Respiratory distress syndrome in calves

Reference limits for blood gas analysis performed from coccygeal vessels of multiparous Holstein dairy cows: Effects of stage of lactation and season of sampling

Blood gas analysis is a great support to the diagnostic process of critically ill patients. Its correct application to the medicine of dairy cows depends on the availability of specific reference intervals that are still difficult to find in the literature. They may vary according to the type of blood sampled, animals' age and production stage, and climatic conditions. This study aimed at calculating the reference limits for some blood gas parameters in the blood collected from the coccygeal vessels of multiparous Holstein dairy cows. This site of sampling implies the risk of withdrawing blood of unknown origin (venous, arterial, or mixed), but has a high practical interest for the easy and quick performance and the minimal animal restraint required. Data from 379 cows were used, and reference limits were produced for pH, partial pressure of carbon dioxide (pCO2), bicarbonate concentration (HCO3), total carbon dioxide concentration (tCO2), oxygen saturation (sO2), hemoglobin (Hb), hematocrit (Hct), base excess (BE), glucose, Na, K, and ionized calcium (iCa). The effects of stage of lactation (5 to 60 vs. > 60 DIM) and season of sampling (cold vs. hot) were investigated, and specific reference limits were produced for each variable and each level of the factors whenever a significant effect was detected. The pH, sO2, K, and iCa were not influenced by season or stage of lactation. All the other blood gas parameters were significantly affected by season of sampling, and Hb, Hct, glucose, and Na were also affected by stage of lactation. Reference limits provided in this study are specific to the site of sampling (coccygeal vessels) and the animal category considered. Further studies are needed to produce reference intervals for other blood gas parameters, cow categories, and blood types.

Analysis of physical traits, clinical parameters, and energy metabolism of in vivo- and in vitro-derived Flemish newborn calves during the first day of life

Studies investigating physiological deviations from normality in newborn calves derived from in vitro fertilization procedures remain important for the understanding of factors that reduce calf survival after birth. The aim of this study was to investigate parameters affecting health and welfare of newborn Flemish calves derived from in vitro embryo production (IVP) in the first hours of life in comparison to in vivo-derived calves. Physical traits of newborn calves and fetal membranes (FM) were recorded soon after birth. Newborn venous blood samples were collected at several time points within the first 24 h of life for analyses of energy substrates, electrolytes, blood gases, acid-base balance, blood chemistry, and haematology. A liver biopsy was taken within the first hour after birth for analysis of gene expression of key enzymes of the fructolytic and glycolytic pathways. Newborn IVP calves were heavier and larger at birth, which was associated with heavier FM. At several time points during the first 24 h of life, IVP-derived calves had altered rectal temperature, blood gases, electrolyte concentrations, blood parameters for liver, kidney and muscle function, and acid-base balance, plasma lipid metabolism, and hemogram parameters. The relative mRNA abundances for triokinase and lactate dehydrogenase-B were greater in IVP calves. In summary, IVP-derived newborn calves were at higher risk of clinical problems after birth, which was markedly greater in heavier and larger calves. Such animals take longer to adapt to extrauterine life and should receive a special attention during the immediate neonatal period.

From ultrasound to microscopy: Actualities in thyroid investigation in cattle

Thyroid ultrasonography examination is widely used in human and small animal medicine. However, it has rarely been applied in cattle. The aim of this study was to determine whether the measurements of the thyroid gland by ultrasound examination correlate to those taken during post-mortem examination. A sample of 22 cows and 23 calves was selected for thyroid gland evaluation. An ultrasound scan was performed ante-mortem, followed by euthanasia (for medical reasons) or slaughtered in the food chain and the dissection of the thyroid gland was therefore performed. Post-mortem, the gland was weighed and its dimensions and volume measured. The volume and weight measurements were compared with the predicted ones on US using the formulas available in the literature. Finally, histological examination was performed on thyroid glands. The dimensions of the thyroid gland measured by ultrasonography were significantly different (p<0.05) from those observed post-mortem, except for lobe lengths in calves (p>0.1). However, in calves, there was no systematic bias between the ultrasound and post-mortem examination of the thyroid gland, which were concordant (with an average error of 18%). Cystic lesions were observed on ultrasound in 9/22 cows and could be found on histological examination in 7 of these. Other lesions, such as follicular hypoplasia and hyperplasia, were seen on histological examination but not on ultrasound. Although the ultrasound measurements did not significantly correlate with those taken post-mortem, this examination may allow to differentiate non-standard thyroids in the case of hyperplastic goiter, as demonstrated in other species. This study also describes and illustrates interesting lesions of the thyroid gland in cattle. These findings are innovative in the description of the use of thyroid ultrasound in cattle, although further studies are needed to allow deeper conclusions.

