Sorghum ergot (Claviceps africana) associated with agalactia and feed refusal in pigs and dairy cattle

Abstract

Objective: To establish the aetiology and define the main clinical features of a syndrome characterised by severe feed refusal, death of piglets and reduced milk production in pigs and dairy cattle.

Design: Clinical, pathological, toxicological and epidemiological examination of clinical cases in 10 piggeries and 4 dairies, located between 50 and 150 km south-west of Rockhampton.

Results: All cases were associated with the feeding of sorghum grain infected with sorghum ergot (Claviceps africana). There was mild to severe feed refusal when the sorghum was first offered. Sows fed ergot before farrowing had shrunken udders, produced no colostrum, and displayed signs of oestrus. All of their piglets died, apparently from starvation: necropsy of a few piglets showed that they were born alive and walked, but had ingested no milk. Sows fed the grain after farrowing had severe reductions in milk production despite aggressive sucking by piglets, leading to very poor growth of piglets. There were no signs of infectious disease. Ergot in sorghum samples ranged from 1 to 31% ergot sclerotes by weight. Total alkaloid concentrations in mixed feeds ranged from 5 to 40 mg/kg, with dihydroergosine accounting for approximately 90%. At the same time, in the same districts, there were reports of feed refusal and reduced milk production from 4 dairy farms. Grain samples from these farms contained up to 17% C africana ergot sclerotia.

Conclusion: Agalactia and feed refusal are classical signs of poisoning by rye ergot (C purpurea), but this is the first time that sorghum ergot has been associated with a similar syndrome.