Antibiotic use in small-scale dairy farming and residue levels of tetracyclines and sulphonamides in milk from Eastern Tanzania

The extensive use of antibiotics in small-scale dairy operations raises concerns regarding food safety and the development of antimicrobial resistance (AMR), especially concerning tetracyclines and sulphonamides. There is a scarcity of evidence connecting the practices of farmers to the levels of antibiotic residues found in Tanzania. This study aims to evaluate the knowledge, attitudes, and practices (KAP) of dairy farmers concerning antibiotic usage and to measure the levels of tetracycline and sulphonamide residues in raw milk from the Kisarawe District in eastern Tanzania. A cross-sectional study conducted from January to March 2024 involved 95 small-scale dairy farmers who completed a structured KAP questionnaire. The raw milk samples were tested for tetracyclines and sulphonamides using competitive ELISA techniques. The concentrations of residues were expressed as medians (IQR), and non-parametric tests were employed to explore associations with KAP areas. A significant majority, 81%, of the farmers exhibited inadequate knowledge, while 35% held unfavorable attitudes, and 58% displayed poor practices. Notably, 63% failed to observe withdrawal periods, and 76% obtained antibiotics from unauthorized sources. Sulphonamide residues were found in 94% of the samples tested, in contrast to 8% for tetracyclines; however, instances of residues exceeding maximum limits were rare (1.2% for sulphonamides and 2.4% for tetracyclines). The median concentrations of sulphonamides were consistently higher than those of tetracyclines across different wards (p < 0.01). A significant association was observed between farming practices and elevated residue levels, although knowledge and attitudes did not show similar associations (tetracyclines p = 0.043; sulphonamides p = 0.023). Antibiotic residues were frequently detected, yet most were within safe regulatory limits. The main contributors to residue levels were substandard practices, particularly failure to adhere to withdrawal times and improper sourcing of medications. Enhancing veterinary education, implementing behavioral change initiatives, and conducting regular residue monitoring are essential steps to ensure milk safety and address AMR challenges.