Semen chilling procedure preserves gametes without reaching the freezing point, which induces deleterious intracellular changes that affect viability and fertilizing potency of spermatozoa. The aim of this work was to compare different egg yolk concentration for dog semen chilling at 5 °C extended in ACP®-106. ACP-Ejaculated of dogs (n=10) were diluted and chilled in ACP -106 without (control group) or containing 5, 10 or 20% egg yolk. Was observed a significant reduction in extender pH using 20% egg yolk on the second day of chilling and after the third day of chilling when using 5 and 10% egg yolk. At the first day of chilling 20% egg yolk extender result in better sperm motility in comparing 5% egg yolk group. After five days of storing, the use of 5 and 10% were inferior to the control group. The reduction on motility was significant at the first day of chilling in the control group, after two days on group with 5% egg yolk and after three days in the other groups. The vigor, sperm and acrossomal morphology, functional plasma membrane integrity were similar in all groups tested. In conclusion, the egg yolk influences the maintenance of the pH in the extender ACP-106 and that the canine semen can be efficiently conserved for up to two days using 10 or 20% egg yolk.A refrigeração consiste na preservação dos gametas sem atingir o ponto de congelação o qual induz a mudanças intracelulares deletérias que afetam a viabilidade e o potencial fertilizante do espermatozóide. O objetivo deste trabalho foi comparar diferentes concentrações de gema de ovo para o resfriamento a 5 °C do sêmen canino diluído em ACP®-106. Ejaculados de cães (n=10) foram diluídos e refrigerados a 4 °C em ACPÒ-106 sem gema de ovo (controle) ou contendo 5, 10, ou 20% de gema de ovo. Foi observada uma redução significativa no pH do diluidor com o uso de 20% de gema de ovo no segundo dia de resfriamento e após o terceiro dia nos grupos contendo 5 e 10% de gema. No primeiro dia de refrigeração o uso de 20% de gema de ovo possibilitou motilidade espermática superior apenas a do grupo contendo 5% de gema. Após cinco dias de conservação o uso de 5 e 10% de gema de ovo resultou em motilidade inferior ao do grupo controle. A motilidade sofreu redução significativa no primeiro dia no grupo controle, após dois dias no grupo contendo 5% de gema e após três dias nos demais grupos. O vigor, morfologia espermática e acrossomal, percentual de espermatozóides com membranas funcionais foram protegidas de maneira semelhante em todos os grupos testados. Diante do exposto, conclui-se que a inclusão de gema de ovo influencia a manutenção do pH no diluidor ACP-106 e que o sêmen pode ser conservado por até dois dias utilizando 10 ou 20% de gema de ovo. Different egg yolk concentrations on the quality of the canine semen diluted inACP-106 and chilled under 4 °CAbstractSemen chilling procedure preserves gametes without reaching the freezing point, which inducesdeleterious intracellular changes that affect viability and fertilizing potency of spermatozoa. Theaim of this work was to compare different egg yolk concentration for dog semen chilling at 5 °Cextended in ACP®-106. ACP-Ejaculated of dogs (n=10) were diluted and chilled in ACP -106 without(control group) or containing 5, 10 or 20% egg yolk. Was observed a significant reduction in extenderpH using 20% egg yolk on the second day of chilling and after the third day of chilling when using5 and 10% egg yolk. At the first day of chilling 20% egg yolk extender result in better sperm motilityin comparing 5% egg yolk group. After five days of storing, the use of 5 and 10% were inferior to thecontrol group. The reduction on motility was significant at the first day of chilling in the control group,after two days on group with 5% egg yolk and after three days in the other groups. The vigor, spermand acrossomal morphology, functional plasma membrane integrity were similar in all groups tested.In conclusion, the egg yolk influences the maintenance of the pH in the extender ACP-106 and thatthe canine semen can be efficiently conserved for up to two days using 10 or 20% egg yolk.