Influence of biostimulation and temporary weaning on follicular dynamics and pregnancy rates in Nelore cows (Bos taurus indicus).

The objective of this study was to evaluate the effect of biostimulation and temporary weaning on the follicular dynamics and pregnancy rates in Nelore cows. We used three groups of 75 cows: a control group without biostimulation and suckling calves (WB), a group that was biostimulated and had suckling calves (BE) and a group that was biostimulated and subjected to temporary weaning for 56 h (BETW). Ovarian dynamics were examined using ultrasonography. All groups showed follicular atresia. The interval between beginning of the treatment and wave emergence was 3.25 ± 0.30 days for BE, 3.40 ± 0.27 days for BETW and 3.37 ± 0.50 days for WB. The time between implant removal and ovulation was 64.50 ± 1.88 h for BE, 66.75 ± 1.35 h for BETW and 60.85 ± 3.10 h for WB. Eight cows were submitted to ultrasound analysis, and the percentages of cows that had ovulatory follicles of the new follicular wave with maximum diameters greater than 0.80 cm were 100 % (8/8) in BE (1.28 ± 0.12 cm), 100 % (8/8) in BETW (1.52 ± 0.07 cm) and 87.5 % (7/8) in WB (1.21 ± 0.10 cm). The pregnancy rate was 52 % (39/75) in BE, 69.3 % (52/75) in BETW and 37.3 % (28/75) in WB. The association of biostimulation and temporary weaning increased follicular development, ovulation synchronisation and, consequently, the pregnancy rate in beef cows.

Use of retinyl acetate, retinoic acid and insulin-like growth factor-I (IGF-I) to enhance goat embryo production.

Experiments were carried out to investigate the beneficial effects of retinyl acetate (RAc) and retinoic acid (RA) on goat oocyte maturation as well as the effects of insulin-like growth factor-I (IGF-I), RAc and RA during embryo culture under chemically defined conditions. In Experiment 1, in vitro maturation (IVM) was performed in a chemically defined basic maturation medium (bMM) supplemented with 0.3 µM RAc or 0.5 µM RA. Presumptive zygotes and embryos (2-4 cells) were cultured in droplets of potassium simplex optimised medium (KSOM); however, none of the embryos reached the blastocyst stage. In Experiment 2, oocytes were matured in bMM + RAc or bMM + RA. Presumptive zygotes and 2- to 4-cell embryos were placed in fresh KSOM droplets supplemented with RAc, RA, IGF-I, RAc+IGF-I or RA+IGF-I. In Experiment 1, addition of RAc and RA to bMM increased (P < 0.05) the proportion of 2- to 4-cell embryos reaching the morula stage as compared to the control. In Experiment 2, supplementation of embryo culture media with retinoids and IGF-I increased (P < 0.05) the proportion of 2- to 4-cell stage embryos developing to the morula and blastocyst stage. Our data demonstrate that goat embryo production in chemically defined media could be improved by exogenous RAc or RA and by the interaction between retinoids and IGF-I, and that goat embryos can be produced in vitro from oocytes following protocols similar to those currently used for cattle.

Migration time of the genital tubercle in caprine and ovine fetuses: comparison between breeds, sexes and species.

The aim of this work was to determine the ideal moment to sex goat and sheep fetuses, to compare the average time of genital tubercle (GT) migration between sexes, breeds and species, and to evaluate the accuracy of fetal sexing between sexes. A total of 317 fetuses of 219 pregnant females were monitored at 24-hour interval, from days 30 to 60 of pregnancy in ewes, and from days 40 to 60 in goats. Examinations were performed using transrectal ultrasound equipped with a linear transducer of double frequency. Fetuses were identified as male when the GT was next to the umbilical cord and female when the GT was next to the tail. The average time of GT migration in ewes (41.3 +/- 3.1 days) was shorter (P < 0.05) than in goats (47.2 +/- 2.3 days)? In goats, the average time of GT migration of Saanen fetuses was later (P < 0.05) than in fetuses of other breeds, with no difference in the average time of GT migration between male (46.9 +/- 2.2) and female fetuses (47.4 +/- 2.4). In ewes, the average time of GT migration did not differ (P > 0.05) among breeds and sexes. In goat and sheep, no difference was noticed in the accuracy of fetal sexing between males and females (P > 0.05). The results show that fetal sexing in ewes must be done earlier than in goats, fetal sexing in Saanen goats must be performed later, and fetal sex does not influence the time of GT migration in either of the two species.

