New research involving more than one million Australian feedlot cattle has found that the strongest predictors of death from bovine respiratory disease (BRD) are established before animals even enter the feedlot, highlighting the importance of preventive measures on source properties.
The study, led by Adelaide University in partnership with Apiam Animal Health and Meat and Livestock Australia—and published in Preventative Veterinary Medicine—analysed health and production records from 1,040,253 cattle across three Australian feedlots between 2018 and 2024, making it the largest Australian investigation of BRD-specific mortality conducted to date.
While overall mortality rate in Australian feedlots is very low (less than 0.5 per cent), bovine respiratory disease is a leading infectious cause of illness and death in feedlot cattle and accounted for nearly 38 per cent of all feedlot deaths recorded in the study.
The team discovered that cattle from supplier properties with a history of elevated BRD mortality were more than four times as likely to die from the disease compared with cattle from lower-risk properties. This may provide a potential basis for using supplier history to identify higher-risk consignments before they arrive.
Researchers also found that where cattle were sourced mattered. Cattle purchased through saleyards had a significantly higher risk of BRD mortality than cattle sourced directly from paddocks, an association consistent with the additional handling, transport and commingling involved in saleyard procurement.
Importantly, the study showed that most BRD deaths occurred early in the feeding period. About 69 per cent of deaths happened within the first 60 days on feed, with the highest mortality risk occurring around day 35 after arrival.
“Our results show that the biggest drivers of respiratory disease mortality are already in place before cattle enter the feedlot,” senior author Professor Darren Trott said.
“Factors linked to the source property, the way cattle are managed before transport, and how they are vaccinated can have a profound impact on survival.
“However, a supplier’s risk profile should not be viewed as permanent. It needs to be continually updated as new performance data become available so that changes in risk can be recognised and management decisions adjusted accordingly.”
