The objectives of this study were to determine whether conception, ovulation rates, presynchronization rates, or follicle and CL characteristics were altered after modifying the Double-Ovsynch (DO) protocol to include human chorionic gonadotropin (hCG) compared to the conventional DO protocol in dairy heifers and lactating dairy cows. We hypothesized that replacing the first injection of gonadotropin releasing hormone (GnRH) in the DO protocol with hCG would increase the proportion of females that ovulate, thus improving the presynchronization rate leading to increased conception rates. Ovulation rates were increased in cows administered hCG compared to GnRH, but subsequent synchronization, and conception rates did not differ between treatments. A greater proportion of hCG-treated cows tended to fail to have undergone luteolysis compared to those treated with GnRH. In conclusion, no improvement in overall fertility was achieved by replacing the first injection of GnRH in the DO protocol with hCG.

O presente estudo objetivou promover incremento no desenvolvimento do concepto e aumentar a taxa de prenhez de búfalas lactantes por meio da administração de P4 injetável (P4i) três ou seis dias após a IATF. Para tanto, foram conduzidos três experimentos. No Experimento 1, foi aferido o padrão de liberação de P4 por meio da administração de P4i em 8 búfalas ovariectomizadas (delineamento crossover) nas doses 300 ou 600 mg (grupo P300 ou P600, respectivamente). Foram realizadas colheitas de sangue, para posteriores dosagens de P4, nos seguintes períodos: -24, 0, 6, 12, 24, 48, 72, 96, 120, 144, 168, 192, 216 e 240 h da administração da P4i. No Experimento 2, 24 búfalas receberam a aplicação de 10 µg im de GnRH em dia aleatório do ciclo estral (D0). No D7, os animais receberam 0,53 mg im de PGF2α. Após 48 h (D9), foram administrados 10 µg im de GnRH e, 16 h mais tarde, todas as búfalas foram submetidas à IATF (D10). No D13, os animais foram avaliados por ultrassonografia e as fêmeas com ovulação positiva foram distribuídas em 3 grupos: Controle (C; n=8); P4D13 (n=8), que receberam 300mg de P4i no D13 e P4D16 (n=8), que receberam 300 mg de P4i no D16. No D26, as búfalas foram abatidas e os genitais removidos para a realização das seguintes avaliações: diâmetro (DCLa) e peso (PCL) do CL, presença de conceptos íntegros (pCI), íntegros e fragmentados (pCT) e comprimento do concepto (CC). Os CLs e endométrios foram seccionados, fixados e corados para aferir o percentual de células luteínicas pequenas e grandes (SLC e LLC) e o número (GEn), a área (AGEn) e o perímetro (PGEn) das glândulas do endométrio. No Experimento 3, 337 búfalas foram submetidas ao protocolo Ovsynch e, assim como no Experimento 2, as fêmeas ovuladas foram distribuídas em 3 grupos (C, n=81; P4D13, n=84 e P4D16, n=85). Foram avaliadas a funcionalidade (fluxo sanguíneo central FSC; e periférico FSP; escore de 0 a 4, em que 0 corresponde à ausência de fluxo e 4 o máximo fluxo) e o diâmetro do CL (DCL) nos D17, D21 e D25 por meio de ultrassonografia em modo color Doppler. Além disso, foram avaliadas por ultrassonografia as taxas de concepção aos 30 (DG30) e 60 (DG60) dias após a IATF e as perdas gestacionais (PG). Os dados foram analisados utilizando o procedimento GLIMMIX do SAS 9.3. Diferenças com P≤0,05 foram consideradas significativas e aquelas com 0,05<P≤0,10 foram consideradas tendência. As concentrações de P4 foram maiores no P600 em relação ao P300 em todos os pontos das colheitas de sangue (Ptrat<0,01, Ptempo=0,04, Ptrat*tempo=0,18). Verificou-se que as concentrações de P4 permaneceram acima de 1 ng/mL por aproximadamente 3 dias (entre as horas 6 e 72) no grupo P300, o que foi utilizado como critério para a dose de P4i utilizada nos Experimentos 2 e 3. Não houve diferenças entre os grupos para as variáveis avaliadas no Experimento 2: DCLa (P=0,39), PCL (P=0,13), pCI (P=0,85), pCT (P=0,41), CC (P=0,19), SLC (P=0,31), LLC (P=0,31), GEn (P=0,28), AGEn (P=0,72) e PGEn (P=0,91). No Experimento 3, houve interação tratamento*tempo (Ptrat*tempo) para as variáveis FSC (P<0,01), FSP (P<0,01) e DCL (P=0,07). Verificou-se redução do fluxo sanguíneo central e periférico e do diâmetro do CL no P4D13 em relação aos grupos C e P4D16 conforme os momentos de avaliação. Não houve diferença entre os grupos C, P4D13 e P4D16 para o DG30 (56,8 vs. 46,4 vs. 