Determining frequency of mortality by cause and association with days-of-age categories at 2 commercial calf ranches

Limited information is available describing mortalities of dairy and beef-dairy-cross calves in calf ranches. Study objectives were to report frequency of gross mortal­ity diagnoses at necropsy in calf ranches and determine associations of age with diagnosis. Necropsies (n = 211) were performed at 2 Kansas calf ranches by field technicians with confirmed diagnoses by a single veterinarian. Mortality diagnoses were categorized as gastrointestinal (GI), respiratory (RESP), septicemia or other based on gross lesions. A subset of calves had age data (n = 145) which were categorized as (1 to 29, 30 to 59, 60 to 89, and greater than 90 days). A generalized linear model was used to evaluate probability of being classified as RESP or GI diagno­ses based on breed type, sex and age categories. Gross necrop­sy revealed 71.1% (150/211) of mortalities were categorized as RESP, 18.5% (39/211) as GI, 7.1% (15/211) as septicemia, and 3.3% (7/211) as other. Breed type and sex were not associated with probability of RESP or GI diagnosis. Calves greater than 60 days of age were at greater (P < 0.05) risk (88 ± 4%) for RESP diagnoses compared to calves less than 30 days (37 ± 8%). Probability of GI diagnosis (46 ± 8%) was greater (P < 0.05) for calves less than 30 days compared to calves between 60 and 89 days (5 ± 3%). The frequency of multiple disease processes em­phasizes the importance of necropsy to determine diagnosis in each case. These data add valuable information about mor­talities in calf ranches.