Estradiol Cypionate Research Articles

19 Interaction of kisspeptin and the somatotropic and lactotropic axes in mares and geldings

Several experiments were conducted to investigate the interaction between kisspeptin and the somatotropic and lactotropic axes in mares and geldings. Light horse, diestrous mares and geldings, weighing approximately 500 kg and aged 6 to 24 years, were randomly assigned to treatment with 1 mg equine kisspeptin-10 (Kp10; n = 10) or 1 mL saline (n = 9), i.v. Blood samples were collected via jugular venipuncture −10, 0, 5, 10, 15, 20 and 30 min relative to treatment. Plasma concentrations of growth hormone (GH) and prolactin (PRL) were determined by RIA and means compared using ANOVA with repeated sampling. Neither GH nor PRL were stimulated by Kp10. In a second experiment, 30 mares and geldings were used to determine if pre-treatment with estradiol or progesterone would elicit a GH or PRL response to Kp10. Five mares and 5 geldings each were assigned to pre-treatment with 50 mg estradiol cypionate in oil (ECP), 600 mg long-acting progesterone, or oil only, i.m. Two days later, all horses received 1 mg Kp10 in saline, i.v., and blood sampling occurred 0, 5, 10, 15 and 20 min relative to Kp10 administration. Mean GH and PRL concentrations and area under the curve were compared by ANOVA. No stimulation of GH or PRL was observed. In a third experiment, 12 diestrous mares, confirmed by plasma progesterone and ultrasound findings, were randomly assigned to treatment with 1 mg Kp10 (n = 6) or 1 mL saline (n = 6) followed by the dopamine antagonist, sulpiride (0.01 mg/kg body weight), 5 min later. Blood sampling occurred 0, 5, 10 and 15 min relative to sulpiride administration. Sulpiride stimulated PRL ( P < 0.0001) in both groups of mares; however, PRL concentrations were lower ( P ≤ 0.01) in Kp10-treated mares compared with saline-treated mares. To determine if estrogen altered the PRL response to sulpiride, 12 seasonally anovulatory mares, confirmed by plasma progesterone and ultrasound findings, were used in a fourth experiment and randomly assigned to receive 50 mg ECP (n = 6) or oil (n = 6), i.m. The next day, mares were challenged with sulpiride. Treatment and blood sampling occurred as described in experiment 3. Plasma PRL was stimulated ( P < 0.001) in both groups of mares and responses were similar between treatments. In the described experiments, 1 mg Kp10 given as a bolus failed to stimulate circulating GH or PRL within 30 min in mares or geldings regardless of steroid milieu. This is in contrast to reports of GH stimulation in ruminants. Kp10 did alter the PRL response to sulpiride in diestrous mares, perhaps suggesting an interaction between Kp10 and dopaminergic input to the pituitary in a progesterone dominant environment.

Hormonal combinations aiming to improve reproductive outcomes of Bos indicus cows submitted to estradiol/progesterone-based timed AI protocols

The aim was to study reproductive outcomes of Nelore (Bos indicus) cows submitted to a 7-d estradiol (E2)/progesterone (P4)-based timed artificial insemination (TAI) protocol, receiving various combinations of doses and hormones. Primiparous (n = 962) and multiparous (n = 1935) cows were submitted to synchronization (n = 2012) and resynchronization (n = 885 non-pregnant cows at pregnancy diagnosis 30 d after TAI) protocols, following a 2 × 2 × 2 factorial arrangement of eight treatments. At the initiation of the TAI protocol (Day −9), all cows received a 1.0 g intravaginal P4 insert, 2.0 mg E2 benzoate and received (PGF1) or not (PGF0) 0.5 mg cloprostenol sodium (PGF). On Day −2, the P4 insert was removed, all cows received 0.5 mg PGF, 300 IU equine chorionic gonadotropin (eCG) and 0.5 (EC0.5) or 1.0 mg estradiol cypionate (EC1.0). On Day 0, cows were treated (G1) with 8.4 μg buserelin acetate (GnRH) or not (G0), concurrently with TAI. The eight treatments were generated: 1) PGF0-EC0.5-G0 (n = 364), 2) PGF0-EC0.5-G1 (n = 363), 3) PGF1-EC0.5-G0 (n = 363), 4) PGF1-EC0.5-G1 (n = 360), 5) PGF0-EC-1.0-G0 (n = 360), 6) PGF0-EC1.0-G1 (n = 363), 7) PGF1-EC1.0-G0 (n = 361), and 8) PGF1-EC1.0-G1 (n = 363). Pregnancy per AI (P/AI) was greater at first AI compared with resynchronization (58.9 [n = 2012] vs. 54.9% [n = 885]). Presence of CL on Day −9 resulted in more cows expressing estrus (81.3 [n = 680] vs. 67.1% [n = 2033]) and greater P/AI (66.0 [n = 692] vs. 54.9% [n = 2106]). There was no difference in P/AI between cows that received or not PGF on Day -9 (58.7 [n = 1447] vs. 56.6% [n = 1450]). In contrast, PGF tended to increase P/AI of cows with CL on Day −9 (with PGF = 69.1 [n = 375] vs. without PGF = 62.5% [n = 317]). Cows that received 1.0 mg EC expressed more estrus than those treated with 0.5 mg (73.8 [n = 1414] vs. 67.9% [n = 1398]) and had greater P/AI (60.2 [n = 1447] vs. 55.1% [n = 1450]). P/AI was greater in cows treated with GnRH at TAI (59.8 [n = 1449] vs. 55.5% [n = 1448]), particularly in cows that did not show estrus (52.7 [n = 393] vs. 38.1% [n = 420]). Moreover, GnRH on Day 0 increased P/AI in cows with BCS < 3.0 (57.1 [n = 723] vs. 48.6% [n = 698]), in primiparous (50.1 [n = 465] vs. 41.9% [n = 497]) and in cows that received 0.5 mg EC (58.9 [n = 723] vs. 51.3% [n = 727]). In conclusion, 1.0 mg of EC on Day −2 and GnRH at TAI improved P/AI, but the combination of a higher dose of EC and GnRH treatment at AI did not enhance this effect. Furthermore, GnRH improved P/AI especially in Bos indicus cows with lower expression of estrus, such as primiparous, thinner cows, and cows treated with 0.5 mg of EC.

