12 EFFECT OF HUMAN CHORIONIC GONADOTROPIN (hCG) ADMINISTRATION ON DAY 2 OR DAY 5 AFTER OESTRUS ON PREGNANCY RATE IN HIGH-YIELDING DAIRY COWS

2015 ◽  
Vol 27 (1) ◽  
pp. 98 ◽  
Author(s):  
J. M. Sanchez ◽  
V. Maillo ◽  
L. Molina ◽  
C. C. Perez-Marin ◽  
P. Lonergan ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Pregnancy Rate ◽  
Body Condition Score ◽  
Significant Proportion ◽  
Prostaglandin F2α ◽  
Gonadotropin Releasing Hormone ◽  
Pregnancy Rates ◽  
Holstein Cows ◽  
Control Group ◽  
Releasing Hormone

In cattle, ~40% of embryonic loss occurs in the period from Day 8 to Day 16 of pregnancy. A significant proportion of embryo loss may be due to inadequate circulating progesterone (P4) concentrations. Low P4 concentrations have also been implicated as a causative factor in the low pregnancy rates (PR) observed in high-yielding dairy cows. Administration of hCG during the early luteal phase stimulates hypertrophy of the original corpus luteum (CL) and, depending on the day of administration, induces ovulation of the first-wave dominant follicle and formation of a functional accessory CL, which increases circulating P4 concentrations. The aim of this study was to examine whether administration of hCG on Day 2 or Day 5 after oestrus after timed AI (TAI) would lead to an increase in pregnancy rates in dairy cattle. Lactating Holstein cows (n = 194) from 12 commercial dairy herds in Southern Spain (37.8833° N, 4.7667° W) with an average milk production at 37.8 L/cow per day and typically with a PR to first AI of ~30% were randomly assigned based on their body condition score (2.65 ± 0.05; mean ± SEM), parity (2.60 ± 0.09), and days in milk (75.06 ± 0.63) to 1 of 3 treatments and administered a single intramuscular injection of 3000 IU of hCG (4 mL of Veterin Corion) either (1) on Day 2 = 36 h after TAI (n = 65; hCG2 group), (2) Day 5 = 108 h after TAI (n = 64; hCG5 group), or (3) 4 mL of saline on Day 2 = 36 h after TAI (n = 65; control group). Cows were synchronized using a 7-day Ovsynch TAI protocol that included a P4-releasing intravaginal device (PRID DELTA 1.55 g). First, gonadotropin-releasing hormone (Cystorelin 100 mg) treatment was administered at PRID insertion (Day 0) followed by 25 mg Dinoprost (prostaglandin F2α: Enzaprost T) on Day 7 at PRID withdrawal. Then, 56 h later, the second gonadotropin-releasing hormone (100 mg) treatment was administered and all cows were inseminated 16 h later. Pregnancy was diagnosed by ultrasonography 28 to 32 days after TAI. Logistic regression model and chi-squared test were used to analyse data. Pregnancy rate to AI was significantly higher in the hCG2 and hCG5 groups than in the control group (43.1 and 45.3%, v. 27.7%; P < 0.05). A treatment-by-parity interaction was observed; while pregnancy rate for primiparous cows was not affected by treatment, multiparous cows from the hCG2 group had greater pregnancies per AI than those in the control group (47.2% v. 21.1%, respectively; P < 0.05). In conclusion, these preliminary results suggest that hCG administration on Day 2 and 5 after oestrus increases PR at first postpartum AI in Holstein cows. In addition, hCG on Day 2 increases the fertility in multiparous cows.This study was funded by the Spanish Ministry of Science and Innovation (AGL2012–37510) and partially supported by Ceva Salud Animal S.A., Spain – synchronization protocol and DFV, Spain – hCG treatments.

