Grad Student Competition
Effect of Dehydration on Physiological Changes and Vaccine Response in Shipped Calves
| Date/Time: |
8/28/2026
10:45
|
| Author: |
Ashley Boone |
| Clinic: |
University of Georgia Department of Population Health |
| City, State, ZIP: |
Athens, GA 30605 |
Ashley Boone, DVM
1
;
Roy Berghaus, DVM, MS, PhD, DACVPM (Epidemiology)
1
;
Bradley Heins, DVM, MFAM, DACVPM
1
;
Emmanuel Rollin, DVM, MFAM
1
;
1Department of Population Health,University of Georgia College of Veterinary Medicine, Athens, GA 30601
Introduction:
The objective of this study was to evaluate the effects of induced dehydration on the physiological changes and vaccine response of 9-month-old calves after shipping.
Materials and methods:
10 weaned Holstein bulls (305.5 +/- 14.75 kg) were randomly assigned to 2 groups prior to shipping. Treatments were as follows: (1) fluid bolus: bolus of water via ororumen tube prior to shipping (0.57(BW/45.4) L) and (2) control: no fluids prior to shipping. Calves were held off of feed and water overnight and then shipped for 8 hours on day 0, with samples being collected pre-shipping (timepoint 1), mid-shipping (timepoint 2), and post-shipping (timepoint 3) and calves were vaccinated with a parenteral modified live Bovine Diarrheal Virus vaccine following sample collection at timepoint 3. Calf body weight and blood samples were collected on days -2, -1, 0 (timepoints 1, 2, 3), 1, 2, 5, 7, 17, 24, and 38. Complete Blood Counts and serum biochemistry was performed on days -2, -1, 0 (timepoints 1 and 3), 1, 2, 5, and 7 and Bovine Viral Diarrhea Virus titers for both type 1 and 2 were performed at days 1, 8, 10, 17, 24, and 38 post-vaccination. All variables were analyzed using the MIXED model on STATA.
Results:
There was a significant correlation between body weight and time, with day 0 timepoint 3 having a significantly decreased body weight compared to all other timepoints (p<0.001). This indicates that all calves experienced considerable shrink during the course of the shipping day, representing a potential welfare and increased health risk. There was a significant correlation between time and plasma osmolality on timepoint 3 on day 0 (p<0.001), with Bonferroni groups showing a higher plasma osmolality at this timepoint when compared with any others, indicating that our experimental model of dehydration was successful. Pre-study titers confirmed all calves were naïve to Bovine Viral Diarrhea Virus prior to the initiation of this study, and no calves showed a titer response prior to day 24 following vaccination. No significant interaction was seen between treatment group and vaccine response, but there was a trend indicating that calves in the treatment group receiving the oral fluid bolus had higher titer levels for BVD type 1 at day 38 than those within the control group (p=0.056).
Significance:
While titer levels aren’t necessarily directly correlated with degree of protection, the more robust response within the bolused calves may represent an avenue for more appropriate management within our shipped population. There is no well-established reference range for plasma osmolality within our sample population (weaned calves), but our finding of significant elevation following shipping may indicate a value representing hydration status and risk level, creating a possible decision point in health and welfare management of calves entering feedlots or stocker facilities. While effect of treatment was not consistently statistically significant, the sample size was small and therefore didn’t allow for adequate power or comparison. The findings and trends represented within this pilot study are promising and warrant further investigation into the role of dehydration on calf health as they move into the next phase of production.