61,2 %; P=0,13) e para a PG (0,0 vs. 10,3 vs. 5,8 %; P=0,73). No entanto, houve menor taxa de concepção no DG60 para o P4D13 em comparação aos C e P4D16 (41,7b vs. 56,8a vs. 57,7a %; P=0,07). Conclui-se que o tratamento com 300 mg de P4i administrados três ou seis dias após a IATF não foi eficiente para aumentar o comprimento do concepto e a taxa de prenhez de búfalas lactantes submetidas à IATF. Ainda, o tratamento com P4i três dias após a IATF reduziu o fluxo sanguíneo central e periférico do CL, o diâmetro do CL e a taxa de prenhez. / The present study aimed to promote improvements on the conceptus development and to increase the pregnancy rate in lactating buffaloes through the administration of injectable P4 (P4i) three or six days after TAI. For this, three experiments were performed. In Experiment 1, was measured the pattern of P4 release by the P4i administration in 8 ovariectomized buffaloes (crossover design) at doses 300 or 600 mg (P300 or P600 group, respectively). Blood samples were collected for subsequent P4 dosages in the following periods: -24, 0, 6, 12, 24, 48, 72, 96, 120, 144, 168, 192, 216 and 240 h of P4i administration. In Experiment 2, 24 buffaloes received the application of 10 µg im GnRH at random day of the estrous cycle (D0). On D7, the animals received 0.53 mg im PGF2α. After 48 h (D9), were administered 10 µg im GnRH and, 16 h later, all buffaloes underwent TAI (D10). In D13, the animals were evaluated by ultrasonography and females with positive ovulation were allocated to one of three groups: Control (C, n=8); P4D13 (n=8) that received 300 mg P4i on D13 and P4D16 (n=8), that received 300 mg P4i on D16. On D26, buffaloes were slaughtered and genitals removed to perform the following assessments: CL diameter (CLDs) and CL weight (CLW), presence of integrate conceptus (pIC), integrate and fragmented (pCT) and the conceptus length (CLe). The CLs and endometrium were sectioned, fixed and stained to assess the percentage of small and large lutein cells (SLC and LLC) and the number (GEn), the area (AGEn) and the perimeter (PGEn) of endometrial glands. In Experiment 3, 337 buffaloes were submitted to the Ovsynch protocol and, as well as in Experiment 2, the ovulated females were divided to one of three groups (C, n=81; P4D13, n=84 and P4D16, n=85). The functionality (central blood flow - CBF, and peripheral blood flow - PBF; score from 0 to 4, where 0 corresponds to absence of flow and 4 the maximum flow) and the CL diameter (CLD) were evaluated on D17, D21 and D25 by ultrasonography in color Doppler mode. Furthermore, the conception rates at 30 (CR30) and 60 (CR60) days after TAI, and pregnancy loss (PL) were evaluated by ultrasonography. Data were analyzed using the GLIMMIX procedure of SAS 9.3. Differences were considered significant with P≤0.05 and those with 0.05<P≤0.10 were considered tendencies. The P4 concentrations were higher in the P600 compared to P300 in all points of blood sampling (Ptreat<0.01, Ptime=0.04, Ptreat*time=0.18). It was found that the P4 concentrations remained above 1.0 ng/ml for approximately 3 days (between hours 6 and 72) in the P300 group, which was used as standard for P4i dose used in Experiments 2 and 3. There were no differences between the groups for the variables evaluated in Experiment 2: CLDs (P=0.39), CLW (P=0.13), pCI (P=0.85), pCT (P=0.41), CoLe (P=0.19), SLC (P=0.31), LLC (P=0.31), GEn (P=0.28), AGEn (P=0.72) and PGEn (P=0.91). In Experiment 3, there was interaction treatment*time (Ptreat*time) for the CBF (P<0.01), PBF (P<0.01) and CLD (P=0.07). There was a reduction of the central blood flow, peripheral blood flow and CL diameter for P4D13 compared to C and P4D16 groups according to the evaluation moments. There was no difference between C, P4D13 and P4D16 groups for the CR30 (56.8 vs. 46.4 vs. 61.2 %; P=0.13) and for the PL (0.0 vs. 10.3 vs. 5.8 %; P=0.73). However, there was lower conception rate in CR60 for P4D13 compared to C and P4D16 (41.7b vs. 56.8a vs. 57.7a %; P=0.07). It was concluded that treatment with 300 mg P4i administered three or six days after TAI was not efficient to increase the conceptus length and the pregnancy rate in lactating buffaloes submitted to TAI. Furthermore, the treatment with P4i three days after TAI reduced the central and the peripheral CL blood flow, the CL diameter and the pregnancy rate.

