7 KISSPEPTIN SLOWLY ADMINISTERED DURING PROESTRUS IMPROVES FOLLICLE GROWTH AND OVULATION IN ANESTROUS COWS

2016 ◽  
Vol 28 (2) ◽  
pp. 133 ◽  
Author(s):  
G. G. Macedo ◽  
R. V. Sala ◽  
L. F. Martins ◽  
P. S. Baruselli
Keyword(s):  
Growth Rate ◽  
Body Condition Score ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Ovulation Rate ◽  
Growth Promoter ◽  
Dominant Follicle ◽  
Follicle Growth ◽  
Growth Promoters ◽  
Follicle Diameter

This study evaluated whether kisspeptin (Kp) administered slowly from the moment of prostaglandin F2α (PGF) treatment for fixed-time AI protocol of anestrous cows provides suitable dominant follicle (DF) growth similarly to eCG. Postpartum, anestrous, primiparous Nelore cows (n = 50; <8-mm follicles with no corpus luteum) and lean (body condition score 2.7 ± 0.1; 0–5 score scale) were enrolled. On Day 0, females received an intravaginal device with 1.0 g of progesterone (Sincrogest®, Ourofino, Brazil) and 2 mg of oestradiol benzoate IM (Sincrodiol®, Ourofino, Brazil). On Day 8, the device was removed, and cows were administered 500 μg of sodic cloprostenol IM (Sincrocio®, Ourofino, Brazil) and 1 mg of oestradiol cypionate IM (E.C.P.®, Zoetis, Brazil). Females were blocked by dominant follicle diameter and allotted in following groups: (1) control (CTRL), 1.5 mL of saline IM; (2) eCG, 300 IU IM of eCG (Novormon®, Intervet, Brazil); and (3) Kp SC with an osmotic minipump (9.65 μg kg–1 of Kp diluted in saline) over 48 h. Dominant follicle growth and ovulation evaluation were performed by ultrasound at 0, 24, 48, 60, 72, 84, and 96 h after PGF treatment. Dominant follicle growth rate was calculated by difference on DF from 0 to 48 h. Ovulation dispersion was analysed by proc GLIMMIX of SAS (SAS Institute Inc., Cary, NC, USA). Follicle variables, ovulation rate, and interval from PGF to ovulation were analysed by orthogonal contrast. Differences were considered when P < 0.05, and tendencies were considered when P < 0.1. There were no difference between CTRL and growth promoters (eCG and Kp) or between growth promoters on DF diameter at 0 h, larger follicle registered from 0 h to ovulation, ovulatory DF diameter, ovulation rate, and interval between PGF treatment and ovulation (Table 1). Dominant follicle diameter at 48 h was larger for growth promoters than for CTRL. Treatment with Kp proved as efficient as eCG in the DF growth rate, with tendency (P = 0.1) to be greater than CTRL. Data from our laboratory (Sales et al. 2011 Anim. Rep. Sci. 124, 12–18.) with same model and animal profile (n = 150 per group) presented positive effect of eCG treatment for growth and size of DF. Cows treated with Kp ovulated in only 3 specific times (60, 72, and 84 h), unlike eCG (48, 60, 72, and 84 h) and CTRL (24, 48, 60, 72, 84, and 96 h; P > 0.05). Also, it is noted that Kp treatment dose and releasing does not cause negative effect on follicle growth and ovulation (down-regulation on LH releasing) or alteration on interval of PGF treatment to ovulation. Thus, synchronized anestrous cows treated with Kp delivered slowly during proestrus have similar results to eCG on follicle growth and ovulation. Table 1.Ovarian variables of anestrous Nelore cows treated with saline, eCG (300 IU), or kisspeptin (Kp; 9.65 μg kg–1). Data were analysed by orthogonal contrast, where C1 = growth promoter (eCG and Kp) v. control; C2 = eCG v. Kp

scholarly journals Effects of prolonging the interval from progestin removal to prostaglandin F2α injection from 16 to 17 days in a long-term estrus synchronization protocol in beef heifers