RESPUESTA REPRODUCTIVA EN OVEJAS DE PELO SINCRONIZADAS CON ACETATO DE MEDROXIPROGESTERONA IMPREGNADO EN ESPONJAS INTRAVAGINALES NO COMERCIALES

&lt;p&gt;&lt;strong&gt;Background.&lt;/strong&gt; Intravaginal sponges impregnated with medroxyprogesterone acetate or fluorogestone acetate are routinely used in oestrus synchronization protocols in sheep, non-commercial sponges are a viable option in the reproductive control of female sheep.&lt;strong&gt; Objective.&lt;/strong&gt; To evaluate the reproductive response in hair sheep synchronized with medroxyprogesterone acetate impregnated in non-commercial intravaginal sponges. &lt;strong&gt;Methodology.&lt;/strong&gt; 31 adult hair sheep 5/8 Pelibuey x 2/8 Black Belly x 1/8 Dorper, average weight of 40 ± 3.2 kg and a body condition of 3-3.5 were used. They were randomly assigned to one of four treatments: T1 (n = 8 ewes), 5 mg of medroxyprogesterone acetate impregnated in non-commercial intravaginal sponges + 1 mg of estradiol cypionate + 200 IU of eCG; T2 (n = 8 ewes), synchronization similar to T1, but 500 IU of eCG were applied; T3 (n = 8 ewes), 20 mg of fluorogestone acetate impregnated in intravaginal sponges + 200 IU of eCG; T4 (n = 7 ewes), synchronization similar to T3, but 500 IU of eCG were applied. In all treatments the sponges were placed for 10 days. Blood samples were collected by jugular puncture and the concentrations of progesterone and LH were determined. &lt;strong&gt;Results.&lt;/strong&gt; The sponge removal interval to estrus was different (P &amp;lt;0.05) between T1 and T3 (14.5 ± 5.5 and 38.8 ± 2.5 h, respectively). Estrus duration was similar (P&amp;gt; 0.05) between T1, T2 and T3 (54.5 ± 5.5, 46.5 ± 5.8 and 38.3 ± 2.6 h, respectively), T4 (59.3 ± 4.1 h) was similar (P&amp;gt; 0.05) to T1 and T2 (54.5 ± 5.5 h and 46.5 ± 5.8 h, respectively) but different (P &amp;lt;0.05) from T3 (38.3 ± 2.6 h). The progesterone concentration was higher than 1 ng ml&lt;sup&gt;-1&lt;/sup&gt;, on days 0 to 4 (T2), 0 to 5 (T4) and 0 to 7 (T1 and T3), then it decreased to &amp;lt;1 ng ml&lt;sup&gt;-1&lt;/sup&gt; in all the treatments. The sponge removal and oestrus onset intervals at the LH preovulatory peak were similar (P&amp;gt; 0.05) between treatments, however, the LH profile at T1 and T2 shows scattered elevations. 5 mg of medroxyprogesterone acetate + 1 mg of estradiol cypionate, impregnated in non-commercial sponges advance oestrus and do not adjust for the occurrence of LH preovulatory peak.&lt;strong&gt; Implications. &lt;/strong&gt;The study demonstrates that it is feasible to use reduced doses of medroxyprogesterone acetate impregnated in non-commercial intravaginal sponges in estrous synchronization protocols in hair sheep, the progesterone profile confirms the inhibitory effect of the drug on GnRH / LH secretion.&lt;strong&gt; Conclusion. &lt;/strong&gt;The application of 200 or 500 IU of eCG does not modify the occurrence or duration of estrus and the LH preovulatory peak. It is suggested that it is feasible to synchronize hair sheep under tropical conditions with reduced doses of medroxyprogesterone acetate impregnated in non-commercial sponges, however, dispersion of ovulation may occur, which would reduce fertility. The use of eCG and estradiol cypionate does not affect the effectiveness of synchronization.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;

Pharmacological approaches to induce follicular growth and ovulation for fixed-time artificial insemination treatment regimens in ewes

In Experiment I, during the non-breeding season, after intravaginal devices containing progesterone (P4) were withdrawn (n = 28), estrous rates were greater with treatment with 400 IU eCG (P < 0.05) than with FSH (10 and 15 mg) and no treatment. During the breeding season (n = 147), estrous and pregnancy rates after fixed-time artificial inseminations (FTAI) were similar among groups: 300 IU eCG; 10 mg FSH; and control (P > 0.05). In Experiment II (non-breeding season), ewes of one group were treated with 300 IU eCG (n = 8) and of two groups were treated with 10 mg FSH. In one FSH group, 250 μg estradiol benzoate (EB) were administered after 24 h (n = 9); in the other, 4 μg GnRH were administered after 36 h (n = 10). Serum P4 concentrations were greater in eCG-treated ewes (P < 0.05). Estrous rates were similar for the eCG- and FSH plus EB-treated ewes (P > 0.05). In Experiment III (breeding season), the treatments were: 300 IU eCG; 250 μg estradiol cypionate; 250 μg EB; or control (n = 22). Follicular growth was greater for eCG-treated ewes within 0−24 h and for control ewes within 48−72 h (P = 0.001). Although estrous and ovulation rates did not differ (P > 0.05), all eCG-treated ewes had ovulations. During the non-breeding season, FSH treatment promoted follicular growth but did not induce ovulations. For FTAI regimens, eCG was more effective than FSH plus GnRH and estradiol esters in inducing estrus and ovulation.

