Duration of estrus and time of ovulation in superovulated Santa Inês ewes.

Abstract: The aim of this study was to determine the intervals between sponge removal and the onset of estrus, sponge removal and the first detected ovulation, and onset of estrus and the first ovulation, and also to determine the duration of estrus, in superovulated Santa Inês ewes subjected to natural mating (NM) and AI. The trial was done in July and February at Cachoeiras de Macacu?Rio de Janeiro (22°27'S, 43°39'W). Fifteen non-pregnant Santa Inês ewes, age 3.4 ± 1.4 years, weighing 47.8 ± 6.3 kg, with 3.3 ± 0.4 body condition score (scale of 1 to 5), were randomly assigned to 2 groups. Both groups were superovulated using the same protocol and were mated in a crossover design by NM and laparoscopic AI. Estrus was synchronized using intravaginal sponges (60 mg of medroxyprogesterone acetate; Progespon®, Schering Plough Animal Health, São Paulo, Brazil) inserted (Day 0) and maintained for 6 days. On Day 5, the ewes received IM injections of 300 IU of eCG (Novormon®, Schering Plough Animal Health) and 0.0375 mg of cloprostenol (Prolise®, Tecnopec, São Paulo, Brazil). Twelve hours after sponge removal, 0.025 mg of gonadorelin acetate (Gestran®, Tecnopec) was administered IM. Superovulation started 60 h after sponge removal and consisted of 5 IU kg -1 of porcine FSH (pFSH; Pluset®, Hertape Calier, Minas Gerais, Brazil) IM in 6 decreasing doses (25, 25, 15, 15, 10, and 10%) at 12-h intervals. At the first pFSH dose, new sponges were inserted. At the fifth pFSH dose, 0.0375 mg of cloprostenol was administered IM and the sponges were removed. After the sponge removal, the NM group was exposed to rams twice per day for mating, until the end of estrus. In the AI group, estrus was detected using a teaser with the penis diverted. The females were permitted to be mounted twice per day until the end of estrus, and were inseminated with frozen-thawed semen 24 and 36 h after the end of superovulation. The follicular development and ovulation time were observed using real-time ultrasonography (8.0 MHz Pie Medical®, Aquila Vet, Tokyo, Japan) at 12-h intervals. For statistical analysis, a Student's t-test was performed (5% significance level) using the BioEstat program. Results are presented as mean ± standard deviation. The time from sponge removal to onset of estrus and the duration of estrus did not differ between NM and AI groups (31.79 ± 5.94 v. 25.25 ± 10.38 h and 29.89 ± 11.54 v. 26.66 ± 8.67 h, respectively). The time from sponge removal to ovulation and from onset of estrus to the first ovulation were shorter (P < 0.001) in the NM group (32.11 ± 12.72 v. 56.48 ± 15.39 h and 8.61 ± 5.99 v. 32.25 ± 18.57 h, respectively). The time from sponge removal to ovulation in July and February was 56.07 ± 7.27 versus 56.83 ± 20.72 in the AI group and 29.54 ± 0.56 versus 33.83 ± 19.02 in the NM group, respectively, suggesting that the season of the year in a tropical region did not influence the ovulation time for each treatment. Possibly, the mechanical stimulation induced by the contact of the penis with the vagina fornix and by the accessory sex glands fluids in mating hastened the ovulation time in the NM group. The service can shorten the time of ovulation

The influence of different methods of frozen-thawed ovine spermatozoa selection on sperm capacitation and viability after incubation.

Abstract: Sperm capacitation is an essential event for fertilization; however, it decreases the sperm lifespan and viability. The aim of this study was to evaluate the effects of four sperm selection techniques on sperm capacitation and viability after incubation. A pool of frozen-thawed sperm from 10 Santa Inês rams was used. The samples were submitted to one of the following sperm selection techniques: sperm washing, Percoll gradient, mini-Percoll gradient, Swim-up and control group. At mini-Percoll technique, was used 400 microliters of 90% and 45% gradients and a centrifugation at 500 xg for 5 minutes. In Percoll, was used 1 mL of each gradient and a centrifugation at 700 xg for 10 minutos. During Swim-up, the sperm was incubated in 1 ml of SPERM-TALP for 45 minutos in humidified atmosphere at 37.5oC. Finaly, at sperm washing the sample suffered centrifugation at 300 xg for 8 minutes, using SPERM-TALP. At the end of each treatment, the selected spermatozoa were incubated at 37oC for 1 h, 2 h, and 3 h. Viability was assessed using acridine orange-propidium iodide combination by computer-assisted sperm analysis. Capacitation status was evaluated using chlortetracycline staining and observed under epifluorescence microscopy. Data were analyzed by ANOVA, followed by Tukey test (P0.05) among Percoll (36%), mini-Percoll (34%) and Swim-up (30%), and were lower (P0,05) entre Percoll (36%), mini-Percoll (34%) e Swim-up (30%), as quais foram inferiores (P<0,05) ao grupo controle (47%) e lavagem por centrifugação (41%). A taxa de espermatozoides não capacitados foi superior (P<0,05) no momento 0 h (12%) e diminuiu após 3 h (1,5%), independentemente do método. Houve interação (P<0,05) entre intervalo de incubação e método na taxa de espermatozoides reagidos. O índice de reagidos foi menor (P<0,05) em 0 h (50%) e 1 h (53%) e maior após 3 h (64%). Percoll (60%) e mini-Percoll (61%) apresentaram maiores valores para reagidos (P<0,05) enquanto o controle apresentou o menor (49%). Observou-se interação (P<0,05) entre intervalo de incubação e método na vitalidade espermática. A taxa de íntegros em 0 h foi a maior (17,5%; P<0,05), após os diferentes métodos. O Swim-up apresentou maior taxa de íntegros (17,4%; P<0,05), independentemente do intervalo de incubação. Em conclusão, o intervalo de incubação interfere nos padrões de capacitação e vitalidade de espermatozoides ovinos congelados. A seleção espermática aumenta a taxa de células reagidas e o Swim-up permite maior vitalidade durante a incubação.Proceedings of the 29th Annual Meeting of the Brazilian Embryo Technology Society (SBTE); Gramado, RS, Brazil, August 20 to 23, 2015. Abstracts

Evaluation of different protocols of epidural anesthesia for relaxing cervical in Santa Inês sheep.

Proceedings of the 28th Annual Meeting of the Brazilian Embryo Technology Society (SBTE), August, 2014, Natal, RN, Brazil. Abstracts

Retorno da ciclicidade de ovelhas lactantes da raça Santa Inês até 105 dias pós-parto com amamentação contínua dos cordeiros em clima tropical quente úmido.

[Return od cyclicity of Santa Ines lactating ewes to 105 days after birth continued suckling of lambs in warm and tropical climate]