. 2013. Objetivou-se avaliar a qualidade dos espermatozoides recuperados da cauda do epidídimo após a refrigeração do complexo testículo-epidídimo (CTE) de cães usando o diluidor ACP-106c. Foram utilizados 60 cães machos adultos, com peso de 10-20 kg.Após a eutanásia, removeu-se o CTE que foi imerso em solução fisiológica 0,9% e transportado em caixa térmica ao laboratório a 30°C. Para a refrigeração e recuperação dos espermatozoides epididimários, os 60 pares do CTE foram divididos em 4 grupos, de acordo com o tempo de refrigeração do CTE e posterior recuperação espermática: G0h, G6h, G12h e G18h, em que cada par do CTE permaneceu por zero, seis, doze ou dezoito horas a 4°C, respectivamente. A recuperação dos espermatozoides da cauda do epidídimo foi realizada pela técnica de flutuação utilizando-se o diluidor ACP-106c ou Tris. Para cada epidídimo foi adicionado 1,0 mL de um dos dois diluidores, pré-aquecidos a 37°C por 5 minutos. Em seguida foram centrifugados a 800g/5 minutos para remoção dos resíduos celulares. Avaliou-se The study aimed to assess the quality of sperm recovered from the epididymal cauda after cooling the complex testis-epididymis (CTE) of dogs using ACP-106c extender. Sixty adult male dogs, weighing 10-20 kg were used. After euthanasia, CTE was removed and it was immersed in 0.9% saline and transported to the laboratory in cooler at 30°C. For cooling and recovery of epididymal spermatozoa, the 60 pairs of CTE were divided into four groups, according to the refrigeration time of the CTE and subsequent sperm recovery: G0h, G6h, G12h and G18h, wherein each pair of CTE remained zero, six, 12 or 18 hours at 4°C respectively. The recovery of sperm epididymal tail was conducted by flotation technique using ACP-106c or Tris extender. For each epididymis, it was added 1.0 mL of either extenders, preheated to 37°C for 5 minutes. They were then centrifuged at 800g/5 minutes to remove the cell debris. Morphology, functionality and total and progressive motility, and parameters obtained by CASA were evaluated. Data were analyzed by ANOVA followed by Turkey test (P <0.05). In all parameters assessed, there was no difference between the extenders used (P>0.05). The values of total motility groups G0h, G6H, G12H, and G18h for ACP-106c were 84.4±7.7, 81.6±11.6, 88.3±6.5 and 69.5±16.9 respectively, and for Tris 85.2±8.7, 77.4±14.3, 79.0±17.8 and 65.4±17.9 respectively. A decrease in sperm quality was observed after 18 hours of cooling in both extenders. Thus it can be concluded that the ACP-106c may be used to recover the epididymal spermatozoa chilled and may be viable for up to 12h cooling.INDEX TERMS: Refrigeration, epididymis, dogs.