Table of Contents and Abstracts

The occurrence of right-sided congestive heart failure (CHF) in dogs with left-sided heart disease is well-recognized, but its mechanisms are incompletely understood. A 12-year-old Maltese dog was admitted to the clinic for left atrial decompression to treat recurrent CHF due to severe myxomatous mitral valve disease (MMVD). Left atrial decompression was successful but atrial fibrillation (AF) occurred during the procedure. Electric cardioversion restored normal sinus rhythm (NSR) and the dog’s recovery was uneventful. This sequence of events made it possible to study intracameral pressures individually in each atrium in a dog with naturally occurring MMVD during AF and again during NSR. Although pressures in both atria declined following cardioversion, the right atrial pressure declined to a greater degree. These findings indicated a disproportionate effect of AF on right atrial pressure. This difference was noteworthy given the long-standing clinical observation that dogs with MMVD have a higher prevalence of right-sided CHF when AF is present.

Key clinical message:
A dog with MMVD had a greater reduction in right atrial pressure than in left atrial pressure when its AF was cardioverted as part of a cardiac catheterization procedure. This observation proposed a mechanism for the well-known but unexplained observation that dogs with MMVD manifest right-sided CHF disproportionately more often when they have AF.

An 8-month-old female Maltese dog was referred for examination with a history of circling, dullness, and drooling. Serum biochemical analysis revealed hyperammonemia, with microhepatica observed on radiography. Computed tomography angiography revealed a portosystemic shunt originating from the right gastric vein and inserting into the prehepatic caudal vena cava. Portal blood flow to the liver was not observed. Based on computed tomography angiography, the dog was tentatively diagnosed with portosystemic shunt with portal vein aplasia. An exploratory laparotomy was done to obtain a definitive diagnosis. The dog had no subjective clinical signs of portal hypertension during a temporary occlusion test of the portosystemic shunt. A thin-film band was placed around the portosystemic shunt to achieve partial attenuation. There was no evidence of hepatic encephalopathy in the long term after surgery, and the dog’s liver volume increased over time. Computed tomography angiography at 6 mo after surgery identified well-visualized intrahepatic portal branches.

Key clinical message:
We inferred that a direct occlusion test is a reliable diagnostic technique that overcomes the limitations of diagnostic imaging methods, including computed tomography angiography, and is a good technique for determining whether surgical attenuation is possible in dogs with suspected portal vein aplasia.

A 3.5-year-old intact male Labrador retriever was seen for hematuria. The results of clinical pathology tests were unremarkable. However, urinalysis revealed dark, cloudy, alkalotic, and isosthenuric urine containing red and white blood cells, epithelial cells, and struvite crystals. Severe bilateral enlargement of ureters and markedly enlarged kidneys were identified on abdominal radiographs. Computerized tomography revealed extensive bilateral hydroureteronephrosis with no definitive cause of obstruction. The dog underwent bilateral ureteral tapering with bilateral neoureterocystostomy and placement of temporary bilateral ureteral stents and a cystostomy tube. The dog was monitored in the intensive care unit for 7 d after surgery and was discharged 9 d after surgery and after the stent and cystostomy tube were removed. The dog remained clinically normal and was reported to have been euthanized at 11 y of age (2021) due to unspecified causes.

Key clinical message:
There are several potential causes of severe bilateral hydroureteronephrosis in animals. Based on this case report, dogs with severe bilateral hydroureteronephrosis that are clinically asymptomatic may have favorable outcomes following bilateral ureteral reconstruction and neoureterocystostomy, even if a definitive cause is not identified.

Pregnancy loss after Day 40 in mares usually results in the expulsion (abortion) of the fetus and placental membranes. However, fetal retention within the uterus is also a possible outcome, leading to either fetal mummification or maceration. Fetal maceration is septic decomposition of fetal tissues within the uterus following failure of expulsion. It requires the presence of bacteria and oxygen within the uterus, likely originating from an open cervix, and results in tissue autolysis, leaving only fetal bones remaining in the mare. Fetal maceration is a rare complication of pregnancy in mares that is usually associated with a recent history of abortion, a persistent vaginal discharge, and retention of numerous fetal bones. Here, we report 2 cases of fetal maceration with retention of only a few fetal bones in mares that were presented without noticeable clinical signs.

Key clinical message:
The unusual presentation of fetal maceration in these mares (only a few fetal bones and no noticeable clinical signs) brings attention to the potential insidious nature of fetal retention. It highlights the importance of a thorough reproductive examination before breeding, along with careful and ongoing monitoring after breeding and throughout pregnancy.

Three dogs were diagnosed with naturally occurring cheyletiellosis based on clinical signs and visualization of parasites and ova. Treatment with fluralaner (orally) resulted in a rapid resolution of clinical signs with no evidence of mites or ova at 1 or 2 mo post-treatment. This is apparently the first published report of an isoxazoline being used to successfully treat cheyletiellosis in veterinary medicine. Therefore, fluralaner may be an effective option for treatment or prevention of canine cheyletiellosis, although research is needed to confirm its effectiveness for treatment of cheyletiellosis in dogs and other species.

Key clinical message:
This is apparently the first published report of an isoxazoline being used to successfully treat cheyletiellosis in companion animal practice. These parasites are both contagious and zoonotic and there are currently no approved products for treatment or prevention of cheyletiellosis.

