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1.
Near infrared spectroscopy (NIBS) was used to detect changes in brain oxygenation in five tranquilised calves that were placed on a hypoxic gas mixture (10 per cent O2/90 per cent N2) and hyperoxic gas mixture (30 per cent O2/70 per cent N2) for five minutes at each concentration. A NIRO 500 (Hamamatsu, Japan) was used for the NIBS, with the incident light source and separate detector (optodes) placed on shaved skin on the most dorsal surface of the frontal bone. Sequential arterial blood gas sample analyses provided confirmation of the appropriate change in systemic oxygenation status. By the end of the five-minute-period of breathing 10 per cent oxygen, NIBS of the calf head detected highly significant changes in haemoglobin oxygenation reflective of hypoxaemia, with oxyhaemoglobin decreasing by 23·5 units (P<0·01) and deoxyhaemoglobin increasing by 45·6 units, (P<0·01) from the baseline of breathing room air. Total haemoglobin (oxyhaemoglobin + deoxyhaemoglobin) showed a significant increase of 22·1 units (P<0·05) but there was no significant change in LAIRS determined cytochrome aa3 oxygenation. Concomitant blood gas alterations included significant decreases in Pa)2 (−27·8 mmHg, P<0·01), haemoglobin saturation (−29·0 per cent, P<0·05), and PaCO2 (−7·8 mmHg, P<0·05) and significantly increased blood pH (0·059, P<0·05). At the end of the five minutes of breathing 30 per cent oxygen NIBS of the calf head detected significantly increased oxyhaemoglobin (13·1 units, P<0·01) and decreased deoxyhaemoglobin (−13·7 units, P<0·05) when compared with baseline breathing of room aim. Total haemoglobin and cytochrome aa3 were unchanged from baseline. The accompanying arterial blood gas changes included significant increases in PaO2 (30·9 mmHg, P<0·05), arterial O2 saturation (11·7 per cent, P<0·05), and significantly decreased pH (−0·026, P<0·05), This study showed that NIRS can be used to continuously and non-invasively detect cerebral oxygenation changes in the live calf in response to both increased and decreased systemic arterial oxygen. Additionally, despite induction of profound hypoxaemia, cytochrome aa3 in the brain did not appear to become reduced.  相似文献   

2.
The effect of dietary chloride content (0·2, 0·4 and 1·3 per cent chloride on a dry matter basis) on the disposition of a single oral dose of bromide (14 mg kg−1 was evaluated in normal beagles. Increasing the dietary chloride content from 0·2 to 1·3 per cent resulted in a significant decrease in the mean apparent elimination half-life from 69 ± 22 days to 24 ± 7 days. The mean area under the concentration curve ( ) for dogs fed 1·3 per cent chloride was significantly smaller than the for dogs fed 0·2 per cent chloride. Dietary chloride had no effect on the maximum serum concentrations (Cmax) or on the time (Tmax) to reach the maximum concentrations. The steady-state serum bromide concentrations predicted from the single dose data for daily doses of 14 mg kg−1 of bromide were significantly lower in dogs fed 1·3 per cent chloride (310 ± 150 mg litre−1) than in dogs fed 0·2 per cent chloride (1950 ± 1140 mg litre−1). The predicted mean daily doses of bromide necessary to maintain serum levels within the therapeutic range for dogs fed 1·3 per cent chloride (43 ± 13 mg kg−1) were almost twice as high as the dose estimated for dogs fed 0·4 per cent chloride (22 ± 3 mg kg−1) and nearly three times as high as the dose estimated for dogs fed 0·2 per cent chloride (15 ± 4 mg kg−l). These differences were statistically significant (P=0·002).  相似文献   

