30 OVULATION AND PREGNANCY RATES IN CYCLING NELLORE HEIFERS AFTER FIXED-TIME ARTIFICIAL INSEMINATION PROTOCOLS USING DIFFERENT CONCENTRATIONS OF PROGESTERONE, ASSOCIATED OR NOT WITH eCG

2010 ◽  
Vol 22 (1) ◽  
pp. 173
Author(s):  
M. F. Pegorer ◽  
R. L. Ereno ◽  
R. A. Satrapa ◽  
C. M. Barros
Keyword(s):  
Hormonal Treatment ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Repeated Measurements ◽  
Blood Levels ◽  
Dominant Follicle ◽  
Device Removal ◽  
Follicle Diameter ◽  
Intravaginal Device

The objective of the present study was to evaluate the influence of different P4 concentrations, associated or not with eCG, in the ovulation and pregnancy rates of Nellore heifers submitted to hormonal protocols for FTAI. In experiment (exp.) 1, heifers (n = 15) presynchronized with a hormonal treatment were randomly allocated in 4 groups. At the time of intravaginal device insertion (Day 0) all animals received 2 mg of estradiol benzoate (EB) and a intravaginal progesterone-releasing device containing 0.558 g of P4 (Triu®, Biogenesis Bago, Buenos Aires, Argentina; group 0.5G, n = 4) or 1g of P4 (Cronipres®, Biogenesis Bago; group 1G, n = 4), or 0.558 g of P4 and PGF2α (150 μg of D-cloprostenol, group 0.5G/PGF, n = 4), or 1 g of P4 and PGF2α (group 1G/PGF, n = 3). Eight days later (Day 8), PGF2α (150 μg D-cloprostenol) was administered to all heifers, and the P4 source was removed. Twenty-four hours after removing the intravaginal device (Day 9), the heifers were treated with EB (1 mg, i.m.). Blood samples were collected on Days 0, 1, 2, 4, 8, and 10 to evaluate plasma P4 concentration. In exp. 2, cycling Nellore heifers (n = 292) were treated with the same protocols as in the exp. 1. However, 30 to 36 h later all animals were FTAI on Day 10. In exp. 3, heifers (n = 459) received the treatments described for groups 0.5G/PGF and 1G/PGF associated with 300 IU of eCG (i.m. groups 0.5G/PGF/eCG and 1G/PGF/eCG) at the time of intravaginal device removal (Day 8). In a subset of heifers from each group, ovarian ultrasonography was performed to determine the diameter of the dominant follicle on Day 9 (exp.3) and the ovulation rate on Day 12 (exp. 2 and 3). ANOVA for repeated measurements was used to compare P4 levels, and the binary variables (ovulation and pregnancy rates) were analyzed by logistic regression. In exp. 1, P4 concentrations were higher in animals that received 1.0 compared with 0.558 g of P4, and lower in heifers that received PGF2α on Day 0. In both exp. 2 and 3 there were no significant differences in ovulation (65 to 77%) and pregnancy (exp.2: 26 to 33%; exp.3: 39 to 43%) rates among the several groups. In exp. 3, the animals that received 0.558 g of P4 had a larger diameter of the dominant follicle on Day 9 compared with heifers treated with 1.0 g (10.3 ± 0.2 v. 9.3 ± 0.2 mm; P < 0.01). It is concluded that reduction of P4 concentration in the intravaginal device or the administration of PGF2α at the beginning of the treatments decreases blood levels of P4 between Days 1 and 8 of the FTAI protocols. However, although the use of intravaginal devices with lower P4 contributed to increase the dominant follicle diameter on Day 9, there was no significant increase on ovulation and pregnancy rates. Additionally, the association of eCG with FTAI protocols did not improve follicular growth or ovulation and pregnancy rates. Supported by FAPESP (Sao Paulo, Brazil).

scholarly journals Development of fixed-time artificial insemination protocols for locally adapted Curraleiro Pé-Duro cows

2016 ◽  
Vol 68 (5) ◽  
pp. 1159-1167 ◽  
Author(s):  
R.D. Tortorella ◽  
M.R. Modesto ◽  
J.P. Neves ◽  
A.F. Ramos
Keyword(s):  
Body Condition Score ◽  
Hormonal Treatment ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Device Removal ◽  
Condition Score ◽  
Equine Chorionic Gonadotropin ◽  
Hot Environments ◽  
To Receive ◽  
Intravaginal Device