Relationship among serum metabolic hormones with pregnancy rates to fixed-time artificial insemination in Bos indicus beef females

Two experiments compared body parameters and serum concentrations of GH, IGF-I, and leptin in Bos indicus females based on their pregnancy status to fixed-time artificial insemination (FTAI). In Exp. 1, 226 nulliparous heifers were assigned to a puberty induction protocol (d -35 to d -23), followed by an estrus synchronization and FTAI protocol (d -11 to 0). Heifers received a controlled internal progesterone releasing insert (CIDR) previously used three times on d -35, followed by 0.6 mg of estradiol cypionate and CIDR removal on d -23. Heifers received 2 mg of estradiol benzoate and a CIDR previously used twice on d -11, 12.5 mg of dinoprost tromethamine in addition to CIDR removal, 0.6 mg of estradiol cypionate and a 200 IU of eCG on d -2, followed by FTAI on d 0. Heifer BW and BCS were recorded on d -35, -11, and 30, whereas blood samples were collected on d -35, -23, -11, 0, and 30. In Exp. 2, 821 multiparous lactating Nelore beef cows were assigned to the estrus synchronization and FTAI protocol described in Exp. 1, but received 300 IU of eCG on d -2. Cow BW and BCS were recorded on d -11 and 30, and blood samples were collected on d -11, 0, and 30. In both experiments, pregnancy status was verified via transrectal ultrasonography on d 30. In Exp. 1, heifers that became pregnant had greater (P = 0.03) IGF-I concentrations on d 0 and less (P = 0.05) IGF-I concentrations on d 30 compared to heifers that did not become pregnant (pregnancy status × day; P < 0.01). No differences in BW, BCS, GH and leptin were detected (P ≥ 0.23) according to heifer pregnancy status. In Exp. 2, cows that became pregnant had less (P = 0.03) leptin concentrations on d -11, and less (P = 0.01) IGF-I concentrations on d 30 compared to cows that did not become pregnant (pregnancy status × day; P ≤ 0.05). No differences in BW, BCS, and GH were detected (P ≥ 0.15) according to cow pregnancy status. In summary, serum leptin at the beginning of estrus synchronization was negatively associated with pregnancy rates to FTAI in multiparous cows. A negative relationship was also observed between serum IGF-I during early gestation with pregnancy rates to FTAI across parities. These results provide novel insights on the relationships among metabolic hormones with reproductive performance of B. indicus females.

Use of Estradiol Cypionate to induce ovulation in buffalo raised in floodplain areas of Itacoatiara, Amazonas

ABSTRACT This study aimed to determine the efficiency of estradiol cypionate (EC) as an ovulation inducer in a Timed Artificial Insemination protocol. 69 buffalo cows received an intravaginal progesterone device and 2mg of estradiol benzoate (EB) at D0. On D9, the intravaginal device was removed and 0.53mg of prostaglandin (PGF2α) and 400UI of equine chorionic gonadotrophin (eCG) were applied. The cows were distributed into two groups: the first group received 1mg of EC (ECG) in D9, and the second group received 1mg of EB (EBG) in D10. Inseminations occurred on D11. Ovarian activity and pregnancy diagnosis were analyzed by ultrasonography. There was no difference (P&gt;0.05) in follicular diameter (9.6 ± 0.89mm vs. 10.7 ± 1.12mm; P=0.06), in ovulation rate (90.9% vs. 90.9%; P=1) and pregnancy rate (58.8% vs. 62.9%; P=0.79), however, buffalo cows from the ECG treatment have less time between P4 removal and ovulation when compared to EBG buffalos (37.4h vs. 52.8h; P=0.001), respectively. Thus, it was concluded that the implantation of TAI in the floodplain of Amazonas is feasible and the use of EC results in successful rates, similar to EB.

Estradiol cypionate administered at the end of a progesterone-based protocol for FTAI induces ovulation and improves postovulatory luteal function and uterine environment in anestrous beef cows

