Economic evaluation of Bovine Respiratory Disease on the Australian beef value chain

Bovine respiratory disease (BRD), a multifactorial disease, is the leading cause globally of mortalities and morbidity in the feedlot industry. The management of animal pre-induction to the feedlot has been shown to affect the disease outcome post induction. A range of risk factors contribute to disease incidence. Previous studies have investigated BRD incidence, severity outcomes and risk factors using information on animal health treatments at the feedlot and post-slaughter gross pathology scores at the abattoir. However, the economic analysis in this study includes the cost of BRD to the feedlot and abattoir sectors, whereas previous studies have focused on the feedlot sector.
This study was developed to evaluate the impact of BRD on economically important production and carcase traits and the subsequent cost to the value chain. A prospective cohort study (n = 1,799) was conducted at a large feedlot in the Riverina district of New South Wales to collect the data required to evaluate the cost of BRD. Animals were monitored from induction to slaughter using both electronically and manually collected data to ensure the accuracy of results obtained. Data were collected on induction records, animal health treatments and feed intake; in addition, Meat Standards Australia carcase data were collected. Post-slaughter gross pathology scores were collected manually for all animals, in addition to the commercially collected datasets. Regression analyses were used to identify associations between the disease, and the production and carcase traits. The multivariable analysis identified that an increased gross pathology score resulted in decreased average daily gain on feed (0.14 kg/day between health severely affected animals, P<0.01), reduced hot standard carcase weight (40kg reduction in HSCW for healthy and rejected animals, P<0.01), and eye muscle area (23.75cm2 reduction in EMA for healthy and rejected animals, P<0.01), on the carcase. The animal induction weight (P<0.01), producer (P<0.01) and pre-induction vaccination (P<0.01) were found to significantly affect the gross pathology score.
Next, the data from the prospective study were incorporated into an economic model for BRD. The model was developed to include the cost of disease to the feedlot and abattoir sectors. Animals were inducted into this trial during the autumn and spring (2011) into a southern NSW, Australia feedlot. The morbidity rate was between 35 and 78% with a mortality rate below 1%. The costs included in the final model were those for pre-induction vaccination ($2.49/head), induction treatments ($14.76 to $16.50/head), animal health treatments ($23.88 to 31.35/head) and mortality costs ($3.64/head), as an increased cost per head inducted to the feedlot. The significantly reduced hot standard carcase weight was the only variable included in the reduced value of carcases sold at $19.60/head inducted. BRD was estimated to cost the abattoir sector $8.70/head, through reduced primal sales and offal sales. The overall cost of BRD to the feedlot value chain was estimated to be between $71.31 and $80.53/head, the cost of BRD presented varies due to seasonality, incidence rate, treatment regium and feedlot. These costs are higher than those estimated by previous studies. Overall, the study developed a multidisciplinary economic model which utilities epidemiological and financial analysis to evaluate the cost of disease from induction to slaughter of grain-fed animals, which was tested using BRD as a case study. BRD is a significant cost to the feedlot with a small portion of cost impacting the processing sectors such as reduced offal sales. The evaluation of the cost of disease needs to be considered at the supply chain level rather than at each individual sector.