Hyperosmotic oral replacement fluid for diarrheic calves

Twenty-five diarrheic neonatal calves, none of which was recumbent, were used to determine oral efficacy of a commercial product for fluid replacement, either by suckle or intubation. Changes in plasma protein, glucose, sodium, potassium, and osmolality as well as blood lactate and PCV were measured. Core body temperature and surface temperature at the hock and fetlock were monitored. Data were analyzed for interaction with time and response according to clinical condition. Significant differences (P less than 0.05) following therapy were restricted to glucose and potassium changes. Beneficial posttreatment trends were observed in cutaneous temperature, blood lactate, plasma protein, and PCV values.     

D-lactate production and excretion in diarrheic calves

The origin of D-lactate, the most important acid contributing to metabolic acidosis in the diarrheic calf, is unknown. We hypothesized that because D-lactate is produced only by microbes, gastrointestinal fermentation is the source. The objective of this study was to determine whether D-lactate production occurs in the rumen, colon, or both, and to measure D- and L-lactate concentrations in urine. Fecal, rumen, blood, and urine samples were obtained from 16 diarrheic and 11 healthy calves. Serum electrolyte concentrations were measured in both groups, and blood gas analyses were performed for diarrheic calves. All samples were analyzed for D- and L-lactate by high performance liquid chromatography (HPLC). Diarrheic calves were generally hyperkalemic with high serum anion gap, depressed serum bicarbonate, and low blood pH. L-lactate was markedly higher in rumen contents (22.7 mmol/ L [median]) and feces (8.6 mmol/L) of diarrheic calves than healthy calves (0.5 mmol/L and 5.1 mmol/L, respectively), but not different in serum or urine. Rumen, fecal, serum, and urine D-lactate concentrations were all significantly higher (P < .05) in diarrheic calves (17.0, 25.4, 13.9, and 19.2 mmol/L, respectively) than in healthy calves (0.5, 9.1, 1.4, and 0.5 mmol/L, respectively). Higher D-lactate concentrations in the rumen and feces of diarrheic calves suggests these sites as the source of D-lactate in blood and urine.     

Model to predict septicemia in diarrheic calves

The difficulty in distinguishing between septicemic and nonsepticemic diarrheic calves prompted a study of variables to predict septicemia in diarrheic calves <28 days old that were presented to a referral institution. The prevalence of septicemia in the study population was 31%. Variables whose values were significantly different (P < .10) between septicemic and nonsepticemic diarrheic calves were selected using stepwise, forward, and backward logistic regression. Variables identified as potentially useful predictors were used in the final model-building process. Two final models were selected: 1 based on all possible types of predictors (laboratory model) and 1 based only on demographic data and physical examination results (clinical model). In the laboratory model, 5 variables retained significance: serum creatinine > 5.66 mg/dL (>500 micromol/L) (odds ratio [OR] = 8.63, P = .021), toxic changes in neutrophils > or = 2+ (OR = 2.88, P = .026), failure of passive transfer (OR = 2.72, P = .023), presence of focal infection (OR = 2.68. P = .024), and poor suckle reflex (OR = 4.10, P = .019). Four variables retained significance in the clinical model: age < 5 days (OR = 2.58, P = .006), presence of focal infection (OR = 2.45, P = .006), recumbency (OR = 2.98, P = .011), and absence of a suckling reflex (OR = 3.03, P = .031). The Hosmer-Lemeshow goodness-of-fit chi-square statistics for the laboratory and clinical models had P-values of .72 and .37, respectively, indicating that the models fit the observed data reasonably well. The laboratory model outperformed the clinical model by a small margin at a predictabilty cutoff of 0.5, however, the predictive abilities of the 2 models were quite similar. The low sensitivities (39% and 40%) of both models at a predicted probability cutoff of 0.5 meant many septicemic calves were not being detected by the models. The specificity of both models at a predicted probability cutoff of 0.5 was >90%, indicating that >90% of nonsepticemic calves would be predicted to be nonsepticemic by the 2 models. The positive and negative predictive values of the models were 66-82%, which indicated the proportion of cases for which a predictive result would be correct in a population with a prevalence of septicemia of 31%.     

