Imageamento digital de paleocavernas colapsadas com georadar

In this study, the methodological procedures involved in digital imaging of collapsed paleocaves in tufa using GPR are presented. These carbonate deposits occur in the Quixeré region, Ceará State (NE Brazil), on the western border of the Potiguar Basin. Collapsed paleocaves are exposed along a state road, which were selected to this study. We chose a portion of the called Quixeré outcrop for making a photomosaic and caring out a GPR test section to compare and parameterize the karst geometries on the geophysical line. The results were satisfactory and led to the adoption of criteria for the interpretation of others GPR sections acquired in the region of the Quixeré outcrop. Two grids of GPR lines were acquired; the first one was wider and more spaced and guided the location of the second grid, denser and located in the southern part of the outcrop. The radargrams of the second grid reveal satisfactorily the collapsed paleocaves geometries. For each grid has been developed a digital solid model of the Quixeré outcrop. The first model allows the recognition of the general distribution and location of collapsed paleocaves in tufa deposits, while the second more detailed digital model provides not only the 3D individualization of the major paleocaves, but also the estimation of their respective volumes. The digital solid models are presented here as a new frontier in the study of analog outcrops to reservoirs (for groundwater and hydrocarbon), in which the volumetric parameterization and characterization of geological bodies become essential for composing the databases, which together with petrophysical properties information, are used in more realistic computer simulations for sedimentary reservoirs.

Sincronização da ovulação em fêmeas suínas submetidas ao desmame precoce

Verificou-se a eficiência de protocolos para sincronizar a ovulação em porcas desmamadas precocemente. Trinta porcas com média de 4,4± 2,0 partos e estádio de lactação de 14,8± 0,7 dias foram distribuídas em três grupos de 10 animais: 1- nenhum tratamento hormonal; 2- 1000 UI de PMSG, via intramuscular (IM), 48h pós-desmame e 0,25mg de GnRH, IM, 72h após a aplicação do PMSG; 3- 1000 UI de PMSG, IM, 48h pós-desmame e 500 UI de hCG, IM, 72h após o PMSG. O momento da ovulação foi detectado por ultra-sonografia transretal. A taxa de sincronização (ovulação até 48h após aplicação de hCG ou GnRH) dos grupos 2 e 3 (94,7%) foi maior (P<0,01) que no grupo controle (40%). Com o uso dos protocolos de sincronização de ovulação, as fêmeas tratadas apresentaram, em relação ao grupo controle, tendência de maior taxa de prenhez (95% vs. 70%; P<0,10) e similares intervalo do desmame ao estro (96,5± 3,0 vs. 130,2± 31,4h) e número de leitões nascidos vivos por fêmea gestante no primeiro cio pós-desmame (10,9± 0,8 vs. 12,0± 0,9). Dessa maneira, os protocolos de sincronização usados neste estudo foram eficientes em sincronizar a ovulação, e podem viabilizar o uso da inseminação artificial em horários predeterminados.

Elevated progesterone concentrations enhance prostaglandin F-2 alpha synthesis in dairy cows

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparison of progesterone-based protocols with gonadotropin-releasing hormone or estradiol benzoate for timed artificial insemination or embryo transfer in lactating dairy cows