The objective of this study was to evaluate the effect of the administration of estradiol cypionate (ECP) at the end of an estradiol and progesterone-based protocol for fixed time artificial insemination (FTAI) on ovarian response and uterine function in postpartum anestrous beef cows. Multiparous suckled cows were randomly assigned to receive ECP at doses of 0 (control, n = 15), 0.5 (n = 15) or 1.0 mg (n = 15) im at the time of progesterone intravaginal insert removal. Serum 17β-estradiol concentrations at 24 h after insert removal were greater (P < 0.05) in both ECP treatments than in controls. No differences in estradiol were found between 0.5 mg and control cows (P > 0.1) from 48 h after insert removal until ovulation, although greater (P < 0.05) concentrations were maintained until ovulation in 1.0 mg ECP treated cows. Maximum 17β-estradiol concentration attained in each female was greater as ECP dose was greater (10.4 ± 0.4, 11.8 ± 0.5 and 13.5 ± 0.7, for control, 0.5 and 1.0 mg ECP treated cows, respectively; P < 005). Proportion of cows that ovulated tended to be greater (P = 0.06) in ECP treated than in control cows. Ovulation occurred earlier and the size of the ovulatory follicle was smaller (P < 0.05) for 1.0 mg but not for 0.5 mg (P > 0.1) when compared with control cows. After ovulation (Day 13 and 14), serum progesterone concentrations were greater (P < 0.05) in 0.5 and 1.0 mg ECP than control cows. Uterine environment on Day 6 after ovulation was affected by treatment; transcript expression of three of nine evaluated genes (i.e., estrogen, IGF-1 and insulin receptors genes) were upregulated (P < 0.05) after ECP treatment. In conclusion, ECP administration at progesterone insert removal in anestrous cows i) induces greater serum estradiol concentrations and tended to induce greater ovulation rate, ii) acts in a dose-dependent manner, as ECP dose increases ovulation occurs earlier and the size of the ovulatory follicle is smaller, iii) improves postovulatory luteal function and affects uterine gene expression. Altogether, this information contributes with the understanding of the effect of preovulatory estradiol exposure on ovulation and postovulatory ovarian and uterine function in anestrous beef cows.

Pancytopenia in a Dog Induced by Concomitant Use of Myelotoxic Drugs

Background: The indiscriminate use of drugs is an issue in Veterinary Medicine, as it has serious consequences for the animals. Many drugs are myelotoxic and cause a decrease in the production of blood cells, which may be irreversible in some cases. The present work reports a case of pancytopenia induced by the concomitant use of myelotoxic drugs (estrogen, metamizole and phenobarbital) in a dog and describes findings on myelotoxicity, hematological alterations and treatment success.Case: A 7-year-old Lhasa Apso bitch was referred to the Veterinary Hospital of Federal University of Paraná, Curitiba campus, with hematuria and a history of treatment with phenobarbital [2 mg/kg twice a day (bis in die, BID)], metamizole [25 mg/kg three times a day (ter in die, TID)], and use of estrogen hormone (estradiol cypionate). At physical examination, the animal was normohydrated and exhibited normal palpable lymph nodes, pale mucous membranes, galactorrhea, and a body temperature of 36°C. A complete blood count including reticulocyte count and a total plasma protein (TPP) exam were requested. The results revealed pancytopenia (18% hematocrit, 1,400 total leucocytes/µL, and 22,000 reticulocytes/µL). An abdominal ultrasound exam did not detect any relevant alterations. In view of the results obtained, medullary aplasia was suspected. A bone marrow aspiration was performed. A myelogram revealed a decrease in cellularity (erythrocytic and granulocytic hypoplasia), with presence of rare erythroid and granulocytic precursors. The diagnosis was medullary aplasia. The animal was treated, and the evolution of the hematological alterations was monitored. The treatment consisted of administration of erythropoietin (100UI/kg subcutaneously every 48 h), prednisone (2 mg/kg BID), Leucogen (3 mg/kg BID), interferon (0.2 IU/kg BID) and Eritrós Dog Tabs [1 tablet once a day (semel in die, SID)]. After five days of treatment, the patient’s clinical picture improved (30% hematocrit, 5,300 total leukocytes/µL, 84,000 platelets/µL, and 195,000 reticulocytes/µL), and the hematological alterations were resolved after 25 days of treatment (43% hematocrit, 5,100 total leukocytes/µL, and 333,000 platelets/µL). The bitch was discharged after 89 days of treatment.Discussion: The hematological alterations found in the patient were consistent with pancytopenia, and the myelogram allowed the establishment of a diagnosis of medullary aplasia. There are various causes of pancytopenia in dogs; in this case, it was caused by medications, as the drugs administered to the patient (estrogens, metamizole, and phenobarbital) are myelotoxic. Canine bone marrow is susceptible to suppression by estrogens, which can induce medullary aplasia even with a single dose. No reports on hematological alterations caused by dipyrone (metamizole) in dogs were found; however, in humans, development of aplastic anemia, agranulocytosis, nephrotoxicity, and allergic reactions have been attributed to the use of this drug. Phenobarbital can cause adverse reactions that lead to anemia, leukopenia, and thrombocytopenia. Evaluating the bone marrow of animals with pancytopenia is important because this procedure allows the establishment of a diagnosis that may prompt treatment while hematopoietic precursors are still present in the bone marrow. In this case, a treatment using hematopoietic stimulants was employed owing to the presence of erythrocytic and myelocytic precursors in the patient’s bone marrow. The treatment instituted was efficacious, as only five days of therapy already improved the hematological condition of the patient, who was discharged after 89 days of treatment.

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

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&amp;lt;0.005). Heifers had a higher PR (51.5%) than suckled buffaloes (38.8%) and dry buffaloes (20%) during the BS (P&amp;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&amp;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&amp;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.

Comparison of three doses of estradiol benzoate for synchronization of follicular wave emergence in suckled Bos indicus beef cows.