12 Effect of additional prostaglandin F2α during the Ovsynch protocol applied in different postpartum intervals in lactating dairy cows: Preliminary results

2019 ◽  
Vol 31 (1) ◽  
pp. 132
Author(s):  
A. Bover ◽  
J. Casellas ◽  
T. Mogas
Keyword(s):  
Dairy Cows ◽  
Pregnancy Rate ◽  
Animal Health ◽  
Prostaglandin F2α ◽  
Gonadotropin Releasing Hormone ◽  
Pregnancy Rates ◽  
Ongoing Research ◽  
Releasing Hormone ◽  
Preliminary Results ◽  
Synchronization Protocol

Timed AI (TAI) programs have been developed to increase the service risk. However, when Ovsynch is used as a synchronization protocol, lack of regression of the corpus luteum after prostaglandin F2α (PGF) administration has been demonstrated, leading to reductions in fertility. In this way, a second PGF administration might increase the frequency of achieving complete luteolysis. This study aimed to evaluate the effect of an additional treatment with PGF on fertility when an Ovsynch synchronization protocol was applied at different postpartum intervals. Multiparous high-production dairy cows (n=471) of a commercial farm were stratified by postpartum intervals [&lt;120 (n=136), 120-150 (n=131), 150-180 (n=92), 180-210 (n=52), and &gt;210 days (n=60)] and randomly allocated to receive either the Ovsynch (n=108) or Ovsynch with second PGF protocol (n=243). Cows inseminated 12h after observed heat detection (AI) served as a control (n=120). The Ovsynch protocol consisted of an injection of gonadotropin-releasing hormone (100 µg; Fertagyl®, Intervet, Millsboro, MD, USA) on Day 0, an injection of PGF (0.5 mg; Estrumate®, Schering-Plough Animal Health, Montréal, QC, Canada) on Day 7, another injection of gonadotropin-releasing hormone (100µg) on Day 9, and timed insemination on Day 10. The Ovsynch with second PGF protocol consisted of the same hormone injection schedule as the Ovsynch protocol, but a second injection of PGF (0.5 mg; Estrumate®) was administered 24h after the first PGF. Data were analysed using the chi-square test. The level of significance was taken as P&lt;0.05. When data were pooled at 120 to 150 days of postpartum interval, pregnancy rate was higher, but not significantly different (P&gt;0.05), for cows that received the Ovsynch (37.5%, n=32) or Ovsynch with second PGF protocol (33.8%, n=77) compared to nonsynchronized cows (22.8%, n=22). After 180 days of postpartum interval, Ovsynch with second PGF protocol triggered pregnancy rates similar to those of nonsynchronized cows (33.3%, n=21 and 28.6%, n=14), whereas the Ovsynch protocol resulted in lower percentages (11.8%, n=17; P&gt;0.05). Similar pregnancy rates (P&gt;0.05) were observed when TAI protocols were administered before 120 days (26.5 and 30.2% for Ovsynch and Ovsynch with second PGF, respectively) or between 150 and 180 postpartum days (31.8 and 33.9% for Ovsynch and Ovsynch with second PGF, respectively) compared with AI cows (25.7 and 28.8% for &lt;120 days and between 150 and 180 postpartum days, respectively). These preliminary results showed a tendency of a better pregnancy rate when both TAI synchronization protocols were applied between 120 and 150 postpartum days when compared with AI. Also, the application of a second dose of PGF seems recommendable when the Ovsynch protocol is used to synchronize cows of &gt;180 postpartum days. Ongoing research will allow an increase in the number of the samples in each postpartum interval in order to confirm these results.

Estrous synchronization and fertility of cross-bred dairy cows using prostaglandin F2α and gonadotropin releasing hormone

2021 ◽  
pp. 171-175
Author(s):  
Abubakr O. Ismail ◽  
◽  
Erneo B. Ochi ◽  
Ambrose S. Jubara ◽  
Bakri Ahmed A/Rahim ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Artificial Insemination ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Gonadotropin Releasing Hormone ◽  
Pregnancy Rates ◽  
Releasing Hormone ◽  
Treatment Groups ◽  
Estrous Synchronization ◽  
Descriptive Statistical Analysis

A comparative hormonal study of prostaglandin, gonadotropin releasing hormone and their combination was conducted on 30 randomly selected cross-bred dairy cows of SEMEX project for artificial insemination in Hillat Kuku, Khartoum North, Sudan. The study attempts to determine the response of the animals to hormonal induction and synchronization of estrous as well as fertility following fixed time artificial insemination. Three treatment groups of 10 cows each were undertaken. Groups 1, 2 and 3 involved administration of prostaglandin F2α (PGF2α), gonadotropin releasing hormone (GnRH) and a combination of PGF2α + GnRH, respectively. Descriptive statistical analysis was performed. The results revealed that all the three protocols induced and synchronized estrous were almost synchronous in all the treated groups. However, protocol 3 revealed a significantly (p<0.05) better result of 70% pregnancy rate compared to other two protocols that equally provided 50% pregnancy rates. The study resolves that protocol 3 be highly recommended to change the mindset of farmers about the spread of reproductive technology in Sudan. Protocols 1 and 2 provided acceptable pregnancy rates that can be enhanced with the improvement of management.

