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.

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.

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).

14 SYNCHRONIZATION OF OVULATION IN ANESTROUS NELORE COWS TREATED WITH HORMONAL PROTOCOL WITHOUT PROGESTERONE OR PROGESTAGENS

2006 ◽  
Vol 18 (2) ◽  
pp. 115 ◽  
Author(s):  
A. F. Souza ◽  
V. G. Pinheiro ◽  
R. L. Ereno ◽  
C. M. Barros
Keyword(s):  
Estrous Cycle ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Preovulatory Follicles ◽  
Estrus Detection ◽  
Calf Removal ◽  
D 12 ◽  
Hormonal Treatments ◽  
In Pregnancy

Postpartum anestrous cows are usually treated with progesterone/progestagen protocols in order to induce ovulation and sustain pregnancy. In the present work, the efficiency of a protocol (modified GPE), in which temporary calf removal (TCR) and/or administration of eCG, replaced the use of progesterone/progestagens, was evaluated in anestrous animals. Anestrous Nelore cows (40 to 60 days postpartum, n = 22) were randomly allocated to two groups: GPE/eCG and TCR/GPE/eCG. At a random stage of the estrous cycle (D0), animals from Group GPE/eCG were treated with GnRH (50 �g, licereline, i.m., Gestran Plus�; Tecnopec, Sao Paulo, Brazil) and seven days later (D7) they received PGF2� (150 mcg, d-cloprostenol, i.m., Prolise�) and eCG (300 UI, i.m., Novormon�). On D8, estradiol benzoate (EB, 1 mg, Estrogin�; Tecnopec) was administered, and 30 to 36 h afterwards all cows were inseminated at fixed-time (FTAI), without estrus detection. The animals from group TCR/GPE/eCG received the same treatment described above, but with temporary calf removal (during 48 h) before beginning hormonal treatments. The ovaries were examined by ultrasonography (Aloka SSD 500, 7.5 MHz probe) before (D-12, D-2), during (D0, D7, D8), and after (D9, D10, D11, D17, D60) hormonal treatments. The absence of CL, during the ultrasonography performed before starting the treatments, was the criterion used to classify the cows as in postpartum anestrus. Administration of GnRH (D0) induced ovulation (determined by the presence of CL on D7) in 6 of 11 cows (54.5%) from Group GPE/eCG and TCR/GPE/eCG. In relation to synchronization of ovulation after EB administration, in Group GPE/eCG, two cows (18.1%) ovulated until 12 h after FTAI, and four (36.3%) 12 h afterwards (24 h after FTAI). In Group TCR/GPE/eCG, one cow (9%) ovulated approximately 6 h before FTAI, two (18.1%) 12 h after FTAI, and two (18.1%) 12 h afterwards. Preovulatory follicles had a diameter of 11.0 � 1.3 and 11.5 � 2.6 mm in Groups GPE/eCG and TCR/GPE/eCG, respectively. Pregnancy rates, determined by ultrasonograpy 40 to 46 days after FTAI, were 27.2% (3/11) and 45.4% (5/11), respectively. The results indicate that association of TCR with protocol GPE/eCG did not improve synchronization of ovulation or pregnancy rates (P > 0.005). However, increase in pregnancy rates was observed in another experiment with a large number of animals (Pinheiro et al. 2005 Reprod. Fert. Dev. 17, 161, abstr), in which cows from Group TCR/GPE/eCG had higher pregnancy rates (51.5%; 34/66) when compared to animals from Group GPE/eCG (28.3%, 21/74; P < 0.05). This work was supported by FAPESP and by fellowships for A. F. Souza and V. G. Pinheiro from CNPq, Brazil.

18 DO TEMPORARY CALF REMOVAL AND/OR EQUINE CHORIONIC GONADOTROPIN ADMINISTRATION INCREASE PREGNANCY RATES IN LACTATING NELORE COWS TREATED WITH A PROGESTERONE-RELEASE INTRAVAGINAL DEVICE?

