Objective-To evaluate the osseous structures of the external acoustic meatus, tympanic cavity, and tympanic bulla of llamas (Lama glama) by use of computed tomography (CT) and establish measurement values for use in detection of abnormalities associated with the external or middle ear in llamas. Animals-10 adult llama heads without any evidence of ear disease. Procedures-Heads of 10 healthy llamas euthanized by use of a captive bolt striking the dorsal aspect of the skull were collected. Transverse images of the heads were acquired with 1-mm slice thickness, and images were reconstructed in sagittal and dorsal planes. Measurements of the bony structures of the external and middle ear of each head were obtained. Results-The osseous external acoustic meatus curved ventrally as it tracked medially. Its narrowest portion was located at the level of the tympanic annulus. The tympanic bulla conformation differed widely from the bubble-shaped tympanic bulla in dogs and cats. The bulla was divided by the stylohyoid fossa into a larger caudolateral and a smaller caudomedial process; its interior had a honeycombed structure with pneumatized cells similar to the honeycombed appearance of the human mastoid process. Conclusions and Clinical Relevance-Results provided new information regarding the shape and dimensions of the osseous external and middle ear structures in adult llamas without ear disease. Specific landmarks for location of the external acoustic meatus, tympanic cavity, and tympanic bulla in relation to each other were identified. Knowledge of the CT appearance of normal structures will help clinicians to identify changes attributable to middle ear otitis, external ear canal stenosis, or congenital malformations of the ear in this species.

OBJECTIVE To compare the effectiveness of an ultrasound-guided paravertebral nerve blockade technique (UGPNB) with distal and proximal paravertebral nerve blockade techniques without ultrasound guidance (DPNB and PPNB, respectively) in calves. ANIMALS 4 calf cadavers and 7 healthy calves. PROCEDURES A suitable acoustic window was identified to facilitate access to the T13, L1, and L2 spinal nerves in cadavers and live calves. In cadavers, nerves were injected with dye under ultrasound guidance. In calves, the UGPNB, DPNB, and PPNB were performed in random order at 10-day intervals by injection of an anesthetic solution containing 2% lidocaine hydrochloride. Nociceptive withdrawal responses were assessed to determine the effects of the blockades. RESULTS In cadavers, nerve staining success rates (ie, ≥ 2-cm-long dye path) achieved with ultrasound guidance were 88% (T13 [ventral branch]), 75% (T13 and L1 [dorsal branches] and L1 and L2 [ventral branches]), and 38% (L2 [dorsal branch]). The nerves were each identified as a hyperechoic band in a longitudinal plane. In calves, the UGPNB, DPNB, and PPNB reduced the withdrawal response to the noxious stimulus, mainly in the dorsal-cranial, dorsal-caudal, and ventral-cranial areas of the flank. Overall, the UGPNB resulted in a better nociceptive cumulative score, administering only one half of the local anaesthetic dose, compared with findings for the DPNB and PPNB. However, time to perform the UGPNB was longer. CONCLUSIONS AND CLINICAL RELEVANCE The UGPNB evaluated may be an improved alternative to the DPNB and PPNB for provision of anesthesia for flank surgery in calves. However, effectiveness of the UGPNB should be evaluated in a clinical setting and in adult cattle.

Objective: To compare acoustic startle reflexes (ASRs) of healthy cats and cats with interstitial cystitis (IC). Animals: 28 healthy cats (11 males and 17 females) and 20 cats with IC (13 males and 7 females). Procedures: To evaluate the effect of neutering on ASRs, ASRs in neutered and unneutered healthy cats were measured. To evaluate the effect of housing facility acclimation on ASRs in cats with IC, ASRs were measured in cats with IC within 1 month after arrival at the housing facility and again 2 to 3 months after arrival. To evaluate the effect of the environment on ASRs, ASRs were evaluated in all cats with and without IC after acclimation but before and then after environmental enrichment. Results: Neutering led to a significant decrease in overall ASR in the healthy cats. Habituation to the housing facility resulted in a significant decrease in overall ASR of female but not male cats with IC. Environmental enrichment led to a significant decrease in ASR in cats with IC but not in healthy cats. Conclusions and Clinical Relevance: The magnitude of the ASR appeared to be sensitive to environmental conditions and affected by sex, both in healthy cats and cats with IC. It was also higher in cats with IC versus healthy cats, except when cats were housed in a highly enriched environment. Impact for Human Medicine: Treatment approaches that include reduction of a patient's perception of environmental unpredictability may benefit humans with IC.

Objective: To noninvasively assess the influence of ingestion of a standard meal on gallbladder volume (GBV) in healthy cats. Animals: 10 healthy adult domestic shorthair cats (4 neutered females, 5 neutered males, and 1 sexually intact male). Procedures: Nonsedated cats were positioned in dorsal and left lateral recumbency to obtain ultrasonographic measurements of the gallbladder via the subcostal and right intercostal acoustic windows, respectively. Gallbladder volume was calculated from linear measurements by use of an ellipsoid formula (volume [mL] = length [mm] × height [mm] × width [mm] × 0.52). Measurements were recorded after food was withheld for 12 hours (0 minutes) and at 5, 15, 30, 45, 60, and 120 minutes after cats were fed 50 g of a standard commercial diet (protein, 44.3%; fat, 30.3%; and carbohydrate, 15.6% [dry matter percentage]). Results: Agreement between gallbladder linear measurements or GBV obtained from the subcostal and right intercostal windows was good. Feeding resulted in linear decreases in gallbladder linear measurements and GBV. Via the subcostal and intercostal windows, mean ± SD GBV was 2.47 ± 1.16 mL and 2.36 ± 0.96 mL, respectively, at 0 minutes and 0.88 ± 0.13 mL and 0.94 ± 0.25 mL, respectively, at 120 minutes. Gallbladder width most closely reflected postprandial modification of GBV. Conclusions and Clinical Relevance: Results indicated that ultrasonographic assessment (via the subcostal or right intercostal acoustic window) of postprandial changes in GBV can be used to evaluate gallbladder contractility in cats. These data may help identify cats with abnormal gallbladder emptying.