Literature Review of the Principal Diagnostic Tests to Detect Bovine Respiratory Disease in Pre-Weaned Dairy and Veal Calves.

Bovine respiratory disease (BRD) is an infection of the upper and lower respiratory tract, characterized by an inflammation of the lung. Different diagnostic tests can be used to detect BRD, including clinical respiratory scoring systems, thoracic auscultation, and imaging tests like thoracic ultrasonography and thoracic radiography. Although commonly used, none of these diagnostic tests are perfect for detecting BRD. This article reviews the advantages and drawbacks of these techniques and their performance in detecting BRD in pre-weaned dairy and veal calves.

Veal calves management in Québec, Canada: Part I. Association between passive immunity transfer at arrival and health disorders.

Morbidity and mortality remain important concerns for veal production which traditionally involves very young calves being transported directly from dairy farms to calf-raising facilities or sold through auction markets from dairy farms. There are few studies that examine the relationship between transfer of passive immunity and health outcomes in veal production in Québec. The objective of this study was to investigate the risk factors associated with morbidity and mortality in milk and grain-fed veal facilities in Québec. Between October 2017 and December 2018, a prospective cohort study was conducted on 59 batches of milk- and grain-fed veal calves from Montérégie and Centre du Québec regions in Québec, Canada. A total of 30 calves per batch were randomly sampled for the transfer of passive immunity (TPI) status using the Brix refractometer (serum threshold ≥ 8.4%). Throughout the production cycle, arrival, treatment, mortality, and slaughter records of each batch of calves were extracted and used to quantify individual- and group-level risk factors. Morbidity and mortality were modelled through generalized linear mixed models (GLMMs) using a logit link, as function of categorical variables (individual inadequate TPI, arrival season, purchasing sites, and arrival weights) and a continuous variable (proportion of inadequate TPI in the batch). Given that the health and performance data are usually collected retrospectively under commercial settings, incomplete data was recognized as a potential issue. Thus, multiple imputation models were used. From 59 batches where 1729 calves were sampled for measuring TPI, 1084 calves had a serum Brix% < 8.4% giving a prevalence of 62.7% of inadequate TPI. The prevalence of morbidity and mortality in those 59 batches were not associated with the batch-level inadequate TPI prevalence. On the other hand, individual calves with inadequate TPI had higher odds of morbidity (OR: 1.56; 95% CI: 1.2-2.05, P = 0.001) compared to those calves with adequate TPI. Odds of mortality, on the other hand, were not significantly affected by inadequate TPI (OR:1.27; 95% CI: 0.74-2.18, P = 0.3). Calves arriving to the facility during the winter season had lower odds of mortality than those arriving in fall (OR:0.16; 95% CI: 0.03-0.78, P = 0.02). In conclusion, this study suggests that inadequate TPI, as assessed upon arrival in veal farms, remains an important concern for negative health outcomes in veal calves.

Comparison of thoracic ultrasonography and thoracic radiography to detect active infectious bronchopneumonia in hospitalized dairy calves.

BACKGROUND: The best test between thoracic ultrasonography (TUS) and thoracic radiography (TR) or the best combination of tests (series or parallel) to detect active infectious bronchopneumonia (BP) in hospitalized dairy calves remains unknown. HYPOTHESIS/OBJECTIVES: To estimate performances of TUS and TR to detect active BP in hospitalized dairy calves and to determine the best strategy for using these tests based on a panel diagnosis method (PDM). Performances of TUS and TR were hypothesized to be equivalent. ANIMALS: Fifty hospitalized dairy calves (≥7 days old; ≤100 kg; standing; pCO2 ≥ 53 mm Hg; any reason of presentation). METHODS: Each calf prospectively and sequentially underwent physical examination, thoracic auscultation, blood analyses, and TUS and TR. Three blinded experts determined whether active BP was present/absent based on PDM. Krippendorff's alpha measured interexpert agreement. The sensitivities (Se) and specificities (Sp) of TUS and TR alone and in series or parallel were compared (McNemar's test; P < .05). RESULTS: Interexpert agreement was moderate at 0.58 (95%CI: 0.42; 0.73). The Se and Sp of TUS were 0.84 (95%CI: 0.60; 0.97) and 0.74 (95%CI: 0.57; 0.86), respectively. The Se and Sp of TR were 0.89 (95%CI: 0.67; 0.99) and 0.58 (95%CI: 0.39; 0.75), respectively. No significant difference was found in the Se and Sp of TUS and TR when analyzed alone, in series or in parallel. CONCLUSION: Thoracic ultrasonography or TR alone equally detected active BP in hospitalized dairy calves. Series or parallel analysis provided no additional benefit. Its ease of use and widespread accessibility support using TUS as a first-line test to detect active BP in hospitalized dairy calves.

Abomasitis in calves: A retrospective cohort study of 23 cases (2006-2016).

BACKGROUND: Abomasitis is a syndrome affecting young milk-fed calves. The current veterinary literature describes mainly its necropsy findings. OBJECTIVES: To describe the clinical presentation, complementary tests, treatments, and case-fatality rate of calves with a clinical diagnosis of abomasitis and to identify potential factors associated with outcome. METHODS: Observational retrospective cohort study (2006-2016). Review of the medical records of calves <3 months of age presented with abdominal and abomasal distension for <7 days that were clinically diagnosed with abomasitis at the Faculty of Veterinary Medicine of the Université de Montréal. A follow-up examination was conducted by telephone interview. ANIMALS: Twenty-three calves clinically diagnosed with abomasitis. RESULTS: Median age of presentation was 3 days (range, 0-62 days). The typical duration of the clinical course was <24 hours (15/23). On admission, the 2 most common clinical signs were anorexia (13/14) and positive succussion (13/14). Hyper-l-lactatemia (15/16) and increased γ-glutamyl-transferase activity (13/14) were the most common laboratory abnormalities. Hypoproteinemia (19/22) and a left shift (15/18) of the neutrophils also were observed. The short-term case-fatality rate was 52% (12/23). The clinical diagnosis was confirmed on all necropsied calves. Clostridium spp. and Escherichia coli were the most frequently isolated bacteria. Based on univariate statistical analysis, the surviving calves were significantly (P < .05) less hypothermic, less acidemic, less hyper-l-lactatemic, and had lower serum creatinine concentrations on admission than did the deceased calves. CONCLUSIONS AND CLINICAL IMPORTANCE: In our study, abomasitis was associated with a guarded prognosis.