Spurious,marked leukocytosis in 2 cats with Heinz body hemolytic anemia

Two domestic shorthair cats were presented with anorexia and dehydration following ingestion of caramelized onions. Shared key findings from a CBC (ADVIA 2120), serum biochemistry, and urinalysis included a spurious, marked leukocytosis with discordant basophil (BASO) channel and peroxidase channel WBC counts, normal manual leukocyte counts, mild, non-regenerative anemia with discrepancies between automated and manual reticulocyte counts, an abundance of large Heinz bodies (HBs), and highly irregular scattergrams. Case 1 also demonstrated a markedly elevated mean corpuscular hemoglobin concentration (MCHC) and discrepancies between RBC hemoglobin indices. Spurious leukocyte results were confirmed through re-analysis of samples (including the acquisition of a new sample, use of an alternate analyzer (Sysmex XT-2000iV; Case 1 only), and evaluation of scattergrams and blood films (Cases 1 and 2). Repeatedly discrepant reticulocyte counts were also identified. In both cases, the erroneous BASO WBC counts, discrepancies in reticulocyte counts and RBC indices, and atypical scattergrams were interpreted to result from various effects of the HBs. These cases emphasize the importance of reviewing blood films, interpreting scattergrams, and the usefulness of duplicate methods for determining various measurands on hematology analyzers.     

Heinz body hemolytic anemia associated with high plasma zinc concentration in a dog

Acute zinc toxicosis from the ingestion of pennies was diagnosed in a dog with Heinz body hemolytic anemia (PCV = 14%), leukocytosis (51,000 cells/ml) with a left shift (3,060 band neutrophils; 37,740 segmented neutrophils) and monocytosis (4,080 cells/ml), azotemia (BUN = 60 mg/dl), bilirubinemia (total bilirubin = 5.3 mg/dl), hypokalemia (3.0 mEq/L), high serum alkaline phosphatase activity (691 U/L), high total plasma solids (8.1 g/dl), hemoglobinuria, and proteinuria. Despite aggressive medical treatment, renal failure ensued, and the dog died of cardiac arrest. The clinical signs, clinical course, and laboratory findings in this dog were similar to what has been reported in other cases of acute zinc toxicosis in dogs, with the exception of a history of generalized seizures and the findings of Heinz bodies. Although a causative relationship between plasma zinc values and Heinz body formation cannot be proven, their association suggests that oxidative damage to erythrocyte hemoglobin and cell membrane proteins may be involved in the pathogenesis of zinc-induced hemolysis.     

Heinz body anemia in a dog that had been sprayed with skunk musk

A 5-year-old pit bull-type dog was examined because of lethargy and black feces, and a presumptive diagnosis of methemoglobinemia was made on the basis of grossly visible brown discoloration of the mucous membranes and urine. Heinz body formation was seen on examination of blood smears, and severe anemia developed 3 days later. The dog did not have any history of exposure to toxins or drugs that have been associated with Heinz body formation. The only remarkable historical finding was that the dog had been wandering loose the day prior to initial examination and returned home smelling strongly of skunk spray. Skunk spray contains thiols and other compounds that are strong oxidizing agents. It was speculated that the methemoglobinemia and Heinz body anemia were a result of exposure to these compounds. Skunk interactions with dogs usually have malodorous but otherwise harmless results. However, findings in this dog suggest that more serious consequences may develop in isolated cases.     

Heinz body hemolytic anemia with eccentrocytosis from ingestion of Chinese chive (Allium tuberosum) and garlic (Allium sativum) in a dog

A 4-year-old, intact male miniature schnauzer was presented with anorexia. The dog had ingested some Chinese steamed dumplings 2 days before, which contained Chinese chive (Allium tuberosum) and garlic (Allium sativum). Hematological examinations revealed severe Heinz body hemolytic anemia with eccentrocytosis and an increased concentration of methemoglobin, which was thought to result from oxidative damage to erythrocytes by constituents in these Allium plants. In this case, eccentrocytosis was a hallmark finding and could be detected easily, suggesting that this hematological abnormality is useful in diagnosing Allium plant-induced hemolysis.     

