scholarly journals Reproductive efficiency Nellore and crossbred cows submitted to administration of melengestrol acetate (MGA) after FTAI protocols

2020 ◽  
Vol 9 (10) ◽  
pp. e5679108897
Author(s):  
Alan Gabriel Valero ◽  
Carlos Renato de Freitas Guaitolini ◽  
Andre Maciel Crespilho ◽  
Gabriela Passamani da Cruz ◽  
Marcio Luiz Denck Tramontin ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Breeding Season ◽  
Medroxyprogesterone Acetate ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Conception Rate ◽  
Reproductive Efficiency ◽  
Crossbred Cows ◽  
Melengestrol Acetate

This study aimed to evaluate the influence of medroxyprogesterone acetate (MGA) supplementation between the 13th and 20th day after Fixed-Time-Artificial Insemination (FTAI), on the conception and gestation rates of Nellore and crossbred cows (Nellore x Angus), pluriparous and lactating. For the study, 349 Nellore cows and 270 crossbred cows were selected, distributed into 1) group G1 (n=176): Nellore cows submitted to the FTAI protocol, without MGA supplementation; 2) group G2 (n=173): Nellore cows submitted to the FTAI protocol, with supplementation for 7 days of MGA® (0.28g/AU/day) from the 13th post-FTAI; 3) group G3 (n=119): crossbred cows: FTAI protocol, without MGA supplementation; 4) group G4 (n=151): crossbred cows: FTAI protocol followed by MGA supplementation for 7 days (0.28g/AU/day), from the 13th to the 20th day after FTAI. For statistical analysis, the procedures MIXED and GLIMMIX from SAS were used. G3 had higher rates of conception (CR=85.7%) and pregnancy (PR=95.8%) at the end of the breeding season (P<0.05), without the interference of supplementation with MGA (P>0.05). G1 females had a lower conception rate (TC=76.7%) (P<0.05), with the use of MGA® (CR-MGA=59.5%), but similar rates of pregnancy (PR=90.3%; PR-MGA=92.5%) to the G2, at the end of the breeding season (P>0.05). When G2 and G4 were compared, we found that crossbred females supplemented had higher rates of conception and pregnancy. In conclusion, crossbred animals have higher conception and pregnancy rates at the end of the breeding season. Besides, we found that Nellore females had a lower conception rate, with the use of MGA® Premix.

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.

scholarly journals STRATEGIES TO INCREASE FERTILITY DURING FIXED-TIME ARTIFICIAL INSEMINATION IN BEEF CATTLE

SPERMOVA ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 73-82
Author(s):  
Ana Clara Canto Souza ◽  
◽  
Gabrieli Dutra Gonçalves ◽  
Andrey Osvaldo Souza Ferro ◽  
Deborah Nakayama Yokomizo ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Estrous Cycle ◽  
Breeding Season ◽  
Critical Points ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Follicular Wave ◽  
New Strategies ◽  
In Pregnancy

The application of Fixed Time Artificial Insemination (FTAI) protocols has strongly boosted artificial insemination in Brazilian bovine herds. The control of the estrous cycle with protocols based on progesterone and estrogen involves synchronizing the emergence of a follicular wave, controlling the progesterone phase, and inducing ovulation in a synchronized manner. The increase in pregnancy rates starts with the preparation of the breeding season and the choice of protocols and females. Thereafter, based on the characteristics of the property and the lots of animals, small adjustments can be made to the hormonal protocols as needed. Finally, resynchronization can increase usability by allowing multiple inseminations within short periods. The search for new strategies is of paramount importance for the development of the FTAI protocol and the increase in final pregnancy rates. Thus, this review sought to highlight the main critical points and adjustments of the FTAI protocols and their applicability in the reproduction of beef cattle.

scholarly journals Different estrous induction methods during the non-breeding season in Kivircik ewes