Evaluation of Blood Lactate, Heart Rate, Blood Pressure, and Shock Index, and Their Association with Prognosis in Calves

Diseases in young calves received as emergencies are often associated with hypovolemic and/or septic shocks. The objectives of our study were to (1) assess the correlation between clinical hemodynamic parameters and blood L-lactates (LAC), systolic blood pressure (SBP), and the shock index (SI) recorded upon arrival; and (2) to evaluate how these parameters were related to short-term outcomes in calves under 4 months of age presented as emergencies. We conducted a single-observer prospective observational study on calves aged from 1 day to 4 months, presented to the Veterinary Clinic for Ruminants of Liège from December 2020 to May 2022. Forty-five calves were included in the study. The statistical analysis revealed a significant correlation between LAC and heart rate (r = 0.570; p < 0.05) and LAC and SI (r = 0.373; p < 0.05). A high LAC value at admission was significantly associated with a negative outcome (death) (p < 0.05). In calves suffering from obstructive digestive diseases, the SI was related to the outcome and the analysis indicated a cut-off value of 1.13 (Se = 0.77, Spe = 1). In conclusion, in our study, the initial blood L-lactate value was correlated with heart rate, the shock index, and the clinical shock score, and admission hyperlactatemia was associated with a poor prognosis in calves under 4 months of age. In this cohort, the shock index in calves suffering from digestive diseases was linked with mortality.

Mastitis in Dairy Cattle: On-Farm Diagnostics and Future Perspectives

Mastitis is one of the most important diseases in dairy cattle farms, and it can affect the health status of the udder and the quantity and quality of milk yielded. The correct management of mastitis is based both on preventive and treatment action. With the increasing concern for antimicrobial resistance, it is strongly recommended to treat only the mammary quarters presenting intramammary infection. For this reason, a timely and accurate diagnosis is fundamental. The possibility to detect and characterize mastitis directly on farm would be very useful to choose the correct management protocol. Some on-field diagnostic tools are already routinely applied to detect mastitis, such as the California Mastitis Test and on-farm culture. Other instruments are emerging to perform a timely diagnosis and to characterize mastitis, such as Infra-Red Thermography, mammary ultrasound evaluation and blood gas analysis, even if their application still needs to be improved. The main purpose of this article is to present an overview of the methods currently used to control, detect, and characterize mastitis in dairy cows, in order to perform a timely diagnosis and to choose the most appropriate management protocol, with a specific focus on on-farm diagnostic tools.

Technical Validation of Ultrasound Assessment of the Thyroid Gland in Cattle

Little is known about thyroid diseases in ruminants, probably due to the lack of diagnosis techniques developed in this species. However, thyroid ultrasound (TU) is widely used in human and in companion animal's medicine. It is a cheap and non-invasive examination, which allows for the identification of thyroid structures or diffuse diseases. The aim of this study was to evaluate the accuracy of TU in five calves and five cows through inter- and intra-observer repeatability. The size of the thyroid gland was measured from three views: left sagittal, right sagittal and transverse; nine measurements per view. The intra-observer coefficient was calculated for each observer. For the inter-observer, the first observer was a board-certified imagist (European College of Veterinary Diagnostic Imaging diplomate), the second was a board-certified specialist in bovine and herd management (European College of Bovine Health Managementdiplomate) and the third was an in-trained veterinarian for the TU. They each scanned the thyroid gland successively, following the same method. The intra-observer variabilities for observers 1, 2 and 3 were 8.22%, 5.53%, 5.38%, and 7.18%, 8.65% and 6.36%, respectively, for calves and cows. The inter-observer variability for calves was 10.4% and for cows, 11.8%. This study confirms the feasibility of repeatable intra- and inter-observer TU-estimated measurements in cattle.

