Research Summary - 4
Associations between preweaning calf health and environmental conditions on individual cow-calf operations in Nebraska
| Date/Time: |
9/13/2025
16:15
|
| Author: |
Lindsay Waechter-Mead |
| Clinic: |
Nebraska Extension |
| City, State, ZIP: |
Red Cloud, NE 68970 |
L.L. Waechter-Mead, DVM, MS
1
;
W.I. Jumper, DVM, PhD, DACPVM
2
;
B.L. Vander Ley, DVM, PhD, DACPVM
3
;
1Nebraska Extension, University of Nebraska-Lincoln, Red Cloud, NE 68970
2Dept of Pathobiology and Population Medicine, Mississippi State University, Mississippi State, MS 39762
3Great Plains Veterinary Educational Center, University of Nebraska-Lincoln, Clay Center, NE 68933
Introduction:
Neonatal calf health is an important factor of productivity and profitability in the beef industry, influencing growth and long-term performance. Environmental stressors may contribute to health challenges, especially when calving occurs during highly variable late winter/early spring weather. In 2007, 6.4% of the United States calf crop was either born dead or died prior to weaning. Of these 6.4%, twenty-five percent of the calves that were less than 3 weeks old died from weather related causes and 10% of calves that were older than 3 weeks old died from the effects of adverse weather conditions. In addition to weather, digestive and respiratory disease are two big drivers of calf mortality. Of calves 3 weeks of age and older that died in 2007, more than one-half died from digestive or respiratory disease. Morbidity also leads to economic loss, with preweaning bovine respiratory disease costing the United States beef cow-calf industry $165 million annually. The objective of this study was to characterize environmental and management risk factors that contribute to preweaning calf health outcomes in cow-calf operations in Nebraska.
Materials and methods:
This prospective observational field study was conducted over three spring calving seasons from 2021 to 2023. Calving management and environmental factors were collected from six cow-calf operations in Nebraska. Data collection included calving date, occurrence of dystocia, environmental conditions present at calving, which included: shelter and/or wind protection, ground conditions (bedding, mud, ice, snow, dry, wet, fecal contamination), and ambient temperatures. Data collection also included calf treatment information, focusing on diseases of interest of pneumonia and diarrhea. Data was collated into Microsoft Excel and descriptive statistics were performed. Logistic regression was used to test the association between the outcome of interest and explanatory variables. Following correlation and collinearity diagnostics, univariable models were assembled for each explanatory variable for each operation. Manual forward variable selection was then used to assemble multivariable models.
Results:
Of the 3,268 calves analyzed in the study, 492 (14.9%) experienced adverse health events other than pinkeye. Statistical analysis was performed on each herd independently. Snow present at birth was significantly associated with illness in Herd A (p<0.04). A 10-degree increase in average temperature on the day of birth was significantly associated with a 47% reduction in odds of illness in Herd D (p = 0.02). The association between birth year and calf illness was significant in Herd F (p = 0.0008). Date of individual calf birth relative to the start of calving season was significant in three herds. Herd B calves born one week later in the calving season had a 23% reduction in odds of illness compared to calves born a week earlier (p = 0.01). Herd E calves had a 13% reduction in odds of illness for every 14-day increase in age (p = 0.0015). The odds of developing illness decreased by 43.5% for every 14-day increase in age in Herd F calves (p = 0.0001). There were no significant associations between all variables tested and calf illness in Herd C (p>0.05) due to small sample size (n=3).
Significance:
Substantial confounding among environmental and management variables across the six operations prevented the use of a unified model. As a result, each operation was analyzed independently to better identify factors influencing calf health. The findings indicate that environmental conditions, management strategies, and other related factors interact in complex ways to affect outcomes. Therefore, we conclude that the tactics used will have variable results depending on the specific operation and consequently any changes should be monitored for efficacy locally. Further research is warranted to understand the herd-specific environmental factors that influence preweaning beef calf health.