104 FACTORS AFFECTING PREGNANCY RATES AND EMBRYO/FETAL LOSSES IN RECIPIENTS RECEIVING IN VITRO-PRODUCED EMBRYOS BY FIXED-TIME EMBRYO TRANSFER

2017 ◽  
Vol 29 (1) ◽  
pp. 160
Author(s):  
A. Tribulo ◽  
A. Cedeño ◽  
B. Bernal ◽  
S. Andrada ◽  
J. L. Barajas ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Body Condition Score ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Gonadotropin Releasing Hormone ◽  
Pregnancy Rates ◽  
Device Removal ◽  
Releasing Hormone ◽  
Condition Score

A retrospective analysis evaluated pregnancy rates and embryo losses with in vitro-produced embryos in a commercial embryo transfer program on 15 different beef farms. Recipients were beef cows and heifers (n = 1841) that were synchronized with 5 different protocols and transferred at a fixed-time (FTET). Recipients were examined by ultrasonography on Day 0, and those with a corpus luteum (CL) or a follicle ≥8 mm in diameter and with body condition score 2 to 4 (1 to 5 scale) were synchronized. The synchronization treatments were as follows. (T1) Recipients received an intravaginal device with 0.5 g of progesterone plus 2 mg of oestradiol benzoate on Day 0; device removal, plus 500 μg of cloprostenol (prostaglandin F2α), 400 IU of eCG, and 0.5 mg of oestradiol cypionate on Day 8; and FTET on Day 17. (T2) This treatment was similar to T1 but 1 mg of oestradiol cypionate was injected at device removal instead of 0.5 mg of oestradiol cypionate. (T3) This treatment was similar to T1 except that animals were tail-painted on Day 8 and observed on Day 10. Those with the tail-paint intact on Day 10 received 100 μg of gonadorelin (gonadotropin-releasing hormone) and all recipients were FTET on Day 17. (T4) Recipients received a progesterone device on Day 0; device removal, prostaglandin F2α, and eCG on Day 5; gonadotropin-releasing hormone on Day 8; and FTET on Day 15. (T5) Recipients received a progesterone device and 2 mg of oestradiol benzoate on Day 0; device removal, prostaglandin F2α, and eCG on Day 6; gonadotropin-releasing hormone on Day 9; and FTET on Day 16. On the day of FTET all recipients with CL ≥18 mm in diameter (G1), ≥16 and <18 mm in diameter (G2), and ≥14 mm and <16 mm in diameter (G3) received in vitro-produced fresh embryos. Pregnancy was diagnosed by ultrasonography at 30 and 60 days of gestation, and data were analysed by logistic regression. The overall proportion of recipients synchronized that were FTET was 80.8% (1487/1841), with a 30-day pregnancy rate to FTET (P/FTET) of 45.6% (678/1487) and the rate of 30- to 60-day embryo/fetal loses on the 528 recipients that were re-checked at 60 days was 12.8% (68/528). There were no significant differences in P/FTET among operators, animal category, time of the year, embryo stage, or body condition score; however, there was a significant effect of farm (P < 0.001) and CL diameter (P < 0.05), but no interaction between CL diameter and farm or treatment (P > 0.1). Recipients with G1 (443/953, 46%) and G2 (221/462, 47%) CL had higher pregnancy rates than those with G3 CL (23/71, 32%). There was a significant effect of synchronization treatment on the proportion of recipients transferred and on P/FTET (P < 0.01) that was highly influenced by farm (farm by treatment interaction P < 0.01). The proportions of recipients selected for embryo transfer were as follows: T1: 386/486, 79.4%; T2: 233/331, 70.3%; T3: 342/377, 90.7%; T4: 126/160, 78.7%; and T5: 400/487, 82.1%. The P/FTET were as follows: T1: 190/386, 49.2%; T2: 96/233, 41.2%; T3: 175/342, 51.1%; T4: 49/126, 38.8%; and T5: 168/400, 42.0%. Although 30- to 60-day embryo/fetal losses were not influenced by synchronization treatments, they were highly influenced by farm (P < 0.001) and ranged from 0 to 34.5%. In conclusion, P/FTET in a commercial program with beef in vitro-produced embryos was influenced by factors related to the recipient (CL diameter) and the environment (farm), whereas embryo/fetal losses were influenced by farm but not treatment or recipient factors.