3.
The influence of training on blood lactate concentrations during treadmill exercise and a 40-minute inactive recovery period was examined in seven trained and seven detrained thorough-bred horses. Lactate concentrations were measured in venous blood collected at the end of each exercise state, and at intervals for 40 minutes afterwards. Measurements were made of maximum oxygen uptake (V̇O2max, ml kg−1 min−1), VLA4 (velocity at which blood lactate concentration was 4 mmol litre−1); LA8 (lactate concentration [mmol litre−1] during exercise at 8 m sec−1), peak lactate (highest lactate concentration after exercise), LA40 (lactate concentration 40 minutes after exercise), the time of peak lactate concentration (minutes after exercise) and the rate of disappearance of blood lactate (Rtd). The trained horses had a significantly lower LA8 (2·1 ± 0·1 vs 6·5 ± 1 mmol litre−1, P<0·01), higher VLA4 (9·8 ± 0·2 vs 5·8 ± 0·6 m sec−1, P<0·01) and higher V̇02max (156·3 ± 3·8 vs 107·1 ± 3·9 ml kg−1 min−1, P<0·001). The value of Rtd and the time of peak lactate concentration were not significantly different.  相似文献   

4.
Six veal calves were medicated with clenbuterol at 20 μg kg bodyweight−1 day−1 for 42 days before they were slaughtered, to evaluate the lesions and residues in target organs. Compared with six unmedicated calves the most noticeable changes were tracheal dilatation, decreased uterine weight, slight mucous hypersecretion in the uterus and vagina and depletion of liver glycogen. The highest concentrations of clenbuterol (62 to 128 ng/g−1) were recorded in the choroid/retina, and the aqueous humour had the lowest concentration (0·5 to 2·4 ng ml−1). The residue concentrations were higher than the maximum residue level set for clenbuterol (0·5 ng g−1)  相似文献   

5.
These studies were undertaken to examine the systemic and renal effects of the pharmacological inhibition of endothelium-derived nitric oxide (EDNO) in cats. In six healthy cats, the intravenous infusion of nitro-L-arginine at a dose of 100 μg kg−1 bodyweight min−1 resulted in a marked increase (P<0·001) in mean arterial pressure from the control value of 116·7 ± 4·6 mmHg to 154·2 ± 6·8 mmHg and an increase (P<0·05) in renal vascular resistance from the control value of 3·69 ± 0·33 mmHg min ml−1 to 6·83 ± 1·15 mmHg min ml−1. The increase in renal vascular resistance was generalised, with comparable increments in preglomerular and postglomerular vascular resistance. Mean values for glomerular capillary pressure (61·1 ± 61·9 vs 1·9 ± 1·6 mmHg), calculated from the sum of arterial colloid osmotic pressure plus proximal tubule stop-flow pressure, did not change in response to the infusion of nitro-L-arginine. However, there was a marked reduction in renal blood flow (29·4 ± 3·1 to 16·9 ± 2·3 ml min−1, P<0·01) and glomerular filtration rate (5·22 ± 0·57 to 3·52 ± 0·45 ml min−1, P<0·01). These results provide evidence that EDNO plays an important role in the basal regulation of systemic arterial blood pressure and renal haemodynamics in cats.  相似文献   

6.
Faecal samples from 150 buffalo calves, one to 150 days old, located in various districts of Sri Lanka, were examined for group A rotavirus antigen by a screening enzyme linked immunosorbent assay (ELISA). Positive samples were confirmed by the blocking ELISA. In the calves studied 27·3 per cent were diarrhoeic, and the rest were non-diarrhoeic but were in contact with the animals showing diarrhoea. Antigen was detected in 36·6 per cent of the diarrhoeic animals and in 11·9 per cent of the nondiarrhoeic animals. There was a strong association between the presence of antigen in faeces and diarrhoea in these animals (ξ2 = 46·98; P<0·001). Of the 146 serum samples examined for antirotaviral antibodies, by the blocking ELISA at a single serum dilution (1:20) against a constant dose of antigen (8 units), 68·5 per cent were positive indicating a widespread infection with the virus in the population studied. This is the first record of the detection of rotavirus and its association with diarrhoea in buffalo calves in Sri Lanka.  相似文献   

