scholarly journals Validation of a novel timed artificial insemination protocol in beef cows with a functional corpus luteum detected by ultrasonography

2018 ◽  
Vol 64 (2) ◽  
pp. 109-115
Author(s):  
Hisashi FUNAKURA ◽  
Ayumi SHIKI ◽  
Yuji TSUBAKISHITA ◽  
Shogo MIDO ◽  
Hiromu KATAMOTO ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Artificial Insemination ◽  
Beef Cows ◽  
Timed Artificial Insemination

Efficiency of mating, artificial insemination or resynchronisation at different times after first timed artificial insemination in postpartum Nellore cows to produce crossbred calves

2019 ◽  
Vol 59 (2) ◽  
pp. 225 ◽  
Author(s):  
Walvonvitis Baes Rodrigues ◽  
Jean do Prado Jara ◽  
Juliana Correa Borges ◽  
Luiz Orcirio Fialho de Oliveira ◽  
Urbano Pinto Gomes de Abreu ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Breeding Season ◽  
Chorionic Gonadotropin ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Beef Cows ◽  
Device Removal ◽  
Oestradiol Benzoate ◽  
Timed Artificial Insemination ◽  
Equine Chorionic Gonadotropin

The objective of this trial was to evaluate different post-timed artificial insemination (TAI) reproductive managements in postpartum beef cows to produce crossbred calves from artificial insemination (AI). Nellore cows (n = 607), with 45 days postpartum, were inseminated at a fixed time, using a protocol that included an intravaginal progesterone-releasing device along with oestradiol benzoate, prostaglandin, equine chorionic gonadotropin, and oestradiol cypionate, followed TAI 48 h post-device removal. Four post-TAI treatments were evaluated: in CONTROL (T1, n = 161), cows were exposed to Nellore clean-up bulls until the end of the breeding season (75 days). In OBSERVATION (T2, n = 132), heat detection was performed for 15–25 days post-TAI, followed by AI. In RESYNC22 (T3, n = 157) and RESYNC30 (T4, n = 157), resynchronisation started after 22 or 30 days, following second TAI at Day 32 or 40 days after first TAI. In T2, T3 and T4, after the second AI, cows were exposed to Nellore clean-up bulls until the end of the breeding season (75 days). The pregnancy rate (PR) for the first TAI did not differ (54.6%, 53.0%, 59.2%, and 51.6% for CONTROL, OBSERVATION, RESYNC 22, and RESYNC 30, respectively; P = 0.66), and no difference was observed for the second TAI (RESYNC 22 = 45.31% and RESYNC30 = 46.05%; P = 0.137), in the PR at the end of the breeding season (86.33%, 86.36%, 78.98%, and 81.52%, P = 0.43), or embryonic losses (4.54%, 2.85%, 6.45% and 7.40%, respectively; P = 0.61), but the percentage of crossbred pregnancy was higher in groups with resynchronisation (RESYNC22 and RESYNC30) than CONTROL and OBSERVATION (98.38%, 90.62%, 63.30%, 78.95%, P < 0.001). In conclusion, resynchronisation programs of 22 or 30 days are more efficient to produce AI products, and the final pregnancy rate is similar among the treatments, differing only in the amount of calves produced by AI.

scholarly journals Vascular and morphological features of the corpus luteum 12 to 20 days after timed artificial insemination in dairy cattle

2019 ◽  
Vol 102 (6) ◽  
pp. 5612-5622 ◽  
Author(s):  
Luiz G. Siqueira ◽  
Eduardo K. Arashiro ◽  
Alberto M. Ghetti ◽  
Eliza D. Souza ◽  
Luiz F. Feres ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Corpus Luteum ◽  
Artificial Insemination ◽  
Morphological Features ◽  
Timed Artificial Insemination

scholarly journals 107 Timing of progesterone exposure effects pregnancy rates following fixed time artificial insemination in postpartum beef cows