ABSTRACT Two experiments were conducted aiming to evaluate the effects of two ovulatory inducers (Exp.1) and equine chorionic gonadotropin (eCG; Exp.2) on follicular and luteal dynamics in a fixed-time AI (FTAI) protocol in locally adapted Curraleiro Pé-Duro cows. In Exp. 1 multiparous cows (n=12) received an intravaginal device containing 1g of progesterone (P4) for 8 days and 2mg of estradiol benzoate (EB) intramuscularly (IM) at device insertion (Day 0). At device removal (Day 8) 0.150mg of Sodium D-Cloprostenol was administered IM and the cows were randomly assigned to receive 1mg of EB (EB8) or 1mg of estradiol cypionate (EC8) IM, or to not receive any ovulatory inducer (Control). All the animals participated in all treatments (crossover). The interval from P4 removal to ovulation was shorter and less variable in the EB8 treatment group (P≤0.05). In Exp. 2 (crossover), multiparous cows (n=12) received the same hormonal treatment as the EB8 group in Exp.1. At device removal (Day 8) cows were randomly assigned to receive 300UI of eCG IM or to not receive eCG (Control). No difference was ascertained on follicular and luteal parameters in Exp. 2 (P>0.05). We concluded that EB can be used as the ovulatory inducer (Exp. 1) in a FTAI protocol in Curraleiro Pé-Duro cows. However, eCG (Exp. 2) was not able to stimulate follicular and luteal development. This result is probably due to the adaptive capacity of Curraleiro Pé-Duro cows that maintained a satisfactory body condition score even in dry and hot environments.

Effect of recombinant bovine somatotropin on pregnancy rates of Nellore cows resynchronized with the use of new DIB and third use, and inseminated at fixed-time

2015 ◽  
Vol 4 (1) ◽  
pp. 356-362
Author(s):  
Josemara Silva Santos ◽  
Tania Cavalcante ◽  
Francisca Elda Ferreira Dias ◽  
Domenica Palomaris Mariano de Souza ◽  
Alencariano J.S. Falcão ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Linear Models ◽  
Plasma Concentrations ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Recombinant Bovine Somatotropin ◽  
Equine Chorionic Gonadotropin ◽  
Rectal Palpation ◽  
Intravaginal Device

The objective of the experiment was to evaluate the effects of recombinant bovine somatropin (rbST), and the reuse of the progesterone (P4) releasing devices in resynchronization, on the pregnancy rates of Nellore cows submitted to fixed-time artificial insemination. A group of 123 multiparae Nellore cows, was submitted to a resynchronization protocol: on day 0 a Bovine Intravaginal Device (DIB® ) with 1,0g of P4 was implanted, associated with intramuscular administration of 2,0mg of estradiol benzoate (IM); on day 8 DIB was removed; and 1,0mg of estradiol cypionate, 0,15mg of prostaglandin F2? and 300 UI of equine chorionic gonadotropin were administered; on day 10, fixed-time artificial insemination was conducted (FTAI). The cows were randomized into G1 (n=12) – without rbST / with used Bovine Intravaginal Device, G2 (n=50) – without rbST / with new DIB, G3 (n=11) - with rbST / with used DIB and G4 (n=50) – with rbST/ with new DIB. rbST was introduced on the eighth day of the protocol. Sixty days after TAI, pregnancy diagnoses were conducted, via rectal palpation. Blood samples were taken on day 0, 8 and 10 of the protocol, in order to assess P4 plasma concentrations. Pregnancy rates were statistically evaluated through Generalized Linear Models Theory and their significance was tested with Analysis of Deviance. Pregnancy rates were 58%, 40%, 81% and 48% for G1, G2, G3 and G4, respectively, with significant statistical difference for G3. Plasma concentrations of P4 were not statistically different among groups, or collections. In view of the results obtained, we concluded that the administration of rbST in association with P4 DIB, used for the third time, improves pregnancy rates. Estrus resynchronization and re-insemination positively impacted pregnancy rates.

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.