2021 ◽  
Author(s):  
N Oosthuizen ◽  
G D Melo ◽  
G E Seidel ◽  
R L Stewart ◽  
L Rowden ◽  
...  
Keyword(s):  
Prostaglandin F2α ◽  
Fixed Time ◽  
Transrectal Ultrasonography ◽  
Dominant Follicle ◽  
Beef Heifers ◽  
Treatment Groups ◽  
Follicle Diameter ◽  
Randomized Design ◽  
Angus Heifers

Abstract To determine effects of delaying the injection of prostaglandin F2α (PGF) and fixed-time artificial insemination (TAI) in the 14-d CIDR-PG protocol, 1,049 Angus heifers at six locations were enrolled in a completely randomized design. Within location heifers were randomly assigned to one of two treatment groups: 1) PG16 (n = 518), heifers received a controlled internal drug release (CIDR) insert on d 0 for 14 d, a 25-mg injection of PGF 16 d after CIDR removal (Day 30), and a 100-µg injection of gonadotropin-releasing hormone concurrent with TAI 66 ± 2 h later; or 2) PG17 (n = 531), heifers were treated the same as PG16, however, PGF was administered 17 d after CIDR removal (Day 31), and heifers were TAI 66 ± 2 h later. Estrus detection patches were applied to a subset (n = 482) of heifers at the time of PGF administration and were examined for activation at TAI. Dominant follicle diameter was determined via transrectal ultrasonography at PGF administration and TAI in a subset of heifers (n = 116). Transrectal ultrasonography was performed to determine pregnancy rates to TAI (PR/AI) between 30 and 45 d after TAI. Estrus expression prior to TAI differed by treatment where PG17 heifers had greater (P &lt; 0.01) expression of estrus than PG16 heifers (57.8 ± 6.1 vs. 43.4 ± 6.1%, respectively). Nevertheless, dominant follicle diameters at PGF and at TAI were similar (P ≥ 0.59) between PG16 and PG17 heifers. In addition, PR/AI did not differ (P = 0.29) between PG16 and PG17 treatments (50.5 ± 3.2 vs. 45.7 ± 3.1%, respectively). Results of this experiment indicate that delaying the injection of PGF and TAI in the 14-day CIDR-PG protocol increased estrus expression prior to TAI yet did not improve fertility in beef heifers.

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

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

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

scholarly journals The Effect of A PRID®Delta-Based Estrus Synchronization Protocol On Pregnancy Rates In Cows With No Estrus Symptoms

2022 ◽  
Author(s):  
Murat Can Demir ◽  
Cihan Kaçar ◽  
Umut Çağın Arı ◽  
Semra Kaya ◽  
Oğuz Merhan ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Prostaglandin F2α ◽  
Pregnancy Rates ◽  
Dominant Follicle ◽  
Serum Progesterone ◽  
Blood Samples ◽  
Follicle Diameter ◽  
Follicle Size ◽  
Equine Chorionic Gonadotropin

Abstract The present study aimed to determine the effects of progesterone-based gonadotropin-releasing hormone (GnRH), prostaglandin F2α (PGF2α), and equine chorionic gonadotropin (eCG) injections on progesterone profiles and pregnancy rates in cows with no estrus symptoms within 60 days after parturition. A total of 80 cows were included in the study. All animals had the progesterone-releasing device PRID®Delta placed intravaginally for nine days with an injection of GnRH. On the eighth day, PGF2α was injected, and PRID®Delta was removed from the vagina on day nine. Artificial insemination was carried out 60 hours after PRID®Delta removal. In half of the animals (n = 40), 600 IU of eCG was injected when PRID®Delta was removed on the ninth day before artificial insemination 60 hours later. Blood samples were taken from the tail vein on days 0 and 8 to determine progesterone levels. The pregnancy rate in the group that received eCG was 37.5%, while it was 27.5% in those that did not (P = 0.4). While the dominant follicle diameter was 15.5 mm in cows injected with eCG during timed artificial insemination, the follicle diameter was 12.4 mm in cows with no eCG injection (P <0.001). There were no differences in serum progesterone values in blood samples taken until the time of artificial insemination. However, progesterone values in the blood taken during artificial insemination were 0.94 ng/ml in the eCG- group and 0.72 ng/ml in the eCG+ group (P <0.05). As a result, it was determined that eCG injections, in addition to progesterone-based GnRH and PGF2α applications, increased the pregnancy rates in cows without symptoms of estrus. The dominant follicle diameter was larger in cows treated with eCG during artificial insemination; however, follicle size did not increase the pregnancy rate.

