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University of Calgary · Veterinary Medicine

This week in research.

28 Sep – 05 October 2026 From the archive

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Here are the new works published in the window 2026-09-28 to 2026-10-05, with cohort authors named and journals cited. Veterinary point-of-care ultrasound probe orientation and location for detection of pleural effusion in canine cadavers: a pilot study — Journal of Small Animal Practice (2026-09-30). Cohort authors: Julie M. Menard; Serge Chalhoub; Soren R Boysen. - The modified Calgary PLUS for pleural fluid technique yielded higher overall detection of pleural effusion (89.1%) than the modified TFAST for pleural fluid technique (60.9%). - Calgary PLUS markedly improved detection of scant-to-mild effusions (84.4% vs 37.5%), with robust statistical significance. - Probe orientation and ventral thoracic location influence detection; parallel-to-ribs positioning in ventral regions may enhance sensitivity. Nasopharyngeal and laryngopharyngeal collapse: intra- and interrater agreement supports novel endoscopic scoring classifications in horses — Journal of the American Veterinary Medical Association (2026-09-30). Cohort author: Renaud Léguillette. - Proposes distinct endoscopic classifications for nasopharyngeal collapse (NPC) and laryngopharyngeal collapse (LPC) with graded scales. - Intrarater and interrater agreement analyses in retrospective barrel-racing horse data support reliable use of the new classifications. - The framework differentiates rostral versus caudal collapse, enabling more precise assessment of airway patency. A Practical Approach to a Realistic Problem: Rapid Blueprinting a Progress Test for Veterinary Medicine in North America — Journal of Veterinary Medical Education (2026-09-30). Cohort author: Kent G. Hecker. - Describes a two-phase rapid blueprinting process: an in-person advisory committee (10–15 experts) to build the framework, then a broader Delphi validation. - Aims to yield a cost-efficient, timely, content-validated progress test applicable across North American veterinary schools. - Intended to assist schools and post-graduate specialty colleges in building tests or curricula with validity support. PS8-3. Comparative Analysis of Soil Microbial Diversity and Communities Under Monocrop and Polycrop Forage Systems Swath-grazed During Winter — Journal of Animal Science (2026-09-29). Cohort author: Nilusha Malmuthuge. - No significant difference in soil microbial alpha diversity between monocrop and polycrop after three years. - Prokaryotic richness increased in both systems; fungal richness declined; community composition shifted from Proteobacteria to Actinobacteria by 2024. - Indicates long-term forage-system effects on microbial communities may converge, with year-to-year shifts in taxa. Enriching Early Life to Promote the Co-development of Microbiome and Immune System in Neonatal Calves — Journal of Animal Science (2026-09-29). Cohort author: Nilusha Malmuthuge. - Neonatal calf gut microbiome development tightly couples with mucosal immune system maturation during the early-life window. - Microbial exposures in this period can shape lifelong immune trajectories and disease susceptibility through region-specific colonization. - Highlights opportunities to actively shape early-life microbiome to enhance health, resilience, and production outcomes. Mitigating the Zoonotic Risk of Shiga-toxigenic Escherichia coli (STEC) O157:H7 in Cattle: Evaluation of Limosilactobacillus Reuteri as a Direct-fed Microbial — Journal of Animal Science (2026-09-29). Cohort author: Eduardo Ruben Cobo. - Two independent calves trials show Limosilactobacillus reuteri R0444 reduces STEC O157:H7 shedding compared with controls. - Fecal shedding dynamics and DFM persistence were tracked, revealing treatment- and time-dependent effects. - Supports direct-fed microbial strategies to mitigate zoonotic STEC risk in cattle production. Effects of Mild Nutritional Restrictions During Mid-gestation on Neonatal Calf Performance and Placental Function in Extended-grazed Beef Cows — Journal of Animal Science (2026-09-29). Cohort authors: Nilusha Malmuthuge; Juan H. Hernandez-Medrano. - Mild mid-gestation protein restriction did not alter calf birth weight or early neonatal performance. - Placental analyses assessed vascularization and collagen distribution to gauge placental health. - Findings inform protein-management strategies for extended-grazing beef cows during mid-gestation. By the numbers - Total works: 7 - Journals: Journal of Small Animal Practice (1); Journal of the American Veterinary Medical Association (1); Journal of Veterinary Medical Education (1); Journal of Animal Science (4) - Window covered: 2026-09-28 to 2026-10-05

