16 FERTILITY RATE OBTAINED WITH A NEW INTRAVAGINAL PROGESTERONE RELEASING DEVICE DICO IN SHEEP

2011 ◽  
Vol 23 (1) ◽  
pp. 114
Author(s):  
C. García-Pintos ◽  
P. C. dos Santos-Neto ◽  
A. Menchaca

A new intravaginal device DICO (Dispositivo Intravaginal Caprino Ovino, 0.3 g progesterone; Syntex, Buenos Aires, Argentina) consisting of a progesterone impregnated medical silicone was developed for oestrus synchronization in sheep and goats. The effectiveness of this device to control serum progesterone concentrations, follicular development and time of ovulation has been recently reported in ewes (Vilariño et al. 2010 Small Rumin. Res. 91, 219–224); however, fertility obtained with DICO has not been evaluated yet. The aim of this study was to determine fertility rate obtained with DICO by fixed-time cervical or intrauterine insemination in sheep. The experiment was performed on a total of 569 Corriedale multiparous ewes in breeding season, with a body condition score of 3.0 ± 0.1 (scale 0–5). Ewes received a Short-term Protocol consisting of a 6 days of treatment with DICO (n = 174), CIDR-G (0.3 g of progesterone, Pfizer, NY, USA; n = 197) or sponges with 60 mg of medroxiprogesterone acetate (MAP, Syntex; n = 198). One dose of prostaglandin F2α analogue (125 μg of cloprostenol, Cilcase DL, Syntex) and 300 IU of eCG (Novormon, Syntex) was given at the time of device withdrawal. Insemination was performed 48 or 54 h after device removal by cervical (200 millions of spermatozoa) or laparoscopic intrauterine insemination (100 millions of spermatozoa), respectively. Pregnancy diagnosis was performed by transrectal ultrasonography (5 MHz, Well D, Beijing, China) 40 days after insemination. Pregnancy rate (pregnant ewes/inseminated ewes) was compared by logistic regression, and number of fetuses/pregnant ewes was analysed by Poisson regression. Regarding pregnancy rate, a significant difference (P < 0.05) was found between cervical (39.5%, 109/276) v. intrauterine insemination (58.3%, 172/295), as well as between progesterone devices (DICO: 55.7%, 97/174; CIDR-G: 55.8%, 110/197) v. MAP sponges (37.4%, 74/198). The results are shown in Table 1. In conclusion, the current study shows that the new intravaginal device DICO is useful to obtain acceptable fertility with fixed-time insemination in sheep. When cervical insemination at 48 h or intrauterine insemination at 54 h after device removal is performed, similar or better results than CIDR-G or MAP sponges are achieved, respectively. Table 1.Results obtained with DICO, CIDR and sponges after cervical or intrauterine insemination in sheep Supported by Syntex.

2011 ◽  
Vol 23 (1) ◽  
pp. 115
Author(s):  
P. C. dos Santos-Neto ◽  
C. García-Pintos ◽  
A. Menchaca

The new intravaginal device DICO (Dispositivo Intravaginal Caprino Ovino, 0.3 mg progesterone, Syntex, Buenos Aires, Argentina) is effective in controlling serum progesterone concentrations, follicular development and time of ovulation in sheep, even in its second use after 6 days of treatment (Vilariño et al. 2010 Small Rumin. Res. 91, 219–224). The pregnancy rate obtained with DICO in its first use is similar to that obtained with CIDR-G (Pfizer, New York, NY, USA) (abstract of García-Pintos et al. in this issue). However, pregnancy rate with the reutilisation of DICO has not been evaluated yet. The aim of this study was to determine fertility rates in ewes synchronized with a reused DICO in comparison with a reused CIDR-G. The experiment was carried out on 314 Corriedale multiparous ewes during breeding season (March, 33°S, Uruguay), with a body condition score of 3.0 ± 0.1 (scale 0–5). Ewes received a short-term-protocol using DICO (n = 139) or CIDR-G (n = 175) during 6 days, previously used for 6 days. One dose of prostaglandin F2α analogue (125 μg cloprostenol, Ciclase DL, Syntex) and 300 IU eCG (Novormon, Syntex) were given at the time of device removal. Cervical insemination (200 million spermatozoa) or laparoscopic intrauterine insemination (100 million spermatozoa) was performed with fresh semen at fixed-time 48 or 54 h from device removal, respectively. Pregnancy diagnosis was done by transrectal ultrasonography (5 MHz, Well D, Beijing, China) 40 days after insemination. Pregnancy rate was analysed by logistic regression, and number of fetus/pregnant ewes and fetus/inseminated ewes was analysed by Poisson regression. No differences were found between reused DICO and CIDR-G devices (Table 1). Overall, pregnancy rate was affected by the method of insemination (P ≤ 0.05), being lower for cervical (37.0%; 57/154) than intrauterine insemination (55.0%; 88/160). In conclusion, the reutilization of DICO devices in the short-term protocol (6 days of treatment) allows similar fertility rates compared to re-used CIDR-G devices, by both cervical and intrauterine insemination. Table 1.Fertility rate obtained with the reutilisation of DICO and CIDR in short-term protocol (6 days of treatment) in sheep