Importance of Monitoring Fetal and Neonatal Vitality in Bovine Practices

Prior to initiating any obstetrical intervention for anterior or posterior presentation, it is imperative to emphasize the need for a precise and accurate diagnosis of fetal viability and to select the most appropriate approach for assistance. In uncertain cases, diagnostic tools such as ultrasonography, pulse oximeter, or measurement of acid-base balance or lactate concentration may be employed to confirm the diagnosis. In situations of severe asphyxia, a cesarean section is preferred over traction, even if the duration of asphyxia is less than 60 s, to maximize the likelihood of the survival of the fetus. Postcalving, several vitality scores have been proposed to evaluate the vigor of the newborn calf. Originally, four different clinical signs were recommended for assessing the well-being of newborn calves. Subsequently, five or more different clinical signs were recommended to evaluate vitality. However, despite the efforts for devising a practical tool to assess newborn calf vitality; a user-friendly and highly accurate instrument that can be used on farms remains elusive. Measuring the acid-base balance or lactate concentration may increase the diagnostic accuracy. It is critical to emphasize the importance of reducing the incidence of dystocia to mitigate the occurrence of severe asphyxia. In instances where asphyxia is unavoidable, adequate treatments should be administered to minimize losses.

Acute Kidney Injury Is Associated with Higher Serum Cys-C and NGAL Concentrations, and Risk of Mortality in Premature Calves with Respiratory Distress Syndrome

The purpose of the present study was to establish the development of acute kidney injury (AKI) and evaluate the usefulness of kidney-specific biomarkers in diagnosing AKI in premature calves with respiratory distress syndrome (RDS). Ten-term healthy and 70 premature calves with RDS were enrolled. Clinical examination, blood gases, and chemical analysis were performed at admission and 72 h. Serum concentrations of blood urea nitrogen (BUN), creatinine (Cre), phosphorus (P), cystatin-C (Cys-C), neutrophil gelatinase-associated lipocalin (NGAL), uromodulin (UMOD), and liver-type fatty acid-binding protein (L-FABP) were measured to evaluate kidney injury. Our findings showed that 38.5% of the premature calves with RDS developed AKI. The RDS-AKI group had a 4-fold higher mortality risk than the RDS-non-AKI group. Cys-C, with 90% and 89% specificity, and NGAL, with 100% sensitivity and 85% specificity, were the most reliable biomarkers to determine AKI in premature calves. The usefulness of any biomarker to predict mortality was not found to be convincing. In conclusion, AKI can develop as a consequence of hypoxia in premature calves and may increase the risk of mortality. In addition, serum Cys-C and NGAL concentrations may be useful in the diagnosis of AKI in premature calves with RDS.

The Usefulness of Serum Brain Damage Biomarkers in Detection and Evaluation of Hypoxic Ischemic Encephalopathy in Calves with Perinatal Asphyxia

The purpose of the present study was to determine hypoxic brain damage in calves with perinatal asphyxia using brain-specific damage biomarkers. Ten healthy and 25 calves with perinatal asphyxia were enrolled in the study. Clinical examination, neurological status score, and laboratory analysis were performed at admission, 24, 48, and 72 h. Serum concentrations of ubiquitin carboxy-terminal hydrolysis 1 (UCHL1), calcium-binding protein B (S100B), adrenomodullin (ADM), activitin A (ACTA), neuron-specific enolase (NSE), glial fibrillary acidic protein (GFAP) and creatine kinase-brain (CK-B) were measured. Histopathological and immunohistochemical examinations of the brain tissue were performed in 13 nonsurvivor calves. The neurological status score of the calves with asphyxia was significantly (p < 0.05) lower. Mix metabolic-respiratory acidosis and hypoxemia were detected in calves with asphyxia. Serum UCHL1 and S100B were significantly (p < 0.05) increased, and NSE, ACTA, ADM, and CK-B were decreased (p < 0.05) in calves with asphyxia. Histopathological and immunohistochemical examinations confirmed the development of mild to severe hypoxic-ischemic encephalopathy. In conclusion, asphyxia and hypoxemia caused hypoxic-ischemic encephalopathy in perinatal calves. UCHL1 and S100B concentrations were found to be useful markers for the determination of hypoxic-ischemic encephalopathy in calves with perinatal asphyxia. Neurological status scores and some blood gas parameters were helpful in mortality prediction.

