scholarly journals Pregnancy-associated glycoproteins (PAGs) and progesterone concentrations in Holstein heifers following two methods of estrus syncronization

2019 ◽  
Vol 6 (2) ◽  
Author(s):  
Mehmet Akkose ◽  
Cigdem Cebi Sen ◽  
Adnan Kirmit ◽  
Omer Korkmaz ◽  
Murat Onur Yazlik ◽  
...  

Pregnancy-associated glycoproteins (PAGs) and progesterone concentrations were assessed in Holstein heifers 28 days post-insemination, following estrus synchronization with either a double prostaglandin (PG) injection or the ovsynch protocol. Animals between 15 and 20 months of age, with a 3-3.5 BCS, were randomly assigned to three groups: Heifers in the control group (n = 70) were monitored for estrus behaviour for 21 days and inseminated when detected in standing heat; Estrus of heifers in the Ovsynch group (n = 70)) was synchronized following the Ovsynch protocol, and timed artificial insemination was performed 16 h after the completion of treatment; Animals in the PG group (n = 70) received two prostaglandin-F2α injections 11 days apart, were monitored for estrus behaviour for 2-5 days following the last injection, and inseminated when in heat. Serum PAGs and progesterone concentrations were measured in pregnant heifers (control group n = 25; ovsynch group n = 22; PG group n = 21) on day 28 after artificial insemination (AI). Mean serum PAGs concentrations (OD: optical density) were similar between groups (control = 3.37 ± 0.148, Ovsynch = 3.21 ± 0.136, and PG = 3.34 ± 0.143; p > 0.05). However, serum progesterone concentrations were found to be lower in the ovsynch group (4.70 ± 0.17 ng/mL) when compared to the PG (5.34 ± 0.13 ng/mL) or the control (5.37 ± 0.08 ng/mL) groups (p < 0.001). There was no correlation between serum PAGs and progesterone levels at day 28 post-insemination, or between early pregnancy PAGs concentrations and fetal death rates. Further research, including multiple sampling time points throughout gestation, after estrus synchronization protocols is warranted, to determine if there are associated temporal changes in PAGs and progesterone profiles that could impact reproductive parameters in dairy 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 ◽  
...  

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.


2015 ◽  
Vol 27 (1) ◽  
pp. 97
Author(s):  
L. F. M. Pfeifer ◽  
N. A. Castro ◽  
L. G. B. Siqueira ◽  
K. R. Lagos ◽  
A. Bagon ◽  
...  

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.


2013 ◽  
Vol 96 (11) ◽  
pp. 7054-7065 ◽  
Author(s):  
F.S. Lima ◽  
E.S. Ribeiro ◽  
R.S. Bisinotto ◽  
L.F. Greco ◽  
N. Martinez ◽  
...  

2022 ◽  
Author(s):  
Murat Can Demir ◽  
Cihan Kaçar ◽  
Umut Çağın Arı ◽  
Semra Kaya ◽  
Oğuz Merhan ◽  
...  

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.


2014 ◽  
Vol 19 (1) ◽  
Author(s):  
Emanoel Faleiros Silveira ◽  
Luiz Ernandes Kozicki ◽  
Marcio Saporski Segui ◽  
Romildo Romualdo Weiss ◽  
Ivo Walter Santos ◽  
...  

The aim of this study was to investigate estrus synchronization in prepubertal and pubertal heifers (crossbred ½ Nelore x Red Angus - commercial herd) submitted to a long-term progesterone-based protocol for timed artificial insemination (TAI), as well as overall pregnancy rates. Four hundred forty-seven heifers underwent ultrasound examination of the ovaries and were assigned to one of 3 groups: (1) prepubertal heifers (PPNS; n = 114) with ovarian follicles <8 mm in diameter and no corpus luteum (CL) that were submitted to natural service (NS) by bulls for 10 days; (2) prepubertal heifers (PPTAI; n = 124) with follicles <8 mm in diameter and no CL that underwent estrus synchronization with injection of 4.0 mg estradiol benzoate (EB) and insertion of a controlled-release intravaginal progesterone (P4) device containing 0.558 g P4 on d 0, followed by P4 device removal and injection of 150 mg prostaglandin F2α and 0.6 mg estradiol cypionate (ECP) on d 8, and TAI on d 10; and (3) pubertal heifers (PTAI; n = 209) with follicles >8 mm in diameter and/or a CL that underwent the same protocol as PPTAI heifers. Overall pregnancy rate was determined by transrectal ultrasonography on d 45 after NS or TAI. Data were analyzed using the FREQ procedure of SAS (SAS Inst. Inc., Cary, NC). Pregnancy rates were as follows: 20.1% in PPNS, 37.0% in PPTAI, and 48.5% in PTAI (P < 0.05). In conclusion, TAI after estrus synchronization with a hormonal protocol using EB and ECP in prepubertal and pubertal heifers resulted in higher pregnancy rates than prepubertal heifers exposed to natural service, and exposure of prepubertal heifers to a long-term progesterone-based protocol effectively synchronized estrus.


2014 ◽  
Vol 26 (1) ◽  
pp. 121
Author(s):  
D. G. Souza ◽  
A. Martins ◽  
E. Oba ◽  
A. S. Camargos ◽  
E. P. Moreira ◽  
...  

Reducing animal handling and costs in timed artificial insemination (TAI) systems are of great interest in animal production, regardless of the species. Thus, this study was carried out to investigate the effects of administering oestradiol cypionate (EC) or hCG to induce ovulation in buffalo (Bubalus bubalis) in TAI programs. The 79 Bufalipso heifers housed at Institute of Animal Science, San José de las Lajas, Cuba, were, on average, 24 months of age with a body weight of 310 to 380 kg at the beginning of the experiment. The investigation was conducted out of the breeding season (25 June through 28 July 2012). Heifers were randomly assigned to 1 of 3 treatment groups; either hCG (control group) or EC1 and EC2, in which TAI was performed at either 48 or 56 h after the EC injection, respectively. On the first day of the treatment regime (Day 0), animals received oestradiol benzoate (2 mg i.m.; Sincrodiol®, Ourofino, Brazil), followed by the insertion of an intravaginal device containing 1 g of progesterone (Primer®, Tecnopec, São Paolo, Brazil). On Day 9, an intramuscular luteolytic dose of cloprostenol (500 μg; Ciosin®, Intervet, Brazil) and eCG (500 UI; Novormon®, Intervet) were given in all heifers along with the removal of the intravaginal device. On the same day, 0.5 mg of EC (ECP®, Pfizer, Brazil) was administered intramuscularly in the EC1and EC2 groups. Animals in the hCG group received hCG (1000 IU i.m.; Vetecor®, Hertape Calier, Spain) on Day 11 and were inseminated 14 h later. Pregnancy diagnosis was performed by ultrasound 35 days after TAI. Data were analysed by a chi-squared test, with P < 0.05 taken as significant. There were no differences among treatment groups, with values of 57.7 (15/26), 60.7 (17/28), and 64% (16/25) for the EC1, EC2, and hCG groups, respectively. In conclusion, oestradiol cypionate was effective at inducing ovulation in buffalo heifers in TAI programs comparable to the control group, as evidenced by the conception rates. In addition, animals subjected to the EC protocol pass just 3 times through the corral instead of 4 when receiving hCG, which decreases the animal handling and costs.


Sign in / Sign up

Export Citation Format

Share Document