O objetivo do experimento I foi avaliar a redução do tempo de permanência do dispositivo de P4 de 9 para 7 dias sob parâmetros reprodutivos de vacas Nelore. Foram utilizadas 674 vacas lactantes entre 40-60 dias pós parto que receberam no início do protocolo (d0) BE + CIDR. No momento da retirada do CIDR foi administrado PGF2 &#945;, ECP e eCG. A IATF ocorreu 55 e 48 horas após a retirada do dispositivo nos tratamentos 7d-CIDR e 9d-CIDR, respectivamente. Dez dias após a IA foi realizada colheita de sangue para dosagem de P4 sérica e confirmação da ovulação. Vacas tratadas com 7d-CIDR apresentaram menor (p < 0,01) folículo ovulatório em relação ao 9d-CIDR. No entanto, a concentração de P4 pós-IA, taxas de ovulação, detecção de estro e prenhez não foram influenciadas pelo tempo de permanência do CIDR. Assim, o uso do CIDR por 7 dias promoveu desempenho reprodutivo semelhante em vacas Nelore comparado ao protocolo com 9 dias. O experimento II teve o objetivo de avaliar os efeitos da reutilização do CIDR por até 35 dias de uso em vacas e 42 dias em novilhas Nelore. Utilizou-se 749 vacas lactantes 40-60 dias pós parto e 92 novilhas púberes. No d0 os animais receberam BE + CIDR novo (CIDR1) ou previamente usado por 7 (CIDR2), 14 (CIDR3), 21 (CIDR4), 28 (CIDR5) e 35 (CIDR6) dias. No momento da retirada do CIDR (d7) foi administrado PGF2 &#945;, ECP, eCG e exame de US para mensuração do maior folículo (FD), além de colheita de sangue para dosagem de P4. A IATF ocorreu 55 horas após a retirada do dispositivo. O diâmetro do FD foi maior (p < 0,01) de acordo com o maior número de usos do CIDR nas vacas, a concentração de P4 reduziu nos CIDRs reutilizados porém se mantiveram acima de 1,5 ng/ml e a taxa de prenhez não foi afetada pela reutilização do dispositivo por até 5 vezes em vacas e o sexto uso em novilhas. O protocolo com 7 dias de permanência permite a reutilização do CIDR por até 6 vezes mantendo a mesma eficiência reprodutiva. No experimento III o objetivo foi avaliar se a aplicação do eCG dois dias antes da retirada do dispositivo aumenta o tamanho do FO, CL e taxa de prenhez. Foram utilizadas 681 vacas lactantes 40-60 dias pós parto e 182 novilhas púberes. Os animais foram distribuídos em dois tratamentos com aplicação de eCG no quinto (5d-eCG) ou sétimo dia (7d-eCG). No d0, os animais receberam BE + CIDR e no dia 7 o CIDR foi retirado e administrado PGF2 &#945; e ECP. Dez dias após a IA foi realizada US para mensuração do CL e colheita de sangue para dosagem de P4. A IATF ocorreu 55 horas após a retirada do dispositivo. O tratamento 5d-eCG aumentou (p < 0,01) o FO nas vacas em relação ao grupo 7deCG e o mesmo ocorreu nas novilhas. Em vacas, a concentração de P4 pós IA foi mais alta (p = 0,04) no 5d-eCG. Em novilhas o diâmetro do CL pós-IA foi maior (p < 0,01) no 5d-eCG. No entanto, a antecipação da aplicação do eCG foi eficiente em aumentar o folículo ovulatório no momento da IATF, mas não aumentou a taxa de prenhez / The aim of the experiment I was to evaluate the reduction of the time of P4 device from 9 (9d-CIDR) to 7 (7d-CIDR) days and its impacts on reproductive parameters of Nellore cows. Six hundred and seventy-four suckling cows 40-60 days postpartum received EB + CIDR at d0 of the protocol. At CIDR removal, there were administered PGF2 &#945;, ECP, eCG. The FTAI occurred 55 and 48 hours after device removal in the treatment 7d-CIDR and 9d-CIDR, respectively. Ten days after AI blood samples were collected for P4 analysis and ovulation rate. Cows of treatment 7d-CIDR showed lower (p <0.01) ovulatory follicle (OF) than 9d-CIDR. The CIDR length in cows and