We aimed to compare the effect of three estradiol benzoate (EB) doses on follicular wave emergence (FWE) and dominant follicle growth of suckled Nelore cows submitted to TAI (D0). On a random day of estrous cycle (D−10), multiparous (MULT; n=36) and primiparous (PRIM; n=20) suckled Nelore cows received an intravaginal progesterone (P4) device and were assigned in three groups. Cows in the EB-1 (n=20), EB-1.5 (n=15) or EB-2 (n=21) groups received, respectively, an im treatment with 1, 1.5 or 2 mg EB. A subgroup (n=10-13 cows/group) were subject to daily ovarian evaluations from D−10 to D0. On D−2, P4 devices were removed, and all cows received the same treatment: 1 mg estradiol cypionate, 0.53 mg sodium cloprostenol, and 300 IU eCG. Statistical analyses were performed considering only the main effects of treatment group and parity order. The proportion of cows with a synchronized FWE and the moment of the FWE did not differ (p>0.05) among the treatment groups (overall: 80% [28/35] and 4.1 ± 0.4 days); however, the FWE occurred earlier (p=0.007) in MULT (3.8 ± 0.2 days) than PRIM (5.1 ± 0.4) cows. The proportion of animals detected in estrus was greater (86% [31/36] vs. 70% [14/20]; p=0.02) and the dominant follicle was larger on D−2 (9.7 ± 0.3 mm vs. 7.8 ± 0.7 mm; p=0.006) and D0 (11.9 ± 0.4 mm vs. 10 ± 0.5 mm; p=0.008) in MULT than PRIM cows. In conclusion, the three EB doses presented similar efficiency to synchronize the FWE in suckled Nelore cows. Moreover, a delayed FWE and smaller dominant follicle is observed in PRIM cows, contributing to the reduced reproductive performance in this parity category when using similar TAI protocols of MULT cows.

Effect of the Estrus Expression on Follicular and Luteal Morphofunctional Characteristics and Fertility in Bos indicus females Synchronized for FTAI

Background: Recent studies have been conducted with the aim of improving the fertility rates in the FTAI programs in beef females. The observation of the estrus expression constitutes an important indicator of fertility in zebu females. Therefore, this work has as an objective to evaluate the impact of the estrus expression on the follicular, luteal and fertility morphofunctional characteristics of Nelore females synchronized for FTAI.Materials, Methods &amp; Results: Sixty five lactating female Nelore (Bos taurus indicus) were used. On a random day, denominated day 0 (D0), the 65 Nelore females received a progesterone-releasing device associated to the application of 2.0 mg of estradiol benzoate intramuscularly (IM). On D9, the progesterone-releasing intravaginal devices were removed and was administered 500 μg of cloprostenol sodium IM; 0.6 mg of estradiol cypionate IM and 300 UI of Equine Chorionic Gonadotropin IM. At this point, the animals were marked with a marking stick for the determination of the estrus expression. On D11 of the synchronization protocol, the animals were characterized in two groups: without estrus expression (WO/ ESTRUS) and with estrus expression (W/ ESTRUS). The evaluation of the follicle diameter (FOLD), of the follicle wall area (FOLA), of the follicle wall vascularization (FOLV) and the percentage of vascularization in the area of the preovulatory follicle wall (%FOLV) were conducted on D11 using B-mode ultrasonography and color Doppler and then the artificial inseminations were performed. The evaluation of the corpus luteum diameter (CLD), the total area of the corpus luteum (CLA), of the area of vascularization of the corpus luteum (CLV), of the percentage of vascularization of the in the area of the corpus luteum (% CLV) and the collection of blood for the evaluation of the serum levels of progesterone were carried out on D24. The analysis of the serum progesterone concentration were performed by the chemiluminescence method using the Access immunoassay systems Progesterone, with a sensitivity of 0.1 ng/mL. The diagnosis of gestation was carried out by transrectal ultrasonography on D45. The animals of the WITH ESTRUS group presented superior FOLD, FOLA, FOV (P &lt; 0.05) averages to those presented by the cows of the WITHOUT ESTRUS group. In relation to the luteal characteristics, in the WITH ESTRUS group the cows exhibited averages for CLD, CLA, CLV and P4 significantly higher than those of the WITHOUT ESTRUS group. However, the bovines of the WITH ESTRUS group presented a % CLV similar to the presented by the females of the WITHOUT ESTRUS group. As for the fertility rates, there was difference between the experimental groups WITH ESTRUS and WITHOUT ESTRUS.Discussion: The present work demonstrated the impact of the estrus expression on the follicular morphological parameters, therefore in accordance with other studies. These authors show a relation between the estrus expression and levels of estradiol, which is directly related to the sperm transport in the female reproductive tract, oocyte maturation and fertilization directly affecting the fertility of females submitted to the FTAI program. Similarly, there was an interrelation between the estrus expression and the luteal morphological parameters, corroborating with the findings of some researches, where were verified higher luteal morphological parameters associated to higher conception rates in cows that demonstrated estrus behavior in the FTAI. Therefore, the estrus detection can be used as a tool to direct matings in synchronization protocols, promoting the identification of the animals with a higher probability of conception, owing to better follicular and luteal hemodynamic conditions.

