PSV-3 Ovarian dynamics of brahman cows submitted to five-day or twelve-day progesterone-based estrus synchronization protocol

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 310-311
Author(s):  
Ramiro Oliveira Filho ◽  
Rafael R Paiva ◽  
Gabriela Dalmaso de Melo ◽  
Rodolfo C Cardoso ◽  
George A Perry ◽  
...  
Keyword(s):  
Prostaglandin F2α ◽  
Ovarian Response ◽  
Estrus Synchronization ◽  
Serum Concentrations ◽  
Estrus Detection ◽  
Extended Length ◽  
Estrus Response ◽  
To Receive ◽  
Ovarian Dynamics ◽  
Synchronization Protocol

Abstract The aim of this study was to investigate the ovarian response of Brahman cows submitted to two different estrus synchronization protocols and to determine the estrus response and ovulation time. A total of 153 Brahman cows were randomly assigned to receive one of the following estrus synchronization protocols: 1) CIDR insert and an injection of prostaglandin F2α (25 mg, PGF) on Day -5 and CIDR removal with PGF on Day 0 (CIDR5; n = 77); 2) CIDR insert on Day -12 and an injection of PGF on Day -12, Day -5 and Day 0 upon CIDR removal (CIDR12; n = 76). Estrotect breeding indicator patches were placed on Day 0 and cows were artificially inseminated (AI) 12h after estrus detection; cows not detected in estrus after 96h received TAI coupled with 100 µg of GnRH. Ovarian dynamics were observed during the protocol and follicular diameter were measured every 12h after AI until ovulation. Cows synchronized with CIDR12 had increased follicular diameter (CIDR5, 10.19 ± 0.51 vs. CIDR12, 13.12 ± 0.52 mm; P = 0.01) and decreased serum concentrations of progesterone (CIDR5, 1.68 ± 0.12 vs. CIDR12, 0.81 ± 0.12 ng/ml; P < 0.01) at CIDR removal. The percentage of cows exhibiting estrus did not differ between treatments (CIDR5, 66.2 vs. CIDR12, 64.5%; P = 0.25). No difference was observed in ovulation rate (CIDR5, 94.1 vs. CIDR12, 94.1%; P = 0.6). Time of estrus expression and ovulation time after CIDR removal did not differ (CIDR5, 59.9 ± 2.3 vs. CIDR12, 61.5 ± 2.3h; P = 0.71 and CIDR5, 88.1 ± 2.6 vs. CIDR12, 90.9 ± 2.6h; P = 0.75; respectively). In conclusion, extended length of CIDR with additional PGF increased follicular diameter and decreased concentrations of progesterone but did not influence estrus response and ovulation time in Brahman cows.

scholarly journals 218 Effect of GnRH injection at -72 h in MGA-PG estrus synchronization protocol

2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 122-122
Author(s):  
McKay Erickson ◽  
Rick N Funston
Keyword(s):  
Pregnancy Rate ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Estrus Synchronization ◽  
Estrus Detection ◽  
To Receive ◽  
Observation Period ◽  
Synchronization Protocol

Abstract Beef heifers (n = 1524) from two operations in central Nebraska were randomly assigned to one of two treatments [0 or 5 μg GnRH at prostaglandin F2α (PGF) administration 72 hrs before insemination]. Both locations utilized MGA-PG fixed-time AI (TAI) estrus synchronization protocol. The first location (L1, n = 1076, 382 ± 3 kg) processed heifers 72 hours prior to insemination and every third heifer was assigned to receive an injection of GnRH (5 ug) (TRT) and an injection of PGF. The remaining heifers received PGF and 0 μg GnRH. At insemination all heifers received 100 ug GnRH. Heifers were then observed for estrus behavior from 10–21 days post TAI and re-inseminated if estrus was detected. Heifers pregnant from the second breeding were added to final pregnancy rate. The second location (L2) utilized estrus detection patches and performed only TAI (n = 448, 363 ± 7 kg) following MGA-PG synchronization protocol outlined above without the estrus observation period. Treatment did not significantly (P > 0.20) improve TAI pregnancy rates [L1 TAI 56.3% (TRT) vs 57.3%; L1 AI Total 78.3% (TRT) vs 73.9%; L2 TAI 58.5% (TRT) vs 52.5%] among the two herds. The administration of 5 μg GnRH at PGF tended to increase (P = 0.12, 74% vs 63%) pregnancy rates for those inseminated during the follow up heat detection period at L1. The treatment did not (P > 0.20) improve pregnancy for the time-AI heifers. In addition, TAI pregnancy rates were similar (P > 0.20) at L2. There were greater (P < 0.20) effect of pen on pregnancy rate.