8 EFFECT OF SEMEN TYPES (SEXED v. NONSEXED) ON CONCEPTION RATES OF GIROLANDO HEIFERS INSEMINATED IN FIXED-TIME AI

2010 ◽  
Vol 22 (1) ◽  
pp. 162
Author(s):  
J. Almeida ◽  
O. A. Resende ◽  
D. L. Silveira
Keyword(s):  
Body Condition Score ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Sao Paulo ◽  
São Paulo ◽  
Device Removal ◽  
Conception Rates ◽  
Sexed Semen ◽  
Condition Score ◽  
Intravaginal Device

With the goal of optimizing protocols, fixed-time artificial insemination (FTAI) was performed under field conditions in a study to evaluate conception rates in Girolando (5/8) heifers (18 to 24 months of age) treated with estradiol benzoate (BE) to induce ovulation. Forty heifers were allocated to 2 groups with 20 animals each: GI-sexed semen (2 million spermatozoa/dose) and GII-nonsexed semen (20 million spermatozoa/dose), with body condition score (BCS) of 3.0 ± 0.14 (scale of 1 to 5), middleweight of 335 ± 38 kg, so that it was made for reutilization of progesterone device. On Day 0 (morning), the animals received 2.0 mg of BE (RIC-BE®,Tecnopec, São Paulo, Brazil), 0.075 mg of D-cloprostenol (Prolise®, ARSA S.R.L., Buenos Aires, Argentina), and an intravaginal device of 1 g of progesterone (Primer®, Tecnopec). On Day 8 (morning) the device was removed and 0.075 mg of D-cloprostenol was managed in the GI animals, then these animals received 1.0 mg of BE 24 h after device removal. The insemination was in the late afternoon of Day 10 with a 6-hour delay (4 to 6 pm). The GII animals received Primer previously used for 8 days (being used in the GI animals under the same protocol). After pregnancy diagnosis at 60 days, a third group was created (GIII) using the not-pregnant animals of GI and GII. In GIII, Primer from third use [disinfected in solution Kilol®-L 1:250 (Quinabra, São Paulo, Brazil) and rinsed with water, dried, and packed in plastic sacks and kept for 60 days] was used following the GI protocol with sexed semen. There were no significant differences (P > 0.05) in the conception rates of 40, 58, and 65% among groups GI (8/20), GII (11/20), and GIII (13/20). These results indicate very good conception rates for heifers, contrary to recommendations of commercial companies of sexed semen that alert for the conception rate for mated animals to be lower when using FTAI and mating protocols in mass, compared with that of AI after estrus observation.

Presynch-Heatsynch: A New Approach to Improve Ovarian and Fertility Responses in Water Buffalo (Bubalus bubalis)

2021 ◽  
Author(s):  
Harmeet Singh Sandhu ◽  
Shahbaz Singh Dhindsa ◽  
Harpreet Singh ◽  
Mrigank Honparkhe ◽  
Prahlad Singh
Keyword(s):  
Fixed Time ◽  
Estradiol Benzoate ◽  
Bubalus Bubalis ◽  
Gnrh Analogue ◽  
Dominant Follicle ◽  
New Approach ◽  
Follicle Diameter ◽  
Group I ◽  
Follicle Size ◽  
Group Ii

Background: Standard estrus synchronization regimens resulted in variable outcomes in buffaloes. The present study evaluated ovarian and fertility responses following presynchronization in Heatsynch protocol administered in postpartum buffaloes. Methods: In group-I (Presynch-Heatsynch group, n = 30), PGF2α was administered on days -14 and -2. Then, GnRH analogue, PGF2α (Cloprostenol) and Estradiol benzoate were administered on day 0, 7 and 8, respectively followed by fixed-time artificial insemination (FTAI) 48 hours later. In group-II (Heatsynch group, n = 30), rest protocol was same, except that first two PGF2α injections were not administered. Result: The progesterone concentrations differed (P less than 0.01) between the two groups on days -2, 0 and 7. Post-treatment, progesterone profiles were also higher in pregnant compared to non-pregnant buffaloes in both the groups except on day 10. CL diameter differed (P less than 0.01) between groups on days -2, 0 and 7. It was larger in pregnant than non-pregnant buffaloes on day 7 in both the groups. Dominant follicle diameter remained larger on days -2, 0 and 8 in group-I than -II. Buffaloes getting pregnant had a larger (P less than 0.01) dominant follicle size on the day of FTAI in group-I than of group-II. Ovulatory response of 93.33 and 90.00% was observed in group-I and II. The conception rate was higher (66.66 vs. 40.00%; P less than 0.05) in group-I than Group-II. Presynchronization improved reproductive efficiency in Heatsynch treatment and may aid for better fertility in buffaloes.

