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Trends in mortality ratios among cattle in US feedlots
G H Loneragan1, D A Dargatz, P S Morley
1Department of Clinical Science, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Ft Collins 80523, USA.
Journal of the American Veterinary Medical Association
|November 10, 2001
Summary
Feedlot cattle mortality did not significantly increase overall, but respiratory disease deaths rose, impacting beef heifers and dairy cattle. These findings suggest potential adverse production effects in surviving animals due to increased non-fatal respiratory illnesses.
Area of Science:
- Veterinary epidemiology
- Animal health economics
- Livestock production management
Background:
- Feedlot cattle mortality rates are a critical indicator of animal welfare and economic viability in the beef industry.
- Understanding trends in mortality by body system and animal type is essential for targeted disease prevention and management strategies.
Purpose of the Study:
- To analyze temporal trends in feedlot cattle mortality ratios.
- To investigate mortality patterns based on the primary body system affected.
- To compare mortality risks across different cattle types (beef steers, heifers, dairy cattle).
Main Methods:
- A retrospective cohort study design was employed.
- Data from approximately 21.8 million cattle across 121 U.S. feedlots (1994-1999) were analyzed.
- Poisson regression models were used to assess mortality trends and relative risks over time and by animal type.
Main Results:
- The overall mortality ratio averaged 12.6 deaths/1,000 cattle, with a non-significant increase from 1994 to 1999.
- Cattle entering in 1999 showed a significantly higher risk of death from respiratory tract disorders (RR, 1.46) compared to 1994 entrants.
- Respiratory tract disorders constituted 57.1% of all deaths; dairy cattle and beef heifers faced increased mortality risks for specific causes compared to beef steers.
Conclusions:
- While overall feedlot mortality did not significantly rise, a concerning increase in deaths due to respiratory tract disorders was observed.
- Elevated fatal respiratory disease rates may indicate a concurrent rise in non-fatal cases, potentially impacting the productivity of surviving feedlot cattle.
- These findings underscore the importance of respiratory disease surveillance and control programs in feedlot operations.