2011 ◽  
Vol 23 (1) ◽  
pp. 163 ◽  
Author(s):  
R. Núñez ◽  
T. de Castro ◽  
L. Cutaia ◽  
G. Bó ◽  
A. Menchaca

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.


2016 ◽  
Vol 28 (2) ◽  
pp. 184
Author(s):  
M. Pelizzari ◽  
A. Tribulo ◽  
J. Garzon ◽  
B. Bernal ◽  
R. Tribulo ◽  
...  

A retrospective analysis of factors that affect pregnancy rates from 4214 fresh in vitro-produced (IVP) embryos that were transferred at a fixed-time (FTET) in 20 different farms. Recipients were all cycling cows or heifers that were synchronized with 1 of 3 treatments: 1) treatments with progesterone (P4) devices and 2 mg of oestradiol benzoate (EB) on Day 0 (day of insertion) and 24 h after device removal (Day 8); 2) treatments with P4 devices and EB on Day 0, but with 0.5 mg of oestradiol cypionate (ECP) at device removal (Day 8); or 3) treatments with P4 devices and GnRH on Day 0 and a second GnRH 60 h after device removal (Day 5). Cows in all treatment groups also received 500 µg of cloprostenol (prostaglandin F2α) at the time of P4 device removal and 400 IU of eCG either at device removal or 3 days before device removal. All embryos were transferred 7 or 8 days after the expected time of oestrus (24 h after EB, 48 h after ECP or at the time of the second GNRH for each synchronization treatment, respectively). On the day of embryo transfer, recipients were examined by ultrasonography and those with corpus luteum >14 mm in diameter received a fresh, IVP embryo in the uterine horn ipsilateral to the corpus luteum. Pregnancy rates were determined by ultrasonography 35 days after FTET. Data were analysed by logistic regression. Independent variables were classified into the following three categories. 1) Factors related to the recipient and the environment; there were no significant differences in pregnancy rates for corpus luteum diameter (≥14 and <16 mm, ≥16 and <18 mm, or ≥18 mm; P = 0.46), number of corpus luteum (1 or ≥2; P = 0.26), and category of recipient (cow or heifer; P = 0.21). However, there were significant effects of farm (P = 0.01) and body condition score (BCS; P = 0.01). Cows with BCS ≥4.5 (1 to 5 scale) resulted in lower pregnancy rates (4/20, 20.0%) than those with BCS 2 (74/225, 32.9%), 2.5 (502/1434, 35.0%), 3 (570/1467, 38.9%), 3.5 (193/532, 36.3%), and 4 (44/118, 37.3%). 2) Factors related to the synchronization treatment; there were no significant differences between recipients receiving eCG at device removal (84/209, 40.2%) or 3 days before device removal (874/2291, 38.1%; P = 0.35). However, recipients synchronized with P4 devices and ECP had higher (P = 0.01) pregnancy rates (232/483, 48.0%) than those treated with EB (679/1888, 36.0%) or gonadotropin-releasing hormone (47/129, 36.4%). 3) Factors related to the embryo transfer technique; day of the recipient’s oestrous cycle (P = 0.36), stage of embryo transferred (IETS stages 6 or 7; P = 0.62), and operator (P = 0.57) did not affect pregnancy rates. However transfers made in the anterior third of the uterine horn resulted in higher (649/1545, 42.0%) pregnancy rates than those in the mid-third (845/2511, 33.6%) or in the distal third (6/35, 17.1%; P = 0.01). It was concluded that factors related to the recipient and the environment (farm and BCS), the synchronization treatment (ECP), and the embryo transfer technique (site of deposition) affect pregnancy rates in recipients of embryos produced in vitro and transferred at a fixed time.