Early fetal sexing of Saanen goats by use of transrectal ultrasonography to identify the genital tubercle and external genitalia.

OBJECTIVE: To define the optimum period for sexing of Saanen goat fetuses by use of transrectal ultrasonography. ANIMALS: 82 Saanen goats pregnant with 124 fetuses. PROCEDURES: Fetal sexing was performed on the basis of the final location of the genital tubercle or identification of external genitalia. In experiment 1, fetuses (n = 78) were monitored every 48 hours from days 40 to 60 of gestation, whereas for experiment 2, 46 fetuses were examined only once between days 47 and 77 of gestation. RESULTS: For experiment 1, accuracy of fetal sexing was 20 of 20 (100%) for a single fetus, 39 of 42 (92.8%) for twin fetuses, and 10 of 16 (62.5%) for triplet fetuses. Diagnostic accuracy was significantly lower for triplet fetuses than that for single or twin fetuses. Final location of the genital tubercle was detected between 45 and 55 days of gestation (mean +/- SEM, 48.9 +/- 1.8 days). For experiment 2, accuracy of fetal sexing for a single fetus (24/24 [100%]) was significantly higher than the accuracy for twin fetuses (16/22 [72.7%]). Considering all fetuses that were born, accuracy of diagnosis was 69 of 78 (88.4%) for experiment 1 and 40 of 46 (86.9%) for experiment 2. Accuracy did not differ significantly between experiments. CONCLUSIONS AND CLINICAL RELEVANCE: Real-time ultrasonography after day 55 of gestation is a suitable method for determination of sex of Saanen goat fetuses by observation of the genital tubercle or identification of external genitalia.

Ultrasonographic fetal sex identification in pregnant sheep derived from natural mating and embryo transfer.

The objective of this study was to identify the migration period of the genital tubercle and the period of visualization of external genital structures in fetuses of the Dorper breed of sheep derived from natural mating and from fresh, frozen and vitrified embryo transfer. Transrectal ultrasound was performed using a double-frequency linear transducer (6.0 and 8.0 MHz) to monitor 130 ewe fetuses distributed in the four treatments regarding embryo origin. The accuracy of the ultrasound was 100% in this experiment. The fetuses originated from controlled natural mating (NM) and from fresh (FrE), frozen (FE) and vitrified (VE) embryo transfer, with embryos collected 7 days after breeding. Migration of the genital tubercle occurred earlier (P<0.05) in NM (42.21+/-2.86 days) than in FrE (43.98+/-3.00 days), FE (44.97+/-1.83 days) and VE (44.58+/-1.97 days). Visualization of the scrotal bag, prepuce and vulva occurred, respectively, earlier (P<0.05) in NM (45.22+/-1.25, 45.95+/-1.53 and 45.01+/-1.03 days) than in FrE (48.91+/-1.92, 48.52+/-1.41 and 47.41+/-1.41 days), FE (49.97+/-1.08, 49.18+/-2.00 and 47.64+/-1.82 days) and VE (50.12+/-1.66, 49.27+/-1.61 and 47.93+/-1.92 days). The results show that fetal sexing can be accomplished from the 50th day onward in fetuses produced by natural mating and from the 55th day onward in fetuses derived from fresh, frozen and vitrified embryos. It can also be concluded that real-time ultrasonography is a reliable tool for fetal sex determination in sheep taking into account both the location of the genital tubercle and the identification of external genital structures.

Sexagem fetal em ovelhas Santa Inês por ultra-sonografia / Fetal sexing in Santa Inês ewes by ultrasonography