117 Effect of length of insertion of a progesterone device on follicular diameter, time of ovulation, and pregnancy rates in Bos indicus cows treated with an oestradiol/progesterone-based protocol with a prolonged proestrus

Three experiments were designed to evaluate the effect of the length of insertion of a intravaginal progesterone (P4) device on follicular and corpus luteum (CL) diameter, time of ovulation, and pregnancy rates following fixed-time AI (P/FTAI) in Bos indicus cows treated with an oestradiol/P4-based treatment with a lengthened proestrus, named J-Synch. Multiparous suckled Bos indicus beef cows that were 35 to 60 days postpartum were used in Experiments 1 and 2, whereas non-lactating cows were used in Experiment 3. All cows had a CL or a follicle of at least 8mm in diameter and a body condition score between 2.5 and 4 (1 to 5 scale) at the time of treatment. On Day 0, all cows received 2mg of oestradiol benzoate (EB; Sincrodiol, Ourofino, Brazil) and a previously used intravaginal device (1g of P4; Sincrogest, Ourofino). The P4 device was removed on Day 6 in the J-Synch 6-day group and on Day 7 in the J-Synch 7-day and Control groups. All cows received 500µg of cloprostenol (Sincrocio, Ourofino) and 400IU of equine chorionic gonadotrophin (SincroeCG, Ourofino) at the time of P4 device removal, and cows in the Control group also received 0.5mg of oestradiol cypionate (ECP, SincroCP, Ourofino) at the same time. In Experiment 1, cows (n=20 per group) were examined every 12h, from P4 device removal to determine the time of ovulation and 7 days after ovulation to measure the CL. In Experiment 2, all cows (n=200 per group) were tail-painted for oestrous detection. Cows with=50% of the tail-paint rubbed-off by 72h (J-Synch groups) or 48h (Control group) after P4 device removal, were FTAI at that time. Cows not designated as showing oestrus at that time received 10µg Buserelin (GnRH, Sincroforte, Ourofino) and were FTAI 8h later. In Experiment 3, P/FTAI was compared in cows that received the J-Synch 7-day treatment (n=265) or the 7-day Control treatment (n=250). Data were analysed using the GLM mixed procedure (InfoStat). In Experiment 1, the diameter of the ovulatory follicle was larger (P&amp;lt;0.05) and the interval to ovulation was longer (P&amp;lt;0.05) in the J-Synch groups (J-Synch 7 d: 16.4±0.2mm and 86.0±3.0 h; J-Synch 6 d:15.5±0.3mm and 83.0±4.0h) than in the Control group (13.8±0.2mm and 64.0±3.0h). Furthermore, CL diameter was greater (P&amp;lt;0.05) in the J-Synch 7-day group (21.9±0.8mm) than in the J-Synch 6-day (18.7±0.8mm) and Control (16.8±0.9mm) groups. In Experiment 2, P/FTAI was higher (P&amp;lt;0.05) in the J-Synch 7-day group (116/200; 58.0%) than in the J-Synch 6-day (93/200; 46.5%) and Control (98/200; 49.0%) groups. In Experiment 3, P/FTAI was higher (P&amp;lt;0.05) in the J-Synch 7-day group (161/265; 60.7%) than in the Control group (124/250; 49.6%). In conclusion, delaying the removal of the P4 device by 1 day (i.e. Day 7 vs. Day 6) in the J-Synch protocol and lengthening the proestrous period (i.e. J-Synch 7-day vs. 7-day Control) resulted in higher P/FTAI in Bos indicus cows.

Effect of expression of estrus and treatment with GnRH on pregnancies per AI in beef cattle synchronized with an estradiol/progesterone-based protocol

Three experiments evaluated the effects of expression of estrus and gonadotropin releasing hormone (GnRH) treatment on pregnancies per AI (P/AI) in beef cattle that were treated with an estradiol/progesterone (P4)-based protocol for fixed-time artificial insemination (FTAI). In Experiment 1, 20 non-lactating beef cows were treated with 2 mg estradiol benzoate (EB) and an intravaginal device containing 0.5 g of P4. Seven days later, P4 devices were removed and all cows received prostaglandin F2 alpha (PGF2α) and 0.5 mg estradiol cypionate (ECP). Estrus was detected using tail paint and cows that did not show estrus by 48 h after P4 device removal were randomized to receive GnRH or no treatment. Ovulation, as determined by ultrasonography, occurred earlier in cows that showed estrus (68.0 ± 2.5 h) than in cows that did not (82.0 ± 2.1 h, P < 0.05). Furthermore, cows that received GnRH ovulated earlier (78.0 ± 2.6 h) than those that did not (86.0 ± 2.0, P < 0.05). Experiment 2 determined whether expression of estrus and the administration of GnRH to animals that did not show estrus increased P/AI. Non-lactating beef cows and heifers (n = 1356) were treated as in Experiment 1 (P4 device removal, PGF2α and ECP administration on Day 7) or extended until Day 8. All animals in estrus by 48 h after P4 device removal were inseminated and those not showing estrus received GnRH or no treatment and were FTAI 8 h later (i.e., at 56 h). P/AI were greater (P < 0.01) in animals that were observed in estrus by 48 h (56.4%) than in those that did not show estrus (46.5%). Likewise, animals that did not show estrus but were treated with GnRH had greater P/AI (53.8%, P < 0.04) than those that did not receive GnRH (37.9%). Experiment 3 was designed to determine the effect of delaying GnRH treatment to the time of FTAI (at 56 h) in cows not showing estrus by 48 h after P4 device removal. Suckled beef cows (n = 969) were treated as in Experiment 1, except that all cows also received 400 IU of eCG at the time of P4 device removal on Day 7. Cows that showed estrus by 48 h or 56 h had greater P/AI (62.3%, P < 0.05) than those did not show estrus (51.5%). Furthermore, when cows that did not show estrus by 48 h were analyzed separately, P/AI were greater (P < 0.05) in those that received GnRH at 48 h and were FTAI by 56 h (64.9%) than in those that received GnRH concurrent with FTAI by 56 h after device removal (54.6%). In summary, expression of estrus was associated with earlier ovulations and resulted in greater P/AI in cows and heifers treated with an estradiol/P4-based protocol for FTAI. Furthermore, GnRH treatment in animals that did not show estrus hastened the time of ovulation and increased P/AI.

