Relation of aflatoxin M1 contamination with milk production, health, and reproductive performance of commercial dairy herds in Punjab, Pakistan.

Aflatoxins in feedstuffs of dairy animals are recognized as a serious threat in terms of milk contamination and compromised animal performance. This survey investigated dairy cow performance at randomly selected 30 commercial Holstein Friesian farms, in addition to the estimation of aflatoxin contamination of milk with subsequent division of farms in two groups of low (< 0.5 µg/kg) and high aflatoxin M1 (> 0.5 µg/kg) farms. A pre-planned questionnaire was designed to investigate the production performance, reproductive efficiency, and health disorders of the dairy cows. Results of the study showed that farms with high aflatoxins had low 3.5% fat corrected milk yield by 23.2%, resulting into decreased feed efficiency. Milk fat, protein, and lactose yields were also decreased by 17.2, 27.0, and 19.6%, respectively in farms with high aflatoxin contamination. The number of repeat breeding cows tended to be higher leading to an increase in calving interval of herds with high aflatoxins. Mastitis, as a health indicator, numerically increased from 6.44% in low aflatoxin farms to 14.0% in high aflatoxin farms. However, no difference observed in udder oedema, lameness, body condition score, and retained placenta except for a numeric increase in services per conception with aflatoxin contamination. In conclusion, farms with high aflatoxin M1 contamination in milk had decreased herd performance through reduced milk production and poor reproductive efficiency in commercial setup.