A comparison of three oral electrolyte solutions in the treatment of diarrheic calves

Thirty-six diarrheic calves infected with rota- and coronaviruses were randomly allocated to one of three oral electrolyte treatments: Ion-Aid (Syntex Agribusiness), Life-Guard (Norden Inc), or Revibe (Langford Inc). The calves were also allowed voluntary access to milk which was offered at the rate of 5% of body weight per feeding in two feedings daily. There were significant differences in recovery rate among calves treated with the different electrolytes. Only 33% of Ion-Aid-treated calves recovered; Revibe- and Life-Guard-treated calves had high recovery rates of 92% and 83%, respectively. The much higher recovery rates with Life-Guard and Revibe were attributed to the presence of an alkalizing agent in these preparations. Life-Guard uses bicarbonate to counteract acidosis and there was some evidence that this may have interfered with milk digestion. Revibe uses acetate; this was effectively metabolized within the calves' tissues and produced alkalization without interference with milk digestion.     

Determination of lactose and xylose malabsorption in preruminant diarrheic calves.

In preliminary studies feeding the poorly absorbed carbohydrate sorbitol at 2.3 g/kg body weight as an indication of maximal fermentative capacity failed to produce the expected large increase in breath hydrogen excretion but did produce a transient diarrhea in five out of six control calves. Twelve healthy control and eighteen diarrheic calves were fed lactose or D-xylose on consecutive days at 1.15 g/kg body weight and a concentration of 46 g/L. Breath and blood samples were collected at 1 h intervals from 0 to 7 h. After administration of lactose, there was a significant increase in breath hydrogen excretion in diarrheic versus control calves. The increase in plasma glucose concentrations was delayed in diarrheic calves but the area under the absorption curve was similar in control and diarrheic calves. After administration of D-xylose, breath hydrogen excretion did not increase significantly but plasma D-xylose concentrations were significantly reduced in diarrheic calves. The pathogens commonly isolated from the feces were Cryptosporidium species, rotavirus and coronavirus. The number of pathogens and the severity of the calves' acid-base deficit were not related to the severity of carbohydrate malabsorption. Decreased absorption of lactose and D-xylose may be the result of intestinal villous atrophy caused by viral or parasite infection. It was concluded that carbohydrate malabsorption rather than a specific lactose maldigestion is a significant problem in diarrheic calves. Diarrheic calves appear to digest and absorb lactose when fed in small amounts.     

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.     

Fluid therapy for diarrheic calves. What, how, and how much

The pathophysiologic consequences of neonatal diarrhea in calves are presented. A brief discussion of intestinal function, nutrient absorption, and osmolar effects follows. A rationale for appropriate fluid therapy is presented, and comparison of some currently marketed products are made.     

Clinical evaluation of sodium bicarbonate, sodium L-lactate, and sodium acetate for the treatment of acidosis in diarrheic calves

Thirty-six dehydrated diarrheic neonatal calves were used to study the effects of various alkalinizing compounds on acid-base status, the changes in central venous pressure (CVP) in response to rapid IV infusion of large volumes of fluid, and the correlation of acid-base (base deficit) status, using a depression scoring system with physical determinants related to cardiovascular and neurologic function. Calves were allotted randomly to 4 groups (9 calves/group). Over a 4-hour period, each calf was given two 3.6-L volumes (the first 3.6 L given in the first hour) of a polyionic fluid alone (control group) or were given the polyionic fluid with sodium bicarbonate, sodium L-lactate, or sodium acetate added (50 mmol/L). Acid-base status, hematologic examination, and biochemical evaluations were made immediately before infusion of each fluid (at entry) and after 3.6, 4.8, and 7.2 L of fluid had been given. Compared with control values, bicarbonate, lactate, and acetate had significantly greater alkalinizing effects on pH (P less than 0.01) and base deficit (P less than 0.01) after 3.6, 4.8, and 7.2 L of fluid were given. Bicarbonate had the most rapid alkalinizing effect and induced greater changes in base deficit (P less than 0.01) than did acetate or lactate at each of the 3 administered fluid volumes evaluated. Acetate and lactate had similar alkalinizing effects on blood. Rehydration alone did not improve acid-base status. The CVP was elevated in 10 (28%) of the 36 calves after 1 hour of fluid (3.6 L) administration, but significant differences in body weight, PCV, and clinical condition or depression score at entry were not found between calves with elevated CVP and those with normal CVP.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of a rapid reagent strip test for blood glucose determination in diarrheic calves

Sixty-three blood samples from 10 diarrheic calves were tested for glucose concentration by two methods. Plasma glucose concentration was measured by the conventional glucose-6-phosphate dehydrogenase method in the clinical laboratory, and the results compared to those obtained using a rapid reagent strip test for blood glucose concentration measurement. The rapid reagent strip test result could not be used to make an accurate prediction of the actual plasma glucose concentration as determined by the conventional method, due to the wide variability in actual plasma glucose concentrations corresponding to each rapid test result.     