8 COMBINATION OF OESTRUS DETECTION AND FIXED-TIME ARTIFICIAL INSEMINATION IN BEEF HEIFERS FOLLOWING A SHORTENED OESTRADIOL-BASED PROTOCOL THAT PROVIDES FOR A LENGTHENED PROESTRUS

2015 ◽  
Vol 27 (1) ◽  
pp. 96 ◽  
Author(s):  
J. J. de la Mata ◽  
M. Ré ◽  
G. A. Bó
Keyword(s):  
Pregnancy Rate ◽  
Body Condition Score ◽  
Fixed Time ◽  
Beef Cows ◽  
Gonadotropin Releasing Hormone ◽  
Pregnancy Rates ◽  
Group V ◽  
Releasing Hormone ◽  
Treatment Groups ◽  
Condition Score

Studies have shown that gonadotropin-releasing hormone-based protocols that reduce the period of progestin insertion and prolong the period from progestin removal to gonadotropin-releasing hormone and fixed-time AI (FTAI; named 5-day Co-Synch) results in similar or higher pregnancy rates than the conventional 7-day Co-Synch protocol in beef cows and heifers (Bridges et al. 2008 Theriogenology 69, 843–851). Similar findings have been reported following the use of an oestradiol-based protocol that also provides for a longer period of proestrus (named J-Synch; de la Mata and Bó 2012 Taurus 55, 17–23). An experiment was designed to compare the J-Synch protocol for synchronization of ovulation that allows for a prolonged proestrus with a conventional 7-day oestradiol-based protocol for FTAI in heifers. Cycling 18-month old Angus and Hereford heifers (n = 208) with a body condition score of 6 to 7 (scale of 1 to 9) were randomly allocated to 1 of 2 treatment groups. Heifers in the 7-day EB group (n = 105) received a progesterone (P4) device (DIB 0.5 g of P4, Syntex SA, Buenos Aires, Argentina) and 2 mg of oestradiol benzoate (EB, Syntex SA) on Day 0 and 500 μg of cloprostenol (PGF; Ciclase DL, Syntex SA) and 0.5 mg oestradiol cypionate (Cipiosyn, Syntex SA) on the day of DIB removal (Day 7). Heifers were also tail painted at the time of DIB removal and observed for signs of oestrus (i.e. tail paint rubbed off). Those with the tail paint rubbed off by 36 h after DIB removal were inseminated 12 h later, whereas those not showing oestrus by 36 h were FTAI at 54 h. Heifers in the J-Synch group (n = 103) received DIB and 2 mg of EB on Day 0 and PGF on the day of DIB removal (Day 6). Heifers in this group were also tail painted at DIB removal, and those with their tail paint rubbed off by 48 h were inseminated 12 h later; those not showing oestrus by 60 h received 100 μg of gonadorelin acetate (gonadotropin-releasing hormone, Gonasyn gdr, Syntex SA) and were FTAI at 72 h after DIB removal. Pregnancy was diagnosed by ultrasonography at 55 days after FTAI (Honda 101V, 5.0-MHz transducer). Data were analysed by logistic regression. Oestrus detection rate and pregnancy rate to FTAI did not differ (P > 0.1) between groups (38.8%, 40/103 and 60.3%, 38/ 63 for heifers in the J-Synch group v. 28.5%, 30/105 and 45.3%, 34/75 for those in the 7-day EB group). However, pregnancy rates to observed oestrus tended (P < 0.09) to be higher and the overall pregnancy rate was significantly higher (P < 0.01) in heifers in the J-Synch group (80.0%, 32/40 and 67.9%, 70 /103) compared with those in 7-day EB group (50%, 15/30 and 46.6%, 49/105). Furthermore, heifers within the J-Synch group that had their tail paint rubbed off by 48 h after DIB removal and were AI 12 h later (i.e. 60 h) had higher (P < 0.05) pregnancy rate than those in the same group that were FTAI. In conclusion, reducing the time of progestin device insertion and lengthening the proestrus period, as in the J-Synch protocol, results in higher pregnancy rates than with the conventional oestradiol-based protocol. Furthermore, the combination of oestrus detection and FTAI would appear to improve the pregnancy outcome even more.

