Pneumonia Prevalence in Pre-weaned Dairy Calves

Betsy Karle, UCCE Dairy Advisor, Northern Sacramento Valley

During the summer and early fall of 2014, we visited 31 dairies in three regions of Northern California (Humboldt, Del Norte- Region 1; Sonoma, Marin, Mendocino- Region 2;  Glenn, Tehama, Yuba- Region 3).  We completed a survey focusing on calf management practices and scored calves on the dairy using the California Bovine Respiratory Disease (BRD) scoring system (Figure 1).  The scoring system was developed to be accurate, rapid, cheap, reliable and simple and correctly identified 72.2% of calves with BRD and 89.9% of healthy calves in a validation study.  Calves were considered positive for BRD if their score was equal to or greater than five.                   

A total of 1,438 calves were evaluated in this study.  The average BRD prevalence was 10.2% and ranged from zero to 37%.  The difference in prevalence across the regions was not statistically significant.  The observed prevalence of BRD in Holstein calves was 7.2%, compared to 15.9% and 12.1% for Jerseys and all other breeds, respectively.  Jersey calves were 2.2 times more likely to be positive for BRD in this study.

Figure 2. Group housing and BRD prevalence.

 More than half (54.8%) of the dairies visited were certified organic and were located exclusively in Regions 1 and 2 on the North Coast.  Overall BRD prevalence was 10.5% on organic dairies and 10.8% on conventional dairies, which was not statistically different.

About 70% of the dairies surveyed used some degree of group housing for pre-weaned calves, with pens containing between 2 to 40 calves (Figure 2).  Group housing was correlated with increased odds of BRD compared to calves that were housed individually.  Each additional calf in a pen was associated with a 7% increase in BRD.

Our initial analysis of the data underscores that no single management practice is responsible for pneumonia in pre-weaned calves and there is a need to further examine risk factors.  We would like to collect additional data from the San Joaquin Valley and analyze further management practices that affect prevalence of pneumonia in pre-weaned dairy calves.  For training on the California BRD Scoring System or to participate in this study, please contact Betsy Karle (bmkarle@ucanr.edu, 530-865-1156) or Dr. Sharif Aly (saly@ucdavis.edu, 559-688-1731).

Link to PDF Version: Pneumonia Prevalence in Pre-weaned Dairy Calves