Understanding farmers' naturalistic decision making around prophylactic antibiotic use in lambs using a grounded theory and natural language processing approach.

The routine use of antibiotics for prevention of disease in neonatal lambs has been highlighted as inappropriate, yet research suggests that many farmers in the UK still carry out this practice. The aim of the study was to understand farmers' naturalistic decision-making around prophylactic antibiotic use in lambs. Data from 431 posts by 133 different users of an online discussion forum were analysed quantitatively using natural language processing and qualitatively using a grounded theory approach. Results from the qualitative analysis identified five categories that influenced farmers risk perceptions around prophylactic antibiotic use in lambs: anticipated regret, negative emotions and experiential avoidance; economic considerations; farmer identity; perception of capability; and perception of social judgement. Natural language processing analysis of the posts by the study group were compared to posts on topics unrelated to antibiotic use by control groups from the same forum to understand the underlying style and tone within the text. Analytical thinking and authenticity scores were significantly lower in the study group compared to the control groups (P < 0.01). Words relating to cognitive processes were significantly higher in the study group compared to the control groups (P < 0.01). Results of the qualitative and quantitative analysis were integrated to assess the fit of the data and enhance findings from either method alone. The key findings were the identification of reasons why farmers used antibiotics prophylactically in neonatal lambs. Farmers disassociated the use of oral antibiotics in neonatal lambs from other types of antibiotics within sheep farming. Farmers used the concept of luck and uniqueness to justify their prophylactic antibiotic use. This may explain farmers' low analytical thinking scores as this reflects a more personal style of thinking as farmers express their thoughts on antibiotic use on an individual basis. Farmers' felt that they did not have the capabilities to control neonatal disease without antibiotics during busy periods and this was exacerbated by external economic constraints. For farmers' who used antibiotics for therapeutic use, fear of social judgement was an important factor in their perceptions of risk around antibiotic use. The high frequency of negations and conjunctions suggested feelings of moral duty. As such, antibiotic use has developed into a symbol of their good farming identity which conflicted with the identity held by those who used antibiotics prophylactically. These results can be used to inform knowledge exchange around prophylactic antibiotic use in lambs to improve antibiotic stewardship in the sheep farming sector.