Influence of Elective Cesarean Calving (with and without Dexamethasone Induction) on the Erythrogram and Iron Serum Profiles in Nellore Calves

Simple Summary

The use of elective cesarean section has become common practice in double muscled breeds of in vitro fertilized cattle and cloned calves, particularly before the onset of labor, when it is known that cesarean section negatively affects neonatal respiration and metabolic adaptation in humans and calves. However, there is a lack of information on the effects of cesarean section on the erythrogram of calves. The objectives of this study are to characterize the hematological profile of Nellore calves born spontaneously or by elective C-section (with or without induction with dexamethasone) and to verify the frequency of anemia in these animals. Our data indicate that in the first day of life there was a decrease in the number of red blood cells, hemoglobin rates, and values of the globular volume regardless of the type of birth; however, the recovery of these hematological values happened faster in zebu calves born spontaneously than in the group born by elective C-section (with or without induction). The results suggest that iron supplementation in the first month of life in Nellore calves that underwent cesarean section could be recommended to prevent the iron deficiency anemia observed in this study.

Abstract

The aim of the present study is to evaluate the erythrogram and iron serum profiles of neonatal calves born spontaneously or born by elective cesarean section with or without dexamethasone induction. The research was performed on 38 newborn Nellore calves. Three groups of calves were assigned according to the type of birth: calves born by spontaneous vaginal calving (n = 10), calves born by elective cesarean section without inducing labor (n = 14), and calves born by elective cesarean section with labor induction with dexamethasone (n = 14). Blood samples to assess red blood cell count (RBC), hemoglobin, hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), concentration of mean corpuscular hemoglobin (MCHC), serum iron (SFe), total capacity to bind iron to transferrin (TIBIC), and transferrin saturation index (TSI) were performed at calving (0, 3, 6, and 12 h of life) and on 1, 2, 3, 5, 7, 10, 15, and 30 days of life. Regardless of the experimental group (calves born spontaneously, or born by elective cesarean section with or without dexamethasone induction), in the first day of life there was a decrease in the number of red blood cells, hemoglobin rates, and values of the globular volume. In the period of the first 10 days of life, animals from spontaneous vaginal delivery quickly recovered values of erythrocytes, hemoglobin, and packed cell volume, whereas animals born by elective C-section (induced and uninduced) did not recover as quickly in their rates of hemoglobin and packed cell volume values. In calves born by elective C-section (induced and uninduced), it was observed in their period between 10 and 30 days of life that the MCV and MCH were reduced by passing the presenting microcytic hypochromic when compared with calves obtained by spontaneous vaginal delivery. In the period between 10 and 30 days of life, the levels of SFe and TSI in animals born by elective C-section (induced and uninduced) are significantly lower. The differences in the erythrogram values between Nellore calves born spontaneously and those by elective C-section with or without induction must be considered consequent to the process of neonatal adaptation to extrauterine life. Iron supplementation in the first month of life in calves from cesarean could be recommended to prevent anemia of this iron deficiency.

Serum sRAGE and sE-selectin levels are useful biomarkers of lung injury and prediction of mortality in calves with perinatal asphyxia

The objective of the present study was to evaluate the biomarkers specific to lung endothelial and epithelial damage in the determination of lung injury and its severity in calves with perinatal asphyxia and to evaluate their prognostic importance among survivors and non-survivor calves. Ten healthy calves and 20 calves with perinatal asphyxia were enrolled in the study. Clinical examination and laboratory analysis were performed at admission. Serum concentrations of soluble advanced glycation end-product receptor (sRAGE), soluble E-selectin (sE-selectin), clara cell secretory protein (CC16), and soluble intercellular adhesion molecule-1 (sICAM-1) were measured to assess lung injury. Venous pH, sO₂, HCO₃, and BE of calves with perinatal asphyxia were significantly lower than the healthy calves. sRAGE, sE-selectin, pCO₂, and lactate were significantly high in calves with asphyxia. ROC analysis showed that sRAGE, sE-selectin, pCO₂, lactate, and respiratory rate were higher while HCO₃ and BE were lower in the nonsurvivor calves than survivors. In conclusion, serum sRAGE and sE-selectin concentrations highlight the utility of these biomarkers in determining lung injury in calves with asphyxia. Also, pH, pCO₂, lactate, HCO₃, BE, and respiratory rate along with serum sRAGE and sE-selectin were useful indicators in the prediction of mortality.

Biomarkers in premature calves with and without respiratory distress syndrome

BACKGROUND

Approaches to the evaluation of pulmonary arterial hypertension (PAH) in premature calves by using lung-specific epithelial and endothelial biomarkers are needed.