7.
Mammary secretions contain leucocytes which may be of value to the neonate. The cells obtained from sow colostrum (1 to 2·5 × 106 ml−1) are mainly lymphocytes (10 to 25 per cent) and epithelial cells (more than 20 per cent). In milk, there are few lymphocytes (0·5 to 2 per cent) and mostly alveolar epithelial cells. The study of lymphocytes in the mammary secretions of sows has been made difficult by the high proportion of epithelial cells, which could not be separated from lymphocytes, and by a high background in membrane immunofluorescence labelling. This paper describes a method for the study of the cells in the mammary secretions of sows by flow cytometry. It showed that 70 to 90 per cent of colostral lymphocytes were T lymphocytes, with T8 lymphocytes predominating over T4, and that the ratio T4/T8 was significantly lower in colostrum (0·57) than in blood (0·80). There were no lymphocytes expressing interleukin-2-receptors in the colostrum of sows.  相似文献   

8.
Bovine serum amyloid-A (b-SAA) was purified from a pool of acute phase serum using hydrophobic interaction chromatography and gel filtration. Serum was applied at a low salt concentration to a phenyl-sepharose column and SAA was eluted with a gradient of 0 to 6 M guanidine-HCI. Fractions containing SAA were pooled, concentrated and further purified by gel filtration on Superose-12. The concentration of SAA in bovine serum was quantified by an indirect ELISA using rabbit anti-human SAA and horseradish peroxidase conjugated donkey anti-rabbit IgG. Dilutions of an acute phase bovine serum sample were used as working standards. The SAA concentration of this standard was determined by comparison with purified b-SAA on SDS-polyacrylamide gel electrophoresis followed by densitometry at 590 nm. The assay detection limit was 3 μg ml−1; the intra-assay coefficient of variation was 4 per cent and interassay coefficients of variation were 5·5 per cent and 7·2 per cent at 66 and 178 μg ml−1 SAA, respectively. In calves experimentally infected with Pasteurella haemolytica type A1 the ELISA was able to detect a 10-fold increase of SAA within 24 hours of inoculation.  相似文献   

9.
Low capacity, high affinity [3H] dexamethasone binding receptors were identified in cytosolic preparations of liver (mean number 45±10·1 fmol mg−1 protein, apparent dissociation constant 0·4±0·1 nM) and skin (mean number 46·4±23·8 fmol mg−1 protein, apparent dissociation constant 1 ± 0·2 nM) of clinically normal dogs. For clinically normal cats, approximately half these numbers of receptors with a lower affinity, were detected in liver (mean number 23·1±10·4 fmol mg−1 protein, apparent dissociation constant 3·2±0·9 nM) and skin (mean number 23·90±10·9 fmol mg−1 protein, apparent dissociation constant 2·2±1·5 nM). This difference between dogs and cats in [3H] dexamethasone binding receptors may contribute to the relative glucocorticoid resistance observed in cats.  相似文献   

10.
The osmotic fragility of the erythrocytes was measured in blood samples collected from randomly selected healthy and infected dogs at a dogs' rescue shelter. The dogs were classified into six groups on the basis of the final diagnoses from clinical, post mortem and laboratory findings. The minimum (less than 5 per cent) and maximum (more than 90 per cent) haemolysis of the erythrocytes of the clinically normal dogs (group 1), occurred in 0·60 per cent and 0·30 per cent solutions of sodium chloride (NaCI). For the non-anaemic hookworm-infected dogs (group 2a) the respective values were 0·8 per cent and 0·4 per cent NaCl, and for the anaemic hookworm-infected dogs (group 2b) they were 0·85 per cent and 0·5 per cent NaCl, respectively. The erythrocytes from dogs with Babesia canis (group 3), concurrent hookworm and B canis (group 4) and Ehrlichia canis infections (group 5) had minimum haemolysis in 0·75 per cent NaCl and maximum haemolysis at between 0·20 per cent and 0·35 per cent NaCI solutions. The derivative fragiligrams for groups 2a, 2b, 3 and 4 were shifted to the left, whereas the fragiligram for group 5 was similar to that for the clinically normal dogs (group 1). The left shift for the hookworm-infected dogs was due to the increased osmotic fragility of a minor sub-population of the erythrocytes, but for the dogs, infected with B canis major sub-populations of the erythrocytes had an increased osmotic fragility.  相似文献   