A closer look

Publications this week

7
Journal of Small Animal Practice

Veterinary point‐of‐care ultrasound probe orientation and location for detection of pleural effusion in canine cadavers: a pilot study · doi/link

UCVM authors Julie M. Menard, Serge Chalhoub, Soren R Boysen

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OBJECTIVES: To evaluate whether point-of-care ultrasound probe location (at or below the costochondral junction) and probe orientation (perpendicular or parallel to the ribs) affect operator ability to detect pleural effusion in a canine cadaver model. MATERIALS AND METHODS: Twelve intubated canine cadavers with scant to large volume pleural effusion were scanned in sternal recumbency while receiving positive pressure ventilation. Twelve operators (2 emergency and critical care specialists, 2 veterinary students and 8 interns) performed blinded bilateral thoracic point-of-care ultrasound using two randomised scanning protocols: a modified TFAST for pleural fluid technique and a modified Calgary PLUS for pleural fluid technique. Hemithoraces were categorised as scant-to-mild or moderate-to-large effusion for statistical analysis. Paired detection rates were compared using McNemar's test. RESULTS: Overall detection of pleural effusion was significantly higher using the modified Calgary PLUS for pleural fluid technique compared with the modified TFAST for pleural fluid technique (89.1% vs. 60.9%; P < .001). There was a statistically significant increase in the detection of scant-to-mild effusion with the modified Calgary PLUS for pleural fluid technique (84.4% vs. 37.5%; P < .001). No significant difference was observed for moderate-to-large effusions (93.8% vs. 84.4%; P = .25). CLINICAL SIGNIFICANCE: The site assessed and probe orientation used with different thoracic point-of-care ultrasound protocols can influence the operator's ability to detect pleural effusion in positive pressure ventilation canine cadavers placed in sternal recumbency. Incorporating a probe orientation that is parallel to the ribs in the more ventral regions of the thorax during point-of-care ultrasound may improve the operator's detection of pleural effusions, particularly when smaller volumes of pleural fluid are present.
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Journal of the American Veterinary Medical Association

Nasopharyngeal and laryngopharyngeal collapse: intra- and interrater agreement supports novel endoscopic scoring classifications in horses · doi/link

UCVM authors Renaud Léguillette

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Objective: The contribution of reduced airway patency from heightened inspiratory pressure or active muscular contraction to the pathophysiology of pharyngeal collapse is unknown. Existing classifications refer to the entire pharyngeal region; however, anatomical differences are evident between rostral and caudal collapse. Novel classifications and grading systems are proposed to differentiate 2 pathologies: nasopharyngeal collapse (NPC; collapse of ≥ 1 pharyngeal wall rostral to the tip of the epiglottis; grades 0 through 4), and laryngopharyngeal collapse (LPC; collapse of ≥ 1 pharyngeal wall caudal to the tip of the epiglottis; grades 0 through 3). Methods: Clinical reports from 99 barrel racing horses in Southern Alberta previously diagnosed with pharyngeal collapse via overground endoscopy (2015 through 2025) were retrospectively analyzed. Horses were referred for respiratory signs and/or poor performance. Two raters independently assessed still images obtained during high-speed exercise in a blinded and randomized fashion. Descriptive statistics and intrarater/interrater agreement for classification (McNemar test) and scoring (weighted κ) were reported. Results: Similar frequencies of NPC (64.6%) and LPC (67.6%) were observed (32% had both). Intrarater agreement for NPC was χ2 = 7.0 (rater 1) and χ2 = 1.0 (rater 2) for NPC and χ2 = 2.0 (rater 1) and χ2 = 1.6 (rater 2) for LPC. Scoring agreement was good to very good for NPC (κ = 0.69 to 0.81) and moderate to good for LPC (κ = 0.56 to 0.80), indicating reliable performance. Interrater agreement was χ2 = 4.6 (rater 1) and χ2 = 0.7 (rater 2) for NPC and χ2 = 0.2 (rater 1) and 2.0 (rater 2) for LPC. Conclusions: Intra- and interrater agreement supports the feasibility and practicality of distinguishing NPC from LPC. Clinical Relevance: Novel classifications reflecting functional anatomy may provide insight into the pathophysiology of pharyngeal collapse.
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Journal of Veterinary Medical Education