OBJECTIVE

To investigate the evaluation of PAH in premature calves with and without respiratory distress syndrome (RDS) by using lung-specific epithelial and endothelial biomarkers and determine the prognostic value of these markers in premature calves.

ANIMALS

Fifty premature calves with RDS, 20 non-RDS premature calves, and 10 healthy term calves.

METHODS

Hypoxia, hypercapnia, and tachypnea were considered criteria for RDS. Arterial blood gases (PaO2 , PaCO2 , oxygen saturation [SO2 ], base excess [BE], and serum lactate concentration) were measured to assess hypoxia. Serum concentrations of lung-specific growth differentiation factor-15 (GDF-15), asymmetric dimethylarginine (ADMA), endothelin-1 (ET-1), vascular endothelial growth factor (VEGF), and surfactant protein D (SP-D) were measured to assess PAH.

RESULTS

Arterial blood pH, PaO2 , SO2 , and BE of premature calves with RDS were significantly lower and PaCO2 and lactate concentrations higher compared to non-RDS premature and healthy calves. The ADMA and SP-D concentrations of premature calves with RDS were lower and serum ET-1 concentrations higher than those of non-RDS premature and healthy calves. No statistical differences for GDF-15 and VEGF were found among groups.

CONCLUSIONS AND CLINICAL IMPORTANCE

Significant increases in serum ET-1 concentrations and decreases in ADMA and SP-D concentrations highlight the utility of these markers in the diagnosis of PAH in premature calves with RDS. Also, we found that ET-1 was a reliable diagnostic and prognostic biomarker for PAH and predicting mortality in premature 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.

Pathological features of cloned calves that died in the neonatal period

ABSTRACT: Somatic-cell nuclear transfer is a cloning technique that enables the creation of a viable embryo from a donor adult to produce a genetically identical individual. This technique opens numerous potential possibilities for medicine and animal reproduction. However, several reports have documented cloning-related issues. Embryo and fetal losses remain significantly higher than in other techniques, and there is a high incidence of dystocia and hydrops, which decreases efficiency and increases costs. Animals delivered at term often exhibit a syndrome known as macrosomia and experience difficulties in adapting to life outside the uterus, and death is a common outcome. In the present study, 41 cloned calves that died in the neonatal period were subjected to gross and histopathological examination. Most important gross lesions were found in the liver (enlargement, congestion, yellowish color), kidneys (brownish color at surface and cut, and cysts), lungs (atelectasis, parenchymal consolidation, and secretions in bronchi and bronchioles), and heart (concentric and eccentric hypertrophy, hematic cysts, persistence of ductus arteriosus). Primary microscopic findings were seen in the liver, kidneys, and lungs from neonatal calves. In the liver, 85% of the animals exhibited hepatic degeneration. The presence of a brownish pigment within the cortical tubules of the kidneys was found in approximately 90% of the samples; the presence of this pigment has not been previously reported in cloned calves. In the lungs, a large number of animals exhibiting lesions characteristic of pneumonia (55%). These changes were the pivotal causes of death, mainly due to problems in adapting to life outside the uterus and opportunistic infections in the neonatal period. Further investigation focusing on pathological anatomical changes is necessary to map these abnormalities in cloned animals.

Chronological echocardiographic evaluation of left ventricular systolic and diastolic function in term and premature neonatal calves

Echocardiographic studies in human neonatology has demonstrated that prematurity can lead to cardiovascular dysfunction and especially compromises the left ventricular (LV) systolic and diastolic functions. As echocardiographic studies have not been performed on cardiovascular dysfunction in premature calves, we echocardiographically evaluated and compared the LV systolic and diastolic function in full-term and premature calves. We followed the hemodynamical changes of LV during first 3 days of life. Twenty premature calves and 10 healthy term calves were enrolled in the study. 2D, M-mode and Doppler echocardiographic examinations were performed at days 1, 2 and 3 after birth to evaluate LV systolic and diastolic functions. Our findings demonstrated that not only was there LV diastolic dysfunction (55% premature calves, 10% term calf at day 1; 65% premature calves, 10% term calf at day 2 and, 75% premature calves, 20% term calf at day 3), but also LV systolic dysfunction (55% premature calves, 60% term calf at day 1; 55% premature calves, 50% term calf at day 2, and 45% premature calves, 40% term calf at day 3) deteriorated in both term and premature calves. In conclusion, the present study, which was the first comparative echocardiographic assessment of LV systolic and diastolic functions in term and premature newborn calves, showed that both systolic and diastolic dysfunctions might occur in term and premature calves.

