Antonio de Lisboa Ribeiro Filho

Fertilidade de fêmeas Nelore após inseminação artificial em tempo fixo conforme a contagem de folículos antrais

The objective of this work was to determine the effect of antral follicle number (AFC) on the conception rates of Nellore females, in a fixed‑time artificial insemination (FTAI) program. For that, 481 females were subjected to a FTAI protocol and evaluated for antral follicle counts (AFC) and pregnancy diagnosis. The animals were grouped into the AFC categories considered as low ( 53). There was no difference between the conception rates obtained for the AFC categories in FTAI protocol with use of chorionic gonatropin.

Taxa de gestação de receptoras de embriões bovinos tratadas com um análogo do GnRH no momento da inovulação

O objetivo com este estudo foi avaliar a taxa de gestacao de receptoras de embrioes bovinos categorizadas de acordo com a qualidade do corpo luteo (CL) e tratadas ou nao com um analogo de GnRH (Fertirelina) no momento da inovulacao. Somente os embrioes viaveis foram selecionados para inovulacao (1- excelente, 2- bom e 3- regular) e transferidos. Para tanto, 272 novilhas foram distribuidas em seis grupos: CL1-S/GnRH (receptoras com area do CL ≤ 1,5cm2 e nao tratadas com GnRH, n =26); CL1-C/GnRH (receptoras com area do CL ≤ 1,5cm2 e tratadas com GnRH, n=29); CL2-S/GnRH (receptoras com area do CL entre 1,5 e 2,0cm2 e nao tratadas com GnRH, n =46); CL2-C/GnRH (receptoras com area do CL entre 1,5 e 2,0cm2 e tratadas com GnRH, n=45); CL3-S/GnRH (receptoras com area do CL > 2,0cm2 e nao tratadas com GnRH, n=63); e CL3-C/GnRH (receptoras com area do CL > 2cm2 e tratadas com GnRH, n=63). As taxas de gestacao das receptoras de embriao em relacao a qualidade do CL e a aplicacao ou nao do GnRH foram respectivamente, 43,31 e 41,38%, 56,52 e 46,67%, e 46,03 e 42,86% para CL1-S/GnRH e CL1-C/GnRH, CL2-S/GnRH e CL2-C/GnRH, e CL3-S/GnRH e CL3-C/GnRH. Nao houve diferenca (P>0,05) entre as variaveis avaliadas. Portanto, a administracao do analogo de GnRH (Fertirelina) nao elevou a taxa de gestacao em receptoras de embrioes bovinos, independente da qualidade do CL, demonstrando que esta estrategia nao foi eficaz em incrementar os indices de fertilidade.

THE EFFECT OF THE INTENSITY OF ESTRUS EXPRESSION ON THE FOLLICULAR DIAMETER AND FERTILITY OF NELLORE COWS MANAGED UNDER A FTAI PROGRAM

The aim of this study was to determine the relationship between the intensity of estrus expression on the ovulatory follicle diameter (OFD) and its effect on the conception rate in zebu females managed under a FTAI program. On a random day of the estrous cycle, day 0, 308 Nellore females received an intravaginal progesterone device and 2.0 mg of estradiol benzoate were administered intramuscularly (IM). On day 8, the progesterone device was removed, and 300 IU of equine chorionic gonadotropin, 150 μg of d-cloprostenol, and 1.0 mg of estradiol cypionate were administered IM. The animals were then painted with animal marker spray between the sacral tuberosity and the tailhead. On day 10, the animals were categorized into three groups: no estrus expression (n = 78), low intensity of estrus expression (n = 66) and high intensity of estrus expression (n = 164). The OFD was then measured, and artificial insemination (AI) was performed. The results suggest that determining the intensity of estrus expression is a good parameter to identify females with greater follicular diameter and increased fertility in Nellore cows submitted to a FTAI protocol.