heifers did not influence concentration of P4, ovulation rate, estrus detection rate and pregnancy rate. Thus, the use of CIDR by 7 days did not impacted reproductive result in suckling cows and Nellore heifers. The aim of experiment II was to evaluate the effects of the CIDR reuse up to 35 days in cows and heifers on reproductive characteristics. We used 749 suckling cows 40-60 days postpartum and 92 pubertal heifers. In d0 animals received EB + new CIDR (CIDR1) or previously used by 7 (CIDR2), 14 (CIDR3), 21 (CIDR4), 28 (CIDR5) and 35 (CIDR6) days. At CIDR removal were administered PGF2 &#945;, ECP, eCG and US to measure the largest follicle (LF), and blood collection for P4 analysis. The TAI occurred 55 hours after device removal. The LF diameter was greater (p <0.01) in CIDR reused in cows. P4 concentration was lower in CIDR reused, but was higher than 1.5 ng / mL, and the device reused up to 5 times in cows and 6 times heifers did not affect pregnancy rate. The 7d-CIDR protocol allowed the reuse of CIDR up to 6 times keeping the same efficiency of CIDR new. In the experiment III the objective was to evaluate whether the application of eCG two days before the device removal increases the size of OF, CL and pregnancy rates. Six hundred and eighty-one suckling cows 40-60 days postpartum and 182 pubertal heifers were used. The animals were divided into two treatments with eCG application in fifth (5d-eCG) or seventh day (7d-eCG) of protocol. In d0, the animals received EB + CIDR and day 7 CIDR was removed and administered PGF2 and ECP. Ten days after AI, US was performed to measure the size of CL and blood collection for P4 analysis. The TAI occurred 55 hours after CIDR removal. The treatment d5 eCG increased (p < 0.01) OF. In cows, the concentration of P4 after AI was higher (p = 0.04) in 5d-eCG. In heifers, the CL diameter was higher in 5d-eCG. However, the 5d-eCG did not increase (p > 0.1) pregnancy rate. The strategy of eCG application in d5 was efficient to increase ovulatory follicle, but did not increase pregnancy rate

O objetivo do experimento I foi avaliar a redução do tempo de permanência do dispositivo de P4 de 9 para 7 dias sob parâmetros reprodutivos de vacas Nelore. Foram utilizadas 674 vacas lactantes entre 40-60 dias pós parto que receberam no início do protocolo (d0) BE + CIDR. No momento da retirada do CIDR foi administrado PGF2 &#945;, ECP e eCG. A IATF ocorreu 55 e 48 horas após a retirada do dispositivo nos tratamentos 7d-CIDR e 9d-CIDR, respectivamente. Dez dias após a IA foi realizada colheita de sangue para dosagem de P4 sérica e confirmação da ovulação. Vacas tratadas com 7d-CIDR apresentaram menor (p < 0,01) folículo ovulatório em relação ao 9d-CIDR. No entanto, a concentração de P4 pós-IA, taxas de ovulação, detecção de estro e prenhez não foram influenciadas pelo tempo de permanência do CIDR. Assim, o uso do CIDR por 7 dias promoveu desempenho reprodutivo semelhante em vacas Nelore comparado ao protocolo com 9 dias. O experimento II teve o objetivo de avaliar os efeitos da reutilização do CIDR por até 35 dias de uso em vacas e 42 dias em novilhas Nelore. Utilizou-se 749 vacas lactantes 40-60 dias pós parto e 92 novilhas púberes. No d0 os animais receberam BE + CIDR novo (CIDR1) ou previamente usado por 7 (CIDR2), 14 (CIDR3), 21 (CIDR4), 28 (CIDR5) e 35 (CIDR6) dias. No momento da retirada do CIDR (d7) foi administrado PGF2 &#945;, ECP, eCG e exame de US para mensuração do maior folículo (FD), além de colheita de sangue para dosagem de P4. A IATF ocorreu 55 horas após a retirada do dispositivo. O diâmetro do FD foi maior (p < 0,01) de acordo