Our objective was to study the effects of pneumonia (cumulative incidence, 25%), diarrhea (29%), umbilical infection (14%), and umbilical hernia (15%) on BW and height gains during the first 3 mo of life. Female dairy calves (n = 410) born from January to December 1990 in 18 commercial herds in New York state were used. Average daily gains during the 1st, 2nd, and 3rd mo were 374, 596, and 719 g, respectively; average gain was 565 g during the 3-mo period. Average monthly height gains during the 1st, 2nd, and 3rd mo were 4.4, 5.6, and 5.7 cm, respectively. Use of multiple linear regression, with farms treated as random effects, indicated that treated, verified pneumonia was associated with a reduction in average daily gain of 66 g and that failure of passive transfer reduced average daily gain by 48 g during the 1st mo. During the 2nd mo, neither disease nor failure of passive transfer affected average daily gain. During the 3rd mo, each additional week of pneumonia reduced average daily gain by 14 g, and umbilical infection reduced average daily gain by 96 g. Each additional week of diagnosed pneumonia reduced total BW gain during the first 3 mo by 0.8 kg. Similarly, each week of pneumonia reduced total height gain by 0.2 cm and failure of passive transfer by 0.9 cm. Prevention of chronic pneumonia and umbilical infection may improve average daily gain of calves.

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)

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)

Puumala hantavirus (PUUV) is apparently transmitted to humans by inhalation of aerosolized secretions of carrier rodents (bank voles). The means of transmission and the associated risk factors are poorly defined. An epidemiological study during the peak of an epidemic season in Finland was conducted based on 282 acute clinical PUUV infections and 204 controls without PUUV infection or immunity. The main risk factors adjusted by age, sex and living environment were cigarette smoking [odds ratio (OR) 3·6, 95% confidence interval (CI) 2·1–5·9, P<0·0001] and buildings with holes allowing rodents to enter (OR 3·3, 95% CI 2·0–5·6); these results were similar in two subsets. Further, use of rodent traps (OR3·5, 95% CI 2·2–5·7) and handling firewood (OR 2·7, 95% CI 1·6–4·4) were associated with a risk. The risk attributed to smoking also remained high using simulated population controls with average smoking habits. The results suggest that hantavirus transmission occurs by inhalation mainly indoors and is dependent on the condition of the respiratory tract.