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 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.

Parenteral Copper Administration at the Beginning of a Fixed-Time Artificial Insemination Protocol in Beef Cattle: Effect on Ovarian Function and Pregnancy Rates

2021 ◽  
Author(s):  
Juan Patricio Anchordoquy ◽  
Santiago Nicolás Lorenti ◽  
Gustavo Sebastián Polero ◽  
Nicolás Agustín Farnetano ◽  
Diana Esther Rosa ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Artificial Insemination ◽  
Ovarian Function ◽  
Fixed Time ◽  
Pregnancy Rates

Pre-synchronization of ovulation timing and delayed fixed-time artificial insemination increases pregnancy rates when sex-sorted semen is used for insemination of heifers

2021 ◽  
Vol 226 ◽  
pp. 106699
Author(s):  
N. Oosthuizen ◽  
P.L.P. Fontes ◽  
R.V. Oliveira Filho ◽  
C.R. Dahlen ◽  
D.M. Grieger ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Fixed Time ◽  
Pregnancy Rates

Response of beef heifers and non-suckling beef cows to different oestrous synchronization protocols

2002 ◽  
Vol 74 (3) ◽  
pp. 547-552 ◽  
Author(s):  
D. Cavestany ◽  
N. Negrin ◽  
R. Negrin ◽  
J. F. Groth
Keyword(s):  
Beef Cattle ◽  
Medroxyprogesterone Acetate ◽  
Artificial Insemination ◽  
Experimental Period ◽  
Fixed Time ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Gnrh Analogue ◽  
Beef Heifers

AbstractThe objective was to evaluate different oestrous synchronization schemes in beef cattle under range conditions. In experiment 1, 202 heifers averaging 26 months of age were assigned randomly to three treatments: (a) GnRH-PG. (no. = 44) day 0 (D0): injection of GnRH; D7: injection of PGF2α; D0 to D25 oestrous detection (OD) and artificial insemination (AI); (b) OD-PG. (no. = 45) D0 to D4; OD + AI; D5: injection of PGF2α; D5 to D25 OD + AI; and (c)Ovsynch. (no. = 113) D0: injection of GnRH; D7: injection of PGF2α; D9: injection of GnRH and 16 h later AI at fixed time. In experiment 2, 318 non-suckling cows were assigned randomly to three treatments: (a) GnRH-PG. (no. = 106) D0: injection of GnRH; D7: injection of PGF2α; D0 to D25 OD + AI; (b) GnRH-MAP-PG. (no. = 106) D0: injection of a GnRH analogue and insertion of an intravaginal sponge impregnated with 250 mg of medroxyprogesterone acetate; D7: injection of PGF2α and sponge withdrawal; D0 to D25 OD + AI; (c) controls. (no. = 106) OD and AI. The experimental period lasted 25 days and, with exception of the Ovsynch treatment, oestrous detection was carried out twice a day (a.m./p.m.) and inseminations performed 12 h later. The pregnancy rates assessed by ultrasonography 30 days after AI were: experiment 1: (a) 30·0%; (b) 28·6% and (c) 62·3% (P < 0·05); experiment 2: (a) 60·2%; (b) 57·8% and (c) 45·5% (P < 0·05). It is concluded that in heifers and non-suckling cows, oestrous synchronization treatments result in higher pregnancy rates. In non-suckling cows, the addition of a progestagen did not improve the response.