108 FACTORS AFFECTING PREGNANCY RATES IN RECIPIENTS RECEIVING IN VITRO-PRODUCED EMBRYOS BY FIXED TIME EMBRYO TRANSFER

2016 ◽  
Vol 28 (2) ◽  
pp. 184
Author(s):  
M. Pelizzari ◽  
A. Tribulo ◽  
J. Garzon ◽  
B. Bernal ◽  
R. Tribulo ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Embryo Transfer ◽  
Body Condition Score ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Uterine Horn ◽  
Device Removal ◽  
Embryo Transfer Technique

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.

115 FOLLICULAR GROWTH AND BLOOD FLOW OF THE DOMINANT FOLLICLE IN CROSSBRED RECIPIENTS TREATED WITH eCG

2014 ◽  
Vol 26 (1) ◽  
pp. 171
Author(s):  
M. P. Palhao ◽  
N. S. Junior ◽  
C. R. B. Guimarães ◽  
C. A. C. Fernandes ◽  
M. E. O. Ferreira ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Sao Paulo ◽  
Ovulation Rate ◽  
São Paulo ◽  
Follicular Growth ◽  
Dominant Follicle ◽  
Follicle Diameter ◽  
Transfer Protocol

This study aimed to explore changes in follicle diameter and blood flow of the dominant follicle (DF), in ovulation and embryo transfer rates, after inclusion of eCG in a protocol for timed embryo transfer. The effect presence or absence of a corpus luteum (CL) at the start of treatment was also included. Crossbred heifers (n = 116, Bos taurus × Bos indicus), with (n = 61) or without (n = 55) CL, were included in the same hormone protocol: Day 0 (D0), insertion of progesterone (P4) device (1.0 g, Sincrogest®, Ouro Fino, São Paulo, Brazil) and 2 mg of oestradiol benzoato (EB, Sincrodiol®, Ouro Fino); D8, removal of P4 device and injection of sodium Cloprostenol (0.250 mg mL–1, Sincrocio®, Ouro Fino). On D8, the animals with and without CL – at the beginning of the protocol – were equally divided into 2 groups (G): G1 – injection of 300 IU (2.0 mL) of eCG (n = 56; Synchro eCG®, Ouro Fino); G2 – 2.0 mL of saline (n = 60). The ovulations were synchronized with 1 mg of EB on D9. From D8 to D11, the diameter of the DF and blood flow in its wall were recorded daily (M5 ultrasound with colour Doppler technology, 7.5-MHz linear array, DPS medical equipment, São Paulo, Brazil). Approximately 100 frames in colour-flow mode, containing entire cross-sections of the DF, were recorded during each examination. The area of the follicular wall with coloured pixels was measured with ImageJ software (Image Processing and Analysis in Java) from the frame with the largest blood flow signal. Before embryo transfer, all heifers were evaluated, and those with good-quality CL received frozen/thawed embryos (ethylene glycol 1.5 mol). Follicle diameter and blood flow area were compared between groups with or without CL before timed embryo transfer protocol and between eCG treatments. The PROC GLM procedure of SAS (version 9.0) and the t-test were used to assess the differences between means. Pregnancy diagnosis was performed on D35. Embryo transfer (ET) rate of the recipients and pregnancy rate were compared between CL or eCG treatments by the chi-squared test. Ovarian status, before hormone protocol, did not change (P > 0.05) the follicular growth of the DF. However, ovulation rate (78.8 v. 65.4%, P < 0.05) and ET rate (78.7 v. 65.4%, P < 0.05) were higher in animals with CL on D0. From D8 to D10, the inclusion of eCG did not affect (P > 0.05) follicular growth and blood flow of the DF. The time effect (P < 0.0001) for follicular blood flow had shown an increase in area of blood flow 24 h after implant removal (7.7 ± 0.7,b 10.2 ± 0.7,a and 12.3 ± 1.0a mm2, for Days 8, 9, and 10, respectively). The eCG did not affect (P > 0.05) the ovulation rate (71.4 and 73.3%, respectively, eCG and no eCG), however, approached an increased (P < 0.06) ET rate (78.8 v. 66.7%). The overall pregnancy rate (51.2%, 43/84) was not affected (P > 0.05) by evaluated variables. In summary, the addition of 300 IU of eCG on D8 of the timed embryo transfer protocol did not change the development of DF but increased the ET rate of the recipients. Biotran, FAPEMIG (project number APQ-1454-12), and CnPQ are acknowledged.