2010 ◽  
Vol 22 (1) ◽  
pp. 172
Author(s):  
A. Menchaca ◽  
M. Vilariño ◽  
E. Rubianes

The short-term protocol with progesterone, prostaglandin F2α (PGF2α), and eCG is used to control follicular dynamics and luteal activity synchronizing the ovulation for fixed-time AI in sheep. The objective of this experiment was to compare the pregnancy rate obtained with short-term protocol (6 d) and long-term protocol (14 d) using cervical or intrauterine fixed-time AI in sheep. Three hundred fifty-two Merino ewes with a body condition score of 2.9 ± 0.3 (mean ± SD; scale 0 to 5) were used during the breeding season (April, 33S, Uruguay). All the females received a CIDR-G (0.3 g of progesterone, InterAg, Hamilton, New Zealand) for 6 d (short-term protocol; n = 178) or 14 d (long-term protocol, n = 174). One imdose of eCG (300 IU, Novormon, Syntex, BA, Argentina) was given at the moment of device withdrawal for the both protocols, and one imdose of PGF2α (10 mg of dinoprost, Lutalyse, Pfizer, New York, NY, USA) was given at the end of the short-term protocol to ensure luteolysis. Cervical AI (short-term protocol, n = 85; long-term protocol, n = 104) or intrauterine AI (short-term protocol, n = 93; long-term protocol, n = 70) was performed 48 or 54 h after device withdrawal, using 200 × 106 or 100 × 106 spermatozoa per ewe, respectively. Fresh semen was extended in UHT skim milk (1000 × 106 spermatozoa mL-1) and used within 1 h of collection. Estrus was recorded twice a day for 4 days after device withdrawal using vasectomized males. Pregnancy diagnosis was performed by transrectal ultrasonography 40 d after AI (5.0 MHz, Aloka, Tokyo, Japan). Logistic regression was used to analyze the effect of the treatment (P < 0.05), the AI technique (P < 0.05), and their interaction (P = NS). Pregnancy rate was higher for the short-term than for the long-term protocol, and for intrauterine than for cervical AI (Table 1). The highest pregnancy rate was achieved with short-term protocol using intrauterine AI (54.8%, 51/93), and the lowest response was obtained with long-term protocol using cervical AI (33.7%, 35/104; P < 0.05). These data were not different from data of short-term protocol using cervical AI or long-term protocol using intrauterine AI (42.4%, 36/85; and 44.3% 31/70, respectively). Ewes in estrus/treated ewes was not different among short-term and long-term protocols (83.7%, 149/178; and 82.8%, 144/174, respectively; P = NS). In summary, regardless of insemination technique, short-term protocol of 6 d enhances pregnancy rate in fixed-time AI programs in sheep. Table 1.Main effects of short-term (6 d) v. long-term (14 d) protocol using cervical or intrauterine fixed-time AI on pregnancy rate in sheep Financially supported by Pfizer, SP, Brazil.


2010 ◽  
Vol 22 (1) ◽  
pp. 162
Author(s):  
J. Almeida ◽  
O. A. Resende ◽  
D. L. Silveira

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.


2017 ◽  
Vol 29 (1) ◽  
pp. 113 ◽  
Author(s):  
E. Pradebon da Silva ◽  
A. B. Machado ◽  
L. S. Gambin ◽  
A. V. Gonsioroski ◽  
M. da Silva ◽  
...  

