Influence of D-lactate on metabolic acidosis and on prognosis in neonatal calves with diarrhoea

Three hundred bucket-fed diarrhoeic calves up to the age of 21 days were used to investigate the degree in which D-lactic acid contributes to metabolic acidosis in bucket-fed calves with naturally acquired neonatal diarrhoea. Fifty-five percent of all diarrhoeic calves had serum D-lactate concentrations higher than 3 mmol/l. Mean (+/-SD) D-lactate values were 5.7 mmol/l (+/-5.3, median: 4.1 mmol/l). D-lactate values were distributed over the entire range of detected values from 0 to 17.8 mmol/l in calves with base excess of -10 to -25 mmol/l. Serum D-lactate concentration was higher in patients with ruminal acidosis (6.6 +/- 5.2 mmol/l; median: 5.9 mmol/l) than in those with physiological rumen pH (5.3 +/- 5.4 mmol/l; median: 3.7 mmol/l). There was no evidence of a correlation (r = 0.051) between the serum levels of D-lactate and creatinine (as an indicator of dehydration). D-lactate was correlated significantly with both base excess (r = -0.685) and anion gap (r = 0.647). The proportion of cured patients was not significantly different between the groups with elevated (>3 mmol/l) and normal serum D-lactate concentrations. This study shows that hyper-D-lactataemia occurs frequently in diarrhoeic calves, has no impact on prognosis but may contribute to the clinical picture associated with metabolic acidosis in these animals.     

Investigations on the influence of serum D-lactate levels on clinical signs in calves with metabolic acidosis

Correlations between the degree of acidosis and clinical signs (changes in posture, behaviour, intensity of suckling reflex) in neonatal diarrhoeic calves have been described in various studies. However, base excess values varied widely in calves exhibiting similar clinical symptoms. The objective of this study was to elucidate whether the clinical picture of acidotic calves with neonatal diarrhoea is influenced more by D-lactate concentration than by degree of acidosis. Eighty calves up to three weeks old that were admitted to the II Medical Animal Clinic with acute diarrhoea and base excess values between -10 and -25 mmol/L were included in the prospective study. Posture, behaviour, suckling and palpebral reflexes, and position of the eyeballs were scored during the initial examination. Base excess and serum D-lactate and urea concentrations were determined in venous blood. In order to quantify the influences of base excess and d-lactate on the clinical parameters, groups of different clinical categories were compared. The results show that variations in behaviour, and in posture can be better explained by elevations of serum D-lactate concentrations than by decreases in base excess. Disturbances of the palpebral reflex appear to be almost completely caused by high levels of D-lactate.     

Investigations of D-lactate metabolism and the clinical signs of D-lactataemia in calves

Five clinically healthy calves received an intravenous injection of 25 g sodium D-lactate (223 mmol) in 100 ml sterile water and five control calves were given the same volume of 0.9 per cent sodium chloride. Two clinical examiners who were blinded to the status (test or control) of the calves observed that between eight and 40 minutes after the injections the calves that had received sodium-D-lactate could be distinguished with certainty from the control calves on the basis of their clinical signs, for example, an impaired palpebral reflex, somnolence and a staggering gait. One-compartment and two-compartment analyses of the changes in the plasma concentration of D-lactate, and its renal clearance, indicated that the calves metabolised considerable amounts of D-lactate.     

Studies on rotavirus infection and diarrhoea in young calves.

The occurrence of diarrhoea in calves was monitored during the first three weeks of life. Calves fed amounts of colostrum sufficient to produce serum Ig levels in excess of 30 mg per ml did not develop diarrhoea, whereas calves fed less colostrum did. Rotaviruses and mycoplasma-like particles were observed in the faeces of calves with and without diarrhoea. The epidemiology of rotavirus infection in calves is discussed.     

Effects of intravenous infusions of sodium bicarbonate on blood oxygen binding in calves with diarrhoea

Twelve diarrhoeic calves were treated intravenously with an isotonic solution containing sodium bicarbonate, and their oxygen equilibrium curves (OECS) were calculated under standard conditions and compared with those of a group of healthy calves. The relationships between the OECS for arterial and venous blood and the oxygen extraction ratio were investigated. In the diarrhoeic calves, the affinity of haemoglobin for oxygen, measured under standard conditions, was increased compared with the healthy animals. During the infusion, the standard partial oxygen pressure at 50 per cent saturation of haemoglobin (P50) values stayed below the values recorded in the healthy animals. At the end of the infusion the mean standard P50 of the diarrhoeic calves was lower than before the infusion. The combined effects of all the regulating factors on blood oxygen binding resulted in the OECS of the arterial and jugular venous blood of the diarrhoeic calves remaining unchanged compared with the healthy calves. However, the administration of the infusion decreased the P50 of both the arterial and venous blood to below the value recorded in the healthy calves. Oxygen extraction by the tissues was impaired in the diarrhoeic calves throughout the infusion, and they remained dehydrated and depressed until 120 minutes after the infusion began.     