Comparison between thoracic ultrasonography and thoracic radiography for the detection of thoracic lesions in dairy calves using a two-stage Bayesian method

Infectious bronchopneumonia is a lower respiratory tract disease with major economic consequences in dairy calves. Thoracic radiography (TR) and thoracic ultrasonography (TUS) are two imaging diagnostic procedures available in bovine medicine for identifying thoracic lesions. However, no study has investigated whether one of these tests is superior to the other or if they provide comparable results for the detection of thoracic lesions in calves. The objective of this study was therefore to estimate and to compare the performances of TUS and TR for the detection of thoracic lesions in dairy calves. A prospective cross-sectional study was performed in a hospital setting. A total of 50 calves (≥7 days old; ≤100 kg; standing; pCO2 ≥ 53 mmHg; any reason of presentation) were enrolled. Every calf underwent TUS and TR. Only calves with thoracic lesions on TUS and/or TR were controlled by thoracic computed tomography (CT) (the gold standard). Calves without lesions were not controlled by CT. A two-stage Bayesian framework was used. The sensitivities (Se) and specificities (Sp) of both tests individually and used in series or parallel were estimated. The Se and Sp of TUS were 0.81 (95 % BCI (Bayesian Credible Interval): 0.65; 0.92) and 0.90 (95 % BCI: 0.81; 0.96), respectively. The Se and Sp of TR were 0.86 (95 % BCI: 0.62; 0.99) and 0.89 (95 % BCI: 0.67; 0.99), respectively. This study did not reveal any differences between both tests. Using TUS and TR in series was more specific than using both tests in parallel. The performances of TUS alone were not different from the performances of both tests in series or in parallel. In conclusion, TUS and TR were equivalent in detecting thoracic lesions in this study. Using TUS alone allowed an accurate detection of thoracic lesions in dairy calves. Further studies enrolling a larger sample (> 400 calves) and allowing adequate power to be achieved would be necessary to confirm these results.

Clinical and blood gas analysis of calves conceived by artificial insemination, in vitro fertilization and animal cloning

ABSTRACT: In order for successful extra-uterine adaptation to occur, it is necessary for the neonate to be able to establish its respiratory functions effectively, guaranteeing efficient oxygenation and good vitality. Respiratory disorders are the major cause of death during the neonatal period in cattle, and this mortality is even more significant when it comes to calves originated by in vitro fertilization (FIV) or animal cloning (CA). Blood gas analysis assesses acid-base balance changes effectively, and when associated with the neonate’s clinical examination, provides subsidies for accurate diagnosis and early treatment of neonatal maladaptation. The objective of this study was to study neonates born from artificial insemination (IA) and to compare them to calves conceived by FIV and CA, regarding blood gas and clinical examination. For that, 20 AI calves, 15 FIV calves, and 15 cloned calves were evaluated immediately after calving and at 6, 12, 24 and 48 hours of life. At all experimental times, venous blood samples were collected for blood gas and clinical examination was performed. In the postpartum evaluation, Apgar score and column length and respiratory amplitude measurements were used. IVF animals showed no alterations, resembling Group IA calves. The calves from CA showed more pronounced acidosis postpartum than expected physiological acidosis mixed for neonates, with decreasing values of bicarbonate (HCO3-), and base excess (BE) and the increase in carbon dioxide pressure (PCO2) when compared to the other groups. This disorder may have reflected lower mean values of Apgar scores and increased heart and respiratory rates. Intensive follow-up of these neonates is suggested, with monitoring by clinical and hemogasometric examination for early diagnosis of this condition and treatment based on oxygen therapy and bicarbonate replacement.

Pharmacokinetics and bioavailability of cefquinome and ceftriaxone in premature calves