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 PSXIII-14 The impact of estrus intensity on variables associated with fertility in Bos taurus-influenced beef cows

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 362-363
Author(s):  
Reinaldo F Cooke ◽  
Nicola Oosthuizen ◽  
Kelsey Schubach ◽  
Alice Brandão ◽  
Ramiro Oliveira Filho ◽  
...  
Keyword(s):  
Physical Activity ◽  
Bos Taurus ◽  
Fixed Time ◽  
Beef Cows ◽  
Estrus Synchronization ◽  
Estrus Detection ◽  
Follicle Size ◽  
The Impact ◽  
Ovarian Dynamics ◽  
Synchronization Protocol

Abstract To evaluate the impact of estrus expression and intensity on parameters associated with reproductive performance, 219 lactating, multiparous Bos taurus-influenced beef cows were enrolled in this study. Cows were exposed to an estrus synchronization protocol, where they received a 100-µg injection of GnRH and a CIDR insert on d -10, a 25-mg injection of PGF2a at CIDR removal on d -3, and an injection of GnRH 60–66 h following CIDR removal at fixed-time AI (TAI; d 0). Cows were fitted with a pedometer behind their right shoulder on d -10, and an estrus detection patch was applied to their tail-head on d -3. Estrus expression was defined as removal of &gt; 50% of the rub-off coating from the patch on d 0. Net physical activity during estrus was calculated by subtracting daily activity during the non-estrus period (d -10 to -3) from activity during the expected estrus period (d -3 to 0). Cows were classified into 3 groups: cows that did not express estrus (NOESTR; n = 119), cows that expressed estrus with net physical activity greater than the median (HIESTR; n = 50), and the remaining cows (LWESTR; n = 50). Ultrasonography was performed on d -3, 0, and 7 to determine the presence and size of ovarian structures. Pregnancy diagnosis was performed 29 d after TAI. Net physical activity was greater in HIESTR compared to both LWESTR and NOESTR (P &lt; 0.01). Dominant follicle size was greater in HIESTR compared to both LWESTR and NOESTR (P &lt; 0.01). Furthermore, HIESTR had greater corpus luteum volume on d 7 than LWESTR and NOESTR (P &lt; 0.01). Pregnancy rates to AI (PR/AI) were greater in HIESTR and LWESTR compared to NOESTR (P &lt; 0.01). In conclusion, cows that expressed estrus at a greater intensity had improved ovarian dynamics. Additionally, cows that exhibited estrus had greater PR/AI compared to non-estrual cows.

scholarly journals PSIII-7 Determining the requirement of puberty induction to the reproductive performance of Bos indicus-influenced heifers submitted to AI

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 231-232
Author(s):  
Thiago Martins ◽  
Felipe A C C da Silva ◽  
Mariana Sponchiado ◽  
Gabriela A Soriano ◽  
Leonardo M F Pinto ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Reproductive Tract ◽  
Bos Indicus ◽  
Prostaglandin Analogue ◽  
Estrus Synchronization ◽  
Point Increase ◽  
Estrus Response ◽  
To Receive ◽  
D 23 ◽  
Synchronization Protocol

