Health implications and toxicokinetics of short-term graded dietary exposure of Ochratoxin A in dairy cows

Ochratoxin A (OTA) is a nephrotoxic and hepatotoxic mycotoxin commonly found in animal feed, posing health risks to dairy cattle and potential contamination of dairy products. This study examined the effects of short-term (7-day) dietary OTA exposure on dairy cow health and the distribution of OTA and its metabolite ochratoxin α (OTα) across different biological matrices, including plasma, serum, milk, urine, and faeces. Twelve Simmental cows were randomly allocated into two groups receiving either a low (LD, 5 mg/cow/day) or a high (HD, 50 mg/cow/day) OTA dose. Cows were monitored for health parameters including blood chemistry and haematology, chewing, milk and faecal parameters, as well as for the kinetics of OTA from feed to blood, urine, milk and faeces. OTA and OTα were analysed using HPLC-MS. No significant health effects were observed, except for a slight decrease in faecal scores (LD: 2.72 vs. HD: 2.35) and an increase in chewing activity in the HD group (LD: 53.3 vs. HD: 59,9), both within normal ranges. Plasma and serum OTA and OTα levels stabilised after 60 h of exposure, with OTα dominating in faeces and urine, indicating efficient metabolism. OTA was not detected in milk. The results suggest that daily OTA exposure up to 50 mg per cow for seven days does not harm cow health or contaminate milk.