Paradoxic aciduria in bovine metabolic alkalosis.

Cows with metabolic alkalosis secondary to abomasal displacement and other abomasal disorders were often found to excrete acidic urine. This paradoxic aciduria contradictsthe classical view that the pH of the urine may be used to estimate the acid-base status of the body. Data from bovine clinical patients with metabolic alkalosis, serum electrolyte changes, and paradoxic aciduria suggested that the balance of sodium potassium, and chloride in the body places limits on the kidneys' ability to regulate the acid-basebalance.     

The effects of different environmental conditions on thermoregulation and clinical and hematological variables in long-distance road-transported calves

The aim of this study was to investigate the effects of long-distance road transport (19 h, from Poland to Italy) during 2 seasons (summer vs. winter) on clinical and hematological variables in calves. The environmental temperature range that could compromise the thermoregulation system (thermal stress) of the calves was tested. For the 7 Holstein calves in each transport, the BW and rectal temperature (RT) were measured, and blood samples were collected at the farm of origin, before loading at the transit center (T2), after unloading at the farm of destination (T3), and 1, 2, 3, and 4 d after arrival. The body temperature (BT) and heart rate (HR) were continuously monitored from T2 to T3. The data were statistically analyzed according to a mixed model that considered the fixed effects of transport (repeated measurements), season of journey, and their interaction. Within the observed temperature-humidity index (THI) range (30 to 80), effective thermoregulation allowed the calves to maintain their BT with small physiologic changes to prevent thermal stress, particularly in the summer. With no seasonal differences, the HR was greater at loading than unloading (120 vs. 115 beats per min; P = 0.012). As for the transport effect, the BW was less (P < 0.001) after unloading, and the RT was greater (P = 0.004). This effect was more marked in summer. The hematological variables indicated a moderate effect of transport on the hydration condition, reactive and muscular systems, and metabolism, although hematocrit (P = 0.004), erythrocytes, cortisol, NEFA, β-hydroxybutyrate, lactate, creatine kinase, lactate dehydrogenase, and aspartate aminotransferase activity (P < 0.001), and total protein (P = 0.007) were greater after unloading. This was confirmed by a moderate decrease in total leukocytes (P = 0.031) and glucose concentration (P = 0.002). The changes in the clinical variables were similar for both seasons even though in the summer, hematocrit (P < 0.001), urea (P = 0.008), and total protein (P = 0.010) increased and glucose concentration (P = 0.038) decreased. In conclusion, the data did not show a pronounced effect attributable to the season of the journey. Long-distance road transport leads to notable changes in clinical and hematological variables at the end of the journey. However, these variables remained within their physiological ranges and returned to basal values within a few days after the journey.     

Visceral leishmaniasis in a dog: clinical, hematological and pathological observations.

Visceral leishmaniasis was diagnosed in a dog that had been living with his owners in Spain for two years. Clinical diagnosis was somewhat delayed as the disease is largely unknown to Canada and was manifested by a nonresponsive anemia which was not easily explained on peripheral blood evaluation alone, and concomitant interstitial nephritis. On post mortem examination splenomegaly was the main gross pathological finding. Light microscopic examination of bone marrow aspirates and subsequent electron microscopic examination of splenic and hepatic tissues revealed numerous Leishman-Donovan bodies in cells of the reticuloendothelial system. Parasitized reticuloendothelial cells were seen singly or forming granulomata. These latter did not contain giant cells and were confined mainly to the liver and spleen, being sparse and single in the first but extremely numerous and coalescing in the latter. Accumulation of intrafollicular hyaline material was seen in a small number of splenic follicles. Leishman-Donovan bodies on electron microscopic examination had a trilaminar periplast, a large round nucleus with heavy blocks of marginated chromatin and two nucleoli, a short flagellum and a kinetoplast. Lymph nodes and bone marrow had numerous parasitized macrophages but no granulomata. Leishman-Donovan bodies were not detected in the lungs and kidneys both of which exhibited a chronic intersitital reaction. The comparative hematological profile as well as the importance of bone marrow and electron microscopic examinations of the spleen and liver in diagnosis are discussed. The potential public health hazard of leishmaniasis to North America and particularly to Canada is considered.     

Changes in hematological, blood gas, and serum biochemical variables in broilers during exposure to simulated high altitude.