Abstract Induction of puberty by treating heifers with progesterone (P4) inserts may favor pregnancy/AI (P/AI) to a subsequent estrus synchronization program. However, it remains to be elucidated whether induction is required when the synchronization program contains P4 supplementation. To address this question, yearling, Brahman-influenced heifers (mostly 3/8 Brahman) classified as pubertal (PUB; n = 363) or prepubertal (PRE; n = 214) based on the presence of a CL, were assigned to receive no P4 supplementation (NoCIDR) or a CIDR for 10 days, starting on D-23. On D-13, all heifers received a dose of prostaglandin analogue and CIDRs were removed. On D-9, all heifers were enrolled in a 6-day CIDR & TAI protocol. Heifers were serviced based on heat between D-2 and D0 or were TAI on D0. Reproductive tract scores (RTS, 1 to 5 scale) were evaluated on D-23 and D-3. Induction increased the proportion of PRE heifers bearing a CL on D-3 (PRE|CIDR: 60.3% vs. PRE|NoCIDR: 42.7%). Among heifers with CL on D-3, P/AI of PRE heifers (42.5%) was similar to that PUB (47.7%). Conversely, for heifers without CL on D-3, P/AI of PRE (14.7%) was lower than PUB (37.3%). RTS increased between D-23 and D-3 from 2.3 to 4.0 (CIDR) and 2.3 to 3.6 (NoCIDR). For every 1-point increase in RTS, P/AI was 6–9% greater. Despite hastened puberty, P/AI of PRE heifers were less (PRE|NoCIDR: 29.2% and PRE|CIDR: 30.4%) than that of PUB (PUB|NoCIDR: 50.7% and PUB|CIDR: 42.2%). Less PRE (42.5%) than PUB animals (69.7%) were AI at estrus, and heifers showing estrus had a higher P/AI (52.8% vs. 18.7%). In conclusion, induction is not required when the subsequent synchronization protocol for AI contains progesterone. Induction hastened puberty attainment but failed to improve estrus response and fertility to the synchronization protocol.

scholarly journals Use of hormonal subdoses applied in Bai Hui acupuncture in estrus synchronization protocols for goats

2019 ◽  
Vol 40 (4) ◽  
pp. 1501 ◽  
Author(s):  
Diego Oliveira de Souza ◽  
Monna Lopes de Araújo ◽  
Carmo Emanuel Almeida Biscarde ◽  
Claudinéia da Silva Mendes ◽  
Mariana Alves de Andrade Silva ◽  
...  
Keyword(s):  
Estrus Synchronization ◽  
Reproductive Parameters ◽  
Follicular Growth ◽  
Plasma Progesterone ◽  
Significant Difference ◽  
Estrus Detection ◽  
Detection Coverage ◽  
Equine Chorionic Gonadotropin ◽  
The Cost ◽  
Synchronization Protocol

The objective of this study was to evaluate the efficacy of delivering reduced doses of hormones via the Bai Hui acupoint in estrus synchronization in goats. A total of 40 goats received intravaginal sponges with medroxyprogesterone acetate for 7 days. The goats were then randomly distributed into 5 treatment: T1 - application of 132.5 ?g of cloprostenol and 300 IU of equine chorionic gonadotropin (eCG), both by intramuscular injection (IM); T2 - application of 39.75 ?g cloprostenol at the Bai Hui acupoint, and 300 IU of eCG by IM; T3 - application of 132.5 ?g of cloprostenol by IM, and 90 IU of eCG at the Bai Hui acupoint; T4 - application of 39.75?g of cloprostenol and 90 UI of eCG, both in Bai Hui and T5 acupuncture: application of 39.75?g of cloprostenol and 90 UI of eCG, both applied in false acupoint. The goats were subjected to an estrus synchronization protocol and monitored for estrus detection, coverage and evaluation of reproductive parameters to detect entry into estrus. The data were subjected to normality tests, followed by appropriate statistical analyses of each variable. There was no significant difference (P > 0.05) in the percentage of animals in estrus (95.00 ± 11.18%), interval between sponge removal and beginning of estrus (49.72 ± 8.93 h), interval between sponge removal and end of estrus (76.84 ± 11.98 h), duration of estrus (27.08 ± 8.68 h), size of the largest follicle (6.82 ± 0.44 mm), interval between sponge removal and ovulation (78.28 ± 10.82 h), time from ovarian onset to estrus (28.52 ± 5.44 h), follicular growth rate (0.86 ± 0.29 mm/day), number of ovulations (1.32 ± 0.23), plasma progesterone concentration at 7 days after ovulation (10.28 ± 1.65 ng.mL-1), and gestation rate at 30 days after the beginning of estrus (75 ± 12.5%). However, the cost of the synchronization protocol per animal was 43.42% lower in treatments 4 and 5 (30% of the doses) than in treatment 1 (100% of the dose). Ovulation and estrus were efficiently synchronized with the use of 39.75 ?g of sodium cloprostenol and 90 UI of eCG, applied at the Bai Hui acupoint or at a false acupoint.