The objective was to compare two protocols for synchronizing ovulation in lactating Holstein cows submitted to timed AI (TAI) or timed ET (TET). Within each farm (n = 8), cows (n = 883; mean +/- SEM 166.24 +/- 3.27 d postpartum, yielding 36.8 +/- 0.34 kg of milk/d) were randomly assigned to receive either: 1) an intravaginal progesterone insert (CIDR (R)) with 1.9 g of progesterone + GnRH on Day -10, CIDR (R) withdrawal + PGF2 alpha on Day -3, and 1 mg estradiol cypionate on Day -2 (treatment GP-P-E; n(TAI) = 180; n(TET) = 260); or 2) a CIDR (R) insert + 2 mg estradiol benzoate on Day -10, PGF2 alpha on Day -3, CIDR (R) withdrawal + 1 mg estradiol cypionate on Day -2 (treatment EP-P-E; n(TAI) = 174; n(TET) = 269). Cows were subsequently randomly assigned to receive either TAT on Day 0 or TET on Day 7. Serum progesterone concentration on Day -3 was greater in GP-P-E than in EP-P-E (2.89 +/- 0.15 vs 2.29 +/- 0.15 ng/mL; P < 0.01), with no significant effect of group on serum progesterone on Day 7. Compared to cows submitted to TAI, those submitted to TET had greater pregnancy rates on Day 28 (44.0% [233/5291 vs 29.7% [105/354]; p < 0.001) and on Day 60 (37.6% [199/529] vs 26.5 [94/354]; P < 0.001). However, there were no effects of treatments (GP-P-E vs EP-P-E; P > 0.10) on synchronization (87.0% [383/440] vs 85.3% [378/443]), conception (TAI: 35.3% [55/156] vs 33.8% [50/148]; TET: 50.7% [115/227] vs 51.3% [118/230]) and pregnancy rates on Days 28 (TAT: 30.5% [55/180] vs 28.7% 150/174]; TET: 44.2% [115/260] vs 43.9% [118/2691) and 60 (TAI: 27.2% [49/80] vs 25.9% [45/174]; TET: 38.8% [101/260] vs 36.4% [98/269]). In conclusion, GP-P-E increased serum progesterone concentrations on Day -3, but rates of synchronization, conception, and pregnancy were not significantly different between cows submitted to GP-P-E and EP-P-E protocols, regardless of whether they were inseminated or received an embryo. (c) 2011 Elsevier B.V. All rights reserved.

Effect of progesterone and/or estradiol treatments prior to induction of ovulation on subsequent luteal lifespan in anestrous Nelore cows

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Strategies to improve fertility in postpartum multiparous Bos indicus cows submitted to a fixed-time insemination protocol with gonadotropin-releasing hormone and prostaglandin F-2 alpha

In Exp. 1, we evaluated the effects of 2 lengths of progesterone exposure [CIDR (controlled intravaginal drug release); 7 vs. 14 d] before a modified CO-Synch protocol [50.0-mu g injection of GnRH 6.5 d before a 25.0-mg injection of PGF(2 alpha) followed by another injection of GnRH and fixed-time AI (TAI) 2 d after PGF(2 alpha)], with or without temporary weaning (TW) before GnRH treatments, on fertility of suckled multiparous Bos indicus cows (n = 283) and on calf performance. Timed AI pregnancy rates for cows receiving 7 d CIDR + TW, 7 d CIDR, 14 d CIDR + TW, and 14 d CIDR were 53, 47, 46, and 41%, respectively (P > 0.10). Calves submitted to two 48-h TW 6 d apart had decreased mean BW at 240 d (187.9 +/- 2.7 vs. 195.5 +/- 2.7 kg; P < 0.05), but BW at 420 d was not affected by TW (240.1 +/- 5.1 kg). In Exp. 2, we evaluated the effect of no treatment and treatment with or without a CIDR insert between GnRH and PGF(2 alpha) treatments of a modified CO-Synch protocol on pregnancy rate to TAI, and throughout a 90-d breeding season in suckled multiparous Bos indicus cows (n = 453). The inclusion of a CIDR between first GnRH and PGF(2 alpha) treatments of a modified CO-Synch protocol did not improve pregnancy rate (29 and 33% for cows receiving CO-Synch + CIDR and CO-Synch protocol, respectively), and cycling cows had poorer TAI pregnancy rates than anestrous cows treated with either synchronization protocol (21.7 vs. 40.7%; P < 0.05). However, regardless of treatment with CIDR, cows submitted to TAI protocol had greater (P < 0.05) pregnancy rates at 30 (54.8 vs. 11.2%), 60 (72.1 vs. 38.8%), and 90 d (82.0 vs. 57.9%) of breeding season than untreated cows.