11.
The amelioration of aflatoxicosis in Japanese quails was examined by the dietary addition of live yeast (Saccharomyces cerevisiae; SCE). Yeast incorporated into the diet at 1 g kg−1was evaluated for its ability to reduce the deleterious effects of 2·5 mg total aflatoxin ( ; 82·30 per cent 1 , 2·06 per cent 2, 7·68 per cent 1and 7·96 per cent 2) kg−1diet on growing Japanese quail chicks from 10 days to 45 days of age. Forty 10-day-old Japanese quail chicks were assigned to 2×2 factorial arrangement of treatments (control, , , plus ) each consisting of 10 quails. The performances of birds were evaluated. The treatment significantly and dramatically decreased food consumption and body-weight gain from the first week onwards. The significant adverse effect of on the food conversion ratio was also determined from week 1 to the end of the experiments. The addition of to the -containing diet significantly reduced these deleterious effects of on food consumption, body-weight gain and food conversion ratio. Compared to controls, the cumulative body weight gain was reduced by 37 per cent among the quails consuming without , but increased 15 per cent for the birds fed plus . Interestingly, the single inclusion of to the -free diet provided significant improvements in all the investigated growth performances of birds (approximately 40 per cent) compared to controls.  相似文献   

12.
A new continuous separation method was developed for the determination of five different tetracyclines (oxytetracycline, tetracycline, chlortetracycline, methacycline and doxycycline). A bioassay using minimum medium (mm) seeded with Bacillus subtilisatcc 6633 was carried out for the detection, with simple extraction from the agar block of the clear inhibition zone on the MM produced by the mixed tetracyclines. The extract was subjected to continuous identification by high performance liquid chromatography using a μ-Bondapack C18 column. The tetracyclines were separated at ambient temperature using a mobile phase of 0·01 M oxalic acid: acetonitrile: N,N-dimethylformamide (74:18:8, v/v/v) at a flow rate of 1·0 ml min−1. A variable-wavelength detector set at 355 nm and recorder set at 4 mm min−1 were used for the detection. The entire mixture was resolved as five peaks with retention times ranging from 2·75 to 9·65 minutes. This continuous, simple and rapid method of detection, extraction and identification may be useful for routine laboratory testing of residual antimicrobial agents in food.  相似文献   

13.
Intravenous infusions of hydrocortisone sodium succinate (HSS) were given at 0·625 mg kg−1 hour−1 and 0·312 mg kg−1 hour−1 to six dogs. Plasma cortisol concentrations were measured by radioimmunoassay at 0, 15, 30, 45 and 60 minutes and then every 30 minutes for a further five hours. Chronic hypocortisolaemia was induced and maintained with mitotane and the HSS infusions were repeated after 31 and 50 days. No statistically significant difference was observed in the plasma cortisol concentrations after either period of hypocortisolaemia, but the plasma cortisol concentrations tended to be higher in most of the dogs.  相似文献   