A Practical Approach to a Realistic Problem: Rapid Blueprinting a Progress Test for Veterinary Medicine in North America · doi/link

UCVM authors Kent G. Hecker

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A blueprint is a template for an assessment that outlines the knowledge, skills, attributes, species, and systems to be assessed and the respective weightings (percentage of the assessment) for the key content areas. This is a foundational step in building content validity for an assessment method. The rapid blueprinting process is reported to be a quick and cost-effective approach to developing a blueprint that consists of two phases. The first is an in-person advisory committee meeting consisting of educational experts and key stakeholders (10-15 people) to build the framework of the assessment, based on identified foundational knowledge and skills (common across schools) at a specific time point (e.g., graduation). Key documents used to guide these discussions could include information on the type of assessment (low-stakes or high-stakes assessments), the types of items to be used (i.e., multiple-choice questions), and competency frameworks from which to build the assessment (i.e., the Competency-Based Veterinary Education framework and the Council on Education competencies). The second phase involves engaging the broader community in a validation step, via a modified Delphi procedure, to review the content and provide emphasis on those areas. Here, we outline the steps of the rapid blueprinting process to build a test blueprint for academic veterinary medicine progress test in North America. This method could assist both schools and post-graduate veterinary specialty colleges in building test or curriculum blueprints in a rapid, cost-effective manner and to develop validity evidence for the use and interpretation of test scores.
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Journal of Animal Science

PS8-3. Comparative Analysis of Soil Microbial Diversity and Communities Under Monocrop and Polycrop Forage Systems Swath-grazed During Winter. · doi/link

UCVM authors Nilusha Malmuthuge

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Abstract The popularity of polycrop forage systems among livestock producers is increasing because of its perceived benefit to soil health through increased microbial diversity. Winter swath grazing has been reported to significantly reduce feed and labor costs as compared to drylot systems. Over 3 years, this study evaluated soil microbial diversity in paddocks under either an oat monocrop (OM) or a 4-species polycrop (PS; oat, turnip, forage pea and rapeseed) forage system. Each year, six 2-ha paddocks were seeded in June, swathed in August/September. Freshly weaned steers were randomly assigned to swath graze either OM or PS from November to January/February. Baseline and endline soil cores (0-7.62 cm) were collected from four predetermined GPS points per paddock at the beginning (2021) and the end (2024) of the trial. The compositions of prokaryotic and fungal communities were profiled by sequencing the V4 region of the 16S rRNA gene and the ITS1 region, respectively. Alpha-diversity indices were used to evaluate richness, evenness, and overall microbial diversity and beta-diversity based on Bray–Curtis dissimilarity was used to evaluate the effects of forage system and sampling year on microbial community composition. No significant difference in soil microbial community alpha diversity between OM and PS was observed after 3 years. By the end of the trial, the richness of prokaryotic soil microbiota increased significantly (P < 0.05) in both forage systems, while that of fungi decreased significantly (P < 0.05). The most abundant bacterial phylum changed from Proteobacteria in 2021 to Actinobacteria in 2024 in both systems. The most abundant archaeal and fungal phyla in both sampling years were Crenarchaeota and Ascomycota, respectively. Beta-diversity analysis revealed that samples clustered primarily by sampling year across all microbial communities, indicating that temporal variation strongly influenced microbial community composition in both forage systems. The interaction between sampling year and forage system was significant (P < 0.001) and explained 27%, 33% and 17% of the variation observed in bacterial (PERMANOVA-R² = 0.27, P < 0.001), archaeal (PERMANOVA-R² = 0.33, P < 0.001) and fungal (PERMANOVA-R² = 0.17, P < 0.01) communities, respectively. The bacterial phyla Actinobacteriota, Firmicutes, Chloroflexi and Myxococcota and fungal phylum Ascomycota were significantly enriched (LDA > 3.0, P < 0.05) by the endline. These findings suggest that the contribution of grazing cattle to soil microbial diversity is more profound and could have masked the contributions of the individual forage systems. This may also suggest that the PC requires more than three years to alter the diversity of microbial communities during grazing. The findings of this study can guide livestock operations in adopting new production strategies that enhance soil microbiota.
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Journal of Animal Science

