“One Step and Two Steps” freezing methods of dog’s semen in coconut water and ethylene glycol extender Métodos de congelamento "One Step" e "Two Steps" do sêmen de cães, diluído em solução de água de coco e etilenoglicol

The objective of this study was to verify the influence of One Step and Two Steps freezing methods on dog’s spermatic viability. The experiment was performed using 20 ejaculates from 11 previously selected dogs which presented progressive motility over 70% and vigor equal or superior to 3. The samples were frozen in medium composed by coconut water and ethylene glycol as crioprotectant by the methods, One and Two Steps. After thawing, progressive motility, vigor, live spermatozoa percentage and plasmatic membrane integrity were evaluated. The results showed that there was no difference (P&gt;0.05) in evaluated seminal characteristics. For progressive motility, the results (mean ± standard deviation) were respectively for One and Two Steps, 47.3% ± 16.6% and 50.5% ±1 7.4%. As well as, the results for vigor, live spermatozoa percentage, plasmatic membrane integrity were 2.64 ± 0.67 and 2.9 ± 0.74; 52.2% ± 24.16 and 52.2% ± 24.48%; 15.27% ± 10.19% and 23.3% ± 11.6% for One and Two Steps methods, respectively. In conclusion, the One Step and Two Steps techniques can be used as semen cryopreservation methods in dog’s assisted reproduction and there is no difference between the evaluated characteristics of frozen-thawed semen using one or other technique.<br>Objetivou-se, com este estudo, verificar a influência dos métodos de congelamento, One Step e Two Steps, na viabilidade espermática em cães. Foram utilizados 20 ejaculados de 11 cães, previamente selecionados, que apresentaram motilidade progressiva acima de 70% e vigor igual ou superior a três. As amostras foram congeladas em meio composto de água de coco e etilenoglicol, pelos métodos de One e Two Steps, e avaliadas após descongelamento, quanto à motilidade progressiva, vigor, porcentagem de espermatozóides vivos e integridade de membrana plasmática. Após o processo de diluição e congelamento One Step e Two Steps, verificou-se que não houve diferença (P&gt;0,05) nas características seminais, cujos resultados (média ± desvio padrão) foram, respectivamente, de 47,3% + 16,6% e 50,5% + 17,4% para motilidade progressiva; 2,64 + 0,67 e 2,9 + 0,74 para o vigor; 52,2% + 24,16% e 52,2%+24,48% para porcentagem de espermatozóides vivos e de 15,27% + 10,19% e 23,3% + 11,6% para a integridade de membrana plasmática. A ausência de diferenças entre as características avaliadas para o sêmen congelado, permite inferir que as técnicas One Step e Two Steps podem ser utilizadas para a criopreservação do sêmen de cães.