An 8-month-old spayed female golden retriever × standard poodle dog was presented for assessment because of vocalization, destructive behavior, and urination when left home alone and confined in a crate. Previous treatments included multiple medications, graduated departures, decoupling of departure cues, and punishment-based techniques. Adverse reactions to paroxetine and lorazepam were noted before successful treatment with clomipramine, “safe haven” training, and behavior modification.

Key clinical message:
Separation anxiety is a common behavioral disorder in dogs. It is often treatable but may require changes in the approach to both medication and behavior modification based on patient and client factors.

Objective
To examine antimicrobial resistance (AMR) in commensal fecal Escherichia coli (E. coli) from extensively managed beef calves and cows in western Canada and describe the differences among cows and calves in the spring and fall.

Animal
Beef cattle, cow-calf.

Procedure
Antimicrobial susceptibility testing was conducted on generic E. coli isolates collected from 388 calves and 387 cows from 39 herds following calving in 2021, 419 calves from 39 herds near weaning, and 357 cows from 36 herds at pregnancy testing. Minimum inhibitory concentrations were measured with the NARMS CMV5AGNF plate for Gram-negative bacteria and interpreted using Clinical and Laboratory Standards Institute standard breakpoints for humans.

Results
Only 16% (242/1551) of all isolates from 97% (38/39) of herds were resistant to ≥ 1 antimicrobial. Generic E. coli isolates were most commonly resistant to sulfisoxazole (11%, 175/1551), followed by tetracycline (9.3%, 145/1551) and chloramphenicol (3.5%, 55/1551). Isolates from calves in the spring were more likely to be resistant to sulfisoxazole, tetracycline, and chloramphenicol than those from cows in the spring or calves in the fall. Multiclass-resistant isolates were identified in 5% (39/807) of calves. Only 2 isolates recovered from cows were resistant to antimicrobials of very high importance for human health.

Conclusion and clinical relevance
Most generic E. coli isolates were pansusceptible. The observed resistance patterns were consistent with earlier studies of AMR from commensal E. coli in this region. Baseline AMR data for cow-calf herds are not currently collected as part of routine surveillance, but are essential to inform antimicrobial use policy and stewardship.

Background
The study of the morphological parameters of teeth on dental radiographic images, especially evaluation of the pulp canal/root ratio (PCRR), has been presented as a reliable method to estimate age both in humans and animals. Evaluating PCRR involves a simple, nondestructive procedure that can be used both in living individuals and in cadavers. There is a scarcity of studies assessing the relationship between PCRR and age in dogs (Canis lupus familiaris).

Objective
The aim of this study was to evaluate the relationship between PCRR and age in Yorkshire terrier dogs.

Animals and procedures
Dental radiographs of 53 Yorkshire terrier dogs from the database of the Odontovet Veterinary Dentistry Center (Brazil) were analyzed. Using ImageJ software, 3 consecutive measurements of the widths of 2 roots (mesial and distal) and their respective pulp canals were taken at both mandibular molar teeth (left, 309 and right, 409). The PCRR was then calculated using width means.

Results
The PCRR decreased with increasing age in both mesial (0.21 ± 0.09 in animals aged < 24 mo, 0.12 ± 0.04 in animals aged between 25 and 96 mo, and 0.09 ± 0.03 in dogs aged > 96 mo) and distal (0.24 ± 0.11, 1.01 ± 0.03, and 0.09 ± 0.03, by the same order) roots. A statistically significant, moderate negative correlation was demonstrated between age and PCRR of the mesial [rs (97) = −0.545; P < 0.001] and distal [rs (98) = −0.578; P < 0.001] roots.

Conclusion and clinical relevance
This work contributes to the knowledge of PCRR in dogs and its relationship with age, paving the way for further studies using larger samples in different canine breeds.

Background
Emergency cases can present at any time of the day or night. All small animal practitioners need to have the skills to triage and stabilize common emergency cases even if they ultimately aim to refer the patient to another facility.

Objectives and procedures
The first part of this 3-part review article series covers respiratory distress and seizures. A stepwise approach to categorize and stabilize these cases is outlined, along with helpful tips to optimize the referral experience, if indicated.

Results
Having a strong methodical approach to animals in respiratory distress optimizes treatment. Similarly, achieving cessation of seizures, along with having a good understanding of the causes of seizures, allows for patient stabilization.

Conclusion and clinical relevance
Do NOT refer emergent cases before completing basic stabilization. Many emergency cases do not require emergent referral and can be worked up by the primary veterinarian or sent to a referral clinic on an appointment basis after appropriate stabilization steps are completed.

Objective
To describe a case of small intestinal obstruction secondary to kinetic sand ingestion in a dog.

Animal
An 11-year-old neutered male shih tzu dog with a 2-day history of anorexia.

Procedure
Abdominal radiographs revealed a small intestinal bowel loop dilated with radiopaque material, consistent with sand ingestion. The dog’s only sand exposure was to kinetic sand. After 8 h of medical management, radiographs were consistent with a small intestinal obstruction.

Results
The dog underwent exploratory laparotomy, which revealed distal jejunal and ileal distention with palpable soft foreign material that could not be milked into the colon. The sand was removed through a single enterotomy. The dog was discharged 4 d after surgery.

Conclusion and clinical relevance
The hydrophobic properties of kinetic sand may make it more likely than regular sand to cause intestinal obstruction that requires surgery. With the increasing popularity and availability of kinetic sand for domestic use, clinicians should have a high index of suspicion for kinetic sand impaction and secondary intestinal obstruction.