Effects of postbreeding gonadotropin treatments on conception rates of lactating dairy cows subjected to timed artificial insemination or embryo transfer in a tropical environment

The objective of experiment 1 was to evaluate the effects of treatments with human chorionic gonadotropin (hCG) or GnRH 7 d after induced ovulation on reproductive performance of lactating dairy cows submitted to timed artificial insemination (TAI) or timed embryo transfer (TET). A total of 834 potential breedings were used from 661 lactating Holstein cows (37.3 +/- 0.3 kg of milk/d). Cows had ovulation synchronized and were assigned randomly to receive TAI on d 0 or TET on d 7. Within each group, cows were assigned randomly to receive on d 7 no additional treatment (control; n(TAI) = 156; n(TET) = 126), a 100 mu g i.m. injection of GnRH (n(TAI) = 155; n(TET) = 124), or a 2,500 TU i.m. injection of hCG (ITA = 151; n(TET) = 122). Postbreeding treatment affected the percentages of pregnant cows at TET on d 28 (control: 38.1%; GnRH: 52.4%; hCG: 45.1%) and on d 60 (control: 32.5%; GnRH: 41.1%; hCG: 38.5%), but postbreeding treatment did not affect percentages of pregnant cows at TAT on d 28 (control: 30.1%; GnRH: 32.2%; hCG: 32.4%) or on d 60 (control: 25.6%; GnRH: 27.1%; hCG: 29.8%). The objective of experiment 2 was to evaluate the effect of a treatment with GnRH 7 d after TET on reproductive performance of lactating dairy cows that received a previous GnRH treatment at TET. A total of 285 potential breedings were used from 257 lactating Holstein cows (35.1 +/- 0.8 kg of milk/d). Cows had ovulation synchronized and were assigned for TET on d 7. Immediately after TET, all cows were treated with a 100 mu g i.m. injection of GnRH. on d 14, cows were assigned randomly to receive (G7-14; n = 147) or not (G7; n = 138) an additional injection of GnRH. Pregnancy diagnosis were performed on d 28 and 60. The additional treatment with GnRH on d 14 did not affect the percentages of pregnant cows on d 28 (G7: 48.5%; G7-14: 42.9%) or on d 60 (G7: 39.8%; G7-14: 37.4%). In conclusion, treatment with GnRH or hCG 7 d after induced ovulation increased conception rates in lactating dairy cows submitted to TET, but not in cows submitted to TAI. Moreover, treatment with GnRH 7 d after TET did not enhance reproductive performance of lactating dairy cows that received a previous GnRH treatment at TET.

Serum progesterone concentration and conception rate of beef cows supplemented with ground corn after a fixed-time artificial insemination protocol

Avaliaram-se os efeitos de diferentes níveis de ingestão de suplemento com milho moído finamente (MF) em vacas de corte, mantidas em pasto, após inseminação artificial em tempo fixo (IATF), sobre a concentração sérica de progesterona (P4) no dia 7, e sobre a concepção no dia 28 pós IATF. Trezentas e sessenta e quatro vacas Brangus, multíparas lactantes, tiveram as atividades folicular e luteal sincronizadas por tratamento com benzoato de estradiol (Estrogin; 2,0mg IM) e inserção de dispositivo intravaginal de P4 (CIDR) no dia -11, seguido por tratamento com PGF2 α (Lutalyse; 25mg IM) no dia - 4, retirada do CIDR e remoção temporária de bezerros no dia -2, e tratamento com GnRH (Fertagyl; 100 µ g IM), IATF e retorno dos bezerros no dia 0. No dia 0, as vacas foram aleatoriamente distribuídas para receber um dos quatro tratamentos: G1 -2kg/dia de MF do dia 0 ao dia 21; G2 -2kg/dia de MF do dia 0 ao dia 7, e 6kg/dia de MF do dia 8 ao dia 21; G3 -6kg/dia de MF do dia 0 ao dia 7, e 2kg/dia de MF do dia 8 ao dia 21; G4 -6kg/dia de MF do dia 0 ao dia 21. Amostras de sangue foram colhidas no dia 7, e o diagnóstico de gestação foi realizado por ultrassonografia no dia 28. As vacas suplementadas com 2kg/dia de MF apresentaram maior concentração sérica de P4 no dia 7 em relação às vacas suplementadas com 6kg/dia (1,58 vs. 1,28ng/mL; P<0,01, EPM=0,08). As vacas do G4 apresentaram maior taxa de concepção em relação às vacas do G1 (58,4 vs. 41,9%, respectivamente; P<0,05). O nível de consumo do suplemento energético após a IATF é negativamente associado às concentrações séricas de P4, porém positivamente associado à taxa de concepção em vacas de corte em pasto.

