Feed-related incidents, such as the incorrect formulation or contamination of feed with toxic substances can result in significant illness and welfare problems in animals, as well as having considerable cost implications for the farmer and the feed company. There is also the possibility of contaminated animals or their products entering the food chain. Early detection and good communication channels between the various sectors of the farming and veterinary community are therefore essential to deal with such cases. This short communication reports the identification and risk management of several cases of hypervitaminosis A in lambs due to incorrect formulation of some batches of milk replacer. In April 2011, the Animal Health and Veterinary Laboratories Agency (AHVLA) investigated the cause of unusual clinical signs in lambs. These were orphans and surplus lambs removed from ewes with triplets. They were between three and 40 days of age and were fed milk replacer through communal feeders. Postmortem material was received from 10 flocks, and four affected farms were visited. Lambs were exposed at different ages because of differing management practices and the timing of the introduction of the incorrectly formulated batch of milk replacer. Irrespective of the age of the lambs, clinical signs of malaise and wet greasy fleece were seen within 24–48 hours of exposure. After two to seven days the affected lambs developed a pungent uraemic smell and moist erythematous skin of the axillary, inguinal and perineal areas resembling urine scald. After seven to 14 days of exposure, alopecia and lameness reminiscent of infectious arthritis (‘joint ill’) with a hunched posture and reluctance to stand or walk were described. Excessive thirst was described in some affected groups. The morbidity within the first two weeks of exposure was 50–100 per cent. Mortality ranged from 0 to 20 per cent. Lambs on the same farms that were …