Suitable systems for the assessment of animal welfare are in increasing demand. In Austria, the TGI 35 L Animal Needs Index is widely used and has been shown to be a feasible and reliable tool for animal welfare assessment on farms. Here we focus on the validity of TGI 35 L assessments, and explore the correlation between animal welfare as assessed by the TGI 35 L and animal health and behavioural parameters. From the results, it can be determined whether the criteria assessed by the TGI 35 L are preconditions for a high level of health and normal behaviour. Behaviour and health were examined in 11 cattle houses, totalling 169 animals. Behaviour was observed for two days on each farm. Data on resting behaviour, comfort behaviour, social behaviour, feed intake behaviour and eliminative behaviour were collected. Health was assessed using veterinary examinations carried out according to the General Clinical and the Orthopaedic Examination Proceedings. Significant correlations were found between the TGI scores and behaviour and health, including results for skin lesions and injuries. This indicates good validity of the TGI 35 L assessment system for cattle. A comprehensive system for the assessment of animal welfare on farms must comprise parameters of housing, climate, management and stockmanship, and animal-related parameters.