Correlation Between Sociodemographic Factors and the Acceptor Knowledge Level on Injectable Contraceptive Containing Medroxyprogesterone Acetate and Estradiol Cypionate in Several Primary Health Centers of Malang

Combined injectable contracetive is one of the effective, practical, and affordable ways to prevent pregnancy.An injection with Medroksiprogesteron Acetate 25mg and Estradiol Cypionate 5mg can be given once a month. It takes a regular injection according to the schedule to reach the effective result. Knowledge of injectable contraceptives may affect its effectiveness. This study aimed to determine the correalation between sociodemographic factorsand the acceptor's knowledge of contraception among four primary health centers (Puskesmas) in Malang. It employed observational analytic study with cross sectional approach and convenience sampling technique, with 40 samples obtained. This study was declared ethical with letter number230/EC/KEPK-S1-FARM/08/2019.The data obtained were then analyzed by using Spearman's test statistics and Cramer v contingency coefficient with 95% significancy. The resultshowed that the acceptors’ level of knowledge was average (50%), poor (30%), and good (20%). The sociodemographic factors that had significant correlation with level of knowledge including age (p=0.019), education (p=0.002), andincome level (p=0.020), while job had no correlation (p=0.161). It can be concluded that the sociodemographic factors correlated with acceptors’ level of knowledge in primary health centers of Malangwere age, education, and income level

PSX-24 Seminal characteristics or Dorper rams with different social hierarchies in northern Mexico

Abstract The aim of this study was to evaluate the possible difference in seminal characteristics of Dorper rams of either high, medium or low social ranks in northern Mexico (26º N). The male’s social status was quantified through a competitive behavioral test in a herd of 36 adult males, the aggressive interactions and their consequences were registered to calculate the success index (SI), where low hierarchy (LH) rams had a SI of 0 to 0.33, medium hierarchy (MH) rams had a SI of 0.34 to 0.66 and high hierarchy (HH) had a SI of 0.67 to 1. Afterwards, the rams were subjected to an estrogenized female (2 mg of estradiol cypionate) for teasing in order to collect a semen sample with an artificial vagina. The semen was evaluated for volume, motility and concentration. The seminal characteristics differences were analyzed using a one-way ANOVA tests and stablishing a p-value of 0.10 as significance level in the SPSS statistical package. Results are shown in table 1. In conclusion, low hierarchy Dorper rams show a statistical tendency to have a lower sperm concentration.

Pregnancy rate to FTAI in Braford heifers submitted to J-Synch protocol

The objective of the present work was to evaluate the effect of J-Synch protocol on pregnancy rate (PR) of heifers artificially inseminated after detected estrus (DEAI) or at fixed-time (FTAI). Two hundred ninety-three Braford heifers were used. On day 0, all animals received 2.0 mg of estradiol benzoate administered intramuscularly (IM) and an intravaginal progesterone-releasing device (DIB, 0.5 g). Heifers were assigned to the following group: 1) J-Synch: on day 6, DIB devices were removed and 500 µg of d-Cloprostenol sodium (d-CS) was administered IM and paint was applied on tail base (tail-paint). On day 9 (60 h after DIB removal), heifers with ? 40% of the tail-paint rubbed off were inseminated. Those not showing estrus by 72 h after DIB removal received 100 µg of GnRH at that time and were FTAI. 2) Conventional: on day 7, DIB devices were removed, and 500 µg of d-CS and 0.5 mg of estradiol cypionate were administered IM and tail-paint. Forty-eight hours after DIB removal, heifers with the tail-paint rubbed off were DEAI. Those not showing estrus by 54 h after DIB removal were FTAI. Pregnancy rate was diagnosed by ultrasonography 30 days after FTAI in all heifers and did not differ between protocols (44.28% and 42.48%, P = 0.673). In both protocols, higher PR was observed in DEAI heifers (P = 0.047). In conclusion, the use of the J-Synch protocol generated similar PR to the Conventional protocol, allowing its use with the same efficiency. Furthermore, the DEAI generated better PR than the FTAI, regardless of the protocol used.

Effects of equine chorionic gonadotropin administered via the Baihui acupoint on follicular ovarian dynamics and the luteal function of cattle during an ovulation synchronization treatment regimen for fixed-time artificial insemination

Objectives were to evaluate effects of a smaller than typically used dose of equine chorionic gonadotropin (eCG) during a fixed-time artificial insemination (FTAI) treatment regimen. Transrectal ultrasonic (US) examinations were conducted on dairy cows on Day 0 (D0) and the treatment regimen was initiated with administrations of an intravaginal progesterone (P4) implant, estradiol benzoate (im), and prostaglandin F2α (PGF2α; im). On D8, the P4 implant was removed and PGF2α and estradiol cypionate were administered to all animals. Subsequently, cows were randomly assigned to three groups and eCG was administered to Groups 1, 2, and 3 in doses of 300 (im); 100 (im); and 100 (Baihui acupoint) IUs, respectively. The B-mode and power-flow US cineloops were performed to assess follicular dynamics and evaluate various morphological and vascular characteristics of the corpus luteum. Blood samples were collected to quantify serum P4 concentrations. There were no differences between the ovulation synchronization treatment regimens for all follicular dynamic variables tested; however, cows in Group 3 differed from Group 2 having a larger follicle diameter (FD) on D10 (P = 0.06) and larger preovulatory FD (P = 0.09), as well as a blood perfusion area of the dominant follicle wall on D8 (P = 0.07). There were no differences in responses to the ovulation synchronization treatment regimens for the luteal variables evaluated subsequent to ovulation. In conclusion, the Baihui acupoint was effective as an alternative route for eCG dose reduction when FTAI treatment regimens were imposed without detrimentally affecting values for reproductive variables.