Suplementação com progesterona oral para gado de corte após a inseminação em programas de IATF

The objective of this work was to evaluate the effects of supplementation with melengestrol acetate (MGA), after timed artificial insemination (TAI), on the conception rate of Nellore cows, according to cyclicity during the protocol, estrus expression between intravaginal device withdrawal and insemination, and diameter of the largest follicle at the time of insemination, in order to identify predictors of the use of MGA. Multiparous lactating cows (577) were subjected to a hormonal protocol for ovulation synchronization. On day -2 of the protocol, the animals were painted with a marker on the base of their tail. On day 0, they were evaluated for estrus expression; the preovulatory follicle diameter (POFD) was measured by ultrasonography, and the artificial insemination was performed. The animals were assigned to two experimental groups according to the supplementation or not with 0.50 mg MGA, between 13 and 18 days after TAI. Pregnancy diagnosis was performed using an ultrasound examination 35 days after TAI. A positive effect of the treatment with MGA on the conception rate occurred generally in animals in anestrus, irrespective of the estrus expression. For animals treated with MGA, only those with POFD greater than 14 mm showed better conception rates that the control group.

Comparação de dois ésteres de estradiol como indutores da ovulação sobre o diâmetro folicular e a taxa de gestação de bovinos leiteiros submetidos a programa de Inseminação Artificial em Tempo Fixo

Objetivou-se com este trabalho avaliar o efeito da utilizacao de dois esteres de estradiol, sobre o Diâmetro do Foliculo Ovulatorio (DFOL) e taxa de gestacao de femeas bovinas leiteiras submetidas a um programa de Inseminacao Artificial em Tempo Fixo (IATF). Para tanto, 94 femeas mesticas Holandes-Gir foram submetidas ao seguinte protocolo hormonal, iniciado em um dia aleatorio, D0, por meio da insercao de um dispositivo intravaginal de progesterona (P4) associado a 2mg de Benzoato de Estradiol (BE) via intramuscular (i.m.). No D8, os dispositivos foram removidos e administrados 500 µg de Cloprostenol sodico – prostaglandina – F2α e 300 UI de Gonadotrofina Corionica equina (eCG) i.m. Neste momento, os animais foram divididos em dois grupos experimentais: 50 vacas foram alocadas no grupo Cipionato de Estradiol (CE) e receberam 1mg dessa substância via i.m., enquanto outras 44 receberam 1mg de BE i.m., 24 horas apos a retirada dos dispositivos (D9), sendo chamadas grupo BE. No D10, foram realizadas as inseminacoes e, previamente a cada procedimento de IA, foi executada a mensuracao do DFOL por meio de ultrassonografia transretal. O diagnostico de gestacao foi realizado 55 dias apos as IATFs. Nao houve diferenca significativa entre as medias de DFOL encontradas para os grupos BE e CE sendo, respectivamente, 11,45 ± 2,34 e 10,71 ± 2,43mm. O grupo BE tambem apresentou um indice de gestacao de 34,10%, semelhante ao grupo CE que foi de 40,00%. Conclui-se que o CE pode substituir o BE em protocolo de IATF em vacas leiteiras, representando uma alternativa para simplificar o protocolo de IATF.

Resposta superovulatória de caprinos da raça Boer submetidos a produtos com diferentes relações FSH:LH

This study aimed to investigate the efficiency and standards in the superrovulatory response to products with different relationships FSH:LH. It Were used 43 female Boer goats breed. On a random day of the estrous cycle, the animals received half of an implant of progesterone (Crestar®). In the eleventh day, began stimulation to superovulation through the use of FSH fractionated in six decreasing doses administered every 12 hours and the animals were separated into two groups: group I (GI, n=22) received 200mg of FSH (Folltropin®) intramuscularly (i.m) on days D11 (62,5mg), D12 (35,0mg) and D13 (2,5mg), while the group II (GII, n=21) received 300UI FSH (Pluset®) intramuscularly on days D11 (75UI), D12 (50UI) and D13 (25UI). In 60 and 72h after onset of superovulation the implants were removed and applied two doses of 125µg de Cloprostenol (Ciosin®) by intravulvosubmucosal in all animals. Twelve, 24 and 36 hours after removal of the implant, the females were placed with four breeders to be covered. In D16, the implants were reinserted and 24 hours before collection of embryos the implants were withdrawl and administered 125µg de Cloprostenol in each animal intramuscularly. Embryo were collected on D21, selected and classified. The results obtained in this study showed no statistical difference between groups regarding the number of recovered structures, viable embryos, degenerate embryos and unfertilized structures. So, the different relationships FSH:LH evaluated did not affect embryos production and quality.