com o maior número de usos do CIDR nas vacas, a concentração de P4 reduziu nos CIDRs reutilizados porém se mantiveram acima de 1,5 ng/ml e a taxa de prenhez não foi afetada pela reutilização do dispositivo por até 5 vezes em vacas e o sexto uso em novilhas. O protocolo com 7 dias de permanência permite a reutilização do CIDR por até 6 vezes mantendo a mesma eficiência reprodutiva. No experimento III o objetivo foi avaliar se a aplicação do eCG dois dias antes da retirada do dispositivo aumenta o tamanho do FO, CL e taxa de prenhez. Foram utilizadas 681 vacas lactantes 40-60 dias pós parto e 182 novilhas púberes. Os animais foram distribuídos em dois tratamentos com aplicação de eCG no quinto (5d-eCG) ou sétimo dia (7d-eCG). No d0, os animais receberam BE + CIDR e no dia 7 o CIDR foi retirado e administrado PGF2 &#945; e ECP. Dez dias após a IA foi realizada US para mensuração do CL e colheita de sangue para dosagem de P4. A IATF ocorreu 55 horas após a retirada do dispositivo. O tratamento 5d-eCG aumentou (p < 0,01) o FO nas vacas em relação ao grupo 7deCG e o mesmo ocorreu nas novilhas. Em vacas, a concentração de P4 pós IA foi mais alta (p = 0,04) no 5d-eCG. Em novilhas o diâmetro do CL pós-IA foi maior (p < 0,01) no 5d-eCG. No entanto, a antecipação da aplicação do eCG foi eficiente em aumentar o folículo ovulatório no momento da IATF, mas não aumentou a taxa de prenhez / The aim of the experiment I was to evaluate the reduction of the time of P4 device from 9 (9d-CIDR) to 7 (7d-CIDR) days and its impacts on reproductive parameters of Nellore cows. Six hundred and seventy-four suckling cows 40-60 days postpartum received EB + CIDR at d0 of the protocol. At CIDR removal, there were administered PGF2 &#945;, ECP, eCG. The FTAI occurred 55 and 48 hours after device removal in the treatment 7d-CIDR and 9d-CIDR, respectively. Ten days after AI blood samples were collected for P4 analysis and ovulation rate. Cows of treatment 7d-CIDR showed lower (p <0.01) ovulatory follicle (OF) than 9d-CIDR. The CIDR length in cows and heifers did not influence concentration of P4, ovulation rate, estrus detection rate and pregnancy rate. Thus, the use of CIDR by 7 days did not impacted reproductive result in suckling cows and Nellore heifers. The aim of experiment II was to evaluate the effects of the CIDR reuse up to 35 days in cows and heifers on reproductive characteristics. We used 749 suckling cows 40-60 days postpartum and 92 pubertal heifers. In d0 animals received EB + new CIDR (CIDR1) or previously used by 7 (CIDR2), 14 (CIDR3), 21 (CIDR4), 28 (CIDR5) and 35 (CIDR6) days. At CIDR removal were administered PGF2 &#945;, ECP, eCG and US to measure the largest follicle (LF), and blood collection for P4 analysis. The TAI occurred 55 hours after device removal. The LF diameter was greater (p <0.01) in CIDR reused in cows. P4 concentration was lower in CIDR reused, but was higher than 1.5 ng / mL, and the device reused up to 5 times in cows and 6 times heifers did not affect pregnancy rate. The 7d-CIDR protocol allowed the reuse of CIDR up to 6 times keeping the same efficiency of CIDR new. In the experiment III the objective was to evaluate whether the application of eCG two days before the device removal increases the size of OF, CL and pregnancy rates. Six hundred and eighty-one suckling cows 40-60 days postpartum and 182 pubertal heifers were used. The animals were divided into two treatments with eCG application in fifth (5d-eCG) or seventh day (7d-eCG) of protocol. In d0, the animals received EB + CIDR and day 7 CIDR was removed and administered PGF2 and ECP. Ten days after AI, US was performed to measure the size of CL and blood collection for P4 analysis. The TAI occurred 55 hours after CIDR removal. The treatment d5 eCG increased (p < 0.01) OF. In cows, the concentration of P4 after AI was higher (p = 0.04) in 5d-eCG. In heifers, the CL diameter was higher in 5d-eCG. However, the 5d-eCG did not increase (p > 0.1) pregnancy rate. The strategy of eCG application in d5 was efficient to increase ovulatory follicle, but did not increase pregnancy rate