O presente estudo objetivou promover incremento no desenvolvimento do concepto e aumentar a taxa de prenhez de búfalas lactantes por meio da administração de P4 injetável (P4i) três ou seis dias após a IATF. Para tanto, foram conduzidos três experimentos. No Experimento 1, foi aferido o padrão de liberação de P4 por meio da administração de P4i em 8 búfalas ovariectomizadas (delineamento crossover) nas doses 300 ou 600 mg (grupo P300 ou P600, respectivamente). Foram realizadas colheitas de sangue, para posteriores dosagens de P4, nos seguintes períodos: -24, 0, 6, 12, 24, 48, 72, 96, 120, 144, 168, 192, 216 e 240 h da administração da P4i. No Experimento 2, 24 búfalas receberam a aplicação de 10 µg im de GnRH em dia aleatório do ciclo estral (D0). No D7, os animais receberam 0,53 mg im de PGF2α. Após 48 h (D9), foram administrados 10 µg im de GnRH e, 16 h mais tarde, todas as búfalas foram submetidas à IATF (D10). No D13, os animais foram avaliados por ultrassonografia e as fêmeas com ovulação positiva foram distribuídas em 3 grupos: Controle (C; n=8); P4D13 (n=8), que receberam 300mg de P4i no D13 e P4D16 (n=8), que receberam 300 mg de P4i no D16. No D26, as búfalas foram abatidas e os genitais removidos para a realização das seguintes avaliações: diâmetro (DCLa) e peso (PCL) do CL, presença de conceptos íntegros (pCI), íntegros e fragmentados (pCT) e comprimento do concepto (CC). Os CLs e endométrios foram seccionados, fixados e corados para aferir o percentual de células luteínicas pequenas e grandes (SLC e LLC) e o número (GEn), a área (AGEn) e o perímetro (PGEn) das glândulas do endométrio. No Experimento 3, 337 búfalas foram submetidas ao protocolo Ovsynch e, assim como no Experimento 2, as fêmeas ovuladas foram distribuídas em 3 grupos (C, n=81; P4D13, n=84 e P4D16, n=85). Foram avaliadas a funcionalidade (fluxo sanguíneo central FSC; e periférico FSP; escore de 0 a 4, em que 0 corresponde à ausência de fluxo e 4 o máximo fluxo) e o diâmetro do CL (DCL) nos D17, D21 e D25 por meio de ultrassonografia em modo color Doppler. Além disso, foram avaliadas por ultrassonografia as taxas de concepção aos 30 (DG30) e 60 (DG60) dias após a IATF e as perdas gestacionais (PG). Os dados foram analisados utilizando o procedimento GLIMMIX do SAS 9.3. Diferenças com P≤0,05 foram consideradas significativas e aquelas com 0,05<P≤0,10 foram consideradas tendência. As concentrações de P4 foram maiores no P600 em relação ao P300 em todos os pontos das colheitas de sangue (Ptrat<0,01, Ptempo=0,04, Ptrat*tempo=0,18). Verificou-se que as concentrações de P4 permaneceram acima de 1 ng/mL por aproximadamente 3 dias (entre as horas 6 e 72) no grupo P300, o que foi utilizado como critério para a dose de P4i utilizada nos Experimentos 2 e 3. Não houve diferenças entre os grupos para as variáveis avaliadas no Experimento 2: DCLa (P=0,39), PCL (P=0,13), pCI (P=0,85), pCT (P=0,41), CC (P=0,19), SLC (P=0,31), LLC (P=0,31), GEn (P=0,28), AGEn (P=0,72) e PGEn (P=0,91). No Experimento 3, houve interação tratamento*tempo (Ptrat*tempo) para as variáveis FSC (P<0,01), FSP (P<0,01) e DCL (P=0,07). Verificou-se redução do fluxo sanguíneo central e periférico e do diâmetro do CL no P4D13 em relação aos grupos C e P4D16 conforme os momentos de avaliação. Não houve diferença entre os grupos C, P4D13 e P4D16 para o DG30 (56,8 vs. 46,4 vs. 61,2 %; P=0,13) e para a PG (0,0 vs. 10,3 vs. 5,8 %; P=0,73). No entanto, houve menor taxa de concepção no DG60 para o P4D13 em comparação aos C e P4D16 (41,7b vs. 56,8a vs. 57,7a %; P=0,07). Conclui-se que o tratamento com 300 mg de P4i administrados três ou seis dias após a IATF não foi eficiente para aumentar o comprimento do concepto e a taxa de prenhez de búfalas lactantes submetidas à IATF. Ainda, o tratamento com P4i três dias após a IATF reduziu o fluxo sanguíneo central e periférico do CL, o