The objective was to evaluate the chemical composition and in vitro fermentation of spineless cactus of the genus Nopalea, F-21 (Nopalea cochenillifera Dyck), IPA-Sertania (Nopalea cochenillifera Dyck) and Mi & uacute;da (Nopalea cochenillifera Salm Dyck), in different phenophases. There was no effect (P < 0.05) of the phenological phases of spineless cactus on DM, ash, OM, EE, and CP. Varieties F-21 and Mi & uacute;da presented higher values of DM and OM, whereas the CP was higher for IPA-Sert & aring;nia. The contents of NDF, ADF, and ADL, as well as the fractions of carbohydrates B2 and C were higher in the mature stage, irrespective of the variety. The Mi & uacute;da variety showed higher levels of NFC and fractions A + B1 and the lower levels of pectin compared to the F-21 and IPA-Sert & aring;nia varieties, but not differ of TC to F-21. The volume of gas produced via the degradation of NFC was higher for young phenological phases. The young and intermediate stages showed a higher in vitro digestibility of DM. Based on the results, varieties IPA-Sertania and Miuda have a high potential for use in animal feed because of their high nutritional quality. Mature cladodes showed a higher fibrous fraction and lower digestibility in all varieties.