61. Enriching Early Life to Promote the Co-development of Microbiome and Immune System in Neonatal Calves. · doi/link

UCVM authors Nilusha Malmuthuge

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Abstract Early life is a period of heightened developmental plasticity during which biological systems are particularly responsive to environmental, nutritional, and microbial inputs. In neonatal calves, the pre-weaning period represents a critical window for the establishment of the gastrointestinal microbiome and the development of mucosal immune system. These processes are tightly interconnected, as pioneer microbiota provides essential signals that guide the gut-associated immune system development. Evidence from human and rodent studies has demonstrated that microbial exposures during early life can exert long-lasting effects on immune competence and disease susceptibility, suggesting that this developmental window may profoundly influence lifelong health and productivity. The neonatal calf gut microbiome develops rapidly following birth through exposure to the dam, diet, environment, and management practices. Importantly, microbial colonization occurs in a region-specific manner along the gastrointestinal tract, with distinct microbial communities performing specialized functions that support host development. For example, microbes colonizing the rumen contribute to epithelial development and metabolic maturation, whereas microbial communities in the small intestine play key roles in priming mucosal immune responses. In the small intestine, differences in dominant bacterial taxa are associated with enrichment of distinct immune pathways, indicating that the composition of early-life microbial communities can influence the trajectory of immune maturation. Consequently, perturbations to microbial colonization during this critical developmental period may disrupt microbiome-immune system co-development and contribute to variation in disease susceptibility, health, and resilience. However, the high plasticity that characterizes early life provides an opportunity to actively shape microbial colonization and potentially correct perturbations before long-term consequences become established. This concept has stimulated considerable interest in microbiome-targeted interventions in calves, including probiotics, prebiotics, postbiotics such as yeast-derived products, and fecal microbiota transplantation. Although these approaches have shown promise, their effectiveness has been inconsistent across studies and production systems. One potential explanation is that many interventions fail to account for the natural dynamics of microbial succession that are necessary for appropriate immune education and the establishment of long-term immunological memory. Future efforts should therefore move beyond simply altering microbial composition and instead focus on promoting the coordinated development of microbial communities and host immunity. Complementary strategies, including management practices that support healthy colonization dynamics and maternal interventions that enhance the transfer of beneficial microbes to offspring, may further strengthen this developmental programming approach. Together, these strategies offer an opportunity to improve calf health, resilience, and lifetime productivity by harnessing the microbiome-immune axis during this critical window of development.
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Journal of Animal Science

57. Mitigating the Zoonotic Risk of Shiga-toxigenic Escherichia coli (STEC) O157:H7 in Cattle: Evaluation of Limosilactobacillus Reuteri as a Direct-fed Microbial. · doi/link