122 Effect of gonadotropin-releasing hormone plus 7-day progesterone (CIDR) with or without eCG on follicular dynamics, estrus response, and pregnancy rate in anestrous Beetal goats during nonbreeding season under subtropical conditions

2019 ◽  
Vol 31 (1) ◽  
pp. 186
Author(s):  
M. I.-R. Khan ◽  
N. Hameed ◽  
W. Ahmad ◽  
M. Abbas ◽  
A. Murtaza ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Prostaglandin F2α ◽  
Gonadotropin Releasing Hormone ◽  
Ovulation Rate ◽  
Control Group ◽  
Dominant Follicle ◽  
Releasing Hormone ◽  
Nonbreeding Season ◽  
And Control ◽  
Follicular Dynamics

Oestrus induction is a challenging task during the nonbreeding season in goats. Therefore, our objective was to evaluate the efficacy of gonadotropin-releasing hormone (GnRH) plus a 7-day CIDR-based protocol with or without eCG for the induction of oestrus and fertility in acyclic Beetal goats during the nonbreeding season under subtropical conditions. Based on the absence of corpus luteum via ultrasonography, goats (n=56; mean weight=32.8±0.5 kg; body condition scre=2.5±0.1) were inserted with a CIDR (300mg progesterone) along with GnRH (Day 0), and randomly treated either with eCG (400 IU; n=35) or without eCG (control; n=21) on Day 7. The CIDR was removed on Day 7 and all does were administered single dose of prostaglandin F2α (75µg cloprostenol; Fatro, Italy). Following CIDR insertion, ovarian follicular dynamics was monitored daily through a 7.5-MHz transrectal transducer (Honda HS 1500, Japan) until ovulation in a subset of eCG (n=11) and control goats (n=10). Oestrus was detected at every 12h after CIDR removal with aproned bucks and does were bred naturally. Pregnancy was detected 25 days after breeding by transrectal ultrasound. Data were analysed by t-test, ANOVA, and Chi-squared test using SPSS (version 20.0, SPSS Inc., Chicago, IL, USA). Oestrus occurred more often following CIDR removal in eCG v. control goats (94v. 57%; P&lt;0.05). Similarly, onset of oestrus was earlier (36.0±2.1v. 54.2±4.7 h; P&lt;0.05) and the duration of oestrus was longer in eCG v. control goats (i.e. 30.2±1.3v. 22.1±2.3 h; P&lt;0.05). However, diameter of preovulatory follicles and interval to ovulation after CIDR removal were similar between eCG and control goats (P&gt;0.05). In contrast, growth rate of preovulatory follicle after CIDR removal until ovulation in eCG goats was greater, and ovulation rate was higher than control goats (0.7±0.1v. 0.3±0.1 mm/day; 2.2±0.2v. 1.4±0.2, respectively; P&lt;0.05). In eCG goats, the dominant follicle grew rapidly between Days 8 to 9 (P&lt;0.05), whereas within control goats the dominant follicle grew at consistent rate (P&gt;0.05). After CIDR removal, percentage of ovulating goats in eCG was higher as compared to the control group (100v. 44%; P&lt;0.05). Within control goats, size of the dominant follicle in ovulatory goats was greater at the time of CIDR removal than anovulatory goats (5.7±0.3v. 5.0±0.15 mm; P&lt;0.05), whereas wave emergence tended to be earlier after CIDR insertion in anovulatory goats (4.2±1v. 2.6±0.4 days; P=0.09). Pregnancy rate 25 days postbreeding did not differ between eCG and control goats [i.e. 49% (16/33) v. 25% (3/12); odds ratio 2.9/1; P&gt;0.05]. In conclusion, the eCG protocol resulted in higher oestrus response, ovulation rate, and 3 times higher pregnancy rate in anestrous goats during the nonbreeding season.