Contribution of propylene glycol-induced Heinz body formation to anemia in cats

Propylene glycol (PG) is a common preservative and source of synthetic carbohydrates in soft-moist pet foods. Propylene glycol was fed to cats for 5 weeks at concentrations found in commercial diets (1.6 g/kg of body weight; 12% of diet on a dry-weight basis) and for 3 weeks at concentrations exceeding usual intake (8 g/kg; 41% of diet). There was a dose-dependent increase in Heinz body percentage to 28% in cats fed the low dose of PG and to 92% in cats fed the high dose. Erythrocyte half-life, measured using [14C]-cyanate hemoglobin (Hb), decreased significantly (P less than 0.05) by 18.8% and 60% in cats fed the low and high PG doses, respectively. The PCV in cats fed the low dose was unaffected, whereas cats fed the high dose had a mean (+/- SEM) decrease in PCV from 33.5 +/- 1.05% to 26.3 +/- 1.45%, accompanied by punctate reticulocytosis and bone marrow erythroid hyperplasia. A dose-dependent increase in iron pigment was found in the liver and spleen of all cats. In cats fed the low dose of PG, erythrocyte reduced glutathione concentration actually increased from 7.02 +/- 0.56 to 9.74 +/- 0.69 mumol/g of Hb, but decreased to 2.96 +/- 0.27 mumol/g of Hb in cats fed the high dose. There was no significant increase in methemoglobin concentration. These results indicated that PG cannot be considered innocuous even at concentrations consumed by cats eating commercial diets. Heinz body-induced acceleration of RBC destruction develops in a dose-dependent manner, so that cats with greater food intake, ie, lactating queens and nursing kittens, are at greater risk for development of PG-induced Heinz body hemolytic anemia.     

Fiber digestion and voluntary intake in horses after adaptation to extensive large-colon resection

Each of 3 digestion trials (3 forage diets) was performed on 2 groups of horses 6 to 12 months after sham operation (group 1; n = 3) or large-colon resection (group 2; n = 5). Diets were alfalfa pellets, alfalfa hay, and grass hay. Feed and fecal analyses were performed to determine apparent digestion of dry matter, organic matter, and crude protein and true digestion of dry matter, organic matter, crude protein, total plant cell wall, hemicellulose, cellulose, and lignin. Additional fecal and metabolic variables determined were percentage of fecal water, total fecal water, metabolic organic matter, metabolic crude protein, and metabolic nitrogen. Large-colon resection decreased the digestion of plant cell wall because of decreased digestion of cellulose in alfalfa pellet and grass hay diets, but not in alfalfa hay diet. Insufficient digestible energy and/or protein from grass hay was obtained by horses with colon resection, and significant (P less than 0.05) weight loss was observed. Voluntary intake was significantly (P less than 0.05) increased by horses with colon resection. Of the diets studied, alfalfa hay was the most appropriate forage diet, compared with average grass hay and alfalfa pellet diet, for horses after extensive large-colon resection. Additionally, horses with colon resection may have higher levels of feed intake than do horses without colon resection.     

The effect of dietary energy level on the voluntary calorie intake of laying birds

This paper summarises evidence taken from the literature to show the effect of dietary energy level on the voluntary food intake of laying birds. Although groups of pullets offered different diets tend to adjust consumption so as to maintain the same calorie intake, this adjustment is imperfect in the majority of cases. Thus birds fed high energy diets usually “over‐consume” calories and gain more in weight than birds fed lower energy diets. The degree of over‐consumption observed when a particular strain is offered a range of diets of differing energy content is correlated with the characteristic calorie intake of that strain (r = 0.667). Strains with characteristically high energy intakes adjust their food consumption to compensate for differences in energy content of the diet less efficiently than the small strains which have characteristically low calorie intakes.

From the relationships demonstrated, a formula is developed which predicts the expected daily calorie intake for any level of dietary energy, given a knowledge of the calorie intake of the strain when fed some standard diet. The use of this information in the formulation of diets designed to minimise the cost of feeding is illustrated by an example.     

Effects of fallen snow on the voluntary intake and grazing behavior of Hokkaido native horses in winter woodland with underlying Sasa senanensis

The intake, digestibility, and grazing behavior of Hokkaido native horses were investigated in winter woodland with underlying Sasa senanensis. Twenty Hokkaido native horses were grazed in a woodland (8.52 ha) for 14 days in December (snowy; 20 cm of snow fall) and in November (non‐snowy) of the next year. Three mares (360 kg of average bodyweight) were used in each experiment. The fecal collection, used to investigate the intake and digestibility by the double‐indicator method, and behavioral observations were carried out for 24 h on the 6th day in each experiment. During the snowy and non‐snowy periods, the dry matter intakes of sasa foliage were 7.3 and 9.6 kg/d, respectively, which is 2.1 and 2.7% when expressed as a percentage of bodyweight. The apparent digestibility of nutrients and energy released during the snowy and non‐snowy periods were similar. The proportions of digestible energy intakes to maintenance requirement in the mares were 119 and 164% during the snowy and non‐snowy periods, respectively. Their bodyweight remained constant during the non‐snowy period; however, a slight loss in their bodyweight was observed during the snowy period. The duration of grazing on sasa foliage was 416 and 544 min/d during the snowy and non‐snowy periods, respectively, the daily grazing area of the mares during these periods was 2.0 and 5.1 ha, respectively. In other words, the area during the snowy period was smaller than that during the non‐snowy period (P < 0.05). Fallen snow, even with a depth of approximately 20 cm, inhibited the grazing behavior and intake of sasa foliage by Hokkaido native horses grazing in winter woodland pasture.     

