Objective—To quantitatively and qualitatively assess the radiographic appearance of the thorax of clinically normal alpaca crias. Animals—21 clinically normal alpaca crias. Procedures--Left-right lateral (LR), right-left lateral (RL), dorsoventral (DV), and ventrodorsal (VD) projections of the thorax were acquired. To account for differences in cria size, measurements of thoracic structures were compared with other anatomic landmarks. Results—Mean ± SD vertebral heart scale was 9.36 ± 0.65 for LR projections, 9.36 ± 0.59 for RL projections, 8.21 ± 0.51 for DV projections, and 8.65 ± 0.57 for VD projections. Dimensions of the heart were compared with the length of the T3 through T5 vertebral bodies, third to fifth rib distance, and thoracic height and width, which provided additional methods of cardiac evaluation. For RL projections, mean ratio of the right cranial pulmonary artery diameter to the third rib width was 0.41 ± 0.10 and mean ratio of the right cranial pulmonary vein to the third rib width was 0.44 ± 0.10. Caudal lobar pulmonary vessels and the caudal vena cava were difficult to quantitatively assess on DV or VD projections. On lateral projections, the trachea was increased in diameter at the origin of the right cranial lobar bronchus. No qualitative differences were found between LR and RL radiographs. The lungs were generally better inflated on VD projections, with more separation of the heart and diaphragm. Conclusions and Clinical Relevance—Establishment of radiographic values for alpaca crias should prove useful in assessment of thoracic disease in this species.

Objective: To evaluate the in vitro susceptibility of various field isolates of Mycobacterium avium subsp paratuberculosis (MAP) to gallium nitrate. Sample: 10 isolates of MAP, including 4 isolated from cattle, 2 isolated from bison, 1 isolated from an alpaca, and 3 isolated from humans. Procedures: The in vitro susceptibility to gallium nitrate was tested by use of broth culture with detection of MAP growth by means of a nonradiometric automated detection method. For each MAP isolate, a series of 7 dilutions of gallium nitrate (concentrations ranging from 200 to 1,000μM) were tested. Gallium nitrate was considered to have caused 90% and 99% inhibition of the MAP growth when the time to detection for culture of the MAP stock solution and a specific concentration of gallium nitrate was delayed and was similar to that obtained for culture of the MAP stock solution (without the addition of gallium nitrate) diluted 1:10 and 1:100, respectively. Results: Gallium nitrate inhibited MAP growth in all 10 isolates. The susceptibility to gallium nitrate was variable among isolates, and all isolates of MAP were inhibited in a dose-dependent manner. Overall, the concentration that resulted in 90% inhibition ranged from < 200μM for the most susceptible isolates to 743μM for the least susceptible isolates. Conclusions and Clinical Relevance: Gallium nitrate had activity against all 10 isolates of MAP tested in vitro and could potentially be used as a prophylactic agent to aid in the control of MAP infections during the neonatal period.