diâmetro do CL e a taxa de prenhez. / The present study aimed to promote improvements on the conceptus development and to increase the pregnancy rate in lactating buffaloes through the administration of injectable P4 (P4i) three or six days after TAI. For this, three experiments were performed. In Experiment 1, was measured the pattern of P4 release by the P4i administration in 8 ovariectomized buffaloes (crossover design) at doses 300 or 600 mg (P300 or P600 group, respectively). Blood samples were collected for subsequent P4 dosages in the following periods: -24, 0, 6, 12, 24, 48, 72, 96, 120, 144, 168, 192, 216 and 240 h of P4i administration. In Experiment 2, 24 buffaloes received the application of 10 µg im GnRH at random day of the estrous cycle (D0). On D7, the animals received 0.53 mg im PGF2α. After 48 h (D9), were administered 10 µg im GnRH and, 16 h later, all buffaloes underwent TAI (D10). In D13, the animals were evaluated by ultrasonography and females with positive ovulation were allocated to one of three groups: Control (C, n=8); P4D13 (n=8) that received 300 mg P4i on D13 and P4D16 (n=8), that received 300 mg P4i on D16. On D26, buffaloes were slaughtered and genitals removed to perform the following assessments: CL diameter (CLDs) and CL weight (CLW), presence of integrate conceptus (pIC), integrate and fragmented (pCT) and the conceptus length (CLe). The CLs and endometrium were sectioned, fixed and stained to assess the percentage of small and large lutein cells (SLC and LLC) and the number (GEn), the area (AGEn) and the perimeter (PGEn) of endometrial glands. In Experiment 3, 337 buffaloes were submitted to the Ovsynch protocol and, as well as in Experiment 2, the ovulated females were divided to one of three groups (C, n=81; P4D13, n=84 and P4D16, n=85). The functionality (central blood flow - CBF, and peripheral blood flow - PBF; score from 0 to 4, where 0 corresponds to absence of flow and 4 the maximum flow) and the CL diameter (CLD) were evaluated on D17, D21 and D25 by ultrasonography in color Doppler mode. Furthermore, the conception rates at 30 (CR30) and 60 (CR60) days after TAI, and pregnancy loss (PL) were evaluated by ultrasonography. Data were analyzed using the GLIMMIX procedure of SAS 9.3. Differences were considered significant with P≤0.05 and those with 0.05<P≤0.10 were considered tendencies. The P4 concentrations were higher in the P600 compared to P300 in all points of blood sampling (Ptreat<0.01, Ptime=0.04, Ptreat*time=0.18). It was found that the P4 concentrations remained above 1.0 ng/ml for approximately 3 days (between hours 6 and 72) in the P300 group, which was used as standard for P4i dose used in Experiments 2 and 3. There were no differences between the groups for the variables evaluated in Experiment 2: CLDs (P=0.39), CLW (P=0.13), pCI (P=0.85), pCT (P=0.41), CoLe (P=0.19), SLC (P=0.31), LLC (P=0.31), GEn (P=0.28), AGEn (P=0.72) and PGEn (P=0.91). In Experiment 3, there was interaction treatment*time (Ptreat*time) for the CBF (P<0.01), PBF (P<0.01) and CLD (P=0.07). There was a reduction of the central blood flow, peripheral blood flow and CL diameter for P4D13 compared to C and P4D16 groups according to the evaluation moments. There was no difference between C, P4D13 and P4D16 groups for the CR30 (56.8 vs. 46.4 vs. 61.2 %; P=0.13) and for the PL (0.0 vs. 10.3 vs. 5.8 %; P=0.73). However, there was lower conception rate in CR60 for P4D13 compared to C and P4D16 (41.7b vs. 56.8a vs. 57.7a %; P=0.07). It was concluded that treatment with 300 mg P4i administered three or six days after TAI was not efficient to increase the conceptus length and the pregnancy rate in lactating buffaloes submitted to TAI. Furthermore, the treatment with P4i three days after TAI reduced the central and the peripheral CL blood flow, the CL diameter and the pregnancy rate.