Follicular deviation and acquisition of ovulatory capacity in bovine follicles

Selection of dominant follicles in cattle is associated with a deviation in growth rate between the dominant and largest subordinate follicle of a wave (diameter deviation). To determine whether acquisition of ovulatory capacity is temporally associated with diameter deviation, cows were challenged with purified LH at known times after a GnRH-induced LH surge (experiment 1) or at known follicular diameters (experiments 2 and 3). A 4-mg dose of LH induced ovulation in all cows when the largest follicle was greater than or equal to 12 mm (16 of 16), in 17% (1 of 6) when it was 11 mm, and no ovulation when it was less than or equal to 10 mm (0 of 19). To determine the effect of LH dose on ovulatory capacity, follicular dynamics were monitored every 12 h, and cows received either 4 or 24 mg of LH when the largest follicle first achieved 10 mm in diameter (experiment 2). The proportion of cows ovulating was greater (P < 0.05) for the 24-mg (9 of 13; 69.2%) compared with the 4-mg (1 of 13; 7.7%) LH dose. To determine the effect of a higher LH dose on follicles near diameter deviation, follicular dynamics were monitored every 8 h, and cows received 40 mg of LH when the largest follicle first achieved 7.0, 8.5, or 10.0 mm (experiment 3). No cows with a follicle of 7 mm (0 of 9) or 8.5 mm (0 of 9) ovulated, compared with 80% (8 of 10) of cows with 10-mm follicles. Thus, follicles acquired ovulatory capacity at about 10 mm, corresponding to about 1 day after the start of follicular deviation, but they required a greater LH dose to induce ovulation compared with larger follicles. We speculate that acquisition of ovulatory capacity may involve an increased expression of LH receptors on granulosa cells of the dominant follicle and that this change may also be important for further growth of the dominant follicle.

Strategies to improve the ovarian response to equine pituitary extract in cyclic mares