O presente estudo teve a finalidade de identificar o sexo e de determinar o dia da migração do tubérculo genital (TG) de fetos ovinos através da ultra-sonografia em tempo real. O sexo foi identificado no Experimento I (EI) levando-se em consideração a localização do TG e no Experimento II (EII), a presença do pênis, prepúcio e bolsa escrotal no feto macho e das tetas, vulva e clitóris no feto fêmea. No EI, as fêmeas (n=17) foram monitoradas em intervalos de 12 horas, do 35o ao 46o dia de gestação, por via transretal com transdutor linear (6,0 e 8,0 MHz). No EII, as fêmeas (n=30) com gestação de 55 a 75 dias foram examinadas apenas uma vez, utilizando-se o mesmo transdutor e via de exame do EI. Das 17 fêmeas do EI, 11 (64,6 por cento) tiveram seus fetos corretamente sexados, independente da gestação ter sido simples (7/11), dupla (3/11) ou tríplice (1/11). Nas 6 (35,4 por cento) gestações restantes, 3 (17,7 por cento) foram duplas, sendo impossível sexar um feto de cada gestação. Nas outras 3 (17,7 por cento) gestações, os fetos foram corretamente sexados, apesar dos nascimentos não coincidirem com a quantificação. Num feto macho de uma gestação simples, a migração ocorreu no 37º dia e até o 46º, todos os fetos das outras gestações estavam corretamente sexados. Das 30 fêmeas do EII, 16 (53,4 por cento) apresentaram gestações simples e a acurácia da sexagem foi de 100 por cento. Nas 14 (46,6 por cento) restantes, as gestações foram duplas, sendo impossível, em quatro casos, determinar o sexo de, pelo menos, um dos gêmeos. De todos os fetos nascidos, a acurácia geral da sexagem foi de 88,0 por cento (EI) e 90,9 por cento (EII), não sendo observada diferença (P>0,05) entre ambos os experimentos. Os resultados permitem concluir que a ultra-sonografia em tempo real é um método eficiente para diagnosticar o sexo fetal pela visualização do TG, assim como pela identificação do pênis, prepúcio e bolsa escrotal no feto macho e das tetas, vulva e clitóris no feto fêmea, desde que os exames sejam realizados a partir do 50o dia de gestação.

Preparação de rufiões caprinos pela fixação da curvatura caudal da flexura sigmóide do pênis / Preparation of teaser goats by fixation of the caudal curvature of penis sigmoid flexure

Foram utilizados 15 caprinos sem raça definida com idade variando entre 06 e 36 meses objetivando testar uma técnica cirúrgica para preparo de rufiões por fixação da curvatura caudal da flexwa sigmóide do pênis. Para avaliação dos resultados, os animais eram colocados na presença de fêmeas em estro, a partir do décimo dia da intervenção cirúrgica, durante um período mínimo de seis meses. Os rufiões, quando testados, não apresentaram alteração da libido e mostraram-se incapazes de exteriorizar o pênis, permitindo concluir que a técnica descrita, além de ser rápida e de fácil execução, pode ser utilizada com eficiência na prática de preparo de rufiões caprinos.

In the present study fifteen. undefined breed type bucks, with age varing between six and thirty-six months, were used to test a surgery technique by fixation of the caudal curvature of penis sigmoid flexure for preparation of teaser. To evaluate the results, the teasers buck were placed with goats in oestrus for a minimum period of six months after 10 (ten) days of surgery. During evaluations, the teasers did not present any alteration of the sexual behavior and they were unable to project the penis for outside of the prepuce. There fore, it was concluded that the surgery technique used in these investigation can be easily applied and utilized with effïciency in the preparation of teasers buck.

Cocultura de embriões Mus musculus com monocamadas de células de linhagens primária e contínua em um sistema sem fluxo externo de CO2 / Coculture of Mus musculus embryos with monolayers of primary and continuous lineages in a system without external CO2 flow

A eficiência de três monocamadas celulares (linhagem contínua - células Madin and Darby Bovine Kidney/ MDBK;linhagem primária - células de útero e de oviduto bovino) foi testada para verificar a existência de especificidade celular através do desenvolvimento de embriões, desde o estádio de duas células até o de mórula compacta, em um sistema de cocultura sem fluxo externo de CO2. Depois da seleçâo, os embriões (n = 343) foram aleatoriamente distribuídos em diferentes tubos de ensaio, os quais foram colocados a 37°C durante 72 horas. Após o período de cocultura, as porcentagens de mórulas compactas obtidas foram de 87,7 por cento em células de oviduto, 86,2 por cento na monocamada de células uterinas e 88,3 por cento na de células MDBK. Não foi observada diferen- ça significativa entre esses valores e, por isso mesmo, conclui-se que a especificidade celular não é importante para o desenvolvimento in vitro de embriões Mus musculus.

The efficiency of three monolayers (continuous lineage - Madin and Darby Bovine Kidney/ MDBK; primary lineage - bovine celisfrom uterus and oviduct) hás been tested to verify the celular specificity through development of two cells embryos until compact morulaes stage in a coculture system without continuous CO2 flow. The selected mouse embryos (n=343) were randomiy divided into three experimental groups andplaced in closed culture tubes mantained aí 37°C during 72 hours. After the co-culture period, the porcentages of compact morulaes were 87.7 percent in oviduct cells, 86.2 percent in uterus monolayer and 88.3 percent in MDBK cells. It was not observed significative difference between these results and it is possible to condude that celular specificity is not importam to enhance the In vitro development of Mus musculus embryos.