Effects chronic administration of corticosterone and estrogen on HPA axis activity and telomere length in brain areas of female rats

Chronic stress is related to the acceleration of telomere shortening. Recent work showed a correlation between chronic psychosocial stress and reduced telomere length in certain cells. The exposure of T lymphocytes to cortisol promoted a significant reduction in telomerase activity. Although stress can promote changes in telomere length, whether increased glucocorticoid concentrations alter telomere length in brain tissue cells is unclear. In addition to modulating the activity of the stress system, estrogen also influences telomere length. The objective of this study was to verify whether chronic exposure to glucocorticoids promotes changes in the telomere length of encephalic areas involved in the control of HPA axis activity and whether estrogen affects these changes. Wistar rats were ovariectomized and treated with estradiol cypionate [(50 or 100 μg/kg, subcutaneously)] or oil and 20 mg/kg corticosterone or vehicle (isotonic saline with 2% Tween 80, subcutaneously) for 28 days. On the day after the end of the hormonal treatment, the animals were euthanized for collection of blood, brain and pituitary gland samples. Estrogen modulated the activity of the HPA axis. CRH, AVP and POMC mRNA levels were reduced by estrogen. At least in doses and treatment time used, there was no correlation between effects of exposure to glucocorticoids and estrogen on telomere length in the brain areas of female rats. However, estrogen treatment reduced the telomere length in the central amygdala and dorsal hippocampus, but not in the PVN, indicating a variation of reaction of telomeres for estrogen in different brain areas.

Estradiol-17β Pharmacokinetics and Histological Assessment of the Ovaries and Uterine Horns following Intramuscular Administration of Estradiol Cypionate in Feral Cats.

Simple SummaryFeral cats (Felis catus) have a devastating impact on Australian native fauna. Several programs exist to control their numbers through lethal removal, using tools such as baiting with toxins. Adult male cats are especially difficult to control. We hypothesized that one way to capture these male cats is to lure them using female cats. As female cats are seasonal breeders, a method is needed to artificially induce reproductive (estrous) behavior so that they could be used for this purpose year-round (i.e., regardless of season). Estrogens can be given to cats to induce estrous behavior, but it is not known for how long this elevates the blood concentrations of estradiol. Following the administration of a long-acting estrogen, estradiol cypionate, to nine captive feral cats, blood estrogen concentrations remained elevated for several days. This information will be useful to ongoing studies that are investigating ways to reduce the abundance of feral cats in Australia, especially adult male cats.The control of feral cats (Felis catus) in Australia is a key biological conservation issue. Male cats are more difficult to control than female cats. Collared and tagged female cats displaying estrous behavior have been considered as a way to lure male cats and reveal their locations. As female cats are seasonal breeders, artificial induction of estrous behavior following the administration of a long-acting estrogen could improve their use for this purpose. Estradiol cypionate was intramuscularly administered to nine entire non-pregnant female feral cats, of unknown estrous status, at 0.1, 0.3, or 0.5 mg/kg. Mean peak serum concentrations of estradiol-17β were 365 pg/mL (0.1 mg/kg), 1281 pg/mL (0.3 mg/kg), and 1447 pg/mL (0.5 mg/kg). The time-course of estradiol-17β concentrations after various doses of estradiol cypionate was assessed using non-compartmental and non-linear mixed-effects methods. At the highest-studied dose (0.5 mg/kg), the 50th percentile of estradiol-17β concentrations exceeded 0.1 ng/mL for 11.8 days, and 0.05 ng/mL for 14.6 days. The duration increased with increasing dose. No signs of toxicity were noticed in any cat during the study. This information will be useful to ongoing studies that are investigating ways to reduce the abundance of feral cats in Australia, especially adult male cats.

ESTRADIOL AND GNRH ON OVULATION INDUCTION FOR ESTRUS SYNCHRONIZED CROSSBRED COWS1

ABSTRACT Estradiol benzoate (EB), estradiol cypionate (EC), and gonadotrophin releasing hormone (GnRH) were evaluated as ovulation inducers for TAI of crossbred lactating cows. In experiment I (n = 45), the follicular dynamics was evaluated, while in experiment II (n = 171) the reproductive efficiency was evaluated. All females were submitted to a synchronization protocol: insertion on day 0 (D0) of intravaginal progesterone -release intravaginal device (PRID; 1g) plus administration of EB 2mg; D8, PRID removal, administration of 0.150mg PGF2α and 400 IU of eCG, and cows were allocated into three treatments: 1) TEB9 - IM administration of 1mg EB on D9 and AI performed 52 hours after PRID removal; 2) TEC - IM administration of 1mg EC on D8 and AI performed 48 hours after withdrawal of PRID; and 3) TGnRH - administration of 100pg GnRH on D10 and AI performed 52 hours after removal of PRID. The follicular growth rate was lower in the EC group (p &lt;0.05). There was no effect of treatments on ovulation and pregnancy rates (p &gt;0.05). The use of EB, EC, and GnRH as ovulation inducers in the TAI protocol did not show marked differences in the evaluated patterns of follicular dynamics and pregnancy.