The aim of this study was to evaluate the pharmacokinetics and bioavailability of cefquinome (CFQ) and ceftriaxone (CTX) following intravenous (IV) and intramuscular (IM) administrations in premature calves. Using a parallel design, 24 premature calves were randomly divided into the two antibiotic groups. Each of the six animals in the first group received CFQ (2 mg/kg) through IV or IM administration. The second group received CTX (20 mg/kg) via the same administration route. Plasma concentrations of the drugs were analyzed by high-performance liquid chromatography and noncompartmental methods. Mean pharmacokinetic parameters of CFQ and CTX following IV administration were as follows: elimination half-life (t_1/2λz ) 1.85 and 3.31 hr, area under the plasma concentration-time curve (AUC_0-∞ ) 15.74 and 174 hr * μg/ml, volume of distribution at steady-state 0.37 and 0.45 L/kg, and total body clearance 0.13 and 0.12 L hr^-1  kg^-1 , respectively. Mean pharmacokinetic parameters of CFQ and CTX after IM injection were as follows: peak concentration 4.56 and 25.04 μg/ml, time to reach peak concentration 1 and 1.5 hr, t_1/2λz 4.74 and 3.62 hr, and AUC_0-∞ 22.75 and 147 hr * μg/ml, respectively. The bioavailability of CFQ and CTX after IM injection was 141% and 79%, respectively. IM administration of CFQ (2 mg/kg) and CTX (20 mg/kg) can be recommended at 12-hr interval for treating infections caused by susceptible bacteria, with minimum inhibitory concentration values of ≤0.5 and ≤4 μg/ml, respectively, in premature calves. However, further research is indicated to assess the pharmacokinetic parameters following multiple doses of the drug in premature calves.

Pharmacokinetics of enrofloxacin and danofloxacin in premature calves

The aim of this study was to determine the pharmacokinetics/pharmacodynamics of enrofloxacin (ENR) and danofloxacin (DNX) following intravenous (IV) and intramuscular (IM) administrations in premature calves. The study was performed on twenty-four calves that were determined to be premature by anamnesis and general clinical examination. Premature calves were randomly divided into four groups (six premature calves/group) according to a parallel pharmacokinetic (PK) design as follows: ENR-IV (10 mg/kg, IV), ENR-IM (10 mg/kg, IM), DNX-IV (8 mg/kg, IV), and DNX-IM (8 mg/kg, IM). Plasma samples were collected for the determination of tested drugs by high-pressure liquid chromatography with UV detector and analyzed by noncompartmental methods. Mean PK parameters of ENR and DNX following IV administration were as follows: elimination half-life (t_1/2λz ) 11.16 and 17.47 hr, area under the plasma concentration-time curve (AUC_0-48 ) 139.75 and 38.90 hr*µg/ml, and volume of distribution at steady-state 1.06 and 4.45 L/kg, respectively. Total body clearance of ENR and DNX was 0.07 and 0.18 L hr^-1  kg^-1 , respectively. The PK parameters of ENR and DNX following IM injection were t_1/2λz 21.10 and 28.41 hr, AUC_0-48 164.34 and 48.32 hr*µg/ml, respectively. The bioavailability (F) of ENR and DNX was determined to be 118% and 124%, respectively. The mean AUC_0-48CPR /AUC_0-48ENR ratio was 0.20 and 0.16 after IV and IM administration, respectively, in premature calves. The results showed that ENR (10 mg/kg) and DNX (8 mg/kg) following IV and IM administration produced sufficient plasma concentration for AUC_0-24 /minimum inhibitory concentration (MIC) and maximum concentration (C_max )/MIC ratios for susceptible bacteria, with the MIC₉₀ of 0.5 and 0.03 μg/ml, respectively. These findings may be helpful in planning the dosage regimen for ENR and DNX, but there is a need for further study in naturally infected premature calves.

Birth delivery method affects expression of immune genes in lung and jejunum tissue of neonatal beef calves

Background

Caesarean section is a routine veterinary obstetrical procedure employed to alleviate dystocia in cattle. However, CS, particularly before the onset of labour, is known to negatively affect neonatal respiration and metabolic adaptation in humans, though there is little published information for cattle. The aim of this study was to investigate the effect of elective caesarean section (ECS) or normal trans-vaginal (TV) delivery, on lung and jejunal gene expression profiles of neonatal calves.

Results

Paternal half-sib Angus calves (gestation length 278 + 1.8 d) were delivered either transvaginally (TV; n = 8) or by elective caesarean section (ECS; n = 9) and immediately euthanized. Lung and jejunum epithelial tissue was isolated and snap frozen. Total RNA was extracted using Trizol reagent and reverse transcribed to generate cDNA. For lung tissue, primers were designed to target genes involved in immunity, surfactant production, cellular detoxification, membrane transport and mucin production. Primers for jejunum tissue were chosen to target mucin production, immunoglobulin uptake, cortisol reaction and membrane trafficking. Quantitative real-time PCR reactions were performed and data were statistically analysed using mixed models ANOVA. In lung tissue the expression of five genes were affected (p < 0.05) by delivery method. Four of these genes were present at lower (LAP, CYP1A1, SCN11α and SCN11β) and one (MUC5AC) at higher abundance in ECS compared with TV calves. In jejunal tissue, expression of TNFα, Il-1β and 1 l-6 was higher in ECS compared with TV calves.

