Characterization of the ovarian preantral follicle populations and its correlation with age and nutritional status in Brazilian Northeastern donkeys (Equus assinus).

This study aimed to characterize the ovarian follicular population and to determine its correlations with the age and nutritional status of donkeys of the Northeastern Brazilian breed. A total of 10 females with a mean age of 5.1±3.2years were submitted to ovariectomy by videolaparoscopy to obtain the ovaries. In the laboratory, the ovaries were sectioned into 6-12 fragments of approximately 7mm in diameter, which were fixed in Carnoy, dehydrated in increasing concentrations of alcohol (85%, 95% and absolute), clarified using xylol and embedded in blocks of histological paraffin. The blocks were cut in sections of 7µm and each 120th section was mounted on a slide for observation using optical microscopy. The follicle counting and identification allowed the characterization of the population of the preantral follicles. A total of 21.135±10.821 preantral follicles was counted, of which, 91.3% were primordial, 8.3% were primary follicles and 0.4% were secondary follicles. There were no differences between the two ovaries of each animal regarding the follicular population (P>0.05). There was a rate of 9.77% degenerated follicles. Values of 0.99% follicles containing two oocytes were also identified and classified as multi-oocyte follicles, always of the primordial category. The thickness of the granulosa cell layer was 1.85µm±1.39, 3.56µm±2.08 and 21.85µm±17.27, for primordial, primary and secondary follicles, respectively. There was a significant inverse correlation (r=-0.66; P<0.001) between the age of the animals and the population of ovarian follicles. A negative influence of the weight and body score on the ovarian follicular population was also observed, when donkeys had very little or a great amount of body condition. This is the first study to describe the morphometric characteristics and estimation of the population of preantral ovarian follicles in Northeastern Brazilian donkey, showing that number of preantral follicles decreased with increasing age of the animals and this finding may be affected by nutritional status of the animals.

Strategies to improve the fertility of fresh and frozen donkey semen.

Fertility rates of donkey semen in jennies are lower compared to mares. The aims of this study were to evaluate different sperm cryopreservation methods and insemination strategies to improve the fertility of donkey semen in jennies. Three experiments were performed: (1) the comparison of two freezing methods of donkey semen (conventional method and automated method); (2) the determination of a suitable insemination dose of fresh donkey semen for jennies and mares; and (3) the influence of the semen deposition site on fertility of jennies inseminated with frozen donkey semen. For experiment 1, no differences were observed in total motility, angular velocity, curvilinear velocity, straight-line velocity, and plasma membrane integrity between samples frozen with the conventional (Styrofoam box) and the automated method (TK 4000C). However, the automated method provided higher values of progressive motility and rapid cells in frozen-thawed samples in comparison with the conventional method (P < 0.05). For experiment 2, mares were bred using 500 × 10(6) fresh sperm (M); and jennies using 1 × 10(9) (J1) or 500 × 10(6) fresh sperm (J5). Pregnancy rates in M, J1, and J5 were 93% (14/15), 73% (11/15), and 40% (6/15), respectively. When using different insemination doses, 500 × 10(6) or 1 × 10(9) sperm, no significant difference was observed in pregnancy rates of mares (M, 14/15) and jennies (J1, 11/15). Furthermore, there was no significant difference between the two insemination doses in jennies. However, with an insemination dose of 500 × 10(6) fresh sperm, the pregnancy rates were significantly higher in mares (M, 14/15) than in jennies (J5, 6/15; P < 0.05). For experiment 3, the inseminations were carried out in the uterine body (UB) or in the uterine horn of jennies with frozen-thawed donkey semen. No pregnancies were achieved with inseminations performed in the UB (0/12). The pregnancy rate for uterine horn group was 28.26% (13/46) and thus significantly higher than the UB group (0%; 0/12; P < 0.05). In conclusion, the automated method showed higher values on progressive motility and rapid cells parameters compared to the conventional method and can be used as an alternative for freezing donkey semen. The increase in the number of sperm cells per insemination dose using fresh donkey semen improved the fertility rates in jennies. The deep horn inseminations using frozen-thawed donkey semen increased the pregnancy rate in jennies, and the multiple inseminations may be an option to improve the fertility rates of donkey semen in jennies.