29 SHORT-TERM v. LONG-TERM PROGESTERONE PROTOCOL USING CERVICAL OR INTRAUTERINE FIXED-TIME INSEMINATION IN SHEEP

2010 ◽  
Vol 22 (1) ◽  
pp. 172
Author(s):  
A. Menchaca ◽  
M. Vilariño ◽  
E. Rubianes
Keyword(s):  
New York ◽  
Pregnancy Rate ◽  
Body Condition Score ◽  
Skim Milk ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Short Term ◽  
Condition Score ◽  
N 93

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.

129 Ovarian dynamics and gonadotropins during selection of the dominant follicle in postpartum lactating versus non-postpartum cycling mares

2020 ◽  
Vol 32 (2) ◽  
pp. 191
Author(s):  
M. Pastorello ◽  
M. O. Gastal ◽  
G. K. Piquini ◽  
D. B. Godoi ◽  
E. L. Gastal
Keyword(s):  
Growth Rate ◽  
Maximum Diameter ◽  
Sequential Data ◽  
Dominant Follicle ◽  
Follicle Diameter ◽  
The Mean ◽  
Low Levels ◽  
Follicle Selection ◽  
Ovarian Dynamics ◽  
Selection Of

The mare, compared to other livestock, has the shortest interval from partum to the first ovulation. In monovulatory species, the follicle deviation process in a wave is characterised by the continued growth of the dominant follicle (DF) and regression of the subordinate follicle. Although follicle diameter deviation, a key event of follicle selection, has been investigated during the oestrous and menstrual cycles, the occurrence of this phenomenon before the first postpartum ovulation seems to be unclear in all species. This study aimed to compare the follicular dynamics and gonadotropin profiles around the follicle diameter deviation day in postpartum lactating (PP Lactating; n=24) versus non-postpartum cycling (NPP Cycling; n=15) mares. On the day of parturition, every PP Lactating mare was paired with an NPP Cycling mare, and ovarian follicles (&gt;4mm) were tracked daily by transrectal ultrasonography, and blood samples were collected. Data were analysed in the PP Lactating group according to the length of the partum-ovulation interval (POI; ≤22 and &gt;22 days) and the postpartum interovulatory interval (PPIOI), and in the NPP Cycling group during two interovulatory intervals (1st and 2nd IOI). In addition, regardless of group, all four intervals were compared. We performed the FSH and LH assays using radioimmunoassay. Ovarian and hormonal parameters were analysed using ANOVA for sequential data. The day and diameter of the DF at the deviation (overall mean: 14.9±2.5 days; 21.7±0.4mm, respectively) were not different (P&gt;0.05) between PP Lactating and NPP Cycling mares. However, when considering the length of POI, follicle deviation occurred 4.4±0.8 days earlier (P&lt;0.001) in mares with POI ≤ 22 days than in mares with POI&gt;22 days. No difference was found between PP Lactating and NPP Cycling mares within and between groups for the intervals from deviation to maximum diameter of the DF (10.4±0.4 days), for the intervals from deviation to ovulation (12.1±0.5 days), or for the growth rates of the DF from deviation to maximum diameter (2.6±0.1mm per day). The growth rate of the DF from deviation to ovulation (2.4±0.1mm per day) did not differ between PP Lactating and NNP Cycling mares; however, this growth rate was lower (P&lt;0.03) in the POI, PPIOI, and 1st IOI compared with the 2nd IOI. The mean diameter of the DF around deviation (days −3 to 3; 22.5±0.3mm), and systemic FSH (days −4 to 4; 10.3±0.2ngmL−1) were not different between PP Lactating and NPP Cycling mares. Level of LH was lower (P&lt;0.0001) around deviation (days −4 to 4) in the PP Lactating (0.7±0.0ngmL−1) versus the NPP Cycling mares (1.8±0.1ngmL−1). Results demonstrated that a partum effect occurs only on the day of deviation in mares during the foal heat (POI ≤ 22 days) and that low levels of LH during both intervals in PP Lactating mares were not detrimental to prevent ovulation.