scholarly journals 23 PREGNANCY RATE IN NELORE COWS AFTER TEMPORARY CALF REMOVAL, AND USE OF HORMONAL PROTOCOLS WITH eCG

2005 ◽  
Vol 17 (2) ◽  
pp. 161
Author(s):  
V. Pinheiro ◽  
A. Souza ◽  
R. Ereno ◽  
C. Barros
Keyword(s):  
Artificial Insemination ◽  
Buenos Aires ◽  
Post Partum ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Calf Removal ◽  
Exogenous Progesterone ◽  
Intravaginal Device ◽  
Hormonal Treatments

Both temporary calf removal (TCR) and administration of eCG are potentially useful to improve pregnancy rates in animals treated with fixed-time artificial insemination (FTAI) protocols. In the present work, two experiments were performed to compare the efficiency of eCG and/or TCR in FTAI protocols, with or without exogenous progesterone. In experiment 1, lactating Nelore cows (40 to 70 days post-partum, n = 220) were allocated to two Groups. At a random stage of the estrous cycle (Day 0), animals from Group GPE (GnRH/PGF2α/Estradiol)/eCG were treated with GnRH (50 mg lecireline, i.m.; Gestran Plus®; Tecnopec, Sao Paulo, Brazil). Seven days later (Day 7) they received PGF2α (150 mg D-cloprostenol, i.m.; Prolise®, Tecnopec) and eCG (300 UI, i.m.; Novormon®, Syntex). On Day 8 estradiol benzoate (EB, 1 mg, Estrogin®, Tecnopec) was administered, and 30–36 h later the animals were inseminated (FTAI). In Group DIB (bovine intravaginal device)/eCG an intravaginal progesterone-releasing device (1.0 g, DIB®, Syntex, Buenos Aires, Agrentina; Day 0) was inserted into the vagina of cows and EB (2.5 mg, i.m.) was given in parallel. Eight days later (Day 8), eGC (300 UI, i.m.) and D-cloprostenol (150 mg) were administered. Then the DIB was removed. Twenty-four hour after DIB removal, cows were treated with EB (1.0 mg, i.m.), and 30–36 h later the animals were inseminated (FTAI). Ultrasonographic evaluation of ovaries was performed in all experiments 10 days before and at the beginning of the treatments or TCR, in order to detect the presence of CL. Cows from Group DIB/eCG showed higher pregnancy rates than those from Group GPE/eCG (58%, 72/124 vs. 39.5%, 38/96, respectively, P < 0.01). Furthermore, only in Group GPE/eCG were pregnancy rates higher in animals with CL (47.6%, 20/42) when compared to those without CL (33%, 18/54, P < 0.05). In a second experiment, a possibly beneficial effect of TCR on GPE/eCG protocol was tested in lactating Nelore cows (40 to 70 days postpartum, n = 140). Animals of Group GPE/eCG (control) were treated as described above, whereas calves were removed for 48 h from cows in Group RTB/GPE/eCG prior to hormonal treatments. Lactating Nelore cows having their calves removed showed a significant increase in pregnancy rates compared to those without TCR (51.2%, 34/66 v. 28.4%, 21/74, respectively, P < 0.01), in both situations: animals with CL (54.8%, 17/31 v. 33.3%, 11/33, respectively, RTB/GPE/eCG v. GPE/eCG) or without CL (48.5%, 17/35 v. 24.3%, 10/41, respectively, RTB/GPE/eCG v. GPE/eCG). In conclusion, these results indicate that addition of eCG to the GPE protocol was not efficient enough to produce comparable results to those obtained with DIB/eCG protocol. However, calf removal before the GPE/eCG treatment increased pregnancy rates in cycling or anestrous (without CL) lactating Nelore cows.

scholarly journals Evaluation of pregnancy rates of Bos indicus cows subjected to different synchronization ovulation protocols using injectable progesterone or an intravaginal device

