A review of veterinary literature on morbidity or mortality rates in feedlot cattle was performed. Incidence (attack) rates were the only types of rates reviewed. Differences in the definition of terms made reports difficult to compare. Case-definitions were often poorly defined and most were based on chemotherapeutic treatment as a criterion. A summary was made of 14 comparable studies containing disease incidence rates in calves in the first few weeks following arrival in feedlots. The incidence of morbidity ranged from 0% to 69% with most reports between 15% and 45%. The mortality rate in the same period ranged from 0% to 15% with most reports between 1% and 5%. The peak incidence of disease was within the first three weeks after the arrival of calves in the feedlots. Few other epidemiological descriptions (season, day of the week, geographical, age, sex, or breed) had been objectively described. The most common clinical and necropsy diagnoses were respiratory infections, often described as shipping fever.
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