Bulk tank milk quality data is unlikely to give useful information about dairy cow welfare at herd level.

This research communication explores the value of routinely collected bulk tank milk quality data for estimating dairy cattle welfare at herd level. Selected bulk tank milk quality parameters (somatic cell count, total bacterial count, urea, protein and fat contents) recorded during the years 2014-2016 in 287 Italian dairy farms were compared with the animal welfare data of each farm. The welfare assessment data were extracted from the database of the Italian Reference Centre for Animal Welfare (CReNBA), which includes the outputs of the application of the CReNBA welfare assessment protocol for dairy cows, used at national level for on-farm controls. The statistical analysis was carried out using the correlation coefficient for Kendall's Tau ranks, in order to investigate the presence of a categoric relationship between the selected bulk tank milk quality parameters and the overall animal welfare score or the scores of the single areas A (farm management and staff training), B (housing) and C (animal-based measures). Somatic cell count, total bacterial count, urea and proteins demonstrated only a few statistically significant and very weak correlations with farm animal welfare data, while no significant correlations were obtained for milk fat content. Given the weak correlations found, the selected bulk tank milk parameters seems to be able to provide only limited information about the welfare level of the herd, thus it could be difficult to use them for drawing up a pre-screening model for identifying herds at risk of poor welfare.

Characterization of hazards, welfare promoters and animal-based measures for the welfare assessment of dairy cows: Elicitation of expert opinion.

An expert opinion elicitation, based on a modified Delphi technique, was organized to collect the opinion of 16 Italian veterinarians with the aim of conducting a hazard and a welfare promoter characterization for defining and weighing a list of management and housing factors potentially associated with negative or positive welfare outcomes in dairy cows kept in loose housing systems. In addition, the 16 experts judged a set of animal-based measures in order to rate them by appropriateness and by the level of animal pain and suffering due to the welfare consequences they measure. Veterinary experts were asked to score 52 hazards, 47 welfare promoters and 18 animal-based measures. Management and housing hazards, that were determined to be associated with a very high impact on the welfare of dairy cows, were mainly referred to lactating cows (absence of bedding material, presence of inadequate or slippery floor in walking areas, wrong design of the lying area), but also the use of harmful tools for animal handling and the lack of scheduled foot inspection, trimming and foot bathing reached very high impact scores. Management and housing welfare promoters dealing with optimal cow comfort around resting obtained the highest ratings, together with the presence of experienced and trained stockpersons, the implementation of an attentive animal grouping strategy and the control of temperature, humidity and ventilation. Considering animal-based measures, the highest ranking of importance was given to observation of lameness, records of mortality of adult cows and calves, observation of integument alterations and body condition scoring. This study has been the starting point for the development of the first Italian national protocol for the assessment of the welfare of dairy cows farmed in loose housing systems.