Prevalence and contamination levels of aflatoxins in dairy cattle feeds from milk bulking groups in Malawi

There is limited information about the natural occurrence of aflatoxins in dairy feedstuffs in Malawi. The aim of this study was to determine the natural prevalence rate of aflatoxins and quantify aflatoxin contamination levels in dairy cattle feeds collected from smallholder dairy cattle farms distributed across Dzaonewekha, Chitsanzo, Mpemba, Kavuzi and Lusangazi Milk Bulking Groups (MBGs) over three seasons in 2017. In total, 51 samples of feeds from 18 smallholder dairy farms were investigated. Immunoaffinity column chromatography coupled with solution fluorometry was used for quantification of aflatoxin with a detection limit of 1 μg /kg. Aflatoxin was detected in 88.2% of the samples with overall mean total aflatoxin contamination level of 30.57±5.44 ppb (19.36 ppb to 41.78 ppb, 95% confidence interval). Furthermore, 62.7% of the positive samples exceeded the EU limit of 5 ppb. Aflatoxin levels for Chitsanzo and Dzaonewekha MBGs differed significantly (P=0.0001) from those of Lusangazi, Kavuzi and Mpemba MBGs (5.21±12.85ppb and 5.45±14.37ppb vs. 63.38±11.36ppb, 39.57±10.67ppb and 30.08±11.73ppb, respectively for Mpemba, Lusangazi, and Kavuzi, MBGs). The study has reported a high aflatoxin prevalence rate in dairy cattle feeds and that levels of aflatoxin differed significantly by MBGs and season but not by feed type. No interaction was observed between feed type, season and MBG. There is therefore a great need for advocacy in enforcement of regulatory standards on aflatoxin control in Malawi to reduce aflatoxicosis hazards to both humans and livestock.