Anion gap correlates with serum D- and DL-lactate concentration in diarrheic neonatal calves

The objective of this study was to investigate the relationship between serum D- and L-lactate concentrations, and anion gap (AG) in neonatal calves. The association of AG with lactic acidosis in diarrheic calves has only been investigated by measurement of L-lactate in calves with experimentally induced diarrhea. D-lactate has recently been reported to be present in high concentrations in the serum of some diarrheic neonatal calves. The contribution of this acid to AG is not reported. The relationship between AG and L- and D-lactate concentrations was examined in 24 healthy calves and 52 calves with naturally occurring infectious diarrhea with metabolic acidosis. AG was calculated as [Na+ + K+] - [Cl- + HCO3-]. D- and L-lactate were quantified using high-performance liquid chromatography. There was no correlation between L-lactate and AG, contrary to previous reports in the literature. Moderate correlations between D-lactate concentration and AG (r = .74, P < .0001), and between DL-lactate and AG (r = .77), P < .0001) were detected. No differences existed due to the age or sex of the calf. This study indicates that AG provides information on the nature of acidosis in the diarrheic, neonatal calf and reinforces the importance of investigating clinical, in addition to experimental, populations.     

Ultrasonographic imaging of abomasal milk clotting and abomasal diameter in healthy and diarrheic calves

In case of diarrhea calves are treated with oral rehydration solutions (ORS), which are known to increase abomasal pH and inhibit milk clotting in vitro. Nevertheless, recent studies have shown that ORS with HCO₃^‐ ≤ 62 mmol/L do not interfere with abomasal milk clotting in healthy calves. However, in diarrheic calves, feeding ORS and milk simultaneously may disturb abomasal curd formation and exacerbate diarrhea due to faster abomasal passage of ingesta. Therefore, the aim of the present study was to ultrasonographically examine abomasal milk clotting and diameter after feeding milk and milk replacer (MR) with and without ORS to healthy and diarrheic calves. Abomasal curd formation and diameter in healthy and diarrheic calves were ultrasonographically imaged before and after feeding milk, MR and ORS prepared in milk or MR. Feeding mixtures of milk or MR with ORS did not cause any remarkable differences in the ultrasonographic images of abomasal content. Moreover, abomasal milk clotting was not disturbed due to diarrhea. Statistically significant differences of abomasal diameter after feeding between healthy and diarrheic calves indicated that abomasal emptying is delayed in diarrheic calves. Hence, further studies are needed to determine reasons for decelerated abomasal passage in calves suffering from diarrhea.     

Evaluation of various methods for the detection of enteropathogenic Escherichia coli in diarrheic calves.

Evaluation of the Escherichia coli population in the small intestine of diarrheic calves was performed by estimating the number of colony-forming units and the observation of direct gram-stained smears of mucosal scrapings. Enterotoxigenicity of the isolates was determined by the infant mouse test and the ligated intestinal segment in calves. The influence of various broth culture media on the production of enterotoxin was also studied. Serologic characterization of the E coli isolates was performed. A total of 190 cases of diarrhea in bovine neonates was studied and it was found that enteropathogenic E coi was not responsible for more than 20% of the cases. A practical approach for the recognition of enteropathogenic E coli in a routine diagnostic laboratory is proposed.     

Study of virus excretion in feces of diarrheic and asymptomatic calves infected with rotavirus

Infection of calves by rotavirus could lead to diarrhea or subclinical disease. Therein, kinetic of viral excretion from a group of asymptomatic calves, previously exposed to a virulent strain of rotavirus, is compared to that of a group the calves of which had diarrhea associated with rotavirus infection. As determined by an enzyme-linked immunosorbent assay (ELISA), duration of rotavirus shedding in feces and maximum yield of virus antigen were similar within the two groups of calves. Rotaviruses isolated from the two above groups of animals were antigenically related as shown by neutralization tests, and showed a similar RNA electrophoretic profile. In conclusion, it is likely that both asymptomatic and diarrheic calves infected by rotavirus are equally a major source of contamination to contact healthy calves.     

Rotavirus and concurrent infections with other enteropathogens in neonatal diarrheic dairy calves in Spain

Faeces samples from 218, one to 30 days old, diarrheic dairy calves in 65 dairy herds were screened for the presence of rotavirus and concurrent infections with coronavirus, Cryptosporidium, F5+ Escherichia coli and Salmonella spp. Calves were grouped according to their age as follows: 1-7, 8-14, 15-21 and 22-30 days. Rotavirus infection was detected in 46.9%, 45.6%, 33.8% and 48.3% of the calves in the respective age-groups. No significant differences in the detection rate of rotavirus were found among calves on the different age-groups. Rotavirus was the only enteropathogen detected in 39 of the 93 (41.9%) diarrheic calves positive to this agent. Concurrent infections with other enteropathogen(s) were detected in 31.3%, 33.3%, 20.6% and 3.4% of the rotavirus infected calves in the age-groups 1-7, 8-14, 15-21 and 22-30 d, respectively. A significant age-associated decrease in the detection rate of mixed infections (p < 0.01) was found. The detection rates of the other enteropathogens considered in calves with rotavirus infection were 20.4% for coronavirus, 85.2% for Cryptosporidium, 16.7% for F5+ E. coli and 1.8% for Salmonella.     