Effect of gonadotropin-releasing hormone and prostaglandin F2α on reproduction in postpartum dairy cows

1983 ◽  
Vol 19 (6) ◽  
pp. 763-770 ◽  
Author(s):  
G.F. Richardson ◽  
L.F. Archbald ◽  
D.M. Galton ◽  
R.A. Godke
Keyword(s):  
Dairy Cows ◽  
Prostaglandin F2α ◽  
Gonadotropin Releasing Hormone ◽  
Releasing Hormone

scholarly journals Comparison of the effects of Presynch-Ovsynch, Presynch- Ovsynch+CIDR, and G6G protocols on the reproductive performance of lactating Holstein cows in the postpartum period

2021 ◽  
Vol 53 (4) ◽  
Author(s):  
Hesam Kohsari ◽  
Khatereh Berenjian
Keyword(s):  
Serum Concentration ◽  
Pregnancy Rate ◽  
Reproductive Performance ◽  
Body Condition Score ◽  
Dairy Farm ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Holstein Cows ◽  
Treatment Protocols ◽  
Ovulatory Follicle

This study was performed on an industrial dairy farm near Tehran province, Iran, on 666 lactating Holstein cows from September 2019 to June 2020 in order to eliminate the harmful effects of heat stress on the reproductive performance of the cows. The hypothesis of the recent study was that by increasing the serum concentration of progesterone (P4) in the luteal phase before insemination in the form of Presynch-Ovsynch+CIDR (POC) and G6G protocols, the pregnancy rate of cows would be increased compared to the Presynch-Ovsynch (PO) protocol. The aim of the present study was to evaluate the effects of Presynch-Ovsynch (PGF2α-14d- PGF2α-12d-Ovsynch (OVS: GnRH(GnRH1)- 7d-PGF2α(PG)-2d-GnRH)-18h-Fixed-time artificial insemination (FTAI), n=212), Presynch-Ovsynch+CIDR (similar to the PO protocol, plus the use of a CIDR for 7 days, from the start of the OVS+FTAI protocol to the time of PG injection, n=230), and G6G (PGF2α- 2d-GnRH-6d-OVS+FTAI, n=224) protocols on the reproductive performance and pregnancy rate of lactating Holstein cows. The average body condition score (BCS) for the cows was about 2.5 at the time of the onset of the OVS+FTAI program. The average daily milk production for cows at the time of the start of the OVS+FTAI program was 38.3 kg/day. On average, the studied cows were inseminated 86 days postpartum. Implementation of the G6G protocol in comparison to the PO and POC protocols increased the serum concentration of P4 at GnRH1 (P=0.04). The cows that received the G6G protocol had a greater number of corpuses luteum (CL) on their ovaries at PG in comparison to the cows in the PO and POC protocols (P=0.03 and P=0.05, respectively). For all treatment protocols, the pregnancy rate of cows with &gt;2 CLs on their ovaries at PG was significantly higher than for cows with ≤2 CLs on their ovaries at this time. The overall pregnancy rate for all cows studied was 42%. Separately, pregnancy rates for cows in PO, POC, and G6G protocols were calculated at 36.7%, 41.7%, and 47.3% respectively. The highest and the lowest pregnancy rates were obtained in the G6G and PO protocols, respectively (P=0.03). It can be concluded that the G6G protocol increased the pregnancy rate of cows in comparison to the PO but not to the POC protocol. This result can be attributed to the increase in serum concentration of P4 at GnRH1 and the greater number of CLs at PG following implementation of the G6G compared to the PO protocol. Although CIDR administration in the POC protocol led to an increase in the pregnancy rate of cows compared to the PO protocol, possibly by increasing the synchrony rate and the quality of the ovulatory follicle, this increase was not statistically significant (P=0.09).

