Short communication: Diagnostic accuracy of focused lung ultrasonography as a rapid method for the diagnosis of respiratory disease in dairy calves.

This study estimates the accuracy of the focused lung ultrasound (FLUS) compared with systematic thoracic ultrasonography (TUS) as the reference test for diagnosing pneumonia in pre- and postweaned dairy calves. One hundred thirty-five Holstein Friesian calves, aged between 1 to 6 mo were enrolled and were kept in the same pen with one or more animals showing signs of bovine respiratory disease complex (BRDC). One operator performed FLUS on each calf, and then a second, blinded operator performed TUS on the same calf. For the FLUS, we only scanned the lung lobes that are most frequently affected during BRDC and are thus easier to detect, such as the caudal aspect of the cranial lobe of the left lung (fifth and fourth left intercostal spaces; ICS), the middle lobe of the right lung (fifth right ICS), and the caudal aspect of the cranial lobe of the right lung (fourth right ICS). Pneumonia was diagnosed when a calf had a minimum of one small lobular lung lesion that was at least 1 cm deep within a normally aerated lobe (TUS score of ≥2). Diagnostic accuracy indexes of the FLUS were calculated using TUS as the gold standard. The McNemar test was performed to evaluate the differences between the 2 techniques. In addition, an intertest agreement was assessed using the weighted kappa test. A total of 76 out of 135 calves had a TUS score of ≥2 and were therefore considered to be affected by BRDC. The FLUS had a sensitivity of 81.6% (95% CI = 71.0-89.5%), specificity = 100% (95% CI = 93.9-100%), positive predictive value was 100%, negative predictive value was 96.6% (95% CI = 94.7---97.9%), and accuracy was 97% (95% CI = 92.6-99.2%). The McNemar test highlighted a difference of 10.3% between the FLUS and TUS. The agreement between the TUS and FLUS was substantial (weighted kappa test 0.78). Although FLUS shows some limitations in diagnosing lung lesions associated with BRDC compared with the systematic approach, this study shows that the focused method could be used as an additional tool for evaluating consolidation, especially when examining a large number of postweaned dairy calves.

In vitro effects of conjugated linoleic acid (CLA) on inflammatory functions of bovine monocytes.

The conjugated linoleic acid (CLA) isomers, a group of naturally occurring isomers of the essential fatty acid (FA) linoleic acid, have received special attention in animal and human nutrition. Although they have long been used as dietary integrators in dairy cows, the effects of CLA isomers on bovine immune cells remain mostly undisclosed. The present study aimed to cover this gap and investigate the in vitro effects of CLA on inflammatory functions, including chemotaxis, phagocytosis, killing capability, and extracellular respiratory burst of purified bovine monocytes (CD14+). The apoptosis rate of monocytes was addressed as well. Once assessed, the effects of different concentrations (10, 50, 100, and 500 µM) of the 2 main CLA isomers, namely cis-9,trans-11 and trans-10,cis-12, the experiments were carried out using a concentration of 50 µM of the CLA isomers, both individually and in a mixture (50:50). The immunomodulatory activities of linoleic acid, an essential FA, and stearic acid, a saturated FA, were also investigated. Only the 50:50 CLA mixture was able to reduce monocyte apoptosis and to increase the extracellular respiratory burst during experimental proinflammatory conditions, as assessed by measuring production of reactive oxygen species. Linoleic acid and CLA had no effects on chemotaxis, phagocytosis, or killing capability. Remarkably, treatment of monocytes with stearic acid significantly reduced their chemotactic capability. The present results demonstrated that CLA isomers do have immunomodulatory effects on some functions of bovine monocytes, and that the mixture of the 2 CLA isomers is more effective than the CLA isomers individually.

Pharmacokinetics and sedative effects of dexmedetomidine in dairy calves.