A homogeneous group of thirty-one crossbred ewes was used to determine the effect of administering a progesterone Controlled Intravaginal Drug Releasing Device (CIDR) on circulating levels of progesterone in the subsequent cycle following CIDR removal. Circulating progesterone levels were determined for each ewe through daily blood collection via jugular venipuncture. Each ewe underwent a pretreatment 25 day sampling period (Period 1), a 12 day treatment period characterized by the presence of the CIDR (Period 2), and another 25 day sampling period following CIDR removal (Period 3). During the initial period of the study, progesterone levels in peripheral circulation changed (P < 0.0001, effect of day) in accordance with stage of the estrous cycle and were elevated during the luteal phase. In the second period of the study, progesterone levels were elevated (P < 0.0001) in ewes due to exogenous progesterone from the CIDR device (Period 1 versus Period 2: 1.3 ± 0.1 ng/ml versus 2.4 ± 0.1 ng/ml, respectively). After withdrawal of the CIDR in the third period of the study, circulating progesterone levels were not (P > 0.10) different from those observed in the initial period of the study (Period 1 versus Period 3: 1.3 ± 0.1 ng/ml versus 1.4 ± 0.1 ng/ml, respectively). Data collected in this study revealed that treatment with exogenous progesterone via CIDR for a 12- day treatment period does not influence circulating levels of progesterone in subsequent estrous cycles.

The objectives of this study were to determine if fixed-timed artificial insemination (FTAI) at two different times, 0 or 24 h after GnRH administration, in a Presynch-Ovsynch protocol influenced the pregnancy rate (PR) when average and high fertility sires were used. Additionally, a second experiment was conducted to determine the effectiveness of CIDR inserts to allow for resynchronization of estrus in cows that did not conceive or maintain the conceptus at FTAI. Lactating Holstein cows (n = 1,457) from two well-managed dairy herds located in the piedmont region of North Carolina were utilized for 12 mo. First artificial insemination (AI) PR differed for fertility group and was 24.1 and 29.2% for average and high fertility group, respectively. Timing of AI did not influence first AI PR and there was no interaction of fertility group and timing of AI. Cows that received a CIDR insert were detected more frequently in estrus during a 4 d period, d 21 to 24, than control cows, 92.5 and 62.0%, respectively. However, the CIDR insert did not increase the detection of estrus compared to control cows over a normal estrus return interval of 7 d, 18 to 24 d after GnRH administration of a FTAI protocol, 28.8 and 34.2% respectively. In conclusion, the use of high fertility sires is a practical recommendation for improving first AI PR and CIDR inserts allowed more cows to be detected in estrus during a shorter interval, but did not increase the estrus detection rate during a normal estrus return interval. / Master of Science