Effect of diet on Heinz body formation in kittens

Heinz body formation was examined in kittens, in response to consumption of a variety of diets. A commercial salmon-based diet containing 16.5 mg of nitrite, 39 mg of histamine, and 210,000 IU of vitamin A/kg of diet (dry-matter basis) was found to induce Heinz body formation. Purified experimental diets--containing nitrite up to 405 mg/kg; histamine, 50 mg/kg; histamine 50 mg/kg plus nitrite, 45 mg/kg; or vitamin A, 250,000 IU/kg--failed to induce Heinz body formation. The effect of propylene glycol (PG) on Heinz body formation was examined by giving groups of 6 kittens purified diets containing 5 or 10% PG for 12 weeks. Two additional kittens were fed a commercial soft-moist diet containing PG for 12 weeks. All kittens fed PG developed Heinz bodies, with peak values for erythrocytes containing Heinz bodies being: 28% for kittens of the 10% PG group; 20% for kittens of the 5% PG group; and 36% for kittens of the soft-moist diet group. Kittens did not develop anemia or methemoglobinemia. Heinz body percentage required 6 to 8 weeks to decrease to the pretreatment value of less than 1% after diets containing PG were discontinued. 51Chromium-labeled erythrocytes were used to evaluate erythrocyte survival in 4 kittens of the 10% PG-fed group and in 4 control kittens. Kittens with Heinz body formation induced by 10% PG had significantly (P less than 0.001) decreased erythrocyte-survival, compared with that for controls, with half-life of 8.3 days for kittens of the PG group, compared with 12.6 days for kittens of the control group.     

Performance of crossbred calves with dietary supplementation of garlic extract

Twelve crossbred calves (Holstein cross) in their pre-ruminant stage were used to study the effect of garlic extract feeding on their performance and they were randomly allotted into treatment and control groups in equal number. Performance was evaluated by measuring average body weight (BW) gain, feed intake [dry matter (DM); total digestible nutrient (TDN) and crude protein (CP)], feed conversion efficiency (DM, TDN and CP), fecal score and fecal coliform count. Diets were same for both groups. In addition, treatment group received garlic extract supplementation at 250 mg/kg BW/day/calf. BW measured weekly, feed intake measured twice daily, proximate analysis of feeds and fodders analysed weekly, fecal scores monitored daily and fecal coliform count done weekly. There was a significant (p < 0.01) increase in mean BW gain and feed intake and a significant (p < 0.01) decrease in severity of scours as measured by fecal score in the treatment group compared to the control group. The results suggest that garlic extract can be supplemented to the calves for better performance.     

Isotype-specific antibodies in horses and dogs with immune-mediated hemolytic anemia

Classes of antibody bound to erythrocytes were determined using direct immunofluorescence (DIF) flow cytometry in 3 horses and 12 dogs with immune-mediated hemolytic anemia (IMHA). Background levels of antibody binding were determined in samples from 12 horses and 12 dogs that were free of clinical disease. The range of nonspecific binding of a fluorescein isothiocyanate (FITC)-conjugated goat anti-equine immunoglobulin G (IgG) was 19.9–36.7%, but was eliminated by the use of the F(ab)₂ fragment of FITC-conjugated goat anti-equine IgG. Background binding by other class-specific antibodies to equine and canine erythrocytes was negligible. The DIF results were compared to the direct antiglobulin (Coombs) test in 5 horses and 20 dogs with anemia. The former assay was more sensitive in dogs with IMHA than was the Coombs' test (100% versus 58%). In contrast, the Coombs' test had better specificity than the DIF assay (100% versus 87.5%, respectively). Using clinical parameters or response to therapy as the comparison, the positive and negative predictive values for the DIF test were 92% and 100% compared to the values of the Coombs' test of 100% and 62%. The DIF assay detected low levels of cells bound with antibody (<30%) in 5 dogs that were Coombs' test-negative. For both species, performance of the DIF test was independent of the prozone effect. Five dogs with IMHA had IgG and IgM on erythrocytes, 5 had IgG, and 2 had IgM. Three horses had surface-bound IgG, including a horse with suspected penicillin-induced IMHA, a foal with neonatal isoerythrolysis, and a foal with clostridial septicemia. The DIF method was valuable in monitoring the response to therapy in the foal with neonatal isoerythrolysis.