scholarly journals 184PREGNANCY RATES AFTER ESTRUS SYNCHRONIZATION TREATMENT WITH NEW AND REUSED CIDR-B DEVICES

2004 ◽  
Vol 16 (2) ◽  
pp. 214 ◽  
Author(s):  
C.W. Solorzano ◽  
J.H. Mendoza ◽  
J. Oden ◽  
S. Romo
Keyword(s):  
New Zealand ◽  
Ethylene Glycol ◽  
Prostaglandin F2α ◽  
Estradiol Benzoate ◽  
Direct Transfer ◽  
Estrus Synchronization ◽  
Experimental Conditions ◽  
Statistical Comparison ◽  
Rectal Palpation ◽  
To Receive

It is not well known whether used CIDR devices containing progesterone (P4) combined with estradiol benzoate (EB) and prostaglandin F2α (PGF) can provide acceptable estrus synchronization rates (ESR) and pregnancy rates (PR) in ET or AI programs. Three experiments were designed to study the effect of new and used CIDR-B, with different P4, EB and PGF treatments on ESR and PR in a reproductive program in beef cattle in a tropical climate. Experiment 1 was a control to evaluate ESR and PR in lactating recipient females. All cows (n=284) were treated with a new 1.9-g CIDR (CIDR-B, InterAg, New Zealand), combined with 2mg EB and 50mg P4 on Day 0. CIDR devices were removed on Day 8 and all cows received 0.25mg cloprostenol at that time. Estrus was expected to occur 24h later. Seven days after estrus, all cows showing heat were examined by rectal palpation and those with a CL 15mm in diameter or larger were selected to receive a frozen/thawed embryo (1.5M ethylene glycol=EG) by nonsurgical direct transfer (DT). PR were determined by rectal palpation 60d after estrus. Ninety percent of the cows displayed signs of estrus (256/284) and 40% of those that received a frozen embryo were pregnant (96/239). Experiment 2 was designed to evaluate ESR and PR in dry recipient cows treated with a used CIDR-B (first reuse). All cows (n=274) were treated with a reused 1.9-g CIDR combined with 2mg EB and 50mg P4 on Day 0. CIDR devices were removed on Day 8 and all cows received 0.25mg cloprostenol at that time. Estrus was expected to occur 24h later. Seven days after estrus, all cows that showed estrus were rectally evaluated and those with a CL 15mm in diameter or larger received a frozen/thawed embryo (1.5M EG) by DT. A total of 93% of the treated cows showed signs of estrus (254/274) and 51% of those that received an embryo were pregnant (110/217). Experiment 3 was designed to evaluate ESR and PR in virgin heifers, treated with a used CIDR (second reuse). All heifers (n=414) were treated with a reused 1.9-g CIDR combined with 1mg EB on Day 0. CIDR devices were removed on Day 8 and all heifers were expected to show estrus 24h later. Approximately 12h after estrus, all heifers that showed signs of estrus were inseminated, using frozen/thawed semen from a single bull. Of the treated females, 78% showed signs of estrus (323/414) and 69% of the inseminated were pregnant (223/323). These results suggest that in a CIDR that was used in two previous occasions, there is still a remaining amount of P4 that allows estrus synchronization in heifers. Furthermore, the reutilization of CIDR-B devices can contribute to reduce the costs related to ET or AI programs in cattle. However, the diverse existing conditions among the 3 experimental groups in this study make a statistical comparison impossible. Therefore, further studies are needed, under controlled experimental conditions, to confirm the results obtained.