9 Fixed timed artificial insemination during different seasons in Argentina (2016–2019)

2021 ◽  
Vol 33 (2) ◽  
pp. 112
Author(s):  
A. S. Bandeo ◽  
J. A. Berdugo ◽  
G. A. Crudeli ◽  
P. Maldonado-Vargas ◽  
J. L. Konrad
Keyword(s):  
Prostaglandin F2α ◽  
Fixed Time ◽  
Dominant Follicle ◽  
Breeding Performance ◽  
Different Seasons ◽  
Gonadotrophin Releasing Hormone ◽  
Timed Artificial Insemination ◽  
Native Pastures ◽  
Intravaginal Device ◽  
Positive Effect

The objective of this work was to evaluate pregnancy rates in buffaloes subjected to fixed-time AI (FTAI) during the year in Argentina. The data analysed was collected between 2016 to 2019 in a farm located in Paso Florentin City (27°20′33″ latitude and 58°08′27″ longitude) in Corrientes, Argentina. The animals were grazing native pastures (Andropogon lateralis, Paspalum almum). Ten fixed-time AI (FTAI) sessions were performed, 6 within the favourable season (BS, March–June) and 4 in the outbreeding season (OBS; September–December). Murrah and Mediterranean breed (n=141) buffaloes were used. All animals were healthy, without anatomical alterations and with normal reproductive tracts. Heifers (H), adult females with calf (AFC), and dry buffaloes (DB) were used. The average (±s.d.) weight of the animals were 459.0±37.5kg, 581.3±53.6kg, and 583.3±53.1kg, respectively. The presence of corpus luteum (CL) or a dominant follicle (≥8mm) at the beginning of the protocol was recorded. BS ovulation induction: Ovsynch (n=182); Day 0 gonadotrophin-releasing hormone (GnRH; 100μg, busereline acetate), Day 7 prostaglandin F2α (150μg, cloprostenol), Day 9 GnRH and FTAI 16h after the last GnRH injection. For the OBS (n=85): Day 0 intravaginal device (700mg of P4) + oestradiol benzoate (0.2g), Day 8 removal of the device + prostaglandin F2α + oestradiol cypionate (0.1g) + eCG (400IU) and Day 10 FTAI (52–56h) after device removal. Semen from 5 bulls of proven fertility was used, and the same technician performed all the inseminations. A specifically designed format to record the data were used and the average±s.d. of the physiological and the meteorological parameters were calculated. Pregnancy was detected 40 days after FTAI using ultrasonography. Comparison within variables were performed using ANOVA and Tukey test, with InfoStat-Statistical Software. A total of 267 inseminations were performed, and the overall pregnancy rate (PR) was 37.45% (100/267). Comparing BS with OBS, PR were 40.7% (74/182) and 30.6% (26/85) (P&lt;0.005). Heifers had a higher PR (51.5%) than suckled buffaloes (38.8%) and dry buffaloes (20%) during the BS (P&lt;0.05). In the OBS, there were no differences among categories on PR for [36.36 (4/11) H, 28.57 (12/42) AFC, 19.51 (8/41) DB; P&gt;0.05]. The presence of a CL at the beginning of the FTAI protocol had a positive effect on PR during the year in all categories [31.79% (55/173) H, 40.42 (38/94) AFC, 21.51 (17/79) DB vs. 25.45% (28/110) H, 29.68 (19/64) AFC, 19.56 (9/46) DB; P&lt;0.05]. Season had a significant effect over PR, but rain, temperature, daylight, and humidity did not differ during the year. These results show the feasibility of FTAI in water buffalo, confirm that it is possible to maintain the PR during the year, and demonstrate successful performance of protocol induction in cyclic females during the year. More research is needed to improve PR in buffaloes in Argentina, to explain the low results in suckled and dry adult buffaloes, and to analyse the effect of meteorological conditions over the breeding performance of the animals.

