CASE NOTES

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Sudden Death in White Suffolk Ram Lambs

Harry Suddes, District Veterinarian Murray RLPB and Alison Neef, Veterinary Intern Sydney University

Posted Flock & Herd May 2007

History

The owner of a grazing property near Jerilderie found sixteen out of 100 white Suffolk ram lambs dead against a self-feeder. They were some of the heaviest sheep in the mob, and were running in a bare 300 acre paddock. The feeder contained a mixture of lupins, barley, and milled wheaten hay with no added urea. The other sheep in the paddock were all healthy.

Other sheep on the property were on the same feed with no ill effects. There were no overhead or underground powerlines. A couple of days before the owner found the rams he commented that that there was storm activity with thunder and lightning recorded in the area.

Clinical examination

As the dead sheep were decomposed a post-mortem examination was not performed. The other sheep in the mob were all healthy.

Sixteen sheep found in a pile. NB photo taken after self feeder moved away

Discussion

Given that the sixteen sheep were all found dead in a pile, and all other sheep in the mob were healthy, we thought the most common causes of sudden death including clostridial diseases, plant or chemical poisonings, grain poisoning, salmonellosis and anthrax were unlikely.

We considered that the following causes of sudden death were most likely in this case

• Lightning strike
• Asphyxiation (due to crowding around the feeder and subsequent smothering)
• Urea poisoning

We ruled out urea poisoning because the farmer did not add urea to the feed. We thought asphyxiation was unlikely because these were robust White Suffolk ram lambs not physically and cerebrally challenged Merino weaners and two sheep were a small distance from the rest of the pile.

We think it is most likely that lightning struck the feeder while the sheep were eating killing all 16 rams.