The aim of this study was to evaluate the effect of presence of corpus luteum (CL) at the onset of timed AI (TAI) protocol, size of ovulatory follicle and oestrus expression on pregnancy rate using E2 cypionate (EC) or GnRH as ovulation inductor in Angus heifers. On day 0, heifers [n = 414; 317 ± 23 kg; 3.08 ± 0.21 body condition score (1 to 5 scale) and 22–24 months of age] received a 1-g progesterone intravaginal device (Primer®, Agener União, Brazil) and 2 mg of oestradiol benzoate, IM, (RIC-BE®, Agener União, Brazil). On day 8, the device was removed, were administered 500 μg of sodium cloprostenol, IM, (Estron®, Agener União, Brazil) and heifers were divided in 2 groups: EC [n = 213; 0.5mg EC, IM, (SincroCP®, Ouro Fino, Brazil) on day 8] and GnRH [n = 201; 25 μg of Licerelin, IM, (GestranPlus®, Agener União, Brazil) at TAI] TAI was performed 50 h after device removal. Heifers were tail painted (Tell Tail®, GEA, New Zealand) to control oestrus expression from device removal to TAI. Heifers were scanned (7.5-MHz linear transducer MediSono® P3V, USA) to determine presence of CL (Day 0), ovulatory follicle diameter (OFD; Day 10) and ovulation (Day 11). Pregnancy was diagnosed 30 days after TAI. Oestrus expression was confirmed when marking ink was removed on day 10. Data were analysed using logistic regression and ANOVA. Oestrus expression was higher (P < 0.05) in EC (93.90%, 200/213) compared to GnRH group (67.66%, 136/201). The OFD differed (P < 0.05) according to presence of CL on Day 0 (10.3 mm) or not (9.6 mm), but was similar in treatment groups. Ovulation rate did not differ in EC (85%, 17/20) and GnRH (95%, 19/20) groups. Pregnancy rates were similar (P > 0.05) between EC (52.58%, 112/213) and GnRH (59.20%, 119/201) groups; however, in heifers that expressed oestrus, rates were higher (P < 0.05) (EC = 56%, 112/200; GnRH = 71.3%, 97/136) than in those did not show (EC = 0%, 0/13; GnRH = 33.8%, 22/65). Presence of CL at onset of TAI protocol was associated with higher pregnancy (P < 0.05) in GnRH group (68%, 68/100) compared with EC (54.46%, 61/112) group, but in heifers without CL, pregnancy were similar for GnRH (50.5%, 51/101) and EC (50.5%, 51/101) groups. Heifers were also classified in 3 groups according OFD: small (≤9.5 mm), medium (9.6–11.5 mm), and large (≥11.6 mm) to verify its effect on oestrus expression and pregnancy. Medium and large OFD were implicated in higher (P < 0.05) oestrus expression [(EC = 100%, 51/51; 96.97%, 32/33) and (GnRH = 83.02%, 44/53; 97.44%, 38/39)] than small OFD [(EC = 85%, 51/60) and (GnRH = 23.8%, 15/63)]. Pregnancy was lower (P < 0.05) in small OFD groups (EC = 28.3%, 17/60; GnRH = 25.4%, 16/63). In medium and large OFD, pregnancy was similar in EC (72.55%, 37/51; 54.55%, 18/33) groups, but differed (P < 0.05) between GnRH large (82.05%, 32/39) and medium (62.26%, 33/53). Higher pregnancy was achieved in heifers with CL in the beginning of TAI protocol treated with GnRH. Size of ovulatory follicle was associated with higher oestrus behaviour and pregnancy rate in EC and GnRH treatments.


2017 ◽  
Vol 29 (1) ◽  
pp. 160
Author(s):  
A. Tribulo ◽  
A. Cedeño ◽  
B. Bernal ◽  
S. Andrada ◽  
J. L. Barajas ◽  
...  