2006 ◽  
Vol 18 (2) ◽  
pp. 117
Author(s):  
V. G. Pinheiro ◽  
A. F. Souza ◽  
M. F. Pegorer ◽  
R. L. Ereno ◽  
C. M. Barros
Keyword(s):  
Pregnancy Rate ◽  
Body Condition ◽  
Chorionic Gonadotropin ◽  
Buenos Aires ◽  
Post Partum ◽  
Hormonal Treatment ◽  
Pregnancy Rates ◽  
Calf Removal ◽  
Equine Chorionic Gonadotropin ◽  
Intravaginal Device

Reports indicate that either temporary calf removal or equine chorionic gonadotropin administration can increase the efficiency (pregnancy rate) of hormonal treatments with progestins during postpartum anestrus. This experiment evaluated effects of TCR and/or eCG administration in a protocol with progesterone that is frequently used for fixed-time artificial insemination (FTAI) in cows during postpartum anestrus. The protocols were tested at three farms in lactating Nelore cows (40 to 70 days post-partum, n = 361) with body condition scores from 2.5 to 3.0 (0- to 5-point scale). At a random stage of the estrous cycle (Day 0), animals received a basic PEPE (progesterone-estrogen-prostaglandin-estrogen) protocol with insertion of an intravaginal device with 1.0 g progesterone (DIB�, Syntex, Buenos Aires, Argentina) and an i.m. injection of 2.5 mg of estradiol benzoate (EB, Estrogin�, Farmavet, S�o Paulo, Brazil). Eight days later (Day 8) cows were treated i.m. with 150 mg D-cloprostenol (PGF2� Prolise�, ARSA S.R.L., Buenos Aires, Argentina), and the DIB was removed. Twenty-four hours after DIB removal, cows received 1.0 mg EB i.m. and 30 to 36 h later all animals were FTAIed without estrus detection. Cows were allocated randomly to four groups: PEPE, PEPE/TCR, PEPE/eCG, and PEPE/TCR/eCG. In Group PEPE/TCR, calves were removed temporarily for 54 h (from DIB removal until FTAI). In Group PEPE/eCG, animals received PEPE treatment plus one dose i.m. of 300 UI eCG (Novormon�, Syntex) following PGF2� administration (Day 8). In Group PEPE/TCR/eCG, animals were treated as in protocol PEPE/TCR plus eCG on D8. All animals were examined by ultrasonography (Aloka SSD 500, 7.5 MHz probe) 10 days before and at the beginning of hormonal treatment in order to detect anestrous cows (absence of corpus lutcum in both exams). Pregnancy diagnosis was performed by ultrasonography 30 days after FTAI. The data were analyzed by logistic regression. The following variables were considered in the model and did not affect pregnancy rates: farms, inseminators, and semen (sire). A total of 75% of the animals were in anestrus (absence of CL) and the pregnancy rates were similar (P > 0.05) among the four groups: PEPE (43/85 = 50.6%), PEPE/TCR (42/98 = 42.9%), PEPE/eCG (41/88 = 46%), and PEPE/TCR/eCG (39/90 = 43.3%). The results indicate that in Nelore cows, in postpartum anestrus and good body condition, TCR and/or eCG administration do not improve the efficiency (pregnancy rate) of the PEPE protocol. This work was supported by FAPESP. V.G.P. and A.F.S. received fellowships from CNPq, Brazil.

Effects of postpartum energy intake on pregnancy rates in beef cattle subjected to GnRH- or CIDR-based timed artificial insemination protocols

2008 ◽  
Vol 88 (3) ◽  
pp. 439-447 ◽  
Author(s):  
J. J. Wichtel ◽  
E. Charmley ◽  
G. F. Richardson ◽  
J. L. Duynisveld ◽  
R. Lofstedt
Keyword(s):  
Beef Cattle ◽  
Energy Intake ◽  
Artificial Insemination ◽  
Body Condition Score ◽  
Post Partum ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Estradiol Treatment ◽  
Serum Progesterone

The objectives were to determine the effects of three levels of postpartum metabolisable energy (ME) intake on pregnancy rates in beef cattle subjected to either GnRH-based (OVS) or progestin-based (CIDR) protocols for fixed time artificial insemination (TAI). Hereford cross cows were assigned to ME and TAI treatments (within ME) on the basis of parity and predicted calving date. The postpartum grass-silage-based diet was formulated to provide either Low (93 MJ d-1), Medium (103 MJ d-1) or High (120 MJ d-1)] ME from calving (January to February) to turnout (May 25). Lactating cows [n = 175, 5.7 ± 1.1 mean (± SD) body condition score at calving] were subjected to their assigned TAI protocol; OVS [i.m. treatments of GnRH (100 μg) on day 0, PGF2α (25 mg) on day 7, a second GnRH on day 9 and TAI 16 to 18 h later], or CIDR [i.m. treatment with 1 mg estradiol benzoate and 100 mg progesterone concurrent with CIDR (1.9 g progesterone) insertion on day 0, PGF2α treatment at CIDR removal on day 7, a second estradiol treatment on day 8 and TAI 28 to 30 h later). Cows were 60 ± 13 d post-partum at the time of insemination. Lower ME intakes reduced (P < 0.05) maternal body weight and calf weight gain, but ME intake did not affect (P > 0.05) the proportion cycling (113/175 = 65%, based on serum progesterone concentrations on days -5 and -14), ovulation following TAI, or the TAI pregnancy rates (based on ultrasonography). Timed insemination pregnancy rates were greater for CIDR- than OVS-treatment (63 vs. 45%, respectively, P < 0.05), regardless of ME intake. Key words: Beef cow, estrus synchronization, Ovsynch, CIDR, energy intake, reproduction, calf gains