Master of Science / Department of Animal Sciences and Industry / Jeffrey S. Stevenson / The objectives were to evaluate the effects of equine chorionic gonadotropin (eCG) administration on preovulatory follicle diameter, serum estradiol and progesterone concentration, corpus luteum (CL) diameter, estrual activity, and pregnancy rate. Lactating dairy cows were submitted to a Presynch-Ovsynch timed artificial insemination (TAI) protocol. Cows (n = 121) in a single herd were treated with 2 injections of prostaglandin F2α (PGF) 14 d apart (Presynch), with the second injection administered 11 d before the onset of a timed AI protocol (Ovsynch; injection of GnRH 7 d before and 56 h after PGF2α, with TAI administered 16 to 18 h after the second GnRH injection). Cows were assigned randomly to receive either saline or 400 IU eCG concurrent with the PGF2α injection of the Ovsynch protocol (d 0). Blood samples were collected during the study to monitor serum changes in progesterone and estradiol to determine if eCG would facilitate increased estrual activity, improved ovulatory response to GnRH, and enhanced post-ovulatory luteal function. Administration of eCG tended to increase the number of CL and on d 9 and 16 after PGF2α, corresponding to d 6 and 13 post-ovulation. Volume of the post-eCG treatment luteal tissue was increased only on d 16. Timed AI pregnancy rates did not differ between eCG (36.9%) and control cows (41.8%). We concluded that use of eCG provided no profertility advantages to dairy cattle when programmed for a timed insemination at first service.

Master of Science / Department of Animal Sciences and Industry / Jeffrey S. Stevenson / Lactating dairy cows from 2 Kansas farms were used to determine the effectiveness of exogenous progesterone in the form of an intravaginal insert (controlled internal drug release; CIDR) in conjunction with an ovulation-synchronization protocol. Cows were enrolled in a Presynch + Ovsynch protocol after parturition, where they received 2 injections of PGF[subscript]2[alpha], 14 d apart (Presynch) beginning between 30 and 36 DIM. Cows (n = 155) detected in estrus after the second PGF[subscript]2[alpha] injection of Presynch were inseminated (early AI). Remaining cows were assigned randomly to be treated with the Cosynch-72 protocol (GnRH 12 d after last Presynch PGF[subscript]2[alpha] injection, PGF[subscript]2[alpha] 7 d after GnRH, and timed AI + GnRH injection 72 h later) and served as controls (n = 159), or to be treated with the Cosynch-72 protocol and receive a progesterone insert (Ovsynch + CIDR; n = 175) for 7 d between GnRH and PGF[subscript]2[alpha]. Blood was collected at d −22 and −10 (relative to TAI at d 0) to determine cycling status based on progesterone concentrations and again at d 11 post AI to determine luteal competency. Treated cows were assigned body condition scores (BCS) on d −22 and −10. Pregnancy status was confirmed by palpation of the uterus per rectum and its contents on d 38 post-timed AI and verified again 4 wk later. Treatment with the progesterone insert increased timed AI pregnancies per AI in Cosynch- 72 + CIDR-treated cows when compared with controls (38 vs. 24%), but did not differ from early AI cows (38%). Pregnancy loss was numerically less in progesterone-treated cows than in controls (4.4 vs. 11.8%). Our study shows that increased pregnancies per AI can be achieved by the use of a progesterone insert in a reduced population of cows not yet inseminated, but treated with a progesterone insert.

