A multivariable path model of the interrelationships between herd-management policies and herd-level calfhood morbidity and mortality was constructed. Data were from 25 farms in the vicinity of Cornell University, and comprised records from all 962 heifer calves born between 1 November 1983 and 30 April 1985 who lived longer than 24 h and were kept to be raised as replacements. Outcomes of interest were herd-season-year cumulative incidences of the following clinical signs as diagnosed by farmers and recorded on check-off forms: scours/diarrhea within 14 days of birth and from 15 to 90 days of age; dull, listless, droopy ears or off feed within 90 days of birth; cough, runny nose or eyes, or trouble breathing within 90 days of birth; death prior to 90 days of age. Herd-management risk-factor data were based on information from a personal-interview questionnaire administered by the senior author, and were measures of policy rather than of what individual calves actually experienced. Random-effects logistic regression (logistic-normal regression) was used to model incidence rates and to account for the extra-binomial variation due to heterogeneity of disease risk between herds. Herd-management policies directly and indirectly 'affected' the herd cumulative incidences of morbidity and mortality. Farms reporting that calves had periodic, or no, access to water (compared to continuous availability) had less scours from 15 to 90 days of age and less dullness. Damp (versus dry) bedding, tying calves ( (by a collar and tether) versus not tying calves)), use of individual-calf hutches, and feeding milk once daily (versus twice daily) all 'increased' the chance of scours within 14 days of birth. Use of individual-calf stalls 'increased' the chance of scours from 15 to 90 days of age, but 'decreased' the chance of mortality. Feeding high-moisture ear corn to calves 'increased' the chance of scours from 15 to 90 days of age, suggesting that some of the later scours were of nutritional origin. Scours prior to 14 days of age and dullness (but not later scours) 'increased' the chance of respiratory illness. Only respiratory illness directly 'increased' the chance of mortality. Scours prior to 14 days of age and dullness were related to mortality indirectly via respiratory illness. Scours from 15 to 90 days of age were not related to mortality.
