Blood prolactin depression in growing pigs fed sorghum ergot (Claviceps africana)

The toxicity of sorghum ergot (Claviceps africana) was assessed in young pi gs over 28 days. Forty-eight pigs of both sexes and 2 breeds (Large White a nd Duroc) were allocated across 6 grower diets, balanced for fibre and pred icted digestible energy, and containing 0, 0.3, 0.6, 1.3, 2.5, or 5% ergot sclerotia [the 5% sclerotia diet contained 70 mg alkaloids/kg (> 90% dihydr oergosine)]. Blood samples taken on Days 0 and 28 were analysed for prolact in and clinical, biochemical, and haematological indices of health. Feed co nsumption and liveweight were individually monitored. There were no clinica l signs of illness attributable to ergotism in the pigs. Blood prolactin co ncentrations were significantly depressed in pigs receiving 9 mg alkaloids/ kg (0.6% sclerotia) and by >80% in pigs receiving 35 and 70 mg alkaloids/kg , clearly indicating a potential to interfere with lactation in sows. Reduc tions in feed intake and poor feed conversion were observed over the first 7 days with >9 mg alkaloids/kg, but some tolerance developed later. Feed re fusal was more pronounced for pigs of the Duroc breed. Over the full trial period, growth was reduced by about 30% in pigs receiving 70 mg alkaloids/k g, as a result of poor feed intake and feed conversion. Digestible energy o f diets containing ergot was later found to be lower than predicted, which contributed to this result.