Imaging diagnosis--Conventional and functional magnetic resonance imaging of a brain abscess in a goat

Brain Abscesses in Domestic Ruminants: Clinicopathological and Bacteriological Approaches

Brain abscesses in ruminants often arise from primary infection foci, leading to an unfavorable prognosis for affected animals. This highlights the need for comprehensive studies on brain abscesses across different ruminant species. We retrospectively investigated medical records of epidemiological, clinical, neuroimaging, anatomopathological, and bacteriological findings in six ruminants (three goats, two cows, and one sheep) diagnosed with brain abscesses. All animals studied were female. Apathy (50%), compulsive walking (33%), decreased facial sensitivity (33%), head pressing (33%), seizures (33%), semicomatous mental status (33%), strabismus (33%), unilateral blindness (33%), and circling (33%) represented the most common neurologic signs. Leukocytosis and neutrophilia were the main findings in the hematological evaluation. Cerebrospinal fluid (CSF) analysis revealed predominant hyperproteinorrachia and pleocytosis. In three cases, computed tomography or magnetic resonance imaging were used, enabling the identification of typical abscess lesions, which were subsequently confirmed during postmortem examination. Microbiological culture of the abscess samples and/or CSF revealed bacterial coinfections in most cases. Advanced imaging examinations, combined with CSF analysis, can aid in diagnosis, although confirmation typically relies on postmortem evaluation and isolation of the causative agent. This study contributes to clinicopathological aspects, neuroimages, and bacteriological diagnosis of brain abscesses in domestic ruminants.

Radiography, CT, and MRI Diagnosis of Enzootic Nasal Tumor in Goats Infected With Enzootic Nasal Tumor Virus

The aim of this study was to describe radiography, computed tomography (CT), and magnetic resonance imaging (MRI) findings of enzootic nasal tumors in goats infected with enzootic nasal tumor viruses. Five of six goats with a mean age of 2 years, showed clinical signs of respiratory disease. Head radiographs showed increased density of the unilateral or bilateral nasal cavity in four goats, and a CT scan showed that the space-occupying lesion of the nasal cavity originated from the ethmoid bone and was enhanced homogeneously postcontrast in all goats. The nasal concha was destroyed and the paranasal sinus mucosa was thickened and filled with fluid in some goats. On MRI, the mass exhibited equal or slightly higher signal intensity on T2 weighted images, equal signal intensity on T1 weighted images, a high signal on fluid-attenuated inversion recovery images and heterogeneous enhancement postcontrast. After dissection, histopathological examination of the mass and virus genome detection of the nasal secretions confirmed that the intranasal mass was a low-grade adenocarcinoma and that the goats were infected with enzootic nasal tumor virus type 2. In conclusion, CT and MRI have high diagnostic values for enzootic nasal tumors because they match the postmortem findings and are more accurate than radiography.

Cautery Disbudding Iron Application Time and Brain Injury in Goat Kids: A Pilot Study

Cautery disbudding is a painful procedure performed on goat kids to prevent horn growth that may result in brain injury. Thermal damage to the cerebral cortex of the brain and subsequent neurologic disease is a primary concern. Cautery iron application time may affect transmission of heat to the brain; however, research in this area is scarce. Therefore, the objective of this pilot study was to evaluate the effect of iron application time on brain injury of goat kids. A total of six buck and doe kids <9 days of age were obtained from a commercial dairy and transported to an Iowa State University research facility. Kids received a different randomly assigned application time (5, 10, 15, or 20s) on each horn bud. Kids were disbudded using an electric cautery iron (under isoflurane general anesthesia). After a 5-day observation period, the kids were euthanized, and magnetic resonance (MR) images were acquired to evaluate brain injury. Additionally, four of the six kids were presented for gross examination and two kids were selected for histopathologic examination. From the MR images, white matter edema was observed subjacent to four treated areas, representing application times of 5 s (one horn bud), 15 s (one horn bud), and 20 s (two horn buds). With the exception of the horn bud that received 5 s, which had white matter edema restricted to a single gyrus, the remaining three groups had a branching region of edema. No bone abnormalities were identified on any kids. Gross evidence of discoloration and hemorrhage on the cerebral hemispheres was observed on two horn buds that received 20 s, two horn buds that received 15 s, and one horn bud that received 10 s. Microscopic lesions consisting of leptomeningeal and cerebrocortical necrosis were observed in sections of brain from all groups. Lesions were most severe with 20 s. In conclusion, all application times used in this study resulted in some level of brain injury; however, using 15 s or more resulted in more severe and consistent brain injury. These results indicate that extended iron application time may increase the risk of brain injury in cautery disbudded kids.