2016 ◽  
Vol 37 (6) ◽  
pp. 4149
Author(s):  
Jefferson Tadeu Campos ◽  
Fábio Morotti ◽  
Camila Bortoliero Costa ◽  
Larissa Zamparone Bergamo ◽  
Marcelo Marcondes Seneda
Keyword(s):  
Pregnancy Rate ◽  
Bos Indicus ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Estrus Cycle ◽  
Device Removal ◽  
Alternative Source ◽  
Group Iii ◽  
Group I ◽  
Intravaginal Device

This study evaluated the pregnancy rate in Nelore cows (Bos indicus) that were subjected to fixed-time artificial insemination (FTAI) using different protocols consisting of injectable progesterone (P4) or an intravaginal device (impregnated with P4). Multiparous cows 72-84 months in age, 30-45 days postpartum, were selected on the basis of the absence of a corpus luteum (CL) and follicles < 8 mm after transrectal palpation and ultrasound examinations. On a random day of the estrus cycle (D0), the selected animals (n = 135) were randomly assigned to one of three experimental groups (n = 45 each). Group I (injectable P4/FTAI 36 hours) received 250 mg of injectable P4 and 2 mg EB on D0; on D7, they received 500 µg of cloprostenol; on D8, 300 IU of eCG and 1 mg of EB were administered; and finally, FTAI was performed 36 hours after the application of EB. Group II (injectable P4/FTAI 48 hours) received the same protocol as Group I, except that the FTAI was performed 48 hours after ovulation induction. The animals of Group III (Control/CIDR) received a conventional protocol for FTAI using an intravaginal device (D0: P4 and 2 mg EB; D8: device removal, 500 µg cloprostenol, 300 IU eCG, 1 mg EB; and FTAI performed 48 hours after removal of the device). The results showed that cows synchronized with the conventional protocol for FTAI (Control/CIDR) had a higher pregnancy rate (60 %, 27/45) than those synchronized with an injectable P4/FTAI 36 hours (33.33 %; 15/45, P = 0.010). However, the group receiving injectable P4 group/FTAI 48 hours had a similar pregnancy rate (48.9 %; 22/45; P = 0.290) when compared to both the group receiving the conventional protocol and that receiving injectable P4/FTAI 36 hours (P = 0.134). Although the injectable P4 may affect pregnancy rate with the FTAI performed in 36 hours, we found similar pregnancy rates from cows inseminated 48 hours after induction ovulation, considering injectable or intravaginal P4. Therefore, we suggest that injectable P4 represents an alternative source of progesterone for synchronization of cattle for FTAI.

17 INFLUENCE OF DIFFERENT CONCENTRATIONS OF PROGESTERONE DURING FIXED-TIME ARTIFICIAL INSEMINATION PROTOCOLS ON OVULATION AND PREGNANCY RATES IN NELORE HEIFERS

2008 ◽  
Vol 20 (1) ◽  
pp. 89
Author(s):  
M. F. Pegorer ◽  
R. L. Ereno ◽  
C. M. Barros
Keyword(s):  
Artificial Insemination ◽  
Bos Indicus ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
High Concentration ◽  
Serum Progesterone ◽  
Significant Difference ◽  
Intravaginal Device