177 EFFECTS OF MANIPULATION OF DOMINANT FOLLICLE GROWTH ON SIZE AND FUNCTION OF CORPUS LUTEUM IN BEEF CATTLE

2013 ◽  
Vol 25 (1) ◽  
pp. 237
Author(s):  
R. S. Ramos ◽  
F. S. Mesquita ◽  
G. Pugliesi ◽  
S. C. Scolari ◽  
M. L. Oliveira ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Corpus Luteum ◽  
Prostaglandin F2α ◽  
Progressive Increase ◽  
Group Effect ◽  
Dominant Follicle ◽  
Follicle Growth ◽  
Ovulatory Follicle ◽  
Conception Rates ◽  
And Function

Recent evidence indicates that the progesterone (P4) secretion by corpus luteum (CL) during early diestrus is affected by the size of ovulatory follicle and has a significant impact on embryo development and conception rates. Therefore, strategies to promote the growth of the dominant follicle and/or to stimulate the early development of the CL to increase P4 secretion become an alternative to improve conception rates in the beef cattle industry. Our aim was to study the effect of manipulations of the follicle growth on the diameter of the preovulatory follicle (POF) and subsequent size and function of the CL. Cyclic and non-lactating Nelore cows, pre-synchronized by 2 injections of prostaglandin F2α (PGF) 14 d apart, were manipulated to ovulate large or small follicles according to 3 experiments. In Experiment 1 (Exp. 1; n = 23), animals received a second-use intravaginal P4-releasing device along with an injection of oestradiol benzoate on Day –10 (Day 0 = GnRH injection). Cows were split to receive (large follicle group; LF) or not (small follicle group; SF) a PGF injection on Day –10. Progesterone devices were removed on Day –2.5 in the LF group and on Day –1.5 in the SF group. The PGF was injected at the removal of the P4 device. In Experiment 2 (Exp. 2; n = 38), cows in the LF group had the P4 device removed on Day –2.25 or Day –2, whereas in Experiment 3 (Exp. 3; n = 23), the device (first-use) was removed on Day –1.75 in the LF group and on Day –1.25 in the SF group; the other manipulations were similar to Exp. 1. Data analyses were done only on cows that had a functional CL on Day –10 (P4 > 1 ng mL–1) and that ovulated within 24 and 48 h post-GnRH (Exp. 1, n = 14; Exp. 2, n = 14; Exp. 3, n = 12). The three experiments were successful in inducing POF with different sizes, as indicated by the greater diameter of the POF in the LF group compared with SF in Exp. 1 (12.9 ± 0.5 mm v. 10.7 ± 0.6 mm; P < 0.03), Exp. 2 (14.1 ± 0.6 mm v. 11.7 ± 0.4 mm; P < 0.006), and Exp. 3 (13.8 ± 0.6 mm v. 11.7 ± 0.8 mm; P < 0.06). To evaluate the effect of POF size on size and function of the CL, a factorial analysis was performed by SAS software to test the effect of group, day, and their interaction. For CL volume, an effect of group was detected in Exp. 1 (P < 0.02) and in Exp. 3 (P < 0.06), but not in Exp. 2. The group effect represented greater average CL volume from Day 3 to Day 7 in LF (2.42 ± 0.27 and 2.5 ± 0.39 cm3) than in the SF group (1.39 ± 0.18 and 1.2 ± 0.15 cm3) for Exp. 1 and 3, respectively. For P4 concentrations, a group effect was detected only in Exp. 3 (P < 0.007), as indicated by greater average P4 concentrations from Day 3 to Day 7 in LF (2.31 ± 0.31 ng mL–1) than in the SF group (1.37 ± 0.19 ng mL–1). A day effect was detected in all experiments (P < 0.0001), as indicated by a progressive increase of CL volume and P4 concentrations from Day 3 to Day 7. Manipulation of follicle growth performed in Exp. 3 was the most efficient to modify the function and size of the CL. In conclusion, control of POF size by manipulation of P4 concentrations during growth of the dominant follicle alters the size and function of CL postovulation. CNPq, FAPESP, Ourofino, and PUSP-P.

