Disbudding is in the short-term invasive and needs pharmacological pain treatment but it facilitates animal management. The present study investigates the longer-term consequences on behaviour to evaluate possible effects on animal welfare. Experiment 1 (E1) used 81 bulls up to the age of 12 and experiment 2 (E2) 71 heifers up to the age of 11 months. Half of the animals was disbudded at about 2 months of age. Different rearing conditions (RC) were compared, with animals housed in groups containing i) only animals with horns, ii) only disbudded animals, or iii) mixed (half with horns, and half disbudded; only in E1). Each rearing condition had two replicates. The effects of RC were studied on general activity and synchrony at 4 and 9 months (E1 and E2), and 7 and 12 months (only E1) of age. In E2 and during the last measuring period of E1, disbudding and mixing modified physical activity in the field. Behaviour during a novel object test (NOT) and a food competition test (FCT) were studied at 10 and 11 months of age, for E1 and E2, respectively. During the FCT, compared to disbudded, horned (unmixed) animals showed more agonistic interactions with contact in E1, and more agonistic behaviour without contact in E2. In the NOT, disbudded (mixed and unmixed) animals of E1 presented more fear-related reactions compared to horned animals while in E2, the opposite was found. In the NOT and FCT, mixed groups had intermediate levels for behaviours influenced by horn status. In conclusion, the behavioural traits influenced by horn status appeared to be at least partly associated with agonistic behaviour and fear, and may influence welfare status. However, depending on the experiment and the test, different negative and positive effects on welfare were found. The mixing of horned and disbudded animals in rearing groups may also modify the behavioural consequences of horn status.