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 &lt; 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 Estrus Synchronization Using Prostaglandin F2α (PGF2α) and Combination of PGF2α and Gonadotropin-Releasing Hormone In Ongole Crossbred

2020 ◽  
Vol 151 ◽  
pp. 01009
Author(s):  
Pudji Astuti ◽  
Claude M. Airin ◽  
Slamet Widiyanto ◽  
Sarmin Sarmin ◽  
Amelia Hana ◽  
...  
Keyword(s):  
Statistical Methods ◽  
Artificial Insemination ◽  
Luteal Phase ◽  
Prostaglandin F2α ◽  
Gonadotropin Releasing Hormone ◽  
Estrus Synchronization ◽  
Significant Difference ◽  
Estrus Detection ◽  
Female Cattle ◽  
Estrus Phase

The response of estrus can be enhanced by providing PGF2α and a combination of PGF2αGnRH so that the time of mating using Artificial Insemination (AI) can be held precisely. This study aims to compare the response of estrus synchronization using PGF2α compare to PGF2α-GnRH. Twenty female cattle Ongole Crossbreds, 4-6 years, BCS average of 3-4 were used in this research. Cattle were selected based on their luteal phase at the days of 7 to 18 by rectal examination. Then, all of the cattle were injected by cloprostenol® with a dose of 500 ug intrauterine. Ten of the animals were injected by 2.5 mL of Fertagyl® intramuscularly after 48 hours then continued observing and response estrus detection. The onset of estrus using PGF2α was detected on 75.94 ± 0.78, while 41.57 ± 28.40 hours for PGF2α-GnRH Using statistical, there was a significant difference (P<0.05). Duration of estrus phase using PGF2α was 24.65 ± 0.49 whereas PGF2α-GnRH was 10.88 ± 7.45 hours. Using statistical methods, there was a significant difference (P <0.05). It could be concluded that the use of PGF2α was more effective for the duration and intensity of estrus, and a combination of PGF2α -GnRH is more effective for stimulating estrus.

scholarly journals 130 Presynchronization with Prostaglandin F2αand prolonged exposure to exogenous progesterone impacts estrus expression and alters fertility in beef heifers

2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 19-20
Author(s):  
Nicola Oosthuizen ◽  
Pedro Fontes ◽  
Cliff Lamb
Keyword(s):  
Prolonged Exposure ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Beef Heifers ◽  
Randomized Design ◽  
Estrus Detection ◽  
Completely Randomized Design ◽  
Estrus Response ◽  
Exogenous Progesterone