A retrospective analysis evaluated pregnancy rates and embryo losses with in vitro-produced embryos in a commercial embryo transfer program on 15 different beef farms. Recipients were beef cows and heifers (n = 1841) that were synchronized with 5 different protocols and transferred at a fixed-time (FTET). Recipients were examined by ultrasonography on Day 0, and those with a corpus luteum (CL) or a follicle ≥8 mm in diameter and with body condition score 2 to 4 (1 to 5 scale) were synchronized. The synchronization treatments were as follows. (T1) Recipients received an intravaginal device with 0.5 g of progesterone plus 2 mg of oestradiol benzoate on Day 0; device removal, plus 500 μg of cloprostenol (prostaglandin F2α), 400 IU of eCG, and 0.5 mg of oestradiol cypionate on Day 8; and FTET on Day 17. (T2) This treatment was similar to T1 but 1 mg of oestradiol cypionate was injected at device removal instead of 0.5 mg of oestradiol cypionate. (T3) This treatment was similar to T1 except that animals were tail-painted on Day 8 and observed on Day 10. Those with the tail-paint intact on Day 10 received 100 μg of gonadorelin (gonadotropin-releasing hormone) and all recipients were FTET on Day 17. (T4) Recipients received a progesterone device on Day 0; device removal, prostaglandin F2α, and eCG on Day 5; gonadotropin-releasing hormone on Day 8; and FTET on Day 15. (T5) Recipients received a progesterone device and 2 mg of oestradiol benzoate on Day 0; device removal, prostaglandin F2α, and eCG on Day 6; gonadotropin-releasing hormone on Day 9; and FTET on Day 16. On the day of FTET all recipients with CL ≥18 mm in diameter (G1), ≥16 and <18 mm in diameter (G2), and ≥14 mm and <16 mm in diameter (G3) received in vitro-produced fresh embryos. Pregnancy was diagnosed by ultrasonography at 30 and 60 days of gestation, and data were analysed by logistic regression. The overall proportion of recipients synchronized that were FTET was 80.8% (1487/1841), with a 30-day pregnancy rate to FTET (P/FTET) of 45.6% (678/1487) and the rate of 30- to 60-day embryo/fetal loses on the 528 recipients that were re-checked at 60 days was 12.8% (68/528). There were no significant differences in P/FTET among operators, animal category, time of the year, embryo stage, or body condition score; however, there was a significant effect of farm (P < 0.001) and CL diameter (P < 0.05), but no interaction between CL diameter and farm or treatment (P > 0.1). Recipients with G1 (443/953, 46%) and G2 (221/462, 47%) CL had higher pregnancy rates than those with G3 CL (23/71, 32%). There was a significant effect of synchronization treatment on the proportion of recipients transferred and on P/FTET (P < 0.01) that was highly influenced by farm (farm by treatment interaction P < 0.01). The proportions of recipients selected for embryo transfer were as follows: T1: 386/486, 79.4%; T2: 233/331, 70.3%; T3: 342/377, 90.7%; T4: 126/160, 78.7%; and T5: 400/487, 82.1%. The P/FTET were as follows: T1: 190/386, 49.2%; T2: 96/233, 41.2%; T3: 175/342, 51.1%; T4: 49/126, 38.8%; and T5: 168/400, 42.0%. Although 30- to 60-day embryo/fetal losses were not influenced by synchronization treatments, they were highly influenced by farm (P < 0.001) and ranged from 0 to 34.5%. In conclusion, P/FTET in a commercial program with beef in vitro-produced embryos was influenced by factors related to the recipient (CL diameter) and the environment (farm), whereas embryo/fetal losses were influenced by farm but not treatment or recipient factors.


2016 ◽  
Vol 37 (6) ◽  
pp. 4149
Author(s):  
Jefferson Tadeu Campos ◽  
Fábio Morotti ◽  
Camila Bortoliero Costa ◽  
Larissa Zamparone Bergamo ◽  
Marcelo Marcondes Seneda

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.


2008 ◽  
Vol 20 (1) ◽  
pp. 89
Author(s):  
M. F. Pegorer ◽  
R. L. Ereno ◽  
C. M. Barros

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).


2016 ◽  
Vol 68 (5) ◽  
pp. 1159-1167 ◽  
Author(s):  
R.D. Tortorella ◽  
M.R. Modesto ◽  
J.P. Neves ◽  
A.F. Ramos

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.


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