Equine pituitary extract (EPE) has been reported to induce heightened follicular development in mares, but the response is inconsistent and lower than results obtained in ruminants undergoing standard superovulatory protocols. Three separate experiments were conducted to improve the ovarian response to EPE by evaluating: (1) effect of increasing the frequency or dose of EPE treatment; (2) use of a potent gonadotropin-releasing hormone agonist (GnRH-a) prior to EPE stimulation (3) administration of EPE twice daily in successively decreasing doses. In the first experiment. 50 mares were randomly assigned to one of four treatment groups. Mares received (1) 25 mg EPE once daily; (2) 50 mg EPE once daily (3) 12.5 mg EPE twice daily; or (4) 25 mg EPE twice daily. All mares began EPE treatment 5 days after detection of ovulation and received a single dose of cloprostenol sodium 7 days postovulation. EPE was discontinued once half of a cohort of follicles reached a diameter of greater than or equal to35 mm and hCG was administered. Mares receiving 50 mg of EPE once daily developed a greater number (P = 0.008) of preovulatory follicles than the remaining groups of EPE-treated mares, and more (P = 0.06) ovulations were detected for mares receiving 25 mg EPE twice daily compared to those receiving either 25 mg EPE once daily and 12.5 mg EPE twice daily. Embryo recovery per mare was greater (P = 0.05) in the mares that received 12.5 mg EPE twice daily than those that received 25 mg EPE once daily. In Experiment 2, 20 randomly selected mares received either 25 mg EPE twice daily beginning 5 days after a spontaneous ovulation. or two doses of a GnRH-a agonist upon detection of a follicle greater than or equal to35 mm and 25 mg EPE twice daily beginning 5 days after ovulation. Twenty-four hours after administration of hCG, oocytes were recovered by transvaginal aspiration from all follicles greater than or equal to35 mm. No differences were observed between groups in the numbers of preovulatory follicles generated (P = 0.54) and oocytes recovered (P = 0.40) per mare. In Experiment 3, 18 mares were randomly assigned to one of two treatment groups. Then, 6-11 days after ovulation, mares were administered a dose of PGF(2gamma) and concomitantly began twice-daily treatments with EPE given in successively declining doses, or a dose of PGF(2alpha), but no EPE treatment. Mares administered EPE developed a higher (P = 0.0004) number of follicles :35 mm, experienced more (P = 0.02) ovulations, and yielded a greater (P = 0.0006) number of embryos than untreated mares. In summary, doubling the dose of EPE generated a greater ovarian response, while increasing the frequency of treatment, but not necessarily the dose. improved embryo collection. Additionally, pretreatment with a GnRH-a prior to ovarian stimulation did not enhance the response to EPE or oocyte recovery rates. (C) 2002 Elsevier B.V. All rights reserved.

Ovarian response of Suffolk ewes to estrous synchronization using short-term protocol

The efficacy of estrus synchronization using short-term protocol was evaluated by ultrasound exams in Suffolk ewes during the pre-breeding season. The control Group (n = 12) was synchronized by treatment for 12 days with vaginal sponges impregnated with medroxyprogesterone acetate, and 400 IU eCG at sponge withdrawal. Experimental groups I, II and III kept the sponge in place for 4 days, and 100 µg of PGF2a was administered at sponge withdrawal. Additionally, Group I (n = 12) had 0.1 mg of estradiol benzoate (EB) administered during sponge placement and 50 µg of GnRH 48 hours after sponge removal. Group II (n = 6) had 35 mg of progesterone (P4) injected, and 0.1 mg of EB administered during sponge placement, 400 IU eCG at withdrawal and 48 hours after, 50 µg GnRH were administrated. Group III (n = 12) had 35 mg of P4 and 0.2 mg of EB administered at sponge placement, 400 IU eCG at withdrawal, and 50 µg of GnRH was administrated after 56 hours. Ovaries were monitored through ultrasound scanning. Concerning the first wave, no difference was detected between the control group and the experimental groups. However, the characteristics of ovulatory wave were significantly different between the groups. The duration of the follicular wave was shorter for Group III than for Group II. The follicle in Group I reached its maximum diameter before the Group II. The diameter of the follicle at the sponge withdrawal in the control group was larger than in Group I. After sponge withdrawal, the follicular growth rate was smaller in the control group than in Group III. The maximum diameter of the follicle in Group II was larger than in the other groups. The short-term protocol in which estrogen was used did not synchronize the emergence of the wave of follicular development.

Improvement of embryo production by the replacement of the last two doses of porcine follicle-stimulating hormone with equine chorionic gonadotropin in Sindhi donors

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ovarian function in cows submitted to acute stress during proestrus