UCVM authors Eduardo Ruben Cobo

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Abstract Background Shiga toxin-producing Escherichia coli (STEC), particularly serotype O157:H7, remains a major food safety concern in North America. Cattle are the primary reservoir, shedding STEC in feces and contributing to contamination of beef products and farm environments. Direct-fed microbials (DFMs) are beneficial microorganisms administered to livestock to improve gut health and potentially reduce pathogen load. Among them, Lactobacillus spp. are widely used due to their probiotic properties and ability to inhibit enteric pathogens. Objective This study evaluated whether Limosilactobacillus reuteri R0444 could reduce STEC O157:H7 shedding in calves. Methods Two independent animal trials were conducted in 2025. After a two-week adaptation period, twelve Holstein male calves (13-14 weeks old) per trial were randomly assigned to a control group inoculated with a five-strain mixture of nalidixic acid-resistant STEC O157 or a treatment group receiving both STEC and L. reuteri R0444. All calves were orally inoculated with 1010 CFU of STEC O157 on Day 0, while calves supplemented with L. reuteri (1010 CFU) on d 0, 10, and 17. Fecal samples were collected on d 1, 3, 5, 7, 10, 15, 22, and 28 to quantify and detect STEC shedding using selective plating and immunomagnetic separation (IMS). The quantity of DFM strain in fece was monitored by qPCR throughout the experiments. Fecal microbiota was characterized by 16S rRNA gene sequencing processed in QIIME2 with DADA2. Data were analyzed using generalized linear mixed models (SAS PROC GLIMMIX). Results Across both trials, STEC shedding differed by treatment (p = 0.04) and time (p < 0.001), with DFM treatment reducing shedding by an average of 0.7 log10 CFU/g of feces. When the study period was stratified (Days 1-3, 5-7, and 10-28), a treatment-by-time interaction was detected (p = 0.03) along with a strong effect of time (p < 0.001). Differences between groups became evident after the initial post-inoculation phase. Treated calves shed fewer STEC (p < 0.05) during Days 5-7 and Days 10-28 compared with controls. The largest difference occurred on Day 22 (p = 0.003), when only 1-2 treated calves shed STEC (1-2.5 log10 CFU/g), whereas 3-5 control calves shed higher levels (1.4-5.6 log10 CFU/g). At Day 28, STEC O157 was not detected by IMS in 67% (Trial 1) and 83% (Trial 2) of DFM-treated calves. In contrast, STEC was recovered from 67% (Trial 1) and 100% (Trial 2) of control calves. qPCR detected L. reuteri R0444 shortly after administration, but levels declined to below detection at later sampling points. Conclusions Administration of L. reuteri R0444 reduced STEC O157 shedding in calves, supporting its potential as a DFM-based pre-harvest intervention to mitigate this pathogen in cattle.
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Journal of Animal Science

47. Effects of Mild Nutritional Restrictions During Mid-gestation on Neonatal Calf Performance and Placental Function in Extended-grazed Beef Cows. · doi/link

UCVM authors Nilusha Malmuthuge, Juan H. Hernandez-Medrano

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Abstract Extended grazing (EG) is a cost-effective and sustainable winter-feeding strategy for the management of pregnant beef cows. In spring calving herds, EG often overlaps with mid-gestation, exposing cows to mild protein restrictions, potentially affecting placental development and fetal growth. This study investigated whether protein supplementation during EG enhances placental morphology and health, and how these changes relate to calf vigor, birth weight, and growth. Angus cows (n = 32) were assigned to two groups during a simulated EG to either receive an individual protein supplement (S; n = 16) or remain unsupplemented (NS; n = 16). Treatments were applied during mid-gestation (86.0 ± 3.5 to 176.0 ± 3.5 days of gestation), during which S and NS cows were provided either 100% or 80% of their crude protein (CP) requirements, respectively. During early (<86 days) and late (>176 days) gestation, all cows were managed on pasture under similar conditions. Cows were sampled from the start of supplementation until calving to measure serum bovine pregnancy-associated glycoprotein (bPAG) concentrations as an indicator of placental health, and placental cotyledon tissues were collected at calving for histological assessment of vascularization and collagen distribution within the cotyledon tissue. Additionally, calf birth weight, vigor, and weaning weight were recorded. Repeated measures data were analyzed using a generalized linear mixed model approach, while variables measured at a single time point were analyzed using either Student's t-tests or Wilcoxon rank sum tests in R. Mild protein restriction (20% CP decrease) during mid-gestation did not affect calf birth weight, vigor, weaning weight, ADG, or maternal serum bPAG concentrations during gestation (p > 0.05). However, cotyledon vascular area density (NS: 14.01 ± 1.88% vs. S: 9.60 ± 1.16%; p = 0.04) and collagen distributed area fraction (NS: 24.78 ± 3.99% vs. S: 13.35 ± 2.62%; p = 0.01) were significantly higher in NS than S. These findings suggest a compensatory increase in placental vascularization along with an increase in extracellular connective tissue surrounding blood vessels, under protein-restricted conditions. Overall, mild protein restriction during mid-gestation did not affect calf outcomes, possibly due to compensatory placental adaptations. Because these mild restrictions do not produce immediate effects that producers can detect in calves, it remains important to determine whether these compensatory mechanisms occur at the expense of long-term calf health. Therefore, ongoing investigations will evaluate the effects of mild nutrient restrictions during EG on calf immune priming.
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