Orientador: Tereza Cristina Cardoso Silva / Coorientador: Alicio Martins Junior / Banca: Guilherme de Paula Nogueira / Banca: Claudia Maria Bertan Membrive / Resumo: O objetivo do presente trabalho foi verificar os efeitos da administração de meia dose de GnRH na submucosa da vulva sobre os níveis de LH, progesterona, dinâmica folicular ovariana e taxa de concepção em rebanho leiteiro, utilizando o protocolo ―Ovsynch‖, modificado. As vacas (n = 13) e novilhas (n = 11) foram pré-sincronizadas com duas injeções de PGF2α, com intervalo de 14 dias e 12 dias. Após a última prostaglandina, foi iniciado o protocolo ―Ovsynch‖, modificado pela inclusão de duas injeções de PGF2α. No momento da aplicação da segunda dose de GnRH (GnRH-2) os animais foram distribuídos de maneira homogênea para os grupos: controle (CN; n = 8), animais recebendo 2,5 mL de cloreto de sódio 0,9% por via im, intramuscular (IM; n = 8), injetado 10,5 µg de GnRH por via intramuscular e submucosa da vulva (SV; n = 8), recebendo 5,25 µg de GnRH. As amostras de sangue foram colhidas no D0, D7, D9 e D17 para determinação da concentração sérica de progesterona, e para o LH, foram colhidas em cinco momentos no D9 (M-40, M0, M40, M80 e M120 min). Quanto ao LH, não houve diferença significativa entre os grupos IM e SV em todos os momentos, os quais foram significativamente maiores do que o CN, enquanto no SV, maiores valores de média foram obtidos para a área sob a curva de LH (ASC-LH) em comparação com os grupos IM e CN. Não houve diferença significativa entre os grupos quanto à concentração de progesterona, independente do dia avaliado. Todos os grupos apresentaram o mesmo número d... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to verify the effects of low dose of GnRH administered in the vulva submucosa on LH and progesterone levels, ovarian dynamics and conception rate in dairy cattle using a modified Ovsynch protocol. Cows (n = 13) and heifers (n = 11) were pre-synchronized with two injections of PGF2α administered with a 14-days interval. Twelve days after the last prostaglandin dose a modified Ovsynch protocol was initiated and at the time of the second dose of GnRH (GnRH-2) the animals were homogeneously distributed to groups: control (CN; n = 8), receiving 2.5 mL of 0.9% sodium chloride, im, intramuscular (IM; n = 8,) receiving 10.5 μg of GnRH intramuscular; and vulva submucosa (VS; n = 8) with administration of 5.25 μg of GnRH. Blood samples were collected to determine serum progesterone concentration on D0, D7, D9 and D17, and the level of LH at five moments on D9 (M-40, M0, M40, M80 and M120 min). Higher levels of LH were observed in IM and VS groups in comparison with CN, however no significant difference was found between IM and VS for any time of evaluation. The higher mean value for the area under LH curve (AUC-LH) was found in VS than for IM and CN. There was no difference among groups for progesterone levels measured on in the different days of the protocol. The number of ovulated animals was similar among groups, but the time elapsed to ovulation was lower in IM and VS than in control group. The conception rate was higher in IM group, followed by CN and the... (Complete abstract click electronic access below) / Mestre

Doctor of Philosophy / Department of Animal Sciences and Industry / Jeffrey S. Stevenson / Two experiments assessed pregnancy outcomes (pregnancy per AI; P/AI) after 5-d Ovsynch-56 Resynch (RES; GnRH injection 5 d before [GnRH-1; d 0] and 56 h (GnRH-2) after the last PGF2α [PGF] injection on d 6 given 24 h after first PGF injection on d 5, and TAI on d 8) with and without a 5-d progesterone insert. In Exp. 1, only 76% of 1,023 nonpregnant cows enrolled on d 34 post-AI had high (≥1 ng/mL) progesterone. The RES-CIDR cows with low progesterone at treatment initiation had greater P/AI than RES-CON (37.7 vs. 29.4%), whereas RES-CIDR cows with high progesterone had lesser P/AI than RES-CON (27.4 vs. 34.3%) suggesting that supplemental progesterone is progesterone-dependent. In Exp. 2, 381 cows were enrolled in similar treatments on d 31 with RES on d 41post-AI plus a third treatment including PG-3-G (Pre-PGF on d 31, Pre-GnRH on d 34, and RES on d 41. The P/AI was similar among treatments but was greater in cows starting RES on d 41 when progesterone was low (44%) than high (33%).Experiment 3 determined LH and ovulatory responses in cows enrolled in two treatments before AI: 1) Pre10 (n = 37): PGF-1 and PGF-2 given 14 d apart (Presynch); or PG3G (n = 33): PGF given concurrent with the PGF-2, 3 d before GnRH-1 followed in 7 d by Ovsynch [injection of GnRH (GnRH-2) 7 d before PGF (PGF-3) and GnRH-3 at either 56 or 72 h after PGF-3] that was initiated 10 d after PGF-2 for Pre10 or 7 d after GnRH-1 of PG3G. The GnRH- 1 increased incidences of LH surges and ovulation in PG3G compared with Pre10. The LH in serum of Pre10 was greater than that of cows receiving PG3G after GnRH-2. Following GnRH- 3, cows receiving GnRH at 72 h had increased incidence of spontaneous LH surges before GnRH-3. The P/AI for PG3G vs. Pre10 and for 56 vs. 72 h was similar, but the Pre10-72 h treatment combination was less than all other treatment combinations. Release of LH is protocol dependent and flexibility of GnRH timing is an advantage for PG3G before first-service TAI.