2012 ◽  
Vol 51 (No. 4) ◽  
pp. 133-138 ◽  
Author(s):  
I. Dogan ◽  
Z. Nur
Keyword(s):  
Breeding Season ◽  
Medroxyprogesterone Acetate ◽  
Artificial Insemination ◽  
Intramuscular Injection ◽  
Saline Solution ◽  
Fixed Time ◽  
Sterile Saline ◽  
Time To Onset ◽  
Pregnant Mare Serum Gonadotrophin ◽  
Fresh Semen

The efficiency of medroxyprogesterone acetate (MAP) sponges in combination with either pregnant mare serum gonadotrophin (PMSG) or cloprostenol (PGF<sub>2&alpha;</sub>) for inducing and synchronizing the estrous cycle in non-lactating Kivircik ewes was investigated during the natural non-breeding season. All ewes (n = 69) were treated with 60 mg MAP sponges for 12 days. In addition, each ewe received an intramuscular injection of either 1.5 ml sterile saline solution (n = 18); 125 &mu;g PGF<sub>2&alpha;</sub> (n = 14); 500 IU PMSG (n = 18) or 500 IU PMSG and 125 &mu;g PGF<sub>2&alpha;</sub> (n = 19), 48 h before the sponge removal. Cervical artificial insemination (AI) with diluted fresh semen was performed at a fixed time (48 and 60 h) following progestagen withdrawal. The different groups estrous response for the first 24 &plusmn; 6 h and within 120 h, time to onset and duration of the induced estrous, and pregnancy rate was found to be 36.2%, 81.6%, 41.7 &plusmn; 2.3 h, 29.6 &plusmn; 1.5 h, and 54.5%, respectively. There were significant differences between groups MAP and MAP/PGF<sub>2&alpha;</sub> and their with the two latter groups (MAP/PMSG, MAP/PMSG/PGF<sub>2&alpha;</sub>) in terms of the onset of induced estrous (P &lt; 0.05) and between groups MAP and MAP/PGF<sub>2&alpha;</sub> in terms of the duration of induced estrous (P &lt; 0.05) and between the first two groups (MAP, MAP/PGF<sub>2&alpha;</sub>) and the latter two groups (MAP/PMSG, MAP/PMSG/PGF<sub>2&alpha;</sub>) in terms of estrous response at the first 24 &plusmn; 6 h (P &lt; 0.05). These results indicate that, the use of MAP/PMSG, rather than MAP or MAP/PGF<sub>2&alpha;</sub>, was effective in the attainment of early and compact induction and synchronization of estrous in non-lactating Kivircik ewes during the natural non-breeding season.

scholarly journals Estrous synchronization during the natural breeding season in Anatolian black does

2012 ◽  
Vol 50 (No. 1) ◽  
pp. 33-38 ◽  
Author(s):  
I. Dogan ◽  
Z. Nur ◽  
U. Gunay ◽  
H. Sagirkaya ◽  
Soylu MK ◽  
...  
Keyword(s):  
Breeding Season ◽  
Medroxyprogesterone Acetate ◽  
Artificial Insemination ◽  
Saline Solution ◽  
Fixed Time ◽  
Sterile Saline ◽  
Estrous Synchronization ◽  
Natural Breeding ◽  
Time To Onset ◽  
Fresh Semen

The efficiency of medroxyprogesterone acetate (MAP) and fluorogestone acetate (FGA) sponges with or without PGF<sub>2&alpha;</sub> (cloprostenol) for synchronizing estrous in non-lactating does was investigated during the natural breeding season. Does were treated for 11 days with 60 mg MAP (n = 38) or 40 mg FGA (n = 32) sponges. All does also received intramuscular injections of 500 IU PMSG. In addition, 19 and 14 of the does synchronized with MAP and FGA respectively, were injected with 125 &mu;g cloprostenol and the remaining does from both groups were injected with 1.5 ml of sterile saline solution, 48 h prior the sponge removal. Cervical artificial insemination (AI) with diluted fresh semen was performed at a fixed time (36 and 48 h) following progestagen withdrawal. The different groups estrous response for the first 12 &plusmn; 6 h and within 66 h, time to onset and duration of the induced estrous, and pregnancy rate was found to be 52.6%, 92.9%, 20.6 &plusmn; 0.8 h, 29.7 &plusmn; 1.3 h, and 70.0%, respectively. There were significant differences between groups FGA/PMSG/PGF<sub>2&alpha;</sub> and MAP/PMSG in terms of the duration of induced estrous (P &lt; 0.05) and between groups FGA/PMSG/PGF<sub>2&alpha;</sub> and FGA/PMSG in terms of estrous response at the first 12 &plusmn; 6 h (P &lt; 0.05). These results indicate that, the use of MAP/PMSG and FGA/PMSG intravaginal progestagen treatments with or without cloprostenol are equally efficient in synchronizing estrous in non-lactating hair goats during the natural breeding season.