Short communication: Survival of replacement kids from birth to mating on commercial dairy goat farms in New Zealand

Commercial dairy goat systems rely on the successful rearing of kids for herd replacement. The objectives of this study were to (1) determine survival from birth until mating for a large cohort of commercial dairy goat kids; (2) descriptively summarize the causes of mortality and removal from the herd during this period; and (3) compare actual (determined by postmortem examination) and suspected (farmer-reported) causes of mortality. A total of 1,262 female kids were enrolled at birth on 16 commercial dairy goat farms in New Zealand. Median ages at weaning and mating were 86 d [minimum = 54, quartile (Q)1 = 78, Q3 = 97, maximum = 144] and 223 d (minimum = 183, Q1 = 208, Q3 = 237, maximum = 310), respectively. Overall, 87.1% (1,099/1,262) of kids remained on farm at mating, 10.4% (131/1,262) died or were euthanized, and 2.5% (32/1,262) were lost to follow-up or sold. Mortality risk was greatest in early life, with more than 90% of deaths occurring before weaning. Mortality from enrollment to mating varied between farms (minimum = 0%, Q1 = 5.9%, median = 8.9%, Q3 = 15.8%, maximum = 20.5%). The leading cause of death was gastrointestinal disorders (33.6%, 36/107), followed by disbudding-related injury (15.9%, 17/107), and septicemia (12.1%, 13/107). Farmers correctly identified approximately half of the deaths attributed to gastrointestinal disorders (56.0%, 14/25) and disbudding-related injury (44.4%, 4/9), but were less successful at diagnosing septicemia (0%, 0/5), starvation or dehydration (0%, 0/4), and suffocation (18.8% 3/16). This is the largest cohort of dairy goat kids to be systematically followed over time to confirm survival until mating and to determine causes of death by postmortem examination. We found that kid mortality was highest during the preweaning period and there was often a discrepancy between farmer-perceived and actual cause of death. Postmortem examinations should be more widely used to establish causes of death and inform on-farm strategies to reduce kid mortality.

MAGNETIC RESONANCE IMAGING FINDINGS IN SMALL RUMINANTS WITH BRAIN DISEASE

Brain disease is an important cause of neurologic deficits in small ruminants, however few MRI features have been described. The aim of this retrospective, case series study was to describe MRI characteristics in a group of small ruminants with confirmed brain disease. A total of nine small ruminants (six sheep and three goats) met inclusion criteria. All had neurologic disorders localized to the brain and histopathologic confirmation. In animals with toxic-metabolic diseases, there were bilaterally symmetric MRI lesions affecting either the gray matter (one animal with polioencephalomalacia) or the white matter (two animals with enterotoxemia). In animals with suppurative inflammation, asymmetric focal brainstem lesions were present (two animals with listeric encephalitis), or lesions typical of an intra-axial (one animal) or dural abscess (one animal), respectively. No MRI lesions were detected in one animal with suspected viral cerebellitis and one animal with parasitic migration tracts. No neoplastic or vascular lesions were identified in this case series. Findings from the current study supported the use of MRI for diagnosing brain diseases in small ruminants.