Objectives were to evaluate time of insemination relative to estrus and synchronization with melengestrol acetate (MGA) plus prostaglandin (PG) or progesterone insert (CIDR) plus PG on AI pregnancy rate in beef heifers (n = 662) during Fall or Spring. Fall heifers (n = 349) received MGA-PG (MGA for 14 d followed by PG on d 18) or CIDR-PG (CIDR for 7 d, PG administered 1 d before CIDR removal). Estrus was monitored by HeatWatch® (n = 200) or visually (n = 149). Spring heifers (n = 313) underwent CIDR-PG with detection of estrus by HeatWatch®. Heifers not in estrus by 96-100 h after PG were bred AI as non-responsive AI (NRAI). Across seasons, 548 heifers were bred following estrus (EAI). Heifers synchronized during the Fall with MGA received more (P < 0.05) mounts than Fall CIDR heifers (76.8 ± 6.7 and 47.6 ± 7.4, respectively), but duration of estrus was similar. Fall CIDR heifers had greater (P < 0.05) mounting activity and duration of estrus (47.9 ± 5.2 mounts and 15.5 ± 1.1 h) compared to Spring CIDR heifers (34.5 ± 3.1 mounts and 12.7 ± 0.6 h). Heifers grouped in 4 h blocks from 0 to 24 h had no difference (P > 0.05) in pregnancy rates (mean 62.5 %). Treatment had no effect (P > 0.05) on EAI pregnancy rates. Pregnancy rates across seasons for EAI, NRAI and overall was 61.0 %, 26.3 %, and 54.5%. In conclusion, a 24 h window may exist to successfully AI heifers. / Master of Science

An estrus synchronization trial was conducted to determine the efficacy of adding an injection of gonadotropin releasing hormone (GnRH) at initiation of the controlled intravaginal drug releasing device (CIDR®) progesterone synchronization protocol in heifers. Nulliparous (n=121) beef heifers were randomly assigned to one of two treatment groups. All heifers received a CIDR® implant at the initiation of the breeding season. Half of the heifers (Select Synch) received an injection of GnRH. Heifers in the Select Synch treatment group had a lower numerical response (76.7% versus 88.3%) to treatment (detected in heat) and an overall lower artificial conception rate (46.0% versus 53.3%), but no statistical difference was detected. Days to conception and artificial insemination conception rates for both groups were similar for all heifers inseminated. Three hundred multiparous Hereford, crossbred and composite beef cows were assigned to one of two breeding groups (Early and Late) based on calving date and randomly assigned to receive an injection of GnRH at the time of CIDR® insertion (Select Synch). The addition of GnRH did not impact the percentage of cows detected in estrus or days to conception. Conception rates were not affected by the addition of GnRH (Select Synch), however cows in the early breeding group were more likely to become pregnant (58% versus 45%) by artificial insemination (P<0.02). An experiment evaluated the efficacy of the CIDR® protocol to synchronize estrus in Arizona Holstein dairy cows (n=696). Cows assigned to the CIDR® protocol (n=337) received a CIDR® insert at the end of the voluntary waiting period (55 days). CIDR®s were removed and an injection of prostaglandin was administered seven days after insertion. There was no difference due to CIDR® treatment in number of services per conception or first service conception rate. CIDR® treatment reduced days to first service, days open at first service, and days open (P<0.02). Warm season had a deleterious effect on number of services, days to first service, first service conception rate and days open (P<0.0001). In summary, estrus synchronization improved postpartum reproductive performance; however, thermal stress continues to be a major barrier to reproductive efficiency.

Due to the thesis embargo no abstract is provided.