Revisão sobre aspectos reprodutivos de jumentas (Equus asinus) / review on reproduction aspects of jennies (Equus asinus)

Anatomicamente, as jumentas possuem uma cérvix longa e flexível quando comparada a cérvix da égua. Quanto às características reprodutivas das jumentas, o ciclo estral tem duração média de 24 dias, são poliéstricas sazonais em regiões temperadas, possuem como principais sinais de estro a mastigação e orelhas baixas tocando o pescoço. A idade recomendada para a primeira cobertura é de aproximadamente três anos e o estro pós-parto ocorre em média de cinco a onze dias após o parto. Os folículos são divididos quanto ao diâmetro e os mesmos sofrem efeitos significativos conforme o dia do ciclo estral. O reconhecimento materno da gestação ocorre de forma semelhante ao da égua. Tanto o embrião de égua quanto o de jumenta possue uma cápsula acelular glicoprotéica que se assemelha quanto ao conteúdo de aminoácidos e carboidratos e se diferencia quanto ao peso de massa seca. Esta revisão teve como objetivo disseminar informações sobre os aspectos reprodutivos das jumentas no intuito de ajudar na preservação das diferentes raças de asininos, contribuindo para que estes animais sejam tratados com respeito devido a sua contribuição e importância na história, além de mostrar que existe um grande campo a ser estudado, pois dados obtidos para éguas nem sempre podem ser extrapolados para jumentas.

Anatomically, the asses have a long and flexible cervix as compared to the cervix of the mare. As for reproductive traits of asses, the estrous cycle lasts an average time of 24 days, they are poliestric seasonal in temperate regions, have as main signs of estrus chewing and lower their ears to touch the neck. The recommended age for first mating is approximately three years and postpartum estrus occurs on average five to eleven days after the parturition. Follicles are classified according to their diameter and they affected significant effects depending on the day of the estrous cycle. The maternal recognition of pregnancy occurs in a manner similar to the mare. Both embryos such as the mare and asses have an acellular glycoproteic capsule which resemble the contents of amino acids and carbohydrates and differ as to the weight of dry matter. This review aimed to disseminate information on reproductive aspects of the asses in order to help preserve different breeds of donkeys and show that there is a great field to be study, because the data acquire for mares not always may be extrapolated to asses.

Revisão sobre aspectos reprodutivos de jumentas (Equus asinus) / review on reproduction aspects of jennies (Equus asinus)

Anatomicamente, as jumentas possuem uma cérvix longa e flexível quando comparada a cérvix da égua. Quanto às características reprodutivas das jumentas, o ciclo estral tem duração média de 24 dias, são poliéstricas sazonais em regiões temperadas, possuem como principais sinais de estro a mastigação e orelhas baixas tocando o pescoço. A idade recomendada para a primeira cobertura é de aproximadamente três anos e o estro pós-parto ocorre em média de cinco a onze dias após o parto. Os folículos são divididos quanto ao diâmetro e os mesmos sofrem efeitos significativos conforme o dia do ciclo estral. O reconhecimento materno da gestação ocorre de forma semelhante ao da égua. Tanto o embrião de égua quanto o de jumenta possue uma cápsula acelular glicoprotéica que se assemelha quanto ao conteúdo de aminoácidos e carboidratos e se diferencia quanto ao peso de massa seca. Esta revisão teve como objetivo disseminar informações sobre os aspectos reprodutivos das jumentas no intuito de ajudar na preservação das diferentes raças de asininos, contribuindo para que estes animais sejam tratados com respeito devido a sua contribuição e importância na história, além de mostrar que existe um grande campo a ser estudado, pois dados obtidos para éguas nem sempre podem ser extrapolados para jumentas.(AU)

Anatomically, the asses have a long and flexible cervix as compared to the cervix of the mare. As for reproductive traits of asses, the estrous cycle lasts an average time of 24 days, they are poliestric seasonal in temperate regions, have as main signs of estrus chewing and lower their ears to touch the neck. The recommended age for first mating is approximately three years and postpartum estrus occurs on average five to eleven days after the parturition. Follicles are classified according to their diameter and they affected significant effects depending on the day of the estrous cycle. The maternal recognition of pregnancy occurs in a manner similar to the mare. Both embryos such as the mare and asses have an acellular glycoproteic capsule which resemble the contents of amino acids and carbohydrates and differ as to the weight of dry matter. This review aimed to disseminate information on reproductive aspects of the asses in order to help preserve different breeds of donkeys and show that there is a great field to be study, because the data acquire for mares not always may be extrapolated to asses.(AU)