted, even in critically ill patients. However, even these new transfusion thresholds are far beyond the theoretical limits of individual anemia tolerance. For this reason, almost all publications addressing the limits of acute anemia recommend physiological transfusion triggers to indicate the transfusion of erythrocyte concentrates as an alternative. Although this concept appears intuitive at first glance, no solid scientific evidence supports the safety and benefit of physiological transfusion triggers to indicate the optimal time point for transfusion of allogeneic blood. It is therefore imperative to continue searching for the most sensitive and specific parameters that can guide the clinician when to transfuse in order to avoid anemia-induced organ dysfunction while avoiding overtransfusion-related adverse effects. This narrative review discusses the concept of anemia tolerance and critically compares hemoglobin-based triggers with physiological transfusion for various clinical indications.

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