The objectives of this study were to evaluate the effects of flunixin meglumine (FM), an inhibitor of PGF2a synthesis, administered at the time of embryo transfer (ET) and insertion of an intravaginal progesterone-releasing device (CIDR) at the time of ET on pregnancy rates (PR) and the resynchronization of estrus. Beef cows (n = 796) and heifers (n = 108) at three locations were assigned randomly within age to one of four groups in a 2 x 2 factorial arrangement of treatments with injection of FM (500 mg i.m.; Phoenix Scientific, St. Joseph, MO) 2 to 12 min prior to ET and insertion of a CIDR (1.38 g progesterone; Pfizer, New York, NY) for 13 d immediately following ET as main effects. Fresh or frozen embryos (Stage = 4 or 5; Grade = 1 or 2) were randomly assigned to be transferred to recipients on d 6 to 9 of the estrous cycle. At Location 2 a subset of fresh embryos were split and transferred as fresh half embryos (n = 192). Recipients at Location 2 only (n = 493) were observed for signs of return to estrus beginning 9 d after ET. Recipients that returned to estrus at Location 2 were either bred by AI 12 h after estrus or received an embryo 7 d after estrus. Pregnancy was diagnosed by ultrasonography. Pregnancy rates were analyzed using the LOGISTIC procedure of SAS. Pregnancy rates of split embryo recipients were analyzed separately using the same statistical procedure. Variation in the timing of the return to estrus was determined by an F-test for heterogeneity of variances. Following the initial ET, pregnancy rates of recipients receiving whole embryos were not affected by CIDR administration (P > 0.05; 65% with CIDR, 70% without CIDR), however, there was a significant FM x location interaction on PR (Location 1, 89 vs. 57%; Location 2, 69 vs. 64%; Location 3, 64 vs. 67% for FM vs. no FM, respectively). There was a significant CIDR x FM interaction on PR of recipients receiving split embryos. Pregnancy rates of split embryo recipients receiving CIDR treatment (54%) or FM treatment alone (41%) were less than controls (64%). However, recipients receiving both CIDR and FM had PR similar to controls (60%). The timing of the return to estrus was more synchronous (P < 0.01) for recipients fitted with a CIDR, but PR of recipients bred following a return to estrus did not differ in cows receiving or not receiving a CIDR (P > 0.13; 68 and 62%, respectively). Effects of FM on PR were location dependent and CIDR insertion at ET improved synchrony of the return to estrus. / Master of Science

Made available in DSpace on 2016-01-26T18:55:42Z (GMT). No. of bitstreams: 1 GABRIELA SORIANO.pdf: 327520 bytes, checksum: ad8287a2a1dbd4d04e67e925087f4285 (MD5) Previous issue date: 2015-02-27 / The hypothesis tested in this study was that the time of permanence of progesterone implant (short vs. long) in FTAI protocol change the characteristics of the LH surge. Thus, the aim of this study was to determine the timing, duration and amplitude of the LH peak in sheep (Santa Inês x Texel) using short FTAI protocols (6 days) or long (12 days) in cyclic sheep out of the breeding season. We used 43 sheep (Texel-Te x Santa Inês-SI), sorted into two groups according to the time of progesterone release s vaginal device 1st use (Easy-Breed CIDR®, Pfizer, Brazil). In group 12 days (G-12, n = 19) in stage random of the estrous cycle received the insertion of CIDR (D0). On the day of implant removal (D12) was administered intramuscularly, 0.075 mg cloprostenol (Veteglan®, Hertape Calier, Brazil) and 300 IU equine chorionic gonadotropin (eCG, Novormon®, MSD Animal Health, Brazil). The group 6 (G-6, n= 24) received the same protocol of G-12, however the permanence of CIDR was 6 days. Approximately 50 hours after CIDR removal, both groups were inseminated at fixed time by artificial insemination by laparoscopy with frozen semen containing 200x106 sperm of a single player of Dorper. Approximately 40 days after the artificial insemination pregnancy diagnosis was performed using