Conclusions

This novel study shows that ECS delivery affects the expression of key genes involved in the efficiency of the pulmonary liquid to air transition at birth, and may lead to an increased inflammatory response in jejunal tissue, which could compromise colostral immunoglobulin absorption. These findings are important to our understanding of the viability and management of neonatal calves born through ECS.

Efeitos da corticoterapia materna nos valores hemogasométricos de cordeiros nascidos a termo e prematuros

RESUMO: O objetivo do estudo foi avaliar as variáveis hemogasométricas de cordeiros nascidos a termo e prematuros do nascimento às 48 horas de vida. Foram constituídos quatros grupos experimentais: PN (cordeiros nascidos de parto normal, n=15, média de 146 dias de gestação); PNDEX (cordeiros nascidos de parto normal, cujas mães receberam 16 mg de dexametasona aos 141 de gestação, n=8, média de 143 dias de gestação); PRE (cordeiros prematuros nascidos de cesarianas aos 138 dias de gestação, n=10) e PREDEX (cordeiros prematuros nascidos de cesarianas aos 138 dias de gestação, cujas mães receberam 16 mg de dexametasona dois dias antes do parto, n=9). Imediatamente após o nascimento, os cordeiros de todos os grupos apresentaram quadro de acidose respiratória (pH baixo e pCO2 elevada), com maior ênfase nos animais prematuros. A concentração de HCO3 - diminuiu entre 15 e 60 minutos de vida, principalmente nos grupos PRE e PREDEX, com posterior aumento no M24h. Os valores de diferença de base foram menores nos cordeiros prematuros, os quais apresentaram respiração abdominal, intensa dispneia e grande quantidade de líquido pulmonar. A estabilização do equilíbrio ácidobase ocorreu em todos os animais ao longo das primeiras 24 horas de vida. A dexametasona teve influência positiva sobre a condição clínica dos animais prematuros, resultando em adequada ventilação e perfusão tecidual, o que garantiu maior taxa de sobrevivência.

Respiratory Support for Pharmacologically Induced Hypoxia in Neonatal Calves

Practical methods to provide respiratory support to bovine neonates in a field setting are poorly characterised. This study evaluated the response of healthy neonatal calves with pharmacologically induced respiratory suppression to nasal oxygen insufflation and to continuous positive airway pressure (CPAP) delivered via an off-the-shelf device. Ten calves were randomised to receive either nasal oxygen insufflation (Group 1, n = 5) or CPAP (Group 2, n = 5) as a first treatment after induction of respiratory depression by intravenous administration of xylazine, fentanyl, and diazepam. Calves received the alternate treatment after 10 minutes of breathing ambient air. Arterial blood gas samples were obtained prior to sedation, following sedation, following the first and second treatment, and after breathing ambient air before and after the second treatment. Oxygen insufflation significantly increased arterial oxygen partial pressure (PaO₂) but was also associated with significant hypercapnia. When used as the first treatment, CPAP was associated with significantly decreased arterial partial pressure of carbon dioxide but did not increase PaO₂. These results suggest that the use of CPAP may represent a practical method for correction of hypercapnia associated with inadequate ventilation in a field setting, and further research is required to characterise the use of CPAP with increased inspired oxygen concentrations.

Delivery of cloned offspring: experience in Zebu cattle (Bos indicus)

The production of a healthy cloned calf is dependent on a multitude of successful steps, including reprogramming mediated by the oocyte, the development of a functional placenta, adequate maternal–fetal interaction, the establishment of a physiological metabolic setting and the formation of a complete set of well-differentiated cells that will eventually result in well-characterised and fully competent tissues and organs. Although the efficiency of nuclear transfer has improved significantly since the first report of a somatic cell nuclear transfer-derived animal, there are many descriptions of anomalies concerning cloned calves leading to high perinatal morbidity and mortality. The present article discusses some our experience regarding perinatal and neonatal procedures for cloned Zebu cattle (B. indicus) that has led to improved survival rates in Nellore cloned calves following the application of such ‘labour-intensive technology’.