13 Pre-synchronization by Induction of a Dominant Follicle Using a Progesterone Device in a GnRH-Based-Ovulation Synchronization Protocol in Lactating Dairy Cows

2018 ◽  
Vol 30 (1) ◽  
pp. 146
Author(s):  
M. P. Bottino ◽  
L. A. C. L. DaSilva ◽  
L. M. S. Simoes ◽  
G. Santos ◽  
I. Y. H. Martinez ◽  
...  
Keyword(s):  
Sustained Release ◽  
Dairy Cows ◽  
Prostaglandin F2α ◽  
Follicular Development ◽  
Experimental Period ◽  
Ovulation Rate ◽  
Dominant Follicle ◽  
Lactating Dairy Cows ◽  
Intravaginal Device ◽  
Synchronization Protocol

The objective was to compare a pre-synchronization protocol by induction of a dominant follicle using a progesterone intravaginal device before an Ovsynch protocol (Presynch) with Double-Ovsynch in lactating dairy cows. Lactating Bos indicus × Bos taurus crossbred cows (n = 440) were randomly allocated to 1 of 2 treatments (all IM injections): (1) Double-Ov (n = 228): GnRH (Day –17), prostaglandin F2α (PGF2α) 7 days later (Day –10) and gonadotropin-releasing hormone (GnRH) 3 days later (Day –7) followed by an Ovsynch protocol 7 days later (GnRH on Day 0, PGF2α on Day 7, GnRH on Day 9); (2) Presynch (n = 212): insertion of a sustained release progesterone intravaginal device (Day –10), 10 days later (Day 0), an Ovsynch protocol was initiated with progesterone device withdrawal on Day 7. All cows were artificially inseminated 15 to 20 h after the second GnRH injection of the Ovsynch protocol and were pregnancy checked by ultrasonography 30 and 60 days later. On a subsample (n = 102), ultrasonography was performed on Days 0, 7, 9, and 24 of the experimental period. On another subsample (n = 42), blood samples for progesterone analysis were taken on Days 0, 7, and 24. There were no differences between pre-synchronization methods on synchronization parameters [presence of a follicle >12 mm on D0, Double-Ov 94.2% (49/52) and Presynch 92.0% (46/50); P = 0.66], follicular diameter on the 1st GnRH (Double-Ov 17.2 ± 0.7 mm and Presynch 18.6 ± 0.9 mm; P = 0.28), ovulation rate to the 1st GnRH [Double-Ov 86.3% (44/51) and Presynch 81.2% (39/48); P = 0.50], synchronization rate [Double-Ov 84.6% (44/52) and Presynch 86.0% (43/50); P = 0.84], follicular diameter on the 2nd GnRH (Double-Ov 17.5 ± 0.6 mm and Presynch 18.0 ± 0.5 mm; P = 0.48), ovulation rate to the 2nd GnRH [Double-Ov 90.9% (40/44) and Presynch 86.0% (37/43); P = 0.48] and CL diameter on Day 24 (Double-Ov 27.9 ± 0.7 mm and Presynch 29.4 ± 0.9 mm; P = 0.19). Corpus luteum presence on Day 0 was different (P = 0.03) between treatments [Double-Ov 57.7% (30/52) and Presynch 36.0% (18/50)]. Moreover, there was no difference (P = 0.85) between pregnancy rates on Day 30 [Double-Ov 39.0% (89/228) and Presynch 40.1% (85/212)] or Day 60 after AI [Double-Ov 34.8% (79/227) and Presynch 38.7% (82/212); P = 0.41] and gestational loss between 30 and 60 days after AI [Double-Ov 7.9% (7/88) and Presynch 3.5% (3/85); P = 0.13]. Proportion of cows with P4 <1 ng mL−1 on Day 0 was similar between treatments [Double-Ov 13.6% (3/22) v. Presynch 5.0% (1/20); P = 0.37]. Likewise, the proportion of cows with P4 >1 ng mL−1 on Day 7 [Double-Ov 77.3% (17/22) v. Presynch 95.0% (19/20); P = 0.14] and P4 concentration on Day 24 (Double-Ov 4.7 ± 0.6 v. P4-Ov 5.9 ± 0.9; P = 0.84) were similar between treatments. In conclusion, pre-synchronization by induction of follicular persistence using a sustained-release progesterone device before Ovsynch yielded similar results to the Double-Ovsynch protocol on follicular development and regression patterns and on the fertility of lactating dairy cows.

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