Severity and nature of acidosis in diarrheic calves over and under one week of age

A prospective study of the severity of dehydration and acidosis was carried out in 42 calves under 35 days of age presented for treatment of neonatal diarrhea. Clinically the mean level of dehydration was 8 to 10%. The plasma volume was 65% of that in the hydrated calf but the calves only gained 6.5% in weight during therapy.

Calves under eight days of age often had a lactic acidosis. Blood pH was 7.118±0.026 (mean ± 1 standard error), bicarbonate concentration 18.8±1.3 mmol/L, base deficit 11.4±1.7 mmol/L and lactate of 3.6± 0.06 mmol/L. Calves over eight days usually had a nonlactic acidosis. Blood pH was 7.042±0.021, bicarbonate 10.8±1.0 mmol/L, base deficit 19.5±1.2 mmol/L and lactate 1.2±0.3 mmol/L. These values were all significantly different from those in younger calves.

Over all calves there was a poor correlation between the severity of acidosis and dehydration(r=0.05). The severity of lactic acidosis was related to the severity of dehydration. Mean bicarbonate requirements to correct acidosis were calculated to be 200 mmol(17 g of sodium bicarbonate)and 450 mmol(37 g of sodium bicarbonate)in calves under and over eight days of age respectively. Both groups of calves required a mean volume of 4L of fluid to correct dehydration.

     

Cytotoxins in non-enterotoxigenic strains of Escherichia coli isolated from feces of diarrheic calves

We have examined the cytotoxic responses produced in HeLa and Vero cell cultures by sonicates from 15 non-enterotoxigenic (STa-, LT-) strains of E. coli, highly lethal for mice parenterally LD50 less than 3 X 10(7) CFU), which had been isolated from feces of diarrheic calves. Three types of cytotoxic responses were observed. Type 1 (five strains) consisted of enlargement, rounding and polynucleation of HeLa cells, an effect previously reported with cytotoxic necrotizing factor (CNF) in E. coli from infant and piglet enteritis. Type 2 toxicity (three strains and the control Vir strain S5) was also characterized by enlargement and polynucleation of HeLa cells, but in contrast to Type 2 effect, cells were elongated. Sonicates from the latter strains were lethal for chickens, producing the lesions previously described with Vir strains. Type 3 toxicity (two strains and the control VT strain H19), produced an extensive destruction of both Vero and HeLa cell cultures. Cytotoxic effects were completely abolished upon heating for 1 h at 60 degrees C for Type 1 and 2 extracts and at 80 degrees C for Type 3 extracts. Seroneutralization assays showed that cytotoxins of the same type were closely related antigenically. In addition, a slight cross-neutralization was observed between Type 1 (CNF) and Type 2 (Vir) toxins.     

Cryptosporidium parvum in diarrheic calves detected by microscopy and identified by immunochromatographic and molecular methods

Cryptosporidium is an important protozoan parasite that causes diarrhea in neonates and young bovines. The objective of the present study was to determine the frequency of Cryptosporidium infection in animals of dairy farms of the Metropolitan Region (Santiago), Chile. Fecal samples of 205 newborn calves with diarrhea were studied and used for comparing the efficiency of two microscopic staining methods for diagnosis of the parasite, the auramine (AU) and a modified Ziehl-Neelsen (ZN) procedure. Out of the 205 fecal samples, we detected oocysts in 115 (56.1%) with AU and 102 (49.8%) with ZN. Comparison of results obtained with the two microscopic techniques showed significant difference (p<0.05), AU being more sensitive. On the other hand, concordance between the two methods was almost perfect (kappa value of 0.83). The results with these two operator dependent methods were confirmed using an operator independent immunochromatographic (IC) method. The IC method also enabled us to determine the identity of the parasite species as that of Cryptosporidium parvum. Identification of the parasite species was further corroborated by performing a Cryptosporidium species-specific polymerase chain reaction (PCR) test on few samples taken at random. Overall, the results showed a high number of infected animals suggesting the parasite C. parvum as a major parasitic disease agent of neonatal calves with diarrhea in dairy farms of the Metropolitan Region (Santiago) of Chile.