Previous reports indicate that a high concentration of serum progesterone (P4) decreases LH pulse frequency (Burke et al. 1996 Anim. Reprod. Sci. 45, 13–28) and, consequently, follicular growth. This may reduce the efficiency of fixed-time artificial insemination (FTAI) protocols that utilize P4 in Bos indicus heifers (Marques et al. 2005 Acta Sci. Vet.). The objective of the present work was to evaluate the influence of different P4 concentrations on the ovulation and pregnancy rates of zebu heifers subjected to hormonal protocols for FTAI. Four hormonal protocols with different P4 concentrations were used to induce synchronization of ovulation in Nelore (Bos indicus) heifers (n = 292). Before the beginning of the treatments, the animals were subjected to ovary evaluations by ultrasonography (Aloka SSD 500, 5-MHz probe; Aloka, Tokyo, Japan) twice in an interval of 10 days. Only heifers with a corpus luteum (CL) in at least one of the ultrasonographic evaluations were utilized. At a random stage of the estrous cycle, the selected heifers received an intravaginal progesterone-releasing device containing 0.558 g of P4 [Triu�, Biogenesis, Buenos Aires, Argentina; Treatment 1 (T1); n = 76], or 1 g of P4 [Cronipress�, Biogenesis; Treatment 2 (T2); n = 70], or 0.558 g of P4 and prostaglandin F2α (PGF2α) [150 �g d-cloprostenol, IM, Croniben�, Biogenesis; Treatment 3 (T3), n = 75], or 1 g of P4 and PGF2α [Treatment 4 (T4), n = 71]. At the time of intravaginal device insertion (Day 0 = D0), all animals received 2 mg of estradiol benzoate (EB, Bioestrogen�, IM, Biogenesis), and PGF2α was administered only in animals from groups T3 and T4. Eight days later (D8), PGF2α (0.150 g d-cloprostenol) was administered to all heifers and the P4 source was removed. Twenty-four h after removal of the intravaginal device, the heifers were treated with EB (1 mg, IM), and 30 to 36 h later all animals were fixed-time inseminated (FTAI, D10), without estrus detection. In a subset of heifers from each group (T1 = 28; T2 = 34; T3 = 33; T4 = 31), ovarian ultrasonography was performed on D9 (at 8:00 A.M.) and D11 (at 14:00 P.M.) in order to determine ovulation rate after each treatment. The data were analyzed by logistic regression (GENPROC, SAS; SAS Institute, Inc., Cary, NC, USA). Ovulation rates after treatments T1, T2, T3, and T4, were, respectively, 71.4% (20/28), 76.5% (26/34), 84.9% (28/33), and 70.9% (22/31), and there was no significant difference among groups (P > 0.05). Pregnancy rates, ascertained by ultrasonography 40 days after AI, were 30.2% (23/76), 25.7% (18/70), 33.3% (25/75), and 28.2% (20/71), respectively, for T1, T2, T3, and T4, and likewise there was no significant difference among groups (P > 0.05). It is concluded that reduction of progesterone concentration in the intravaginal device (1 g v. 0.558 g) associated or not with administration of PGF2α at the beginning of treatments did not significantly influence ovulation and pregnancy rates in Nelore heifers submitted to a FTAI protocol. Additional experiments are underway to confirm or not the present results. This work was supported by FAPESP (Brazil) and BIOGENESIS (Argentina).

scholarly journals PSII-29 Effects of delayed injection of prostaglandin F2α and TAI in the 14-d CIDR-PG & TAI protocol in replacement beef heifers

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 375-376
Author(s):  
Nicky Oosthuizen ◽  
Gabriela Melo ◽  
Lawton Stewart ◽  
George Seidel ◽  
Graham Cliff Lamb ◽  
...  
Keyword(s):  
Prostaglandin F2α ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Transrectal Ultrasonography ◽  
Dominant Follicle ◽  
Beef Heifers ◽  
Treatment Groups ◽  
Follicle Diameter ◽  
Randomized Design ◽  
Angus Heifers

Abstract To determine the effects of delaying the injection of prostaglandin F2α (PGF) and fixed-time artificial insemination (TAI) in the 14-d CIDR-PG & TAI protocol, 911 Angus heifers at 5 locations were enrolled in a completely randomized design. Within location heifers were randomly assigned to 1 of 2 treatment groups: 1) PG16 (n = 452), heifers received a CIDR insert on d 0 for 14 d, a 25-mg injection of PGF 16 d after CIDR removal [d 30], and a 100-µg injection of gonadotropin-releasing hormone concurrently with TAI 66 ± 2 h later; or 2) PG17 (n = 459), heifers were treated the same as PG16, however, PGF was administered 17 d after CIDR removal [d 31], and heifers were TAI 66 ± 2 h later. Estrus detection patches were applied to heifers at the time of PGF administration and were examined for activation at TAI. Dominant follicle diameter was determined via transrectal ultrasonography at PGF administration and TAI in a subset of heifers (n = 171). Furthermore, transrectal ultrasonography was performed to determine pregnancy rates to TAI (PR/AI) between 30 and 45 d after TAI. Estrus expression prior to TAI was similar (P = 0.50) between treatments (48.9 vs. 52.0%, respectively). Moreover, dominant follicle diameter at PGF and TAI was similar (P ≥ 0.43) between PG16 and PG17 heifers. Pregnancy rates to TAI did not differ (P = 0.48) between treatment groups (46.4 vs. 48.9%, respectively). The results of this experiment indicate that delaying the injection of PGF from d 30 to d 31 along with TAI in the 14-day CIDR-PG & TAI protocol had no effects on fertility parameters in beef heifers. In conclusion, the PGF injection and TAI in the 14-d CIDR-PG & TAI protocol may be delayed, providing more flexibility in scheduling without negatively affecting fertility.