2019 ◽  
Vol 97 (Supplement_1) ◽  
pp. 43-44
Author(s):  
Anna L Smith ◽  
Rebecca K Poole ◽  
Kyle Mayberry ◽  
McKayla A Newsome ◽  
Harrison B Dudley ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Statistical Significance ◽  
Fixed Time ◽  
Beef Cows ◽  
Reproductive Technologies ◽  
Pregnancy Rates ◽  
Estrous Synchronization ◽  
Pregnancy Status ◽  
Timed Artificial Insemination ◽  
The Impact

Abstract Advancements in reproductive technologies have improved pregnancy rates in postpartum cows; however, undesirable consequences leading to reduced fertility still occur. Thus, the objectives were to determine if presence of a corpus luteum (CL) at the start of estrous synchronization (AIM1) or if the length of proestrus (interval from progesterone removal to a GnRH-induced LH surge; AIM2) alters fixed timed artificial insemination (FTAI) pregnancy rates. Cycling postpartum cows (n = 285) at two locations were synchronized using the CO-Synch+CIDR® FTAI protocol. Ultrasonographic measurements of luteal area were recorded at CIDR insertion. To determine the impact of proestrus length, cows were randomly assigned to either undergo CIDR removal at the time of PGF2a injection (long proestrus, n = 145), or CIDR removal 24 hours post PGF2a injection (short proestrus, n = 140). Blood samples were collected at CIDR insertion and at insemination for progesterone (P4) analysis. Pregnancy status to FTAI was assessed using ultrasonographic diagnosis at 30 d post insemination. Data were analyzed using a MIXED procedure of SAS and examined for effects of length of proestrus, P4 concentration, luteal area, sire, location, and age. Statistical significance was determined at P0.05) pregnancy rates. Pregnancy rates were greater in cows with >1 ng/mL P4 compared to cows with 0.05). Cows > 4 y old had higher AI pregnancy rates compared to 2–3 y cows (70.2±7.4 vs. 51±5.8%, respectively; P > 0.05). Based on these data, incorporating a presynchronization program to ensure the presence of a functional CL at the start of a FTAI protocol may improve pregnancy success in postpartum beef cows.

Evaluation of SexedULTRA 4M™ sex-sorted semen in timed artificial insemination programs for mature beef cows

2019 ◽  
Vol 123 ◽  
pp. 100-107 ◽  
Author(s):  
J.M. Thomas ◽  
J.W.C. Locke ◽  
R.C. Bonacker ◽  
E.R. Knickmeyer ◽  
D.J. Wilson ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Beef Cows ◽  
Timed Artificial Insemination

9 TIMED ARTIFICIAL INSEMINATION IN BLOCKS: A NEW ALTERNATIVE TO IMPROVE FERTILITY IN BEEF COWS

2015 ◽  
Vol 27 (1) ◽  
pp. 97
Author(s):  
L. F. M. Pfeifer ◽  
N. A. Castro ◽  
L. G. B. Siqueira ◽  
K. R. Lagos ◽  
A. Bagon ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Meta Analysis ◽  
Bos Indicus ◽  
Prostaglandin F2α ◽  
Beef Cows ◽  
Ovulation Rate ◽  
Control Group ◽  
Block Group ◽  
Preovulatory Follicle ◽  
Timed Artificial Insemination