ultrasound device. Blood samples were taken every 4 hours from 10 animals per group, to measure LH and progesterone plasma concentrations by radioimmunoassay (RIA). From the 20 animals used for progesterone plasma concentration, the percentage of animals showing LH surge in G-6 was 70% (7/10) and the G-12 was 90% (9/10). The maximum amplitude of the LH peak did not differ between the G-6 and G-12 groups (P> 0.05) and the lengh of LH peak was 16,60±2,76 h in the G-6 and 16,40±2,40 h in G-12 (P>0,05). The interval between the implant removal and the LH surge was (P >0.05) in the G-6 27,42±2,76 h and 28,88±5,20 h in G-12. The overall pregnancy rate per group was not different (G-6 58,33% e G-12 52,63%). It was concluded that the permanence of progesterone (6 vs 12 days) did not alter the characteristics of the LH peak in sheep (St. Agnes x Texel) in the tropics, out of the breeding season. / A hipótese testada pelo presente trabalho foi que o tempo de permanência do implante de progesterona (curto vs longo), em protocolo de IATF, altera as características do pico de LH. Desta forma, o objetivo do presente estudo foi determinar o momento, duração e amplitude do pico de LH em ovelhas (Texel x Santa Inês) utilizando protocolos de IATF de curta (6 dias) ou longa duração (12 dias) em ovelhas ciclando na contra estação reprodutiva. Foram utilizadas 43 ovelhas (Texel-Te x Santa Inês-SI), divididas em dois grupos de acordo com o tempo de permanência do dispositivo vaginal de liberação de progesterona de 1° uso (Easy-Breed CIDR®, Pfizer, Brasil). No grupo 12 dias (G-12, n=19), em estádio aleatório do ciclo estral receberam a inserção do CIDR (D0). No dia da retirada do implante (D12) foram administrados, por via intramuscular, 0,075 mg de cloprostenol (Veteglan®, Hertape Calier, Brasil) e 300 UI de gonadotrofina coriônica equina (eCG, Novormon®, MSD Saúde Animal, Brasil). O grupo 6 (G-6, n=24) recebeu o mesmo protocolo do G-12, porém a permanência do CIDR foi de 6 dias. Aproximadamente 50 horas após a retirada do CIDR as ovelhas, de ambos os grupos, foram inseminadas em tempo fixo por laparoscopia com sêmen congelado contendo 200x106 espermatozóides, de um único reprodutor, da raça Dorper. Aproximadamente 40 dias após as inseminações artificiais foi realizado o diagnóstico de prenhez utilizando aparelho de ultra-som. Foram realizadas colheitas de sangue, de 4 em 4 horas em 10 animais por grupo, para mensuração das concentrações plasmáticas de LH e progesterona por radioimunoensaio (RIA). Dos 20 animais utilizados para mensuração das concentrações plasmáticas, a porcentagem de animais que apresentaram pico de LH no G-6 foi de 70% (7/10) e no G-12 foi 90% (9/10). A amplitude máxima do pico de LH não diferiu entre os grupos G-6 e G-12 (P>0,05) e a duração do pico de LH foi 16,60±2,76 h no grupo G-6 e 16,40±2,40 h no grupo G-12 (P>0,05). O intervalo entre a retirada do implante e o pico de LH foi (P>0,05) ocorreu 27,42±2,76 h no grupo G-6 e 28,88±5,20 h no G-12. A percentagem de prenhez total por grupo não diferiu (G-6 58,33% e G-12 52,63%). Conclui-se que o tempo de permanência da progesterona (6 vs 12 dias) não alterou as características do pico de LH em ovelhas (Texel x Santa Inês) nos trópicos, na contra estação reprodutiva.

Made available in DSpace on 2016-07-18T17:53:14Z (GMT). No. of bitstreams: 1 GABRIELA SORIANO.pdf: 327520 bytes, checksum: ad8287a2a1dbd4d04e67e925087f4285 (MD5) Previous issue date: 2015-02-27 / The hypothesis tested in this study was that the time of permanence of progesterone implant (short vs. long) in FTAI protocol change the characteristics of the LH surge. Thus, the aim of this study was to determine the timing, duration and amplitude of the LH peak in sheep (Santa Inês x Texel) using short FTAI protocols (6 days) or long (12 days) in cyclic sheep out of the breeding season. We used 43 sheep (Texel-Te x Santa Inês-SI), sorted into two groups according to the time of progesterone release s vaginal device 1st use (Easy-Breed