14.
This study characterised the peripheral plasma concentration of PSP-60 throughout gestation, and examined the effect of stage of gestation and foetal number on this protein in Holstein cows after non-surgical embryo transfer. Cows (n=12) were divided into two groups; Group 1 contained single embryo recipient cows (n=5), Group 2 contained twin-embryo recipient cows (n=7). Blood was collected approximately every third day from day 0 (first day of standing oestrus), then daily for the last 10 days of gestation and until one day post-partum. Two of the twin-embryo recipient cows had abnormal pregnancies, consequently data from them was considered separately. In both groups PSP-60 increased progressively from about day 20 post-oestrus to 20 days pre-partum (from 0·9 ± 0·2 to 49·7 ± 8·7 ng ml−1, and from 1·3 ± 0·6 to 115 ± 34·9 ng ml−1 (mean ± SEM), in singleton and twin-bearing groups, respectively). The mean concentrations between 20 and 10 days pre-partum increased dramatically by about six-fold (P<0·001) in singleton-bearing cows (from 49·7 ± 8·7 ng ml−1 to 2838 ± 73·7 ng ml−1) to over two-fold in twin-bearing cows (from 115 ± 34·9 ng ml−1 to 284 ± 98·2 ng ml-1). The mean concentrations of the two groups were indistinguishable between 10 days pre-parturn and parturition. Cows giving birth prematurely to stillborn calves or to a schistosomus reflexus calf exhibited abnormal PSP-60 profiles. Our findings indicate that peripheral plasma PSP-60 concentrations are correlated to the stage of gestation and foetal number, and assist in predicting foeto-placental viability.  相似文献   

15.
The effects of a single challenge with 60,000 infective Ostertagia ostertagi larvae on blood and gastrointestinal mucosal gastrin concentrations, gastrin-producing G-cell numbers in the pyloric mucosa and growth of different parts of the gut were investigated in 16, two-and-a-half-month-old calves. Infected calves exhibited a rise in abomasal pH which was accompanied by a 145 per cent increase in wet weight of the fundic mucosa (P<0·05) and a significant rise in blood total gastrin concentrations (P<0·01). Circulating little gastrin (G-17) was unaffected. Pyloric mucosal total gastrin concentrations remained unaltered in the infected calves until day 28 when levels fell to 36·9 per cent of control group values (P<0·01). Pyloric mucosal G-cell numbers declined during the experiment in the infected group. It is suggested that release of previously stored tissue gastrin and not a change in Gcell numbers contributes to the hypergastrinaemia associated with ostertagia infection in the calf.  相似文献   

16.
Fluconazole (100 mg) was administered to six adult cats as an intravenous infusion over 30 minutes, and the same cats received 100 mg of the drug orally 16 weeks later. The cats were bled repeatedly through an indwelling jugular catheter, the plasma fluconazole concentrations were assayed by high performance liquid chromatography, and the concentration-time data were subjected to a non-compartmental pharmacokinetic analysis. The mean (SD) intravenous half-life (13·8 [2·6] hours) was similar to that observed after oral dosing (12·4 [3·0] hours). The plasma clearances (intravenous 0·9 [0·1], oral 0·9 [0·2] ml min−1 kg−1) and the volumes of distribution at steady state (intravenous 1·1 [0·1], oral 1·0 [0·1] litre kg−1) were also similar after the two routes of dosing. The peak plasma concentration was reached 2·6 hours after oral dosing and the drug was completely bioavailable (1·09 [0·05]). On the basis of this single dose study, the administration of 50 mg fluconazole every eight hours to a 4 kg cat should produce average steady state plasma fluconazole concentrations of approximately 33 mg litre−1.  相似文献   

17.
The pharmacokinetics of propofol and ketamine administered together by infusion were investigated in four ponies. Blood propofol and plasma ketamine and norketamine concentrations were measured by high performance liquid chromatography. After premedication with detomidine (20 μg kg−1) anaesthesia was induced with ketamine (2·2 mg kg −1 intravenously). The trachea was intubated and the ponies were allowed to breathe 100 per cent oxygen. A bolus dose of propofol (0·5 mg kg−1) was then administered intravenously and propofol and ketamine were infused for 60 and 45 minutes, respectively. The average mean infusion rate of propofol was 0·136 mg kg−1 min−1, and the ketamine infusion rate was maintained at 50 μg kg−1 min−1. The mean (SD) elimination half-lives of propofol and ketamine were 69·0 (8·0) and 89·8 (26·7) minutes, the mean volumes of distribution at steady state were 0·894 (0·161) litre kg−1 and 1·432 (0·324) litre kg−1 the mean body clearances were 33·1 (4·5) and 23·9 (3·8) ml kg−1 min−1 and the mean residence times for the infusion were 87·1 (4·1) and 110·7 (8·2) minutes, respectively. Norketamine, the main metabolite of ketamine, was detected throughout the sampling period. The mean residence time for norketamine was 144 (16) minutes. All the ponies recovered quickly from the anaesthesia; the mean times to sternal recumbency and standing were 11·1 (5·3) and 30·0 (20·8) minutes, respectively, from the end of the infusion.  相似文献   

