Objective assessment of the cryoprotective effects of dimethylformamide for freezing goat semen

AbstractThe aim of this work was to assess the cryoprotective effects of dimethylformamide (DMF) for freezing goat semen, using an objective analysis by computer-assisted sperm analysis (CASA). Twenty-one ejaculates (seven per animal) were collected from three stud bucks with the aid of an artificial vagina and immediately evaluated for gross and microscopic characteristics. The semen was diluted in two steps with a Tris–egg yolk extender containing 6% glycerol or 6% DMF, frozen in 0.50-mL straws, and stored in liquid nitrogen. Samples were accessed for sperm morphology, sperm membrane structural and functional integrity, and by CASA, immediately after thawing. There were differences (P<0.05) between glycerol and DMF with regard to subjective progressive motility (23.9±2.2% vs. 16.6±2.0%), objective progressive motility (3.5±0.4% vs. 1.8±0.3%), linearity (53.9±1.6% vs. 48.1±1.4%) and amplitude of lateral head (2.3±0.1 vs. 2.9±0.1mm), which confirmed the efficiency of glycerol. In conclusion, dimethylformamide could be used as an alternative cryoprotectant for goat semen freezing. However it was showed that no benefits were derived by using dimethylformamide to replace glycerol at an equal 6% concentration

Monitoramento do ciclo estral de cutias (Dasyprocta leporina Lichtenstein, 1823) através de citologia esfoliativa vaginal e ultrassonografia

O objetivo deste estudo foi monitorar o ciclo estral em cutias (Dasyprocta leporina) criadas em cativeiro no semi&#225;rido brasileiro. Durante 70 dias, cinco cutias foram diariamente submetidas a citologia esfoliativa vaginal, e o monitoramento ultrassonogr&#225;fico ovariano foi realizado a cada tr&#234;s dias. Um total de 8 ciclos estrais foi completamente monitorado, com dura&#231;&#227;o de 28,2&#177;0,7 dias, variando de 24 a 31 dias. Pela citologia esfoliativa vaginal, houve uma predomin&#226;ncia de c&#233;lulas superficiais nas fases de proestro e estro (P<0,05), seguida da predomin&#226;ncia de c&#233;lulas intermedi&#225;rias no metaestro (P<0,05) e de c&#233;lulas parabasais no diestro (P<0,05). Por ultrassonografia, n&#227;o houve diferen&#231;as na morfologia ovariana durante as diferentes fases do ciclo estral (P>0,05). Os fol&#237;culos foram identificados durante as fases estrog&#234;nicas (proestro e estro), com di&#226;metro m&#233;dio de 1&#177;0,5mm. Em apenas 12,5% das fases luteais, corpos l&#250;teos medindo 1,4&#177;0,9mm foram identificados. Conclui-se que a associa&#231;&#227;o da citologia vaginal e da ultrassonografia ovariana constitui uma alternativa vi&#225;vel para o monitoramento de ciclos estrais e identifica&#231;&#227;o das fases estrog&#234;nicas em cutias da esp&#233;cie Dasyprocta leporin