AIMS: To evaluate the pharmacokinetics of dexmedetomidine (DEX) administered I/V at a dose of 5 µg/kg bodyweight in dairy calves and to compare the sedative effects of anaesthetic protocols involving DEX and xylazine. METHODS: Nine dairy calves, aged 17-20 days, were treated with 5 µg/kg I/V dexmedetomidine. For pharmacokinetic evaluation, blood samples were collected over 12 hours and serum samples were analysed by high performance liquid chromatography-mass spectrometry. Another nine dairy calves, aged 16-20 days, were treated with 0.2 mg/kg I/V xylazine. After both treatments, heart rate, respiratory rate and rectal temperature were measured for 20 minutes. Sedation quality and recovery times were also assessed. RESULTS: The kinetics of DEX was best described by a two-compartment model. The distribution and elimination half-lives were 8.7 (SD 5.0) and 83.5 (SD 67.5) minutes, respectively. Mean maximum concentration and body clearance were 12.5 (SD 8.6) ng/mL and 27.9 (SD 13.1) mL/minute/kg, respectively; the mean volume of distribution at steady state was 2,170.8 (SD 1,657.5) mL/kg. A decrease in heart rate was observed after treatments with both DEX and xylazine. No differences in heart or respiration rate, or rectal temperature were observed between the two treatment groups. The onset of sedation occurred after 2.7 (SD 0.67) minutes for calves treated with DEX and 2.8 (SD 0.78) minutes for calves treated with xylazine, and was characterised by a similar degree of deep sedation and ease of handling of the calves. All recoveries were eventless, and no adverse reactions were noted. CONCLUSIONS AND CLINICAL RELEVANCE: Dexmedetomidine treatment resulted in a reliable and long lasting sedation in calves, a transient decrease in heart rate and no modification in respiratory rate or rectal temperature. The results were comparable to xylazine, the most popular alpha-2-agonist among bovine practitioners. The use of DEX in dairy calves for rapid procedures such as dehorning or castration could be suggested.

Effects of storage time on total protein and globulin concentrations in bovine fresh frozen plasma obtained for transfusion.

To evaluate the effects of storage conditions on total protein (TP) and globulin fractions in fresh frozen bovine plasma units prepared and stored for transfusion, TP and globulin fractions were evaluated in fresh plasma and at 1 month and 6 and 12 months after blood collection in plasma stored at -20°C. Significant differences in concentrations were found in the median concentration of total protein (P=0.0336), between 0 months and 1 month (P=0.0108), 0 and 6 months (P=0.0023), and 0 and 12 months (P=0.0027), in mean concentration (g/dL) of albumin (P=0.0394), between 0 months and 1 month (P=0.0131), 0 and 6 months (P=0.0035), and 0 and 12 months (P=0.0038), and beta-2 fraction (P=0.0401), between 0 and 6 months (P=0.0401) and 0 and 12 months (P=0.0230). This study suggests that total gamma globulin concentration in bovine frozen plasma is stable for 12 months at -20°C. Total protein, ALB, and beta-2 fraction have significantly different concentrations (g/dL) when compared to prestorage. This study has shown IgG protein fraction stability in bovine fresh frozen plasma collected for transfusion; therefore, bovine fresh frozen plasma seems to be suitable for the treatment of hypogammaglobulinemia (failure of passive transfer) in calves when stored for 12 months at -20°C.

Perineal choristoma and atresia ani in 2 female Holstein Friesian calves.

Atresia ani, a congenital anomaly of the anus, can be associated with other types of malformation. Two female Holstein Friesian calves had imperforate anus, rectovaginal fistula, and perineal choristomas. In one case, the choristoma was composed of mature adipose and fibrous tissue with nephrogenic rests. In the other calf, the choristoma consisted of fragments of trabecular bone coated by cartilage and containing marrow, mixed with mature adipose and fibrous tissue, striated muscle fibers, nerves, and vessels. This combination of malformations resembles the association of anorectal malformations and perineal masses in children.

Plasma procalcitonin concentration in healthy calves and those with septic systemic inflammatory response syndrome.

