Student Case Presentation
A comparison of the performance of Holstein heifer calves classified by thoracic ultrasound at two time points
| Date/Time: |
8/27/2026 Poster 11
|
| Presenter: |
Jillian Grantz |
| Veterinary School: |
PUR |
Abstract:
The objective of this study was to compare the performance of 851 Holstein heifer calves classified into four groups by thoracic ultrasounds (TUS) performed at 28-34 days of age (TUS1) and repeated at 51-57 days of age (TUS2). Calves were classified based on TUS scores as follows: no lung consolidation at both time points (Clean); clean TUS1 and lung consolidation on TUS2 (New Infection); lung consolidation on TUS1 and no consolidation on TUS2 (Cured); lung consolidation at both time points (Chronic). Each TUS was scored using the University of Wisconsin Calf Lung Ultrasound Scoring system and was determined independently by two study personnel. Calves were considered to have consolidation at a score ≥2. Weights were obtained at birth and at each TUS using a weight tape designed for Holstein calves. An additional weight was taken at 100 days of age using a scale. Farm personnel assessed the health status of all calves using the University of Wisconsin Calf Respiratory Scoring system and treated cases of clinical pneumonia with antibiotics as needed. Average daily gain (ADG), clinical pneumonia diagnosed by farm personnel, culling, and mortality were compared between the four groups. New Infection and Chronic calves received significantly more treatments for clinical pneumonia (New Infection: 24%, P = 0.004; Chronic: 41%, P = <0.001) and had significantly lower pre-weaning ADG (New Infection: 1.6 lb; Chronic: 1.5, P = <0.001) compared to Clean calves. Chronic calves had significantly more culling both before and after weaning compared to Clean calves (pre-wean: 6.6%, P = 0.03; post-wean: 16%, P = 0.003). Notably, Cured calves performed similarly to Clean calves for all performance parameters. There was no difference between all groups for post-weaning ADG. These results demonstrate the value of early detection and cure of pneumonia cases before the end of the milk feeding period.