CIDR®, Pfizer, Brazil). In group 12 days (G-12, n = 19) in stage random of the estrous cycle received the insertion of CIDR (D0). On the day of implant removal (D12) was administered intramuscularly, 0.075 mg cloprostenol (Veteglan®, Hertape Calier, Brazil) and 300 IU equine chorionic gonadotropin (eCG, Novormon®, MSD Animal Health, Brazil). The group 6 (G-6, n= 24) received the same protocol of G-12, however the permanence of CIDR was 6 days. Approximately 50 hours after CIDR removal, both groups were inseminated at fixed time by artificial insemination by laparoscopy with frozen semen containing 200x106 sperm of a single player of Dorper. Approximately 40 days after the artificial insemination pregnancy diagnosis was performed using ultrasound device. Blood samples were taken every 4 hours from 10 animals per group, to measure LH and progesterone plasma concentrations by radioimmunoassay (RIA). From the 20 animals used for progesterone plasma concentration, the percentage of animals showing LH surge in G-6 was 70% (7/10) and the G-12 was 90% (9/10). The maximum amplitude of the LH peak did not differ between the G-6 and G-12 groups (P> 0.05) and the lengh of LH peak was 16,60±2,76 h in the G-6 and 16,40±2,40 h in G-12 (P>0,05). The interval between the implant removal and the LH surge was (P >0.05) in the G-6 27,42±2,76 h and 28,88±5,20 h in G-12. The overall pregnancy rate per group was not different (G-6 58,33% e G-12 52,63%). It was concluded that the permanence of progesterone (6 vs 12 days) did not alter the characteristics of the LH peak in sheep (St. Agnes x Texel) in the tropics, out of the breeding season. / A hipótese testada pelo presente trabalho foi que o tempo de permanência do implante de progesterona (curto vs longo), em protocolo de IATF, altera as características do pico de LH. Desta forma, o objetivo do presente estudo foi determinar o momento, duração e amplitude do pico de LH em ovelhas (Texel x Santa Inês) utilizando protocolos de IATF de curta (6 dias) ou longa duração (12 dias) em ovelhas ciclando na contra estação reprodutiva. Foram utilizadas 43 ovelhas (Texel-Te x Santa Inês-SI), divididas em dois grupos de acordo com o tempo de permanência do dispositivo vaginal de liberação de progesterona de 1° uso (Easy-Breed CIDR®, Pfizer, Brasil). No grupo 12 dias (G-12, n=19), em estádio aleatório do ciclo estral receberam a inserção do CIDR (D0). No dia da retirada do implante (D12) foram administrados, por via intramuscular, 0,075 mg de cloprostenol (Veteglan®, Hertape Calier, Brasil) e 300 UI de gonadotrofina coriônica equina (eCG, Novormon®, MSD Saúde Animal, Brasil). O grupo 6 (G-6, n=24) recebeu o mesmo protocolo do G-12, porém a permanência do CIDR foi de 6 dias. Aproximadamente 50 horas após a retirada do CIDR as ovelhas, de ambos os grupos, foram inseminadas em tempo fixo por laparoscopia com sêmen congelado contendo 200x106 espermatozóides, de um único reprodutor, da raça Dorper. Aproximadamente 40 dias após as inseminações artificiais foi realizado o diagnóstico de prenhez utilizando aparelho de ultra-som. Foram realizadas colheitas de sangue, de 4 em 4 horas em 10 animais por grupo, para mensuração das concentrações plasmáticas de LH e progesterona por radioimunoensaio (RIA). Dos 20 animais utilizados para mensuração das concentrações plasmáticas, a porcentagem de animais que apresentaram pico de LH no G-6 foi de 70% (7/10) e no G-12 foi 90% (9/10). A amplitude máxima do pico de LH não diferiu entre os grupos G-6 e G-12 (P>0,05) e a duração do pico de LH foi 16,60±2,76 h no grupo G-6 e 16,40±2,40 h no grupo G-12 (P>0,05). O intervalo entre a retirada do implante e o pico de LH foi (P>0,05) ocorreu 27,42±2,76 h no grupo G-6 e 28,88±5,20 h no G-12. A percentagem de prenhez total por grupo não diferiu (G-6 58,33% e G-12 52,63%). Conclui-se que o tempo de permanência da progesterona (6 vs 12 dias) não alterou as características do pico de LH em ovelhas (Texel x Santa Inês) nos trópicos, na contra estação reprodutiva.