Submitted by (lucia.rodrigues@ufrpe.br) on 2017-02-07T16:28:31Z No. of bitstreams: 1 Antonio Matos Fraga Junior.pdf: 1236085 bytes, checksum: 13e7f8734f0795648537ab792eac5d87 (MD5) / Made available in DSpace on 2017-02-07T16:28:31Z (GMT). No. of bitstreams: 1 Antonio Matos Fraga Junior.pdf: 1236085 bytes, checksum: 13e7f8734f0795648537ab792eac5d87 (MD5) Previous issue date: 2011-02-08 / This study aimed to assess the follicular dynamics of Guzerat cows treated with three protocols for synchronization of ovulation where they used vaginal implant impregnated with progesterone or the Ovsynch protocol, besides the use of estradiol benzoate or GnRH to induce ovulation.There were used 18 PO Guzerat cows, multiparous non-lactating, aging between four and seven years, good body score condition, ranging from 3.0 to 4.0, The animals were kept in extensive management, where the diet provided met the nutritional requirements including protein mineral salt and water "ad libitum". The animals were divided into three groups, in group 1 (n = 6) it was applied at the D0, an intravaginal device CIDR® along with 2 mg of estradiol benzoate, at D8 it was administered 300 mg of a prostaglandin analogue and 300 IU of eCG besides intravaginal device removal, at D9 it was administered 1 mg of estradiol benzoate and at D11 artificial insemination was carried out. In group 2 (n = 6) it was used the same protocols as in group 1 except for the induction of ovulation when it was used 17 mg of a GnRH analogue and at D11 artificial insemination was carried. In group 3 (n = 6) was applied at D0, 200 mg of GnRH analogue, 0.530 mg of prostaglandin analogue at D7, at D9 it was administered 100 mg of GnRH analogue and at D10 artificial insemination was carried. From D0 to D8 animals were examined daily (24/24 h) by transrectal ultrasound .After removal of the implant on D8 in groups 1 and 2 and application of prostaglandin D7 (group 3) animals were assessed four times a day (6/6 hours) until D10 of the Protocol. A new follicular wave emergence for groups 1, 2 and 3 was observed respectively, 2.6 ± 0.16; 2.7 ± 0.18 and 2.9 ± 0.16 days, with no statistical difference (P < 0.05) between groups .There was statistical difference for groups 1, 2 and 3 in the range of wave emergence and ovulation in days, 7.1  0.18; 6.37 0.31; 5.33 0.66, the interval between implant removal and ovulation in hours, 64.2 6.99, 61.0 12.36, interval between the application of inducing ovulation and in hours, 43.6 6.89, 41.0 11.25, 38.2 7.89, greatest diameter of the DF (day 8), 10.71 0.30, 9.41 0.24, 9.75 0.35, greatest diameter of the DF (day 10), 13.1 0.23, 11.7 0.22, 12.0 0.34, Average follicle growth until day 8 - (mm / day), 1.36 0.07, 0.92 0.10, 1.10 0.11, Average follicle growth of 8-10 days - (mm / day), 2.40 0.08, 2.28 0.11, 2.23 0.10 and the percentage of animals that ovulated, 83.34% (5/6) , 66.67% (4/6), 50% (3/6). So the protocols of experimental groups 1 and 2 were moreeffective in promoting the synchronization of ovulation and are indicated to be used in a program of fixed-time artificial insemination in Guzerat cows. / Este trabalho teve por objetivo avaliar a dinâmica folicular de vacas da raça Guzerá tratadas com três protocolos para sincronização da ovulação onde se utilizaram implantes vaginais impregnados com progesterona ou o protocolo Ovsynch, além da utilização de benzoato de