scholarly journals REDUCTION OF THE VOLUNTARY WAITING PERIOD BY USE OF HORMONAL PROTOCOLS AND FIXED-TIME ARTIFICIAL INSEMINATION (FTAI) IN DAIRY COWS

2012 ◽  
Vol 17 (3) ◽  
Author(s):  
Miriane Suplicy ◽  
Haroldo Suplicy Filho ◽  
Luiz Ernandes Kozicki ◽  
José Carlos dos Santos Breda ◽  
Romildo Romualdo Weiss ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Post Partum ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Control Group ◽  
Waiting Period ◽  
Equine Chorionic Gonadotropin ◽  
Voluntary Waiting Period

ABSTRACT: The aim of this study was to reduce the waiting voluntary period in dairy cows by administration of two different hormonal protocols for estrus synchronization and fixed-time artificial insemination (FTAI). One hundred twenty-eight Holstein dairy cows were studied. Three groups (G) were carried out: G1 (44 treated), G2 (34 treated) and G3 (50 as control). In the treated cows the following hormonal protocols was applied between 40 and 45 days post partum: G1- Day 0 (D0) - bovine intravaginal device containing progesterone (P4) plus 1.0 mg of estradiol benzoate (EB), D8 - removal of the P4, plus 0.5 mg of cloprostenol plus 400 IU of equine chorionic gonadotropin (eCG), D9 - 1.0 mg of EB and FTAI after 36 hours. G2 - D0 - P4 intravaginal plus 50 mcg of gonadotropin-releasing hormone (GnRH), D7 - removal of the P4 plus cloprostenol plus 400 IU eCG; D9 - 50 mcg of GnRH and FTAI 16 hours after. G3 – Control group inseminated 12 hours after the visual estrus. Results: G1 and G2 were inseminated (FTAI) respectively in the D55.5 and D56.8 after calving, while the G3 in the D84.5 (p<0.01).  The pregnancy rate in the G1, G2 and G3 was respectively 47.0, 46.1 and 35.8% (p>0.05).  In Conclusion: there was significant reduction in the voluntary waiting period in treated cows and higher pregnancy rate although not significant.

13 USE OF A NEW INTRAVAGINAL DEVICE TO RELEASE PROGESTERONE IN FIXED-TIMED ARTIFICIAL INSEMINATION IN NELLORE COWS (BOS TAURUS INDICUS)

2010 ◽  
Vol 22 (1) ◽  
pp. 164
Author(s):  
F. A. Braga ◽  
F. J. D. Pardo ◽  
P. H. Miguez ◽  
A. Kehrle ◽  
J. R. V. Pimentel ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Body Condition Score ◽  
Estradiol Benzoate ◽  
Sao Paulo ◽  
Pregnancy Rates ◽  
Control Group ◽  
São Paulo ◽  
Effect Of Treatment ◽  
Intravaginal Device

