PhD in Veterinary Sciences for Animal Health and Food Safety

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Phd thesis

Modelling the risk of bacterial infections, within the framework of the evaluation of the health and welfare of dairy cows in the Northern Apennines

Many studies focus on dairy production on industrial farms. However, farming in mountainous areas helps maintain biodiversity, has a positive socio-economic impact on human communities and prevents risks related to land abandonment. We aim to characterize, from a microbiologic point of view, the remaining dairy herds in three different geographic areas of the northern Apennine.

To meet our objectives we intend to evaluate health indicators, compare mountain herds with industrial herds in the plain, search for mastitis pathogens, and eventually implement a participatory study that involves farmers in the research process.

Research activities

Up to date, we analysed the Italian Breeder Association (AIA) test-day records of 1314 dairy herds from 2015 to 2020 and calculated six health indicators (HI) to assess the health of dairy cows in Piedmont. At cow level, we analysed risk factors for each HI; at herd level, adjusted measures of each HI were used to explore their geographic distribution, comparing herds in mountains and plain, and assessing local aggregation.

On-field sampling was performed between April and September 2021. We sampled 16 herds and 246 lactating cows in three northern Apennine areas. Bacteriological analyses have been performed since July 2021 and provide the identification of 211 strains of mastitis pathogens. For each of them, we extracted and analysed the MALDI-TOF mass spectrum. Preliminary mass-spectra analysis showed that pathogens tend to cluster at the herd level. Also, different bacteriological patterns were observed in the geographical areas. Information about husbandry systems, biosecurity measures and antibiotic use were collected by interviewing farmers. A preliminary analysis showed there was a great deal of variability in milk yield and mastitis, not accompanied by equally high variability in the husbandry systems.

The national reference centre for animal welfare (CReNBA) provided us with welfare assessment scores for several herds we already analysed for HI. We intend to compare HIs and CReNBA evaluation with the scope of identifying herds at risk of poor animal welfare.

We send pathogen strains to Istituto Zooprofilattico Sperimentale of Torino to perform antimicrobial susceptibility testing (AST), measure the minimum inhibitory concentration (MIC) and search for Prototheca spp. The information will provide a detailed characterization of the strains of each herd, which will be furtherly deepened by means of whole-genome sequencing of the most relevant strains.

In collaboration with anthropologist Sarah Henry Whitaker, we are setting up a semi-structured interview about animal welfare and milking hygiene. Scheduled activity for the second year foresees the involvement of a small number of breeders in a training program aimed at improving udder health.