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  • Author or Editor: Anna-Maija K. Virtala x
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Objective

To describe causes of death, mortality, and morbidity from nonrespiratory diseases in dairy calves.

Design

Prospective observational cohort study.

Animals

Convenience sample of 410 dairy heifers born between January and December 1990 in 18 southwestern New York herds.

Procedure

Heifers were examined weekly by a veterinary clinician during the first 3 months of life and all disease conditions were recorded.

Results

Crude risks for diarrhea, umbilical infection, and umbilical hernia were 28.8, 14.2, and 15.1%, and the median ages at first diagnoses were 2, 1, and 3 weeks, respectively. Mean durations of umbilical infection and umbilical hernia were 3.7 and 6.7 weeks, respectively. Crude mortality was 5.6%. Case-fatality risks were 12.8% for diarrhea during the first week of life, 5.1% for diarrhea after the first week of life, and 0% for umbilical infection and umbilical hernia. Diarrhea was diagnosed by the caretaker or the clinician; umbilical conditions were diagnosed by the clinician. The primary cause of death was diarrhea in 43%, pneumonia in 24%, septicemia in 10%, and other single causes in the rest of the 21 necropsied calves.

Clinical Implications

The high incidence and somewhat long duration of umbilical infection, the finding that diarrhea was the primary cause of death, and the high case-fatality risk for diarrhea during the first week of life suggested that calf caretakers need training in the prevention and treatment of these conditions. (J Am Vet Med Assoc 1996:208:2043-2046)

Free access
in Journal of the American Veterinary Medical Association

Objective

To describe the incidence of respiratory tract disease in dairy calves and to compare antibody titers and microbial isolates from transtracheal wash samples between calves with and without respiratory tract disease (cases and controls, respectively).

Design

Prospective observational cohort study, with matched case-control substudy.

Animals

410 dairy heifers; in substudy, 105 cases and 59 controls from the same population.

Procedure

Calves were examined weekly by a veterinarian during the first 3 months of life. Blood samples were collected for serologic testing at the first visit for each calf and during acute and convalescent periods for cases. Transtracheal wash samples also were obtained during the acute period from cases and controls.

Results

Incidence and case-fatality risk for clinician-diagnosed pneumonia were 25.6 and 2.2%, respectively. Mycoplasma sp and Pasteurella multocida together were isolated from 29% of cases and 11% of controls, and Mycoplasma sp alone from 7% of cases and 30% of controls (both P ≤ 0.05). From postcolostral to acute-phase serum samples, Mycoplasma dispar titers increased 1.3-fold among cases, compared with 0.7-fold among controls; from acute- to convalescent-phase samples, Μ dispar titers increased 2.4-fold among cases, compared with 5.6-fold among controls (both P ≤ 0.005).

Clinical Implications

Results of this study suggested a synergistic effect between Mycoplasma sp and P multocida and a possible initiative role of Μ dispar in the development of respiratory tract disease. Postcolostral total IgG values and antibody titers were not significantly different between cases and controls, implying that other factors have an important role in the development of respiratory tract disease. (J Am Vet Med Assoc 1996;208:2035-2042)

Free access
in Journal of the American Veterinary Medical Association