Cooled semen for fixed-time artificial insemination in beef cattle

2016 ◽  
Vol 28 (7) ◽  
pp. 1004 ◽  
Author(s):  
Juliana C. Borges-Silva ◽  
Márcio R. Silva ◽  
Daniel B. Marinho ◽  
Eriklis Nogueira ◽  
Deiler C. Sampaio ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Sperm Motility ◽  
Artificial Insemination ◽  
Egg Yolk ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Reproductive Efficiency ◽  
Sperm Abnormalities ◽  
Hypoosmotic Swelling Test ◽  
Interesting Approach

This study evaluated the use of cooled semen in a fixed-time artificial insemination (FTAI) program compared with frozen–thawed semen to improve pregnancy rates in beef cattle. Ejaculates of three bulls were collected and divided into two treatments: (1) frozen–thawed semen and (2) cooled semen. Egg-yolk extender without glycerol was used for the cooled semen treatment. Straws (25 × 106 spermatozoa) were submitted to cooling for preservation at 5°C for 24 h, after which FTAI was performed. Nelore cows (n = 838) submitted to FTAI were randomly inseminated using frozen–thawed semen or cooled semen. There was a 20% increase in the pregnancy per AI (P AI–1) using cooled semen compared with frozen–thawed semen (59.9 ± 4.7 vs 49.4 ± 5.0%; P < 0.005). There was no difference in P AI–1 among the bulls (P = 0.40). The frozen–thawed semen had fewer functional spermatozoa than did the cooled semen when evaluated by sperm motility (61.7 vs 81.0%), slow thermoresistance test (41.7 vs 66.7%) and hypoosmotic swelling test (38.3 vs 53.7%; P < 0.05). The percentage of sperm abnormalities did not differ between the freeze–thawing and cooling processes (18.6 vs 22.1%; P > 0.05). Because there was less damage to spermatozoa and improvement in P AI–1, the use of cooled semen instead of frozen–thawed semen is an interesting approach to increase reproductive efficiency in cattle submitted to a FTAI protocol.

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.

scholarly journals Effect of progesterone, human chorionic gonadotropin and progesterone + human chorionic gonadotropin treatment on conception rates in repeat breeder cows

2020 ◽  
Vol 89 (4) ◽  
pp. 307-315
Author(s):  
Hasan Alkan ◽  
Huseyin Erdem
Keyword(s):  
Pregnancy Rate ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Group 4 ◽  
Prostaglandin F ◽  
Repeat Breeder ◽  
Group 1

The aim of this study was to investigate the effects of hormonal support on the pregnancy rate in repeat breeder cows. Prostaglandin F2α + Ovsynch oestrus synchronization protocol was applied to the cows. Following the fixed time insemination (day 0), the cows were divided into 4 groups. In Group 1 (n = 42), progesterone releasing intravaginal device (PRID) was placed vaginally at 84 h and removed on the 9th day after the artificial insemination. In Group 2 (n = 40), the cows were administered human chorionic gonadotropin (hCG) on the 7th day. Group 3 (n = 45) was applied a combination of progesterone and hCG. Group 4 (n = 42) was not given any treatment. Blood samples were collected from all cows 4 times on days 3.5, 7, 12, and 18 to evaluate progesterone concentrations. The pregnancy rates were 40.47%, 37.50%, 44.44%, and 30.95% in Group 1, 2, 3, and 4, respectively (P > 0.05). In addition, in cows with progesterone concentrations <2 ng/ml on day 3.5, the pregnancy rates were found to be lower than in the cows with progesterone concentrations >2 ng/ml in Group 4 (P < 0.05). Progesterone supplementation in cows with progesterone concentrations < 2 ng/ml appeared to increase pregnancy rates (P < 0.05) in Groups 1 and 3. As a result, post-insemination hormonal applications in the repeat breeder cows did not increase the pregnancy rate. However, it was concluded that determination of progesterone concentrations on day 3.5 following artificial insemination and then hormonal support in the cows with low concentrations would increased the pregnancy rate.

Influence of a controlled internal drug release after fixed-time artificial insemination on pregnancy rates and returns to estrus of nonpregnant cows1

2009 ◽  
Vol 87 (3) ◽  
pp. 914-921 ◽  
Author(s):  
J. E. Larson ◽  
K. N. Thielen ◽  
B. J. Funnell ◽  
J. S. Stevenson ◽  
D. J. Kesler ◽  
...  
Keyword(s):  
Drug Release ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Pregnancy Rates
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