Artificial insemination results can be improved using fixed-timed AI (FTAI). Currently, progesterone release devices, indispensable in FTAI procedures, such as DIB® (Schering-Plough, Kenilworth, NJ, USA), are made of silicone, a nonbiodegradable biocompatible polymer. Recently, biodegradable progesterone (P4)-releasing devices made of poly(3-hydroxy)butyrate-valerate copolymer (PHB-V) and poly-ϵ-caprolactona (PCL) have been developed. To investigate the efficiency on pregnancy rate of FTAI programs using a new intravaginal device made of PHB-V (Progestar®, Innovare, São Paulo, Brazil), 240 Nellore (Bos indicus) cows, between 3 and 8 years of age, were randomly assigned to 2 experiments. In experiment 1, new P4 devices DIB (control group, DIB1; n = 60) were compared with PHB-V (Progestar1; n = 76); in experiment 2, previously used DIB (DIB2; n = 52) and PHB-V (Progestar2; n = 52) devices were compared. All groups were treated with 2 mg of estradiol benzoate i.m. (Innovare) and received the intravaginal device according to group (Day 0). Together with P4 device withdrawal (Day 8) all animals received 300IU of eCG i.m. (Novormon®, Schering-Plough) and 150 μg i.m. of D-cloprostenol (Croniben®, Biogenesis-Bagó, Buenos Aires, Argentina). On Day 9, all cows were treated with 1 mg of estradiol benzoate and the FTAI was performed 30 h later. The data were submitted to ANOVA (PROC GLM of SAS, SAS Institute, Cary, NC, USA), separating as causes of variance the effect of treatment, postpartum period (PPP1-45 until 70 days and PPP2-71 until 90 days), body condition score (BCS4, BCS5, and BCS6 using a 1 to 9 scale), cyclicity (cycling and noncycling) and clean-up bulls (5 bulls nominated with numbers 1 to 5). Significant differences were considered to have P < 0.05. In experiment 1, interactions were not significant, there was no effect of treatment on FTAI (DIB1: 66.7% v. Progestar1: 65.8%) or breeding season pregnancy rates (BSPR; DIB1: 95.0% v. Progestar1: 94.7%) and no effect of other variables on FTAI pregnancy rates (FTAIPR) and BSPR. In experiment 2 there was no effect of treatment on FTAIPR (DIB2: 61.6% v. Progestar2: 55.8%) and BSPR (DIB2: 94.2% v. Progestar2: 88.5%). As ANOVA indicated a significant effect of clean-up bulls on BSPR, Tukey test was used to split it up. A bull of the Progestar2 group had lower performance (41.7%) causing the difference (albeit nonsignificant) on BSPR. This experiment showed that Progestar and DIB had the same efficiency on pregnancy rate and both treatments have the potential to produce FTAIPR >50% and BSPR >90%. Fapesp-Fundação de Amparo à Pesquisa do Estado de São Paulo. CNPq-Conselho Nacional de Desenvolvimento Científico e Tecnológico.

Effects of temporary calf removal before fixed-time artificial insemination on pregnancy rates and subsequent calf performance in suckled beef cows1

2013 ◽  
Vol 91 (5) ◽  
pp. 2414-2425 ◽  
Author(s):  
G. H. L. Marquezini ◽  
V. R. G. Mercadante ◽  
K. M. Bischoff ◽  
T. E. Black ◽  
N. DiLorenzo ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Calf Performance ◽  
Calf Removal

scholarly journals 128 Pregnancy and calving rates of beef cows comparing the sex-selected semen to conventional semen using timed artificial insemination

2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 1-1
Author(s):  
Jennifer McMurray ◽  
Andrea N DeCarlo ◽  
Nathan Long ◽  
Scott Pratt
Keyword(s):  
Artificial Insemination ◽  
Post Partum ◽  
Statistical Significance ◽  
Fixed Time ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Chi Square ◽  
Estrous Synchronization ◽  
Beef Cow ◽  
Sexed Semen

Abstract A study was conducted over three years to determine if differences in pregnancy rates existed between the use of commercially available sex-selected (SEXED) or conventional semen (STD) coupled to fixed-time artificial insemination (TAI). A total of 240 (2016: n = 80; 2017: n = 95; 2018: n = 65) primi- or multiparous Angus or Angus-cross cows being at 45 days post-partum or greater were blocked by weight and BCS and assigned to be inseminated using SEXED semen or STD semen. Artificial insemination was performed by the same AI technicians (n = 3) across all years. All cows were subjected to estrous synchronization and insemination using the SEXED semen or STD semen with TAI between 63 and 66 h post-CIDR removal. Fourteen days post-TAI all cows were exposed to bulls for natural service. Cows were subjected to transrectal ultrasonography at day 30 and day 45 post-TAI to determine pregnancy rates and calving dates in the subsequent calving seasons were recorded to determine calving rates to TAI. Pregnancy rates were compared using a Chi-square test of two proportions. All statistical calculations were performed using JMP software and statistical significance was based on p-values less than 0.05. Pregnancy rates at day 30 and day 45 were 39.67% and 48.76% for SEXED and 47.90% and 54.62% for STD, respectively (P &gt; 0.05). The percentage of calves born to TAI pregnancies for sex-selected semen and conventional semen were 22.31% and 40.34%, respectively (P &lt; 0.05). These data indicate that the use of sex-selected semen can give similar pregnancy results to conventional semen in beef cow operations using TAI at day 30 of gestation; however, there was a reduction in the number of offspring to TAI comparing calving dates to animals pregnant at day 30.

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).

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