scholarly journals Administration of GnRH on the day of fixed-time artificial insemination (FTAI) and melengestrol acetate (MGA) administration after ftai in non-suckling nelore cattle

2015 ◽  
Vol 36 (5) ◽  
pp. 3149
Author(s):  
Rossane Pereira da Silva ◽  
Karen Martins Leão ◽  
Moraima Castro Rodrigues ◽  
Thaisa Campos Marques ◽  
Natalia Do Carmo Silva ◽  
...  
Keyword(s):  
Oral Administration ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Conception Rate ◽  
Control Group ◽  
Mineral Supplementation ◽  
Melengestrol Acetate ◽  
Buserelin Acetate ◽  
Conception Rates ◽  
Nelore Cattle

<p>The present study evaluated the effect of administering buserelin acetate (GnRH) at the time of fixed-time artificial insemination (FTAI), along with the effect of oral administration of melengestrol acetate (MGA) after FTAI on conception rates in non-suckling Nelore cattle. In Experiment I, the effect of GnRH application at the time of FTAI was evaluated, as was administration of MGA from the 13th through the 18th day following FTAI (D24 to D29 after the initiation of the FTAI protocol). Experiment I was performed in 215 non-suckling cattle of the Nelore breed, divided into four experimental groups: Control group: 56 cows subjected to FTAI without GnRH injection; GnRH group: 51 cows subjected to GnRH at the time of FTAI; MGA Group: 57 cows subjected to FTAI without the application of GnRH with mineral supplementation and the addition of 2.28 g of MGA® Premix per cow per day from D24 to D29 after the initiation of the FTAI protocol; MGA and GnRH group: 51 cows subjected to GnRH injection at the time of FTAI, with mineral supplementation and the addition of 2.28 g of MGA® Premix per cow per day from D24 to D29 after the initiation of the FTAI protocol. In Experiment II, the effect of providing MGA five to ten days after FTAI was evaluated in 196 non-suckling pluriparous Nelore cows, divided into two groups: Control group: 104 cows subjected to FTAI, not supplemented with MGA; treated group: 92 cows supplemented with the addition of 2.28 g of MGA® Premix per cow per day from D15 to D20 after the initiation of the FTAI protocol. Diagnosis of gestation was carried out 45 days after FTAI. Both experiments were conducted using a completely randomised design and analysed via the SAS MIXED procedure. In Experiment I, the control group displayed a lower conception rate (32.1%) compared with the groups administered GnRH, MGA, and both MGA and GnRH, which were respectively provided with MGA after FTAI (45.6%), GnRH at the time of FTAI (50.9%), and the combination of the two treatments (50.9%) (P&lt;0.05). In Experiment II, the control group displayed a higher conception rate (40.38%) compared with the group receiving MGA post-FTAI (18.48%) (P&lt;0.05). It was concluded that the injection of buserelin acetate (GnRH) at the time of FTAI and the oral administration of MGA® Premix from the 13th to the 18th day after FTAI increased the conception rates in non-suckling Nelore cattle. However, when MGA® Premix was administered orally from the fifth to tenth day post-FTAI, conception rates in non-suckling Nelore cattle were reduced.</p>