One-day-old broilers were reared until 35 days of age at both natural low (100 m) and simulated high altitude (2133 m) to assess the incidence and development of ascites syndrome. Clinical measurements were conducted at 7, 14, 21, 28, and 35 days of age. Birds reared at 2133 meters exhibited significantly (P less than or equal to 0.05) reduced body weights at 7 through 28 days of age. Total serum calcium and biochemical enzyme activities were found to be altered at 35 days of age. In addition, the high-altitude group had significantly (P less than or equal to 0.05) higher erythrocyte counts, hematocrits, and hemoglobin at 14, 21, 28, and 35 days of age and higher serum inorganic phosphorus at each weekly sample time than birds at the low altitude. Total mortality was 20.3% at 2133 meters and 4.6% at 100 meters. The incidence of ascites syndrome in the high-altitude group ranged from 16.6% to 61.1% during the 5-week experimental period.     

富硒酵母对大鼠生产性能、脏器指数以及血常规指标的影响

将40只SD大鼠随机均分为4组(雌雄各半):对照组、低剂量组、中剂量组和高剂量组.对照组饲喂基础日粮,低剂量组、中剂量组和高剂最组分别饲喂含0.036%、0.144%和0.288%富硒酵母的日粮,持续28 d.在试验过程中,记录大鼠的增重和采食量,计算食物利用率.试验结束时,记录大鼠心脏、脾脏、肝脏、肾脏、睾丸、卵巢重量并计算脏器指数,试验结束时采取血液样本进行血常规指标测定.结果表明,高、中、低剂量组大鼠的食物利用率、心脏、脾脏、睾丸、卵巢指数以及血液常规指标与对照组相比均无显著差异(P>0.05);高剂鼍组大鼠的增重和采食量显著低于对照组(P<0.05),高剂量组大鼠的肾脏指数和肝脏指数显著高于对照组(P<0.05).低、中剂量富硒酵母日粮对大鼠的增重、采食量、肾脏、肝脏指数无明显影响;高剂量富硒酵母日粮对大鼠的增重、采食量、肾脏、肝脏指数有明显影响.     

Clinical efficacy of tirilazad mesylate for treatment of endotoxemia in neonatal calves.

The clinical efficacy of the lazaroid, tirilazad mesylate, a new therapeutic agent for prophylaxis and treatment of endotoxemia, was evaluated in 24 neonatal Holstein calves. Endotoxemia was induced by IV infusion of commercial Escherichia coli lipopolysaccharide (3.25 micrograms/kg of body weight) over 3 hours. Group-1 calves were given endotoxin alone; group-2 calves were given an infusion of 0.9% sterile saline solution, then were treated with tirilazad mesylate (1.5 mg/kg) 1 hour after the infusion was started. Group-3 calves were treated with tirilazad mesylate 1 hour after the start of the endotoxin infusion, and group-4 calves were given tirilazad mesylate 1 hour before the start of the endotoxin infusion. Clinical signs of endotoxemia were mitigated by tirilazad mesylate. In addition, tirilazad mesylate protected calves from endotoxin-induced hyperglycemia; treatment after endotoxin infusion decreased the severity of hypoglycemia and prevented lactic acidosis. Treatment with tirilazad mesylate after initiation of endotoxin infusion was as protective as was pretreatment.     

Expression of tissue factor in experimental bovine pneumonic pasteurellosis and endotoxemia

Tissue factor (TF), a cell surface-associated cofactor and activator of coagulation factor VII, has been implicated in the local and systemic activation of coagulation associated with sepsis. This study describes the pattern of TF expression in experimental bovine pneumonic pasteurellosis and endotoxemia. Immunohistochemical techniques were used to localize TF antigen in tissue sections. Tissue factor expression was not observed in tissues from control animals. In response to Pasteurella haemolytica challenge, TF was expressed within alveolar walls, by mononuclear inflammatory cells within alveoli, and in walls of arteries, arterioles, bronchi, and bronchioles. Tissue factor was not detected in unaffected lung, liver, spleen, lymph node or kidney tissue. Administration of Escherichia coli endotoxin intravenously resulted in tissue factor expression in lung, spleen, and lymph node tissue. Results of this study indicate that TF is expressed locally at sites of inflammation and systemically in endotoxemia. Therefore, TF may be involved in coagulation events associated with pneumonic pasteurellosis.     