Changes in the profile of liver enzymes in newborn calves induced by experimental,subclinical acidosis in pregnant cows and osmotic diarrhoea

Experimental, subclinical acidosis was induced by oral administration of sacharose during the last 2 months of pregnancy in 15 cows. Seven cows and their newborn calves were used as a control group. The liver enzyme activities in the serum and the blood acid-base status were determined in the 15 calves from the cows in the experimental group. Mannitol was administered orally to 8 calves from the experimental group to induce osmotic diarrhoea. It was concluded that subclinical acidosis in pregnant cows alters the biochemical liver profile of their newborn calves, affecting the aspartate aminotransferase, alanine transaminase, beta glucuronidase, glutamate dehydrogenase and bilirubin activities in the serum, which are associated with oedematous changes to the hepatocytes. Diarrhoea was accompanied by an increase in the alkaline phosphatase and gammaglutamyl transferase activities and a decrease in the total protein concentration in the serum. These changes were apparently related to the numerous necrotic foci in the liver and the proliferation of the Kuppfer cells. It would appear from these results that the liver damage in the newborn calves was associated with the subclinical, metabolic acidosis in their dams and that osmotic diarrhoea occurring in the neonatal period additionally impaired the liver function.Abbreviations ALP alkaline phosphatase - ALT alanine transaminase - AST aspartate aminotransferase - GR betaglucuronidase - bw body weight - ELISA enzyme-linked immunosorbent assay - GD glutamate dehydrogenase - GGT gammaglutamyl transferase - IU international unit     

Metabolic acidosis in diarrheic calves: the importance of alkalinizing agents in therapy

Metabolic acidosis is one of the prime factors responsible for the death of many diarrheic calves. This article begins with a general discussion about the recognition of metabolic acidosis. The remaining sections detail the utilization of certain subjective and objective methods to assess the severity of acidosis as well as the approach to treatment of this metabolic condition.     

Effects of castration on behaviour and plasma cortisol concentrations in young lambs, kids and calves.

Behavioural and cortisol responses to the husbandry practice of castration with tight rubber rings were investigated in lambs and kids one day after birth and in hand reared calves aged one to seven days. There were three treatments: control handling and blood sampling, castration and, in lambs and kids only, intravenous adrenocorticotrophin injection (ACTH). The integrated cortisol responses (area under the cortisol curve) in lambs and kids were least in control, intermediate in castrated and greatest in ACTH animals. No cortisol responses were detected in control or castrated calves. The incidences of behaviour used to assess the intensity of distress apparently experienced in the different species corresponded generally with the magnitudes of the cortisol responses. Behavioural and cortisol responses together suggested that the distress caused by castration was greatest in lambs, intermediate in kids and least but not necessarily absent in hand reared calves.     

Effects of hypertonic sodium bicarbonate solution on electrolyte concentrations and enzyme activities in newborn calves with respiratory and metabolic acidosis

OBJECTIVE: To determine concentrations of electrolytes, total bilirubin, urea, creatinine, and hemoglobin; activities of some enzymes; and Hct and number of leukocytes and erythrocytes of newborn calves in relation to the degree of acidosis and treatment with a hypertonic sodium bicarbonate (NaHCO(3)) solution. ANIMALS: 20 acidotic newborn calves with a blood pH < 7.2 and 22 newborn control calves with a blood pH > or = 7.2. PROCEDURES: Approximately 10 minutes after birth, acidotic calves were treated by IV administration of 5% NaHCO(3) solution. The amount of hypertonic solution infused was dependent on the severity of the acidosis. RESULTS: Treatment resulted in a significant increase in the mean +/- SEM base excess from -8.4 +/- 1.2 mmol/L immediately after birth to 0.3 +/- 1.1 mmol/L 120 minutes later. During the same period, sodium concentration significantly increased from 145.3 +/- 0.8 mmol/L to 147.8 +/- 0.7 mmol/L. Mean chloride concentration before NaHCO(3) administration was significantly lower in the acidotic calves (99.6 +/- 1.1 mmol/L) than in the control calves (104.1 +/- 0.9 mmol/L). Calcium concentration in acidotic calves decreased significantly from before to after treatment. Concentrations of potassium, magnesium, and inorganic phosphorus were not affected by treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of hypertonic NaHCO(3) solution to acidotic neonatal calves did not have any adverse effects on plasma concentrations of several commonly measured electrolytes or enzyme activities. The treatment volume used was smaller, compared with that for an isotonic solution, which makes it more practical for use in field settings.     