The objective of this study was to evaluate whether timed artificial insemination (TAI) according to the diameter of the dominant preovulatory follicle (POF) would improve pregnancy rates in beef cows. In Experiment 1, a retrospective meta-analysis of 5 oestradiol- or gonadotropin-releasing hormone-based TAI experiments from 2011 to 2014 was performed to evaluate the interval from luteolysis to ovulation. In these experiments, crossbred cows (Gyr × Holstein; n = 60) were examined by ultrasonography at 12-h intervals from progesterone-releasing device (CIDR) removal to ovulation. A linear regression model was used to predict the effect of POF diameter on the time of ovulation. Cows with a larger POF at the time of AI ovulated earlier than cows with smaller POF (y = –8.25x + 115.22; R2 = 0.93; P < 0.0001). In Experiment 2, lactating Nelore cows (Bos indicus; n = 59) on random days of the oestrous cycle were given 2 mg of oestradiol benzoate IM and a CIDR device (Day 0) to synchronize follicular waves. The CIDR were removed, and cows were given 500 μg of d-Cloprostenol (prostaglandin F2α) IM, 1 mg of oestradiol cypionate IM, and 300 IU of eCG IM on Day 8. On the morning of Day 10 (07:00 a.m.), the diameter of the POF was assessed by ultrasonography, and cows were randomised into Control (n = 29) and Block (n = 30) groups. 1) Control-group cows were TAI 48 h after CIDR removal (08:00 a.m. on Day 10), and Block-group cows were inseminated at 4 time points according to the diameter of the POF: B0 (POF ≥15 mm, TAI at 08:00 a.m. on Day 10, n = 6), B1 (POF 13 to 14 mm, TAI at 02:00 p.m. on Day 10, n = 8), B2 (POF 11 to 12 mm, TAI at 08:00 a.m. on Day 11, n = 11), and B3 (POF ≤ 10 mm, TAI at 02:00 p.m. on Day 11, n = 5). Pregnancy status was assessed 30 days post-AI by ultrasonography. No differences were detected in the diameter of the POF 48 h after CIDR removal (P = 0.77) or ovulation rate (P = 0.65; combined ovulation rate 52/59, 88%) between Control and Block groups. Block group had a higher pregnancy rate than Control (22/30, 73% v. 13/29, 45%, respectively; P = 0.02). In conclusion, our results document that interval from luteolysis to ovulation depends on the size of preovulatory follicle, timing of AI in relation to ovulation time is critical, and AI time according to the diameter of the POF can be an effective tool to improve fertility of cows in TAI protocols.

scholarly journals Use of Carazolol at Pre-Synchronized Timed Artificial Insemination in Cows

2008 ◽  
Vol 77 (1) ◽  
pp. 59-64
Author(s):  
Ş. M. Pancarci ◽  
Y. Öztürkler ◽  
Ö. Güngör ◽  
C. Kaçar ◽  
S. Yildiz ◽  
...  
Keyword(s):  
Beneficial Effect ◽  
Corpus Luteum ◽  
Artificial Insemination ◽  
Adrenergic Receptor ◽  
Jugular Vein ◽  
Receptor Blocker ◽  
Transrectal Ultrasonography ◽  
Physiologic Saline ◽  
Timed Artificial Insemination ◽  
Rectal Palpation

Efficacy of the β-adrenergic receptor blocker (carazolol) at Timed Artificial Insemination (TAI) was investigated. Cows (n = 73) were pre-synchronized with two PGF2α injections given 14 d apart to initiate the Ovsynch protocol at early and middle luteal stages 14 d later, and received injections of GnRH and PGF2α seven d apart followed by GnRH 48 h later, and TAI 16 - 18 h later. Corpus luteum (CL) was detected via rectal palpation at the beginning of the Ovsynch protocol. Carazolol (Treatment I; n = 41) or physiologic saline (Treatment II; n = 32) were administered via jugular vein five min before TAI. Uterine tone was determined prior to infusion and at TAI via rectal palpation. Pregnancies were diagnosed with transrectal ultrasonography 40 ± 7 d after TAI. Uterine tone was 2.8 (1.4 - 5.3) times higher (P < 0.01) in Treatment I than that in Treatment II at TAI. Increase in uterine tone was affected by treatment × CL × parity (P < 0.05), and 66.7%, 75%, 52.6%, 100% and 16.7%, 33.3%, 25%, 28.6% in primiparous cows with CL and without CL, and in multiparous cows with CL and without CL in Treatments I and II, respectively. Pregnancy rates did not differ between treatments I (34.2%) and II (40.6%). In conclusion, no beneficial effect of carazolol administration prior to TAI was found except for the increased uterine tone.

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