Efficacy of ultrasonography to detect liver abscesses in cattle*

Abstract

Objective

Our aim was to evaluate the use of ultrasonography to identify liver abscesses in cattle.

Materials and Methods

Finishing steers (n = 160, mean final BW = 649 kg) were used in Exp. 1 and Exp. 2 (n = 63, mean final BW = 593 kg). Liver abscess images were obtained 24 h before slaughter. Steers in Exp. 3 (n = 40; mean final BW = 168 kg) and 4 (n = 40; mean final BW = 159 kg) were beef × dairy steers used in a study to experimentally induce liver abscesses. Real-time ultrasound imaging of the liver was conducted on the day of slaughter.

Results and Discussion

In Exp. 1, the sensitivity of ultrasonography for detection of liver abscesses in finishing beef steers was 14.6%, and in Exp. 2 the sensitivity was 5.6%. In the lightweight beef × dairy steers, sensitivity was 50% in Exp. 2 and 41.1% in Exp 3. Ultrasound accuracy ranged from 70% to 75% within all 4 experiments. Specificity of ultrasonography ranged from 84.6% to 100% among all experiments.

Implications and Applications

Low sensitivity of detection in all experiments indicates ultrasonography has limited value for detecting liver abscesses in live cattle. Nonetheless, the greater specificity observed indicates that ultrasonography is effective at diagnosing a steer as negative, but the likelihood of detecting a negative is greater than detecting a positive because of the low prevalence of liver abscesses among the steers in each study. Even with modern ultrasound equipment with improved resolution, liver abscesses remain difficult to detect in live cattle, but sensitivity seems to be improved in lighter versus heavier weight cattle.