Contribution of whole blood L-lactate, pyruvate, D-lactate, acetoacetate, and 3-hydroxybutyrate concentrations to the plasma anion gap in horses with intestinal disorders

Increased anion gap (AG) was due, in part, to L-lactic acidosis in 14 of 14 horses with intestinal disorders. In a few horses, increased whole blood concentrations of D-lactate made a minor contribution to the AG. However, the increase in AG was often greater than the sum of the increases in these 2 acid anions. This unexplained increase was not a result of increases in whole blood pyruvate, 3-hydroxybutyrate, or acetoacetate concentrations or serum albumin or phosphate concentrations. Identification of other anions causing increased AG could lead to better understanding, diagnosis, and treatment of metabolic imbalances in critically ill horses.     

Bile acid concentrations in serum, bile and feces of healthy calves and calves with diarrhea

On 32 calves (age 3 to 14 days) with spontaneously occurring diarrhoea, the following investigations were carried out: Regular examination of serum bile acid concentrations, collection of the entire faeces with determination of bile acid concentrations, as well as microbiological examinations. Six clinically healthy calves served as control group. In addition, bile acids in bile were determined in 16 other calves of the same age group and in 6 beef bulls. There was no significant influence of daytime or feed intake on serum bile acid concentration in diarrhoeic or healthy calves. Possibly due to the low concentrations of bile acids in the bile of young calves (4.8 +/- 3.7 mmol/l, compared to 57 +/- 13 mmol/l in the bulls), the concentrations in faeces were also rather low (control group 623 +/- 92, calves with diarrhoea 318 +/- 277, after diarrhoea. 794 +/- 935 mumol/kg). Most of it was cholic acid, whereas only traces of desoxycholic acid were found. In spite of the comparatively low concentrations of fecal bile acids, the diarrhoeic calves excreted larger amounts of bile acids than the healthy calves (12.7 +/- 13.5 vs. 1.4 +/- 0.8 mumol/kg), but this was independent of the type of enteropathogen or pathogen combinations which were detected. There were no indications for a direct influence of the diarrhoea by bile acids. However, through enteral bile acid losses, profuse diarrhoea lasting several days can cause a reduction in the total bile acid pool.     

Endothelin-1 concentrations in clone calves, their surrogate dams, and fetal fluids at birth: association with oxygen treatment

Increased endothelin-1 (ET-1) plasma concentration in human infants is associated with persistent pulmonary hypertension of the newborn, a problem also identified in calves derived from somatic cell clone technology. Increased ET-1 also is present in the amnionic fluid and plasma of the infant and mother in preeclampsia, a condition associated with abnormal placentation. Abnormalities in placentation are identified in clone calves. We measured ET-1 in fetal fluid, calf plasma, and surrogate dam plasma in 40 clone calves at the time of term delivery. Calves were subsequently identified as being either oxygen treated (O2) or non-oxygen treated based on their postpartum clinical course. Fetal fluid ET-1 concentration greater than 1.4 ng/mL carried a 3-fold increase in odds of the calf being treated with oxygen. Maternal plasma ET-1 concentration was greater in the O2 group (13 pg/ mL: [8-23 pg/mL] versus 25 pg/mL [12-40 pg/mL]; median, 25-75 percentile). Plasma ET-1 concentration in calves was not significantly different between groups. Fetal fluid ET-1 may serve as a marker for neonatal disorders of oxygenation in clone calves and the source of ET-1 may be the placenta.     

Efficacy of danofloxacin 18% injectable solution in the treatment of Escherichia coli diarrhoea in young calves in Europe

The efficacy of danofloxacin 18% against naturally occurring Escherichia coli diarrhoea was investigated in calves at seven European sites. Treatment commenced on day 0, with either a single subcutaneous injection of danofloxacin 18% (n=267) at 6 mg/kg repeated on day 2 if required, or reference product containing baquiloprim/sulphadimidine (n=37) or gentamicin (n=98) administered as recommended. E. coli was isolated from 90% to 100% of calves pre-treatment, and the prevalence of serotypes K99 and F41 was 8-46% and 46-92%, respectively. In both treatments, the majority of calves (93.2-93.9%) showed clinical improvement and completed the studies. There were significant reductions for both treatments, in severity of clinical signs on days 4 and 10 compared to day 0 (P<0.0001), and between days 4 and 10 (P<0.05), but no significant differences between treatments (P>0.05). Danofloxacin 18% was clinically safe, and as effective as the reference products in the treatment of E. coli diarrhoea in calves.