Abstract To determine the effects of 2 presynchronization strategies in conjunction with delayed fixed-time artificial insemination (TAI) on pregnancy rates to TAI (PR/AI), 1,700 Angus beef heifers at 3 locations were enrolled in a completely randomized design with a 2×2 factorial arrangement of treatments. Within location, all heifers were randomly assigned to 1 of 4 treatments: 1) PG54 (n = 434), heifers received a 25-mg injection of prostaglandin F2α (PGF) 7 d prior (d -14) to the initiation of the 7-d CO-Synch + CIDR protocol wherein they received a 100-µg injection of gonadotropin-releasing hormone (GnRH) and a CIDR insert on d -7, a 25-mg injection of PGF at CIDR removal on d 0, and a second injection of GnRH concurrently with TAI 54±2 h later; 2) PG72 (n = 426), heifers were exposed to the same treatment as PG54; however, TAI was performed 72 ± 2 h after CIDR removal; 3) PG-CIDR54 (n = 422), same as PG54 but heifers received a CIDR insert on d -14 in addition to PGF; 4) PG-CIDR72 (n = 418), same as PG-CIDR54; however, TAI was performed 72±2 h after CIDR removal. Estrus detection patches were applied to all heifers on d 0 and were evaluated for activation at TAI. Pregnancy was diagnosed between 30 and 47 d after TAI. The percentage of heifers exhibiting estrus between d 0 and TAI was greater (P &lt; 0.001) in the PG72, PG-CIDR54, and PG-CIDR72 treatments compared to the PG54 treatment (78.11, 86.59, and 91.09 vs. 31.05%, respectively). Furthermore, estrus response was greater (P &lt; 0.001) in PG-CIDR72 heifers when compared to PG72. Pregnancy rates to TAI differed among treatments and were greater (P &lt; 0.05) in the PG72 and PG-CIDR54 treatments when compared to PG-CIDR72 (48.8 and 50.4 vs. 38.4%, respectively), and were greater (P = 0.034) in PG-CIDR54 vs. PG54 (43.1%). Moreover, a tendency (P = 0.097) was determined on PR/AI between PG54 and PG72. In conclusion, presynchronization strategies and prolonged exposure to exogenous progesterone have the potential to alter estrus expression and improve fertility in replacement beef heifers.

scholarly journals Reproductive parameters of dairy goats submitted to estrus synchronization with prostaglandin F2α associated or not to hCG at estrous onset

2013 ◽  
Vol 65 (6) ◽  
pp. 1585-1592 ◽  
Author(s):  
L.V. Esteves ◽  
F.Z. Brandão ◽  
R.C. Cruz ◽  
J.M.G. Souza ◽  
E. Oba ◽  
...  
Keyword(s):  
Body Condition Score ◽  
Prostaglandin F2α ◽  
Blood Collection ◽  
Estrus Synchronization ◽  
Reproductive Parameters ◽  
Dairy Goats ◽  
Dose Administration ◽  
Condition Score ◽  
To Receive ◽  
Different Doses

The objective of this study was to evaluate the efficiency of two doses of PGF associated or not to hCG on the associated reproductive parameters in dairy goats. A total of 29 goats received two doses of 30µg d-cloprostenol latero-vulvar at a 10 day intervals (Day 1 and Day 10). The does were allocated according to body weight and body condition score into two treatments, to receive hCG (250IU) or saline at estrus onset. After the second dose of PGF, estrus was monitored and ultrasound exams were performed twice daily. All does were inseminated 16h after estrus onset. Blood collection was performed every day for progesterone assay. The use of hCG at estrus onset did not affect any studied parameter and therefore the data were pooled. Estrous response rate was similar (P>0.05) after the first (75.9%, 22/29) and the second dose of PGF (79.3%, 23/29). The interval between the administration of PGF and estrus onset was greater (P<0.05) after Day 1 (75.8±53.9h) than Day 10 (47.7±10.1 h). Estrus duration was superior (P < 0.05) after Day 1 (35.4±15.9h) to Day 10 (26.8±15.0h). Ovulation rate was 79.3% (23/29) after the second dose of PGF. No differences (P>0.05) between both experimental groups were detected in the following parameters, averaging: the interval from the second dose administration to the ovulation (86.6±11.4h), interval from estrus to ovulation (39.9±12.3 h), diameter of largest follicle (7.2±1.4) and number of ovulations (1.8±0.6). At Day 1, 52.4% (11/21) of does presented progesterone concentrations <1ng/mL. At Day 10, 100% of the animals presented concentrations >1ng/mL. The results of the present study indicate that estrus can be efficiently synchronized in dairy goats with the use of two doses of PGF at a 10 day interval. Further research should be done evaluating hCG use in different doses or moments of administration.

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