CJVR - April 2024, Vol. 88, No. 2



Comparison of blood profiles between housed and grazing Korean indigenous cattle (Hanwoo)

Youngjun Kim, Ji-Yeong Ku, Kwang-Man Park, Jonghun Baek, Kyoung-Seong Choi, Jinho Park (page 33)

The objective of this study was to compare the hematology profiles of Korean indigenous cattle (Hanwoo) raised in a barn (housed) or on pasture (grazing). Our findings showed significant differences in the red blood cell (RBC) profiles of these 2 groups. When compared to cattle raised in a barn, a significant decrease in hematocrit (P = 0.000), hemoglobin (P = 0.000), and red blood cells (RBCs) (P = 0.000) and a significant increase in mean cell volume (P = 0.015) and reticulocytes (P = 0.000) were observed in grazing cattle, which indicate regenerative anemia. Furthermore, indirect bilirubin was significantly higher in grazing cattle, which indicates intravascular hemolysis and neutropenia (P = 0.000), and monocytosis (P = 0.000) was also identified. To the best of our knowledge, this is the first study that demonstrates changes in reticulocyte count and indirect bilirubin levels secondary to regenerative intravascular hemolysis in grazing cattle.

Production of a new tetravalent vaccine targeting fimbriae and enterotoxin of enterotoxigenic Escherichia coli

ChongLi Xu, Yuhan She, Fengyang Fu, ChongBo Xu (page 38)

Enterotoxigenic Escherichia coli (ETEC) is an important type of pathogenic bacteria that causes diarrhea in pigs. The objective of this study was to prepare a novel tetravalent vaccine to effectively prevent piglet diarrhea caused by E. coli. In order to realize the production of K88ac-K99-ST1-LTB tetravalent inactivated vaccine, the biological characteristics, stability, preservation conditions, and safety of the recombinant strain BL21(DE3) (pXKKSL4) were studied, and the vaccine efficacy and minimum immune dose were measured. The results indicated that the biological characteristics, target protein expression, and immunogenicity of the 1st to 10th generations of the strain were stable. Therefore, the basic seed generation was preliminarily set as the 1st to 10th generations. The results of the efficacy tests showed that the immune protection rate could reach 90% with 1 minimum lethal dose (MLD) virulent strain attack in mice. The immunogenicity was stable, and the minimum immune dose was 0.1 mL per mouse. Our research showed that the genetically engineered vaccine developed in this way could prevent piglet diarrhea caused by enterotoxigenic E. coli through adhesin and enterotoxin. In order to realize industrial production of the vaccine as soon as possible, we conducted immunological tests and production process research on the constructed K88ac-K99-ST1-LTB tetravalent inactivated vaccine. The results of this study provide scientific experimental data for the commercial production of vaccines and lay a solid foundation for their industrial production.

Prevalence of pathogens in honey bee colonies and association with clinical signs in southwestern Quebec, Canada

Gabrielle Claing, Pascal Dubreuil, Martine Bernier*, Julie Ferland*, Yvan L’Homme*, Edisleidy Rodriguez*, Julie Arsenault (page 45)

Honey bees can be affected by a variety of pathogens, which impacts their vital role as pollinators in agriculture. A cross-sectional study was conducted in southwestern Quebec to: i) estimate the prevalence of 11 bee pathogens; ii) assess the agreement between beekeeper suspicion of a disease and laboratory detection of the causative pathogen; and iii) explore the association between observed clinical signs and pathogen detection in a colony. A total of 242 colonies in 31 apiaries owned by 15 beekeepers was sampled in August 2017. The prevalence of Varroa destructor detection was estimated as 48% for colonies and 93% for apiaries. The apparent prevalence of colonies infected by Nosema spp. and Melissococcus plutonius was estimated as 40% and 21%, respectively. At least 180 colonies were tested by polymerase chain reaction (PCR) for deformed wing virus (DWV), acute-Kashmir-Israeli complex (AKI complex), and black queen cell virus (BQCV), which were detected in 33%, 9%, and 95% of colonies, respectively. Acarapis woodi, Paenibacillus larvae, and Aethina tumida were not detected. Varroasis was suspected by beekeepers in 14 of the 15 beekeeping operations in which the mite was detected. However, no correlation was found between suspected European foulbrood and detection of M. plutonius or between suspected nosemosis and detection of Nosema spp. Colony weakness was associated with Nosema spore counts of at least 0.5 × 106 per bee. Melissococcus plutonius was more frequently detected in colonies showing scattered brood.

Comparison of estimations of urinary bladder volume in different scanning positions using 2D linear dimension formula and 3D bladder circumference tracing in client-owned cats

Sabrina Ayoub, Xiu Ting Yiew, Gabrielle Monteith, Allan R. Willms (page 55)

Urinary bladder volume (UBV) can be estimated using point-of-care ultrasound. The purpose of this study was to compare 2 UBV estimation methods, i.e., three-dimensional (3D) bladder circumference tracing and 2-dimensional (2D) linear bladder dimension formula, against actual bladder volumes in awake client-owned cats and identify the best scanning position for UBV estimations. Up to 3 paired sets of orthogonal longitudinal and transverse bladder ultrasound images were acquired by a trained clinician from 21 cats positioned in dorsal, right lateral, and left lateral recumbency. UBV estimation was performed with these images by 2 different observers using both methods. Actual bladder volumes were measured through urethral catheterization and compared to the estimated UBV using Lin’s concordance correlation coefficient and Bland-Altman analyses. Considering all positions, both methods showed substantial strength-of-agreement with actual bladder volumes; the 3D bladder circumference method (ρc = 0.963, 95% CI: 0.952 to 0.974) with a significant median bias of -4.08 mL (P < 0.001, IQR -7.63 to -0.68 mL, LOA -48.55 to 21.75 mL) and the 2D linear dimension method (ρc = 0.974, 95% CI: 0.966 to 0.982) with a median bias of -0.82 mL (P = 0.686, IQR -3.89 to 4.05 mL, LOA -35.23 to 35.21 mL). Scanning in left lateral recumbency provided the strongest strengths-of-agreement and precision against actual bladder volumes for both methods. Regardless of scanning positions, the 2D linear dimension method is more accurate than the 3D bladder circumference method, although both methods are imprecise with increasing volumes and UBV assessment through urinary catheterization remains the gold standard.