Fructo-oligosaccharide supplementation: effects on metabolic, endocrine and hematological traits in veal calves

Fructo-oligosaccharides (FOS) are soluble fibres which exert various effects in the gastrointestinal tract, and induce metabolic and endocrine changes. The effects are favourable in diabetes mellitus, and may be favourable in veal calves, which during late periods of fattening often develop hyperglycemia, glucosuria and insulin resistance, especially during high lactose intake. Based on this we have studied metabolic, endocrine and haematological traits in veal calves (Simmental x Red Holstein) fed FOS (10 g/day; group GrF) or no FOS (group GrC). Whole milk and milk replacer in both groups, on a kg body weight basis, were fed in identical amounts. Experiments, lasting for 3 weeks, started when calves were 10 weeks old and weighed 117 kg. During week 3 lactose was supplemented to enhance post-absorptive glucose loads. Feed intakes were similar in both groups, but weight gain tended to be higher in GrF than GrC. The post-prandial increase of glucose concentrations was significantly smaller, of lactate tended to be smaller, and growth hormone peak frequency tended to be lower, whereas maximal insulin concentrations reached post-prandially were significantly higher in GrF than GrC. Eosinophil granulocytes increased during FOS feeding. In conclusion, FOS had basically similar effects on metabolic and endocrine traits in veal calves as in animals and humans with diabetes mellitus, but changes were small, albeit more prominent after lactose loads.     

Production and related variables in bovine leukaemia virus-infected cows

A newly developed milk dot blot test was used to detect anti-bovine leukaemia virus (BLV) antibody in milk samples from 2079 lactating adult cows from among 61 herds. The milk dot blot test was highly repeatable; the concordance rate, compared with the agar gel immunodiffusion test performed on serum, was 83.5%. All herds contained BLV-positive cows; the prevalence rate was 36%. BLV-positive cows tended to come from larger herds and were older and more often later in lactation. Fourteen production and related variables (herd size, age, days open, days in milk, milk somatic cell count, milk, fat, and protein produced in the current lactation, projected production of milk, fat, and protein, and breed class average deviations for milk, fat, and protein) were compared between BLV-positive and BLV-negative cows. Although somatic cell count, milk produced, and projected production of milk and protein were related significantly to BLV status using simple tests of association, once the variables herd size, age and days in milk were controlled, these differences were removed. Further analyses using logistic (outcome: individual cow BLV status) and least-squares regression (outcome:herd proportion of BLV-positive cows) failed to show an association between any of the measured production or related variables and BLV-positivity. We concluded that the effect of BLV on production and related variables in dairy cows was below the sensitivity of our analytical techniques or was non-existent.Abbreviations ABCA herd average breed class average for milk, fat, and protein production - AVGAGE average age of the herd - ADIM herd average for days in milk - AGID agar gel immunodiffusion - AVGSCC herd average milk somatic cell count - BCA breed class average, a milk, fat and protein production index calculated by comparing a cow's actual 305-day lactation production to the corresponding BCA standard for the same breed, age, and month of calving - BLV bovine leukaemia virus - CALVINT calving interval - COWAGE cow age - DBCA breed class average deviation for milk, fat, and protein production, the difference between an individual cow's BCA and the herd average - DIM days in milk - HS herd size corresponding to the number of lactating cows in a herd - LACT actual amount of milk, fat, and protein produced in a cow's lactation - ODHIC Ontario Dairy Herd Improvement Corporation - PCTPOS percentage of herd that is BLV-positive - PROJ projected 305-day production for milk, fat, and protein by fitting to a standard lactation curve adjusted for days in milk and age at calving - RHBCA rolling herd average for breed class average for milk, fat, and protein production, the average for all cows that completed a lactation (cows must have completed a 305-day lactation) during the previous 12 months - SCC milk somatic cell count     

Effect of repeated regrouping and relocation on the physiological, immunological, and hematological variables and performance of steers

