A slightly lower rate of airflow to the cargo compartment of the plane may have caused 174 sheep meant for the recent korban ritual to die of heat stress, said the Islamic Religious Council of Singapore (Muis) in a statement on Tuesday.
There was no indication of infectious disease, said the statement.
The Singapore authorities launched an investigation after 174 sheep imported from Australia for the korban ritual to mark Hari Raya Haji died during the flight from Perth earlier this month. The sheep were part of a consignment of 2,200 sheep imported by Mini Environment Services via a Singapore Airlines cargo plane.
It was the first time so many deaths had occurred in such a consignment.
"Investigations from SIA Cargo showed that the aircraft had departed Perth, Australia in fully serviceable condition," said the Muis statement.
"However, a few hours into the flight, one of the three air-conditioning packs on the aircraft produced a slightly lower rate of airflow to the cargo compartment on an intermittent basis. This lower airflow rate affected a small section of the aircraft and may have caused a disruption of temperature in that section of the aircraft."
The statement added that investigations by the Agri Food and Veterinary Authority of Singapore showed that the sheep died of heat stress.