The diagnosis of sepsis in calves is challenging. Blood culture and clinical signs combined with a complete blood count have been used for the diagnosis of sepsis. Recent literature in humans and animal species has been focused on sepsis-specific biomarkers, such as procalcitonin (PCT), that may more accurately and efficiently diagnose sepsis. The aim of this study was to evaluate plasma PCT concentrations in healthy and septic calves. Twenty healthy control calves and 58 sick calves with septic systemic inflammatory response syndrome (SIRS) based on SIRS score and clinical findings were included. Calves with septic SIRS were further divided in septic SIRS survivors (SSS) and non-survivors (SSNS). Plasma PCT concentrations were measured with a commercial ELISA assay for cattle. A receiver operating characteristic curve was used to determine cut-off values and corresponding sensitivity and specificity for the diagnosis of sepsis. Differences in plasma PCT concentration between groups (control vs. SSS vs. SSNS) were evaluated. Plasma PCT concentrations in healthy calves and those with septic SIRS were 33.3pg/mL (0-44.3pg/mL) and 166.5pg/mL (85.9-233.0pg/mL), respectively (P<0.001). The optimal cut-off value to predict septic SIRS was 67.39pg/mL (81.0% sensitivity, 95.0% specificity). Plasma PCT concentrations were 127.4pg/mL (72.2-216.0pg/mL) and 234.3pg/mL (204.5-309.4pg/mL) in the SSS and SSNS subgroups, respectively. Statistically significant differences were found among groups (control vs. SSS and SSNS, P<0.0001; SSS vs. SSNS, P>0.05). These results confirmed an increase in plasma PCT concentrations in calves with septic SIRS, as previously reported in humans and other species.

Glucose tolerance test during abomaso-duodenal electromyography in three cows operated for left displaced abomasum.

The objective of the study was to analyze glucose metabolism and abomasal myoelectrical activity during an intravenous glucose tolerance test in cows operated for LDA. Three dairy cows, at the onset of lactation, suffering from left displaced abomasum were selected from the animals presented at the clinic. During surgical therapy, one pair of electrodes was placed in the smooth muscle of the abomasal body, the pars pylorica and the duodenum respectively. The animals were subjected to electromyography on five occasions during hospital admittance (Days 1, 2, 3, 5 and 7 post-operative); their insulin, glucagon, glucose, beta-hydroxybutyrate and NEFA levels were then measured. Two days after surgery, the animals were subjected to an intravenous glucose load (300 g glucose in 30 min) during abomaso-duodenal electromyography. The findings indicate that the three animals had glucose metabolism disorders during hospitalization. The abomaso-duodenal myoelectric activity of Cows 1 and 3 was lower than in Cow 2. During the glucose load, the analysis of hormones and metabolites showed that there were different degrees of reactivity and that myoelectric activity differed in the 3 cows. The results of the study suggest that despite the surgical reposition of the abomasum, disorders of abomasal motility persist in different degrees in cows operated for LDA and could be influenced by glucose administrations.

Risk factors associated with case fatality in 225 diarrhoeic calves: A retrospective study.

The aim of this retrospective study was to identify the major risk factors associated with case fatality in diarrhoeic calves undergoing a standard therapeutic protocol. Clinical and laboratory findings were reviewed in 225 Holstein Friesian diarrhoeic calves over a 2 year period. Calves were treated according to a fluid therapy protocol using an oral electrolyte solution or an IV infusion. After therapy, 159 calves were discharged in a healthy state, whereas 66 calves died. Logistic regression analysis showed that serum total protein (STP) concentration (odds ratio, OR, 0.51; 95% confidence interval, CI 0.31-0.84; P<0.01) and the strength of suckle reflex (OR 4.83; CI 1.17-19.88; P<0.05) were the major risk factors associated with case fatality in diarrhoeic calves. These results could help to distinguish between diarrhoeic calves with a good prognosis and those with a major risk of treatment failure.