To investigate the effect of repeated regrouping and repenning (R&R) on the hypothalamic-pituitary-adrenal axis, immune function, blood biochemical and hematological variables, and ADG, 72 Holstein-Friesian (14-mo-old; 441 +/- 3.2 kg) steers were assigned to either the control (C; n = 30) or regrouped (R; n = 42) treatments and housed six per pen in 12 pens. The R steers were exposed to six R&R over 84 d. New pen cohorts were allowed to stabilize for 14 d, and none of the R steers was allowed to share the same pen or penmates where or with whom they were previously housed. Control steers were housed in the same pen with the same penmates. Steers were blood sampled 2 h before and 2 h after the first, third, and sixth R&R. Steers were weighed the day before each R&R. Median area under the plasma cortisol curve (AUC) was greater (P < 0.05) in R than C steers after the first R&R. Following the first, third, and sixth R&R, the median ACTH AUC did not differ between the treatments. Cortisol AUC in R steers decreased (P < 0.001) following the third and sixth compared with the first R&R, however, cortisol AUC in response to exogenous ACTH (following administration of dexamethasone at -12 h) after the third R&R was greater in C than R steers (P < 0.05). Corticotropin-releasing hormone-induced cortisol and ACTH AUC were not different in C vs. R after the sixth R&R. There were no differences among treatments in haptoglobin, fibrinogen, and concanavalin A-induced interferon-gamma after the first, third, and sixth R&R. Albumin, urea, and NEFA were greater (P < 0.05) in R than C steers after the first R&R. beta-Hydroxy-butyrate and glucose concentrations were greater (P < 0.05) in R than C, whereas no changes in the protein and globulin concentrations were found in C vs. R after the sixth R& R. White blood cell, differential and total count, red blood cell, and platelet numbers did not differ in C vs. R after the first and third R&R. Lymphocyte numbers and mean corpuscular volume were greater (P < 0.05) in R than C steers after the sixth R&R. Monocyte numbers were greater (P < 0.05) in R than C steers following first R&R. There was no difference in the overall ADG in C vs. R; however, there was a tendency (P = 0.10) for lesser ADG by R than C steers following second R& R. In conclusion, steers exposed to R&R responded with increased plasma cortisol, albumin, urea, and NEFA. Repeated R&R did not have a sustained detrimental effect on immune and production measurements.     

Alterations in bovine lymphocyte function during the periparturient period

Lymphocytes from 8 Holstein heifers were evaluated during the periparturient period for mitogen-induced lymphocyte blastogenic responses. Phytohemagglutinin P- and concanavalin A-induced lymphocyte blastogenesis increased 2 and 3 weeks before parturition, respectively. However, by the first week after parturition, lymphocyte blastogenesis was markedly impaired.     

Alterations in bovine neutrophil function during the periparturient period

Neutrophils from 8 Holstein heifers were evaluated for function during the periparturient period. Random migration, ingestion of bacteria, superoxide anion production, native (nonenhanced) chemiluminescence, iodination, and antibody-dependent, cell-mediated cytotoxicity by neutrophils were determined. Foremilk samples were evaluated for bacteria. Significant (P less than 0.05) increases in random migration of neutrophils, iodination, and chemiluminescence were evident 2 weeks before parturition and then decreased dramatically by the first week after parturition. These impairments of neutrophil function after parturition may be manifested as a severe cumulative deficit in the native defenses afforded by the neutrophil.     

Effect of storage on measurement of ionized calcium and acid-base variables in equine, bovine, ovine, and canine venous blood.

The stability of blood ionized calcium (Ca2+) and acid-base variables in equine, bovine, ovine, and canine venous blood samples (n = 15, in each group) stored at 4 C for 3, 6, 9, 24, or 48 hours was studied. Variables included blood Ca2+ and standard ionized calcium (Ca2+ corrected to pH 7.4) concentrations, pH, blood carbon dioxide and oxygen tensions, base excess, bicarbonate concentration, and total carbon dioxide content. Results indicate that storage of blood samples at 4 C for up to 48 hours, despite appreciable acid-base changes, is associated with less than 1.5% change in equine, bovine, and ovine blood Ca2+ concentrations. Similar changes were observed in canine blood during the first 9 hours' storage. After 24 and 48 hours' storage, clinically relevant decrease (10.5 and 15.5%) in canine blood Ca2+ concentration was measured. Therefore, Ca2+ concentration in equine, bovine, and ovine venous blood samples stored up to 48 hours, and in canine blood samples stored up to 9 hours at 4 C is of diagnostic use.