Oestrus synchronisation and fixed time artificial insemination in beef heifers

2010 ◽  
Vol 50 (7) ◽  
pp. 670
Author(s):  
Daniel Cavestany ◽  
Daniela Crespi ◽  
Alvaro Fernandez
Keyword(s):  
Artificial Insemination ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Conception Rate ◽  
Control Group ◽  
Beef Heifers ◽  
Follicular Size ◽  
Follicle Size ◽  
And Control

To compare two oestrus synchronisation protocols in beef heifers presynchronised with two prostaglandin F2α (PG) treatments, 36 h after the second PG treatment one group (hCG-OB group; n = 112) received 250 IU of hCG and 0.5 mg of oestradiol benzoate (OB) followed by fixed time artificial insemination (FTAI) 30 h later. Additional oestrus detection (OD) and artificial insemination (AI) was done in this group for 3 days after FTAI; heifers rebred during this period were considered open to the FTAI. The Control group (n = 112) received only OD and AI for 6 days after the second PG treatment. Follicular size was measured at the time of AI in a subsample of heifers (59 in the hCG-OB group and 34 in the Control group). Results were evaluated separately either considering heifers pregnant at FTAI or those pregnant at FTAI + 3-day OD + AI. The FTAI conception rate was 45.5 vs 76.5% for the Control group (P < 0.0001) and pregnancy rates were 45.5 and 67.0% (P = 0.0014); FTAI + OD + AI conception rates were 63.4 and 76.2% (P = 0.0404) and pregnancy rates 63.4 and 62.8% (P = 0.5719) (hCG-OB and Control groups, respectively). There was a significant correlation (r = 0.713, P < 0.01) between follicle size at FTAI and pregnancy in the hCG-OB group, but not in the Control group (r = 0.3465, P > 0.1). In conclusion, acceptable synchronised conception rate and pregnancy rate were obtained by using this protocol, and the results were improved by complementing it with OD + AI for 3 days after FTAI.

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

scholarly journals Effects on Synchronization and Reproductive Efficiency of Delaying the Removal of the Intravaginal Progesterone Device by 24 h in the 5d Co-synch Protocol in Heifers

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 849
Author(s):  
Aitor Fernandez-Novo ◽  
Sergio Santos-Lopez ◽  
Jose Luis Pesantez-Pacheco ◽  
Natividad Pérez-Villalobos ◽  
Ana Heras-Molina ◽  
...  
Keyword(s):  
Animal Welfare ◽  
Reproductive Performance ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Reproductive Efficiency ◽  
Beef Heifers ◽  
Animal Management ◽  
Commercial Farms ◽  
Beef Herds ◽  
Farm Economics

In beef herds, increasing animal welfare, improving reproductive performance and easing animal management are key goals in farm economics. We explored whether delaying the removal of the intravaginal progesterone device by 24 h in heifers synchronized with a 5d Co-synch 72-h protocol could improve reproductive efficiency of fixed-time artificial insemination (FTAI). In experiment 1, we examined the total synchronization rate (TSR) in cycling Holstein heifers. Heifers (13.4 ± 0.69 mo.) were randomly assigned to the standard 5d Co-synch 56-h protocol (5dCo56; n = 10), 5d Co-synch 72-h (5dCo72; n = 17), or the modified 5d Co-synch 72-h protocol, in which removal of the progesterone device was delayed by 24 h (6dCo48; n = 19). In experiment 2, 309 cycling beef heifers on 18 commercial farms were subjected to the 5d Co-synch 72-h or 6-d Co-synch 48-h protocol and conception rate (CR) studied. In experiment 1, the three protocols led no differences on TSRs of 80.0% (5dCo56), 88.2% (5dCo72), and 89.5% (6dCo48). In experiment 2, the CR from the beef heifers, observed during two consecutive reproductive seasons did not differ: 59.7% for 5dCo72 and 62.0% for 6dCo48 (p = 0.907). Therefore, delaying removal by 24 h provides satisfactory results without reducing reproductive efficiency of heifers.

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