Intravenous immunoglobulin transfusion in colostrum-deprived dairy calves.

Immunoglobulin transfusion is employed in the management of the failure of passive transfer (FPT). The aim of this study was to investigate the dose of immunoglobulin G (IgG) needed to reach a protective concentration (>10 g/L) in colostrum-deprived dairy calves. Twenty-eight Holstein Friesian newborn male calves were randomly assigned to either a control group (CG) or a treatment group (PG). Calves in the CG received 4 L of high quality colostrum within 12 h of birth. Calves in the PG received 62.7 ± 3.1 g of IgG IV in 2.6 ± 0.3 L of plasma within 6 h after birth. Serum immunoglobulin G (sIgG) and serum total protein (sTP) concentrations were assayed before and after (24 h, 72 h and 1 week after birth) plasma transfusion or colostrum ingestion. Serum (s) IgG and sTP concentrations increased in both groups throughout the period of observation. Mean sIgG and sTP concentrations after colostrum ingestion or plasma transfusion were higher in the CG than in the PG (P <0.01). Nine treated calves developed diarrhoea during the study and four were humanely euthanased due to progressive clinical deterioration. None of the calves in the CG showed signs of disease or died during the study. The dose of IgG used in this trial effectively provided an adequate sIgG concentration in colostrum-deprived calves (>10 g/L). Calves in the CG had significantly lower morbidity and mortality rates compared to those in the PG, suggesting that plasma transfusion alone is ineffective in providing complete protection against neonatal disease.

Congenital melanoma in a heifer.

The clinical, intra-operative and pathological findings taken from a case of melanoma in a 9-month-old female Holstein Friesian heifer are reported here. The tumor, hanging on the right side of the thorax, was present at birth and increased in size with time. Muscular invasion by tumoral tissue was detected during surgery. Histological and cytological data indicated that the neoplasia (melanocytoma) was benign but the prognosis, related to the invasiveness of this neoplasm, was considered reserved. Melanoma is a rare tumor in cattle, often congenital, although already reported in pigs and in horses.

Cilia-Associated Respiratory (CAR) bacillus infection in veal calves and adult cattle.

Cilia-Associated Respiratory (CAR) bacillus is a filamentous bacterium that colonizes the ciliated epithelium of the respiratory tract of many animal species and that has been associated with chronic inflammatory lesions in naturally and experimentally infected rats, mice and rabbits. In the present study, the prevalence of CAR bacillus infection and histological lesions of the trachea in veal calf and adult cattle were investigated. Forty five healthy veal calves and 45 adult cattle, raised in 18 different herds were selected at slaughter. From each animal, a tracheal sample was processed for histology, stain-ed with the Warthin-Starry method to evaluate the presence of CAR bacillus, and with haematoxylin and eosin to evaluate the presence of inflammatory lesions. CAR bacillus was identified in 17 veal calves (37.7%) and in 7 adult cattle (15.5%). Inflammatory lesions were found in 42 veal calves (93.3%) and in 41 adult cattle (91.1%). Statistical analysis pointed out a significant correlation between the presence and number of CAR bacilli and the presence and number of lymphoid follicles (P = 0.0071) and the presence and severity of neutrophilic infiltrates (P = 0.0428). These results indicate that CAR bacillus infection is common in cattle and is correlated with tracheal inflammatory lesions.

Segmental spinal cord hypoplasia in a Holstein Friesian calf.

An 8-day-old female Holstein Friesian calf was examined because of congenital spastic paresis of the hind limbs. Myelography revealed deviation and thinning of subarachnoid contrast medium columns in the lumbar segment. Upon magnetic resonance imaging, the 'hour-glass' subdural compression appeared as a T1-hypointense, T2-hyperintense ovoidal area suggestive of cerebral spinal fluid collection, compatible with hydrosyringomyelia. The calf was euthanized and the necropsy confirmed the diagnosis of segmental spinal cord hypoplasia of the lumbar tract associated to hydromyelic and syringomyelic cavities.