A high level of public concern about the welfare of farm animals and compliance with international standards and consumer requirements is triggering the development of animal welfare assessment systems and their implementation on dairy farms. In addition, the welfare assessment allows identification and assessment of existing problems of animal welfare on the farms, allows farmers to solve these problems and ensure proper management, monitor compliance with legal requirements, identify risk factors that have a potential negative impact on animal welfare, present objective information on systems of keeping animals for consumers. The aim of the research was a modern meta-analysis of criteria related to the direct response of animals and their impact on welfare, as well as justification of the use of criteria in systems for assessing the welfare of dairy herd animals. The research data presents an analysis of the direct criteria and justification of the system of 10 protocols and standards for the welfare of the dairy herd, namely: Cow Comfort, Welfare Quality, IDSW, Code of Welfare, Svenskt Sigill, Freedom Foods, AssureWel, RSPCA Dairy Standards, NSF Global Animal Wellness Standards, ClassyFarm. All parameters investigated in these protocols were divided into two groups: 1) indirect -based on resources (farm management, housing conditions) and 2) direct -based on the animals themselves (behaviour, health). It has been established that objective results of the assessment of welfare can be obtained using direct criteria, namely the study of behaviour (postures and gaits, during rest, interaction with humans or other animals, the presence of stereotypical behaviour or positive states, vocalization) as well as health criteria I (lameness, calving, cleanliness and condition of the animal's coat, presence of complications from surgical procedures). Research on indirect animal welfare criteria and protocols will be covered in our next articles.