Studies in which ACTH was administrated in heifers after the occurrence of luteolysis showed a delay in the onset of estrus and the estrus duration was shortened. This study evaluated the effect of acute stress by road transportation on estrous behavior and ovulation, monitored by serum progesterone and cortisol concentrations in cows at the periovulatory period, using a crossover design. Eleven crossbred cows, divided into Control and Transport groups had their estrus cycle synchronized with GnRH, an intravaginal progesterone device, and cloprostenol. Thirty hours after withdrawal of the device, the animals of the Transport group were transported for 60 min by truck and those from the Control group remained at pasture. Ovarian ultrasound examination was performed every 12 h from device withdrawal until ovulation in every cow. From the day after removal of the device until ovulation estrous behavior was monitored 24 h a day. Blood samples for serum cortisol and progesterone concentrations were taken at -90, -60, 0, 30, 60 and 180 min in relation to the end of transportation. Transportation during the estrous period induced stress in cows as reflected by changes in serum concentrations of progesterone and cortisol. However, we did not detect impairment in estrus expression, estrus duration or ovulation (P>0.05). (C) 2010 Elsevier B.V. All rights reserved.

Superovulation and embryo transfer in Bos indices cattle

Compared to Bos taurus breeds, Bos indices breeds of cattle present several differences in reproductive physiology. Follicular diameter at deviation and at the time of ovulatory capability are smaller in B. indicus breeds. Furthermore, B. indicus breeds have a greater sensitivity to gonadotropins, a shorter duration of estrus, and more often express estrus during the night. These differences must be considered when setting up embryo transfer programs for B. indicus cattle. In recent studies, we evaluated follicular dynamics and superovulatory responses in B. indicus donors with the objective of implementing fixed-time AI protocols in superstimulated donors. Protocols using estradiol and progesterone/progestrogen releasing devices to control follicular wave emergence were as efficacious as in B. taurus cattle, allowing the initiation of superstimulatory treatments (with lower dosages of FSH than in B. taurus donors) at a self-appointed time. Furthermore, results presented herein indicate that delaying the removal of progesterone/progestogen-releasing devices, combined with the administration of GnRH or pLH 12 h after the last FSH injection, results in synchronous ovulations, permitting the application of fixed-time AI of donors without the necessity of estrus detection and without compromising the results. (c) 2005 Elsevier B.V. All rights reserved.

Synchronization of ovulation in crossbred dairy heifers using gonadotrophin-releasing hormone agonist, prostaglandin F2a and human chorionic gonadotrophin or estradiol benzoate

Girolando (Gir x Holstein) is a very common dairy breed in Brazil because it combines the rusticity of Gir (Bos indicus) with the high milk yield of Holstein (Bos taurus). The ovarian follicular dynamics and hormonal treatments for synchronization of ovulation and timed artificial insemination were studied in Girolando heifers. The injection of a gonadotrophin-releasing hormone (GnRH) agonist was followed 6 or 7 days (d) later by prostaglandin F2a (PGF2a). Twenty-four hours after PGF2a injection either human chorionic gonadotropin (hCG, GPh-d6 and GPh-d7 groups) or estradiol benzoate (EB, GPE-d6 and GPE-d7 groups) was administered to synchronize ovulation and consequently allow timed artificial insemination (AI) 24 and 30 h after hCG and EB injection, respectively. Follicular dynamics in Girolando heifers was characterized by the predominance of three follicular waves (71.4%) with sizes of dominant follicles (10-13 mm) and corpus luteum (approximately 20 mm) similar to those for Bos indicus cattle. In the GnRH-PGF-hCG protocol, hCG administration induced earlier ovulation (67.4 h, P<0.01) compared to the control group (GnRH-PGF) and a better synchronization of ovulation, since most of it occurred within a period of 12 to 17 h. Pregnancy rate after timed AI was 42.8 (3/7, GPh-d6) to 50% (7/14, GPh-d7). In contrast, estradiol benzoate (GnRH-PGF-EB protocol) synchronized ovulation of only 5 of 11 heifers from the GPE-d7 group and of none (0/7) from the GPE-d6 group, which led to low pregnancy rates after timed AI (27.3 and 0%, respectively). However, since a small number of Girolando heifers was used to determine pregnancy rates in the present study, pregnancy rates should be confirmed with a larger number of animals.