18.
High muscle camosine and anserine contents contribute significantly to intra-cellular physico-chemical buffering. Our aim was to measure carnosine, anserine and taurine contents directly in individual type I, HA and IIB fibres from the middle gluteus muscle of the camel. Mean carnosine contents in type I, IIA and IIB were 24·6 ±9·2, 39·4 ±11·4 and 42·8 ±18·8 mmol kg−1 dry weight (dw), respectively. Mean anserine contents in type I, HA and IIB fibres were 30·0 ±8·4, 37·3 ±10·1 and 34·5 ±9·7 mmol kg−1 dw, respectively. Mean taurine contents in type I, IIA and HB fibres were 42·4 ±15-9, 203 ±12·9 and 24·7 ±15·9 mmol kg−1 dw, respectively. Higher carnosine contents in type II fibres emphasise the importance of carnosine to intra-muscular acid-base regulation. A specific role for taurine in type I fibres is unclear.  相似文献   

19.
The activities of danofloxacin, a novel fluoroquinolone, and two other antimicrobials were determined in vitro against field isolates of seven Mycoplasma species of veterinary importance isolated from cattle, swine and poultry in five European countries. The minimum inhibitory concentrations (MIC) of danofloxacin, tylosin and oxytetracycline were determined against a total of 68 isolates. Danofloxacin showed excellent activity against isolates of all Mycoplasma species (range 0·008 to 0·5 μg ml−1), but in some isolates there was evidence of reduced sensitivity to tylosin (range 0·008 to 2·0 μg ml−1) and oxytetracycline (range 0·008 to over 16·0 μg ml−1). Danofloxacin was more active than other antimicrobials against, M hyopneumoniae, M dispar and M bovigenitalium, and showed activity similar to that of tylosin against M bovis and M gallisepticum. Tylosin was the most active against M synoviae and M hyosynoviae. Generally, oxytetracycline showed the poorest activity, but was superior to tylosin against M bovigenitalium. A second (final) MIC reading was taken for all isolates 14 or 21 days after the initial reading, and MIC values rose during that time. However, the increase seen in danofloxacin values (typically one to two dilutions) was less than that seen for tylosin and oxytetracycline. It is concluded that danofloxacin is highly active in vitro against all of the Mycoplasma species tested, and thus shows great potential for the treatment of respiratory and other infections caused by Mycoplasma species in cattle, pigs and poultry.  相似文献   

20.
Muscle ATP loss with exercise has implications both to the causes of fatigue and muscle damage. To study this at the single muscle fibre level, five trained thoroughbred horses performed consecutive 90 second gallops on an inclined treadmill followed by a final gallop to fatigue. Biopsies of the m. gluteus medius were taken at rest, post-exercise and during 24 hour recovery. Blood lactate was 20·0 mmol litre−1 or more, and plasma NH3 300–800 μmol litre−1, following the final gallop. Minimal changes occurred in the plasma markers, and . ATP loss with exercise was 32·2 ( 12·2) per cent. Following exercise single fibre contents showed a much broader distribution than at rest, with contents in some close to zero. Following five and 24 hour recovery, however, frequency distribution curves were close to those seen at rest. There was no difference in the ATP contents of types I, IIa and IIb at rest of with exercise or recovery. The results pointed to marked heterogeneity between individual fibres in their biochemical response with exercise, independent of fibre type.  相似文献   

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