28 COMPARISON OF NEW v. PREVIOUSLY USED INTRAVAGINAL DEVICE FOR A PROGESTERONE-BASED TIMED ARTIFICIAL INSEMINATION PROTOCOL IN NELORE (BOS INDICUS) COWS

2010 ◽  
Vol 22 (1) ◽  
pp. 171 ◽  
Author(s):  
J. H. Martins ◽  
M. I. S. Silva ◽  
G. A. Crepaldi ◽  
W. O. Melo ◽  
J. R. S. Torres-Júnior
Keyword(s):  
Pregnancy Rate ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Sao Paulo ◽  
Pregnancy Rates ◽  
São Paulo ◽  
Device Removal ◽  
Serum Progesterone ◽  
New Device ◽  
Lactating Cows

The objective of this study was to evaluate the effect of reutilization of intravaginal progesterone devices on pregnancy rate of lactating and nonlactating Nelore cows submitted to fixed-time AI (FTAI). The study used 684 lactating cows (50 to 70 days postpartum) and 361 nonlactating cows (210 to 240 days postpartum). At random stages of the estrous cycle (Day 0), all animals received 2 mg of estradiol benzoate (Estrogin®, Farmavet, São Paulo, Brazil) and the animals of each category (lactating or nonlactating) were allocated in 1 of 2 treatments (new or used). Thus, the 4 groups consisted of lactating/new, lactating/used, nonlactating/new and nonlactating/used. The animals of lactating/new and nonlactating/new groups received a new intravaginal progesterone device (1 g of P4, DIB®, Intervet/Schering-Plough, São Paulo, Brazil) and the cows of lactating/used and nonlactating/used groups received a similar device that had previously been used for 8 days. At the time of P4 device removal (Day 8), the cows were treated with 150 μg of cloprostenol (Preloban®, Intervet/Schering-Plough), 1 mg of estradiol cypionate (ECP®, Pfizer, São Paulo, Brazil), and 300 IU of eCG (Folligon®, Intervet/Schering-Plough). The cows were FTAI on Day 10 (48 to 52 h after device removal). To evaluate the pregnancy rate, an ultrasonographic examination (CHISON 500VET, USP Brasil Eletromedicina, São Paulo, Brazil) was performed 30 days after the FTAI. Data were analyzed using the GENMOD procedure of SAS (SAS Institute, Cary, NC, USA).There was no interaction between treatment and BCS, AI bull, or technician. The pregnancy rates for the groups were 155/300 (51.7%a for lactating/new, 200/384 (52.1%a for lactating/used, 52/154 (33.8%b for nonlactating/new, and 96/207 (46.2%a for nonlactating/used (P = 0.0007). A reduction in pregnancy rate for nonlactating cows occurred when the intravaginal progesterone device was new. Although serum progesterone was not measured in the current trial, it is very likely that this finding might be explained by the high cyclicity rates in beef cows after weaning (210 days postpartum) and by the presence of CL producing additional support of progesterone besides the high P4 from the new device (Baruselli et al. 2004 Anim. Reprod. Sci. 82, 479-486). Many researchers found that greater circulating progesterone concentrations during progesterone implant treatment reduced LH pulsatility, LH follicular receptors, and follicular growth (Ireland and Roche, 1982 J. Reprod. Fertil. 64, 295-302). Furthermore, it seems likely that the presence of smaller-sized ovulatory follicles might contribute to ovulation failures, delayed ovulation, smaller CL area, and decrease in the pregnancy rate (Carvalho et al. 2008 Theriogenology 69, 167-175). In conclusion, lactating cows can be fixed-time inseminated using a new or a previously used DIB® as progesterone source. However, for nonlactating cows, a previously used device may increase pregnancy rates. USP Brasil Eletromedicina, ABS Pecplan and Fazendas Reunidas Rio Bravo.

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