estradiol ou GnRH como indutor da ovulação. Foram utilizadas 18 vacas PO da raça Guzerá, multíparas, não-lactantes, com idades entre quatro e sete anos, escore de condição corporal de 3,0 a 4,0 (escala de 1 a 5). Os animais foram mantidos em regime extensivo, onde a dieta fornecida supriu as exigências nutricionais, receberam sal mineral proteinado e água “ad libitum”. Os animais foram divididos em três grupos, No grupo 1 (n=6) foi aplicado no D0, mesmo dia do dispositivo intravaginal CIRD®, 2 mg de benzoato de estradiol, no dia oito (D8), foram aplicados 0,530 mg de análogo de prostaglandina, 300 UI de eCG e foi retirado o dispositivo intravaginal, no dia nove (D9) foi aplicado 1 mg de benzoato de estradiol. No grupo 2 (n=6) foi aplicado no D0, mesmo dia do dispositivo intravaginal CIRD®, 2 mg de benzoato de estradiol, no dia oito (D8), foram aplicados 0,530 mg de análogo de prostaglandina, 300 UI de eCG IM e foi retirado o dispositivo intravaginal, no dia nove (D9) foi aplicado 17 μg de um análogo do GnRH. No grupo 3 (n=6) foi aplicado no D0, 200 μg de análogo do GnRH, 0,530 mg de análogo da prostaglandina no dia sete (D7) no dia nove (D9) foi aplicado 100 μg de análogo do GnRH. A partir do dia zero até o dia 8 os animais foram examinados diariamente (24/24 h) por via trans-retal com auxílio de ultrassom. Após a retirada do implante no dia 8 (grupos 1 e 2) e aplicação da prostaglandina no dia 7 (grupo 3) os animais foram avaliados 4 vezes por dia (6/6 horas) até o dia 10 do protocolo. Uma nova emergência da onda folicular para os grupos 1, 2 e 3 ocorreu respectivamente, em 2,6 ± 0,16; 2,7 ± 0,18 e 2,9 ± 0,16 dias, não havendo diferença estatística (P <0,05) entre os grupos (Tabela 1). Houve diferença estatística para os grupos 1, 2 e 3 no intervalo entre emergência da onda e ovulação em dias, 7,1  0.18; 6,37 0,31; 5,33 0,66; intervalo entre a retirada do implante e a ovulação em horas, 64,2 6,99; 61,0 12,36; intervalo entre a aplicação do indutor e a ovulação em horas, 43,6 6,89; 41,0 11,25; 38,2 7,89, maior diâmetro do FD (dia 8), 10,71 0,30; 9,41 0.24; 9,75 0,35, maior diâmetro do FD (dia 10), 13,1 0,23; 11,7 0,22; 12,0 0,34; Média de crescimento do folículo até dia 8 – (mm/dia), 1,36 0,07; 0,92 0,10; 1,10 0,11; Média de crescimento do folículo do dia 8-10 – (mm/dia), 2,40 0,08; 2,28 0,11; 2,23 0,10 e na porcentagem de animais que ovularam, 83,34% (5/6), 66,67% (4/6), 50% (3/6). Portanto os protocolos dos grupos experimentais 1 e 2 se mostraram mais eficientes em promover a sincronização da ovulação e são indicados para utilização em programa de inseminação artificial em tempo fixo em vacas da raça Guzerá.

The aim of this thesis was to compare the use of two hormonal preparations for the preparation of dairy cows to be inseminated, considering the matter of success, as well as the matter of the economy. The observation took place in the Agricultural cooperative Chodeč. 83 pcs of heifer were observed under the application of Ovsynch and 294 pieces of heifer were tested for Estrofan. The reference period was March 2013 - March 2014. Parameters were evaluated according to individual lactation. The milk yield (kg) of individual lactation was main parameter of milk performance. Fertility was indicated by these parameters: the length of the service period (days), insemination interval (days) and the insemination index.

No description available.