Inducing ovulation with oestradiol cypionate allows flexibility in the timing of insemination and removes the need for gonadotrophin-releasing hormone in timed AI protocols for dairy cows

2017 ◽  
Vol 29 (3) ◽  
pp. 468 ◽  
Author(s):  
R. M. Ferreira ◽  
H. Ayres ◽  
L. U. Gimenes ◽  
F. P. Torres ◽  
F. A. Lima ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Pregnancy Rates ◽  
Holstein Cows ◽  
Device Removal ◽  
Releasing Hormone ◽  
Ovulatory Follicle ◽  
Oestradiol Benzoate ◽  
Gonadotrophin Releasing Hormone

The effects of addition of gonadotrophin-releasing hormone (GnRH) to a progesterone plus oestradiol-based protocol and timing of insemination in Holstein cows treated for timed AI (TAI) were evaluated. Cows (n = 481) received a progesterone device and 2 mg oestradiol benzoate. After 8 days, the device was removed and 25 mg dinoprost was administered. Cows were allocated to one of three (Study 1; n = 57) or four (Study 2; n = 424) groups, accordingly to ovulation inducer alone (Study 1; oestradiol cypionate (EC), GnRH or both) or ovulation inducer (EC alone or combined with GnRH) and timing of insemination (48 or 54 h after device removal; Study 2). In Study 1, the diameter of the ovulatory follicle was greater for GnRH than EC. Oestrus and ovulation rates were similar regardless of ovulatory stimuli. However, time to ovulation was delayed when GnRH only was used. In Study 2, cows treated with GnRH or not had similar pregnancy per AI (P/AI) 30 days (41.5% vs 37.3%; P = 0.28) and 60 days (35.9% vs 33.0%; P = 0.61) after TAI. TAI 48 and 54 h after device removal resulted similar P/AI at 30 days (40.3% vs 38.5%; P = 0.63) and 60 days (33.8% vs 35.1%; P = 0.72). Thus, adding GnRH at TAI does not improve pregnancy rates in dairy cows receiving EC. The flexibility of time to insemination enables TAI of a large number of cows using the same protocol and splitting the time of AI.

116 PREGNANCY RATES AFTER ADMINISTRATION OF EQUINE CHORIONIC GONADOTROPIN (eCG) AT PROGESTERONE INTRAVAGINAL DEVICE REMOVAL AND 14 DAYS AFTER FIXED-TIME AI IN BEEF CATTLE

2011 ◽  
Vol 23 (1) ◽  
pp. 163 ◽  
Author(s):  
R. Núñez ◽  
T. de Castro ◽  
L. Cutaia ◽  
G. Bó ◽  
A. Menchaca
Keyword(s):  
Beef Cattle ◽  
Pregnancy Rate ◽  
Body Condition Score ◽  
Fetal Loss ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Control Group ◽  
Device Removal ◽  
Embryo Survival ◽  
Intravaginal Device

An important proportion of embryonic deaths in cattle occur during the critical period of embryo development and maternal recognition of pregnancy. High serum progesterone concentrations during this period are associated to higher embryo survival, and the use of eCG could enhance luteal activity. Two experiments were carried out to evaluate the effect of administering eCG at the time of removal of a progesterone-releasing device and 14 days after fixed-time artificial insemination (FTAI) in beef cattle. Multiparous suckled cows between 60 and 90 days postpartum (n = 297; Exp. 1), and two-year old prepuberal heifers (n = 689; Exp. 2) with a body condition score (BCS) between 3.5 and 5 (1 to 8 scale) were used. At the beginning of the experiments, none of females used had a corpus luteum detected by ultrasonography. Females received an intravaginal device containing 0.5 g progesterone (DIB 0.5, Syntex, Buenos Aires, Argentina) and 2 mg oestradiol benzoate i.m. (Benzoato de Oestradiol, Syntex). Eight days later, 500 μg of cloprostenol (Ciclase DL, Syntex) and 0.5 mg oestradiol cypionate (Cipiosyn, Syntex) were given i.m. and devices were removed; FTAI was performed 52 to 56 h after DIB removal. At the time of device removal, the animals were randomly allocated to 4 groups, to receive 400 IU of eCG i.m. (Novormon, Syntex) or placebo at device removal and/or 14 days after FTAI, in a 2 × 2 factorial design. Control group did not receive eCG. In Exp. 1, nose plates were placed on calves on the day of DIB insertion and left for 10 days in order to prevent suckling. Pregnancy diagnosis was performed by ultrasonography at 30 and 60 days after FTAI. Data were analysed by logistic regression. Pregnancy rate at 30 days after FTAI was affected by treatment (P < 0.05; Table 1). Late embryonic/fetal loss rates (non-pregnant females at 60 days after FTAI over those pregnant at 30 days) were 1.6% (3/182) for cows in Exp. 1 and 4.8% (14/292) for heifers in Exp. 2; no differences were detected among groups. In conclusion, administration of 400 IU of eCG at device removal increases pregnancy rate, both in anestrus cows and heifers. However, the administration of a second dose of eCG 14 days after FTAI suggests a possible effect on embryo survival within the first 30 days of pregnancy in cows but not in heifers. Further studies are required to confirm these results. Table 1.Pregnancy rates after administration of eCG at time of progesterone device removal and/or 14 days after insemination in beef cattle Supported by Syntex.

252 EFFECT OF SUPERSTIMULATORY TREATMENT TO DONOR COWS IN OXYGEN CONSUMPTION OF MATURED OOCYTES

2013 ◽  
Vol 25 (1) ◽  
pp. 273
Author(s):  
K. Imai ◽  
S. Sugimura ◽  
M. Ohtake ◽  
Y. Aikawa ◽  
Y. Inaba ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Prostaglandin F2α ◽  
Gonadotropin Releasing Hormone ◽  
Oestrous Cycle ◽  
Control Group ◽  
Releasing Hormone ◽  
And Control ◽  
Bovine Oocytes

We previously reported that follicular wave synchronization and follicular growth treatment (FGT) before ovum pick-up (OPU) were effective in improving oocyte competence, which was associated with an increase in related embryos obtained by somatic cell nuclear transfer (Sugimura et al. 2012 Cell. Reprogram. 14, 29–37). However, oxygen consumption in oocytes remained unknown. The present study was designed to examine the differences in oxygen consumption between bovine oocytes obtained by OPU with or without FGT after in vitro maturation. Holstein dry cows (n = 8) were reared under the same feeding and environmental conditions. Two OPU sessions were conducted in each cow to collect immature oocytes, as described by Sugimura et al. (2012). The first OPU session (OPU group) was performed in cows on arbitrary days of the oestrous cycle, using a 7.5-MHz linear transducer with the needle connected to an ultrasound scanner. Follicles larger than 8 mm in diameter were then aspirated and a controlled internal drug release device (CIDR) was inserted on Day 5 (the day of the first OPU session = Day 0). Then 30 Armour units (AU) of FSH (Antrin, Kyoritsu Seiyaku, Tokyo, Japan) was administrated to cows twice a day from Day 7 to 10 in decreasing doses (6, 6, 4, 4, 3, 3, 2, 2 AU day–1). Cloprostenol (prostaglandin F2α; 0.75 mg) was administered in the morning of Day 9. The second OPU session (FGT-OPU group) was performed 48 h after prostaglandin F2α administration (Day 11), and only follicles larger than 5 mm in diameter were aspirated. The CIDR was removed from the cows just before OPU. Collected cumulus–oocyte complexes in the OPU and FGT-OPU groups were matured in vitro as described by Imai et al. [2006 J. Reprod. Dev. 52(Suppl.), S19–S29]. To collect in vivo-matured oocytes (control group), the CIDR was inserted into the cows on arbitrary days of the oestrous cycle (= Day 0), and oestradiol benzoate (0.8 mg) was administered on Day 1. The cows received the FGT treatment (as described above) from Day 6 to 10; however, the CIDR was removed in the evening of Day 8. Buserelin (gonadotropin-releasing hormone; 200 µg) was then administrated in the morning of Day 10, and OPU was performed at 24 h after gonadotropin-releasing hormone administration (Day 11). Oxygen consumption of matured oocytes was measured noninvasively with a scanning electron microscopy system (HV-405SP; Hokuto Denko Co., Tokyo, Japan). Data were analysed by ANOVA followed by a Tukey-Kramer test. There was no difference in the mean oxygen consumption between the FGT-OPU group (0.34 ± 0.02 × 10–14 mol–1, mean ± SEM) and control group (0.40 ± 0.01 × 10–14 mol–1). However, oxygen consumption in the FGT-OPU and control groups was significantly lower (P < 0.01) than that in the OPU group (0.50 ± 0.02 × 10–14 mol–1). These results revealed significantly lower oxygen consumption in OPU-derived in vitro-matured bovine oocytes after FGT treatment compared with those obtained without FGT treatment. Oxygen consumption of oocytes obtained from FGT-OPU was similar to that of in vivo-matured oocytes, which may reflect their cytoplasmic maturation status with high developmental competence.

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