Comportamento sexual, fertilidade e taxa de recuperação embrionária em jumentas da raça Pêga ao longo do ano

• Ano de defesa: 2013
• Autor(a) principal: Ker, Pedro Gama
• Orientador(a): Carvalho, Giovanni Ribeiro de
• Banca de defesa: Guimarães, José Domingos , Jacob, Júlio César Ferraz
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Zootecnia
• Departamento: Genética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e Forragicul
• País: BR
• Palavras-chave em Português: Embriões; Sêmen; Jumenta pega
• Palavras-chave em Inglês: embryos; semen; donkey picks
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA
• Link de acesso: http://locus.ufv.br/handle/123456789/1871

We aimed with this study to evaluate the effect of photoperiod changes on reproductive characteristics of Pêgabreed jennies along the year and to verify the embryo recovery rate and embryo characteristics on days 7, 8 and 9 postovulation. In Experiment 1, 279 estrous cycles of 44 jennies were evaluated during 3 consecutive years. The experimental groups were split in two periods according to photoperiod along the year in the southern hemisphere: P1: October to March (Long photoperiod); P2: April to September (Short photoperiod). The sexual behavior, ovarian and uterine characteristics, and fertility during 3 years were evaluated. Jennies were checked for estrous behavior by a jack and were evaluated by transrectal palpation every two days to identify females in estrous. Jennies with sexual signs of estrous or with anovarian follicle bigger than 25 mm in diameter were controlled daily until ovulation was detected.Artificial insemination or natural breed was performed every two days when a follicle reached ≥ 35 mm until ovulation. Pregnancy diagnose was done on days 13, 25 and 35 postovulation by ultrasonography using a transrectal linear transducer (5 MHz). Differences were not detected (P>0.05) between the two periods in the following characteristics: follicle diameter at the beginning of estrous (29.80 ± 0.18mm), follicle diameter at ovulation (44.61± 0.24mm), estrous length (7.44± 0.05days),interval from the onset of estrous to ovulation (5.99± 0.06days), interval from ovulation to the estrous end (1.45± 0.03days), follicle growth rate (2.50± 0.04mm/day)frequency of double (16.49%, 46/279) and triple (1.43%, 4/279)ovulations, frequency of ovulation in the left (52.65%, 146/279)and right (47,35%, 133/279)ovaries, and frequency of ovulations with visual signs in the pre-ovulatory follicle (77.85%, 217/279).Total pregnancy rate was 60%; a difference in pregnancy rate between the two periods was not detected (P>0.1).Photoperiod variation did not affect the characteristics of follicle growth, sexual behavior and fertility in jennies of Pêga breed under the present environment conditions.In Experiment 2, the recovery rate, development and quality of embryos on days 7, 8 and 9 were evaluated. For embryo recovery, 90 uterine flushes were performed in seven Pêga breed jennies, aging 6 to 14 years old. Sixty-three embryos from 90 flushes (70%) and 107 ovulations (58.9%) were recovered. Averaged embryo diameter was 747.38 ± 76.45 μm. The proportions of embryos development stages were as follow: morulas,1.59% (1/63);early blastocysts, 6.35% (4/63);blastocysts, 23.81% (15/63); and expanded blastocysts,68.25% (43/63). For quality grades, 90.5% (57/63) of embryos were classified as excellent or good (Grade I and II) and 9.5% (6/63) as regular or poor (Grade III and IV). No difference (P>0.1) in embryo recovery